JP2649584B2 - Multi-layer parison extrusion equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-layer parison extrusion molding apparatus, and more particularly, a plurality of resins are supplied respectively.
Including a plurality of extruders configured to extrude the supplied resin at a predetermined pressure, configured to combine the resin extruded from each extruder to form a multilayer parison composed of a predetermined resin layer And a multi-layer parison extrusion molding apparatus.

Prior art In a hollow molded container composed of a main material resin such as polyethylene, a contained substance contained therein is transmitted through a wall of the container and is prevented from being released outside.
2. Description of the Related Art A multi-layer hollow molded container in which a barrier layer for preventing permeation made of an auxiliary material such as a polyamide resin is provided between main material layers constituting a wall of the hollow molded container is known.

For example, fuel tanks and the like used for vehicles such as automobiles generally have a main material layer composed of a main material such as high-density polyethylene, and a sub-material such as a polyamide resin disposed between the main material layers to prevent gasoline and the like from permeating. And a bonding material layer interposed between the main material layer and the barrier resin layer in order to enhance the adhesion between the main material layer and the barrier resin layer.

Such a multilayer hollow molded container is generally manufactured by blow molding a multilayer parison in which a molten resin constituting each resin layer is arranged at a desired position. An extruder configured to extrude each resin such as a material, an auxiliary material, and an adhesive at a predetermined pressure; and a resin passage that joins each resin extruded from each extruder in a desired arrangement. A multi-layer parison extruder configured to form a multi-layer parison composed of the above resin layers is used.

In such an extrusion molding apparatus, in order to ensure the quality of the multilayer hollow molding container, each resin is extruded at a desired thickness by each extruder and merged, and a multilayer having a uniform resin layer without unevenness throughout. It is necessary to form a parison, and in order to respond to such a need, for example, it is configured to shift the extrusion start timing of each extruder by a timer and to control the rising characteristic of the extrusion pressure of each extruder. By providing a time constant generation type controller, a multilayer parison extrusion molding device that is configured to prevent the occurrence of irregular parts in the multilayer parison immediately after each extruder starts extruding resin is proposed. (For example, Japanese Patent Publication No. 59-23212).

Problems to be Solved by the Invention However, resins having relatively high hygroscopicity, such as polyamide resins, absorb a relatively large amount of moisture from the external atmosphere during storage as pellets or chips, and therefore storage conditions and the like. The water absorption rate changes greatly, and when supplied to the extruder as a molten resin, the melt viscosity of the resin tends to fluctuate greatly, so that the resin is extruded by a predetermined pressure characteristic. In the formed multi-layer parison extrusion molding apparatus, the resin extrusion amount fluctuates due to the fluctuation of the melt viscosity of the resin, and the thickness of the resin layer varies, and as a result, the predetermined resin layer thickness is secured. In some cases, a multilayer parison having a desired resin layer cannot be extruded by forming a resin layer exceeding a predetermined thickness.

Object of the invention The present invention has been made in view of such a point, a plurality of resins are respectively supplied, including a plurality of extruders configured to extrude the supplied resin at a predetermined pressure, each In a multilayer parison extrusion molding apparatus configured to form a multilayer parison composed of a predetermined resin layer by joining resins extruded from an extruder, when a resin having a relatively high hygroscopicity is used, It is an object of the present invention to provide a multi-layer parison extrusion molding apparatus capable of forming a multi-layer parison having a desired resin layer having no unevenness.

The object of the present invention is to provide a multilayer parison extrusion molding apparatus, wherein the water absorption rate detecting means for detecting the water absorption rate of the resin, and based on the water absorption rate of the resin detected by the detection means, And an extrusion pressure control means for variably setting the extrusion pressure of the extruder.

Effect of the Invention According to the present invention, a multilayer parison extrusion molding apparatus detects a water absorption of a resin by a water absorption detection means, and controls an extrusion pressure of an appropriate resin according to the water absorption of the resin by an extrusion pressure control means. Can be set.

Therefore, when the viscosity of the molten resin in the extruder decreases due to an increase in the water absorption rate of the resin, the extrusion molding apparatus sets the extrusion pressure of the extruder low based on the detected water absorption rate, and When the viscosity of the molten resin in the extruder increases due to a decrease in the water absorption of the resin, the extrusion pressure of the extruder is set high based on the detected water absorption. Thus, a desired extrusion amount of the resin can be secured.

Thus, the extruder changes the water absorption of the resin,
When the melt viscosity fluctuates, the desired extrusion rate of each extruder can be secured without being affected by the fluctuation of the viscosity of the resin, and a multilayer parison having a desired resin layer that is uniform throughout is formed. can do.

Examples Hereinafter, based on the accompanying drawings, an embodiment of the present invention will be described.
Add a detailed explanation.

FIG. 1 is a schematic vertical sectional view of a multi-layer parison extruder forming an apparatus for manufacturing a fuel tank of an automobile according to an embodiment of the present invention. FIG. 2 is a schematic vertical sectional view of a blow molding apparatus constituting the manufacturing apparatus, and shows a fuel tank immediately after blow molding.

As shown in FIG. 2, the fuel tank 1 of the automobile manufactured by the automobile fuel tank manufacturing apparatus according to the present embodiment has a high-density polyethylene as a main material, whose walls are arranged in order from the inner side. An internal main resin layer 2 made of modified polyethylene as an adhesive; an auxiliary resin layer 4 made of nylon as an auxiliary material and constituting a barrier layer for preventing gasoline from permeating; an adhesive And an external main resin layer 6 made of a high-density polyethylene as a main material, and correspondingly, high-density polyethylene, nylon and an adhesive are A first extruder 11, a second extruder 12, and a third extruder 13 of the extruder 10 shown in FIG.
, Respectively.

As shown in FIG. 1, the first extruder 11 is disposed above the accumulator head 14, and the high-density polyethylene, which is the main resin, is supplied from the first extruder 11 to the cylinder 15 and the cylinder 15 of the accumulator head 14. An annular main material resin passage formed between a core 16 disposed inside 15 and a core 16
17, is supplied into an annular main material resin storage chamber 18, and is pushed up by an annular annular piston 19, which is slidably provided in the cylinder 15 along the inner peripheral surface thereof in the vertical direction. It is stored in the material resin storage chamber 18.

On the other hand, the second extruder 12 is disposed below the accumulator head 14, and nylon as an auxiliary material resin is supplied into the accumulator 20 by the second extruder 12 while extruding the plunger 21 of the accumulator 20. It is stored in the accumulator 20.

The third extruder 13 is disposed below the accumulator head 14 so as to face the second extruder 12, and the adhesive made of denatured polyethylene is supplied into the accumulator 22 by the third extruder 13. , While pushing up the plunger 23 of the accumulator 22,
Stored in 22.

Thus, the high-density polyethylene is stored in the main-material resin storage chamber 18, the nylon is stored in the accumulator 20, and the adhesive is stored in the accumulator 22, respectively. The hydraulic cylinder 24 is actuated to push down the plunger 25 and the annular piston 19 that is in contact with the lower surface of the plunger 25, and the high-density polyethylene stored in the main resin storage chamber 18 is transferred to the cylinder 15, the cylinder 15. Die 30 and core 16 provided at the lower end of 15
The core 16 is fed at a predetermined pressure to an annular resin passage 32 formed between the core 16 and a core support 31 provided at the lower end of the core 16.

In synchronization with this, the second single-acting hydraulic cylinder 26 is operated, the plunger 21 of the accumulator 20 is pushed down, and the nylon stored in the accumulator 20 is annularly arranged concentrically with the annular resin passage 32. Then, the adhesive is transferred to an annular extruding member 40 having a substantially hexagonal cross section, and the third single-acting hydraulic cylinder 27 is operated, whereby the plunger 23 of the accumulator 22 is pushed down, and the adhesive stored in the accumulator 22 is The agent is sent to the annular extrusion member 40.

FIG. 3 is a schematic vertical sectional view of the annular pushing member 40, and FIG.
As shown in the figure, the annular pushing member 40 includes a sub-material resin passage 41 communicating with the accumulator 20 and an accumulator.
And a branch 2 branching therefrom.
Branch adhesive passages 43a and 43b;
1.Branch adhesive passages 43a, 43b communicate with annular concentric annular nozzles 47, 48, 49 that open on the lower surface of the annular extrusion member 40 through annular slits 44, 45, 46, respectively. ing. In FIG. 3, a slit 44 communicating with the auxiliary material resin passage 41 is provided between slits 45 and 46 communicating with the branch adhesive passages 43a and 43b, and an annular nozzle 47 communicating with the slit 44 is formed of resin. It is arranged between annular nozzles 48, 49 communicating with the slits 45, 46 in the radial direction of the extruder. Therefore, in synchronization with the high-density polyethylene being fed to the annular resin passage 32, the annular extruding member 40 is
Nylon sent through the auxiliary material resin passage 41, the slit 44 and the annular nozzle 47, into the annular resin passage 32 under a predetermined pressure under pressure, the adhesive sent to the annular extrusion member 40,
Adhesive passage 42, branch adhesive passages 43a, 43b and slit
After passing through 45 and 46, the resin is fed under a predetermined pressure into the annular resin passage 32 from annular nozzles 48 and 49 arranged on both sides of the annular nozzle 47 in the radial direction of the resin extruder.

Although not shown, the annular push-out member 40 is supported by the cylinder 15 by four support members 50 provided at intervals of about 90 degrees, and in a portion where the support member 50 is not provided, The flow of the high-density polyethylene pumped through the annular resin passage 32 is divided by the annular extrusion member 40 into a flow flowing inside the annular extrusion member 40 and a flow flowing outside the same. Here, since the annular extrusion member 40 has a substantially hexagonal cross section, the flow of the high-density polyethylene is smoothly divided by the annular extrusion member 40 into an inner flow and an outer flow.

As described above, the flow of the high-density polyethylene is divided into an inner flow and an outer flow by the annular extrusion member 40, and the annular nozzle 47 and the annular nozzle of the annular extrusion member 40 are separated.
From the annular nozzles 48 and 49 arranged on both sides of the 47, nylon and adhesive are respectively extruded at a predetermined pressure by the annular extruding member 40, so that a high density is provided on the downstream side of the annular extruding member 40. A cylindrical resin flow in which the nylon layer is sandwiched between the polyethylene layers via the adhesive layer is formed. Thus, the annular extrusion member 40
In the annular resin passage 32 on the downstream side, a cylindrical resin formed of five layers of a high-density polyethylene layer 2, an adhesive layer 3, a nylon layer 4, an adhesive layer 5, and a high-density polyethylene layer 6 is arranged in order from the inside. A flow will be formed.

In this way, the tubular resin sent to the annular resin passage 32 has the core 33 fitted concentrically with the die 30 on the core support 31.
2 and a die 30, and is extruded between dies 60, 60 of a blow molding machine shown in FIG. In this state, the dies 60 are separated from each other in the left-right direction in FIG. 2 and are held at separated positions. The thickness of the cylindrical resin can be adjusted by moving the rod 35 inserted into the core 16 vertically by a hydraulic cylinder (not shown) and adjusting the gap of the annular die slit 34. .

When the cylindrical resin is extruded by a predetermined amount from the extrusion molding device 10,
The lowering of the plungers 25, 21 and 23 by the first to third single-acting hydraulic cylinders 24, 26 and 27 is stopped, and the pumping of high-density polyethylene, nylon and adhesive is stopped. To form the desired multi-layer parison.

Thereafter, the molds 60, 60 are closed so that the upper resin cutting portion 61 formed on each upper portion and the lower resin cutting portion 62 formed on each lower portion are brought into contact with each other, and the cylindrical resin Air is blown into the hollow portion of, and the multilayer parison is blow-molded as shown in FIG.

FIG. 2 shows a state of the fuel tank 1 immediately after blow molding. As shown in FIG. 2, after the blow molding, the lower burrs 70 are formed below the lower resin cutting portions 62, 62 of the dies 60, 60, and the upper burrs 70 of the dies 60, 60 are formed. Upper burrs 71 are formed above the resin cutting portions 61,61.

As described above, when the blow molding is completed, the fuel tank 1 is moved together with the upper burr 71 and the lower burr 70,
After being removed from the molding apparatus, the upper burr 71 and the lower burr 70 are cut off, and the fuel tank 1 as a product is removed.
Is obtained.

The upper burr 71 and the lower burr 70 thus separated from the fuel tank 1 are collected and reused as a recycled material.

 Next, control of the extrusion molding apparatus 10 will be described.

FIG. 4 is a schematic configuration diagram of a control device of the extrusion molding apparatus 10, and FIG. 5 is a block circuit diagram partially showing a configuration of a sub-material / adhesive material control circuit shown in FIG.

As shown in FIG. 4, first to third single-acting hydraulic cylinders 24, 26, 27 connected to plungers 25, 21, 23, respectively.
Is provided with hydraulic chambers 24b, 26b, 27b partitioned by the pistons 24a, 26a, 27a. Hydraulic chamber 24b, 26
b, 27b are a hydraulic supply device 104 such as a hydraulic pump for supplying hydraulic oil to the hydraulic chambers 24b, 26b, 27b and the hydraulic chambers 24b, 26b.
b, 27b are connected to a hydraulic circuit including first to third electromagnetic proportional pressure servo valves 106, 107, and 108 for controlling the hydraulic pressures respectively.

The extruder 10 has a first electromagnetic proportional pressure servo valve 106
A main material control circuit 101 is provided for controlling the operation of the second material and an auxiliary material / adhesive control circuit 102 is provided for controlling the operation of the second and third electromagnetic proportional pressure servo valves 107 and 108. Have.

The main material control circuit 101 includes a first single-acting hydraulic cylinder 24
An output signal from the piston position detection sensor 103 that detects the position of the piston 24a is input. When a predetermined amount of high-density polyethylene is stored in the main resin storage chamber 18 and the position detection sensor 103 detects the upper end position of the piston 24a, the main material control circuit 101 sends the first single-acting hydraulic cylinder 24 to the plunger 25. To push down the first electromagnetic proportional pressure servo valve
The operation of 106 is controlled, and the high-density polyethylene stored in the main-material resin storage chamber 18 is pressure-fed to the annular resin passage 32 by the annular piston 19 at a predetermined pressure.

On the other hand, the auxiliary material / adhesive control circuit 102 has a water absorption rate sensor 110 installed in a material supply system (not shown) for melting the nylon pellets as the auxiliary material and supplying the melted nylon pellets to the second extruder 12.
, A signal indicating the water absorption of the nylon supplied to the second extruder (hereinafter simply referred to as a water absorption signal) is input.
The water absorption rate sensor 110 is an optical water absorption rate detection device configured to irradiate a nylon pellet with a measurement beam, detect a reflected beam from the pellet, and convert the beam into an electric signal. Further, to the auxiliary material / adhesive control circuit 102, an operation or stop signal of the extrusion operation of the main material is input from the main material control circuit 101, and the auxiliary material / adhesive control circuit 102
The second and third electromagnetic proportional pressure servo valves 107 and 108 are operated in synchronization with the first electromagnetic proportional pressure servo valve 106 based on the operation or stop signal.

The auxiliary material / adhesive control circuit 102, as shown in FIG.
A water absorption calculating circuit 111 that calculates a water absorption based on a water absorption signal from the water absorption sensor 110, converts the calculated water absorption into an extrusion pressure correction signal, and outputs the signal. An extrusion pressure setting device 11 that outputs an extrusion pressure signal so as to form the sub-material resin layers 2 and 4 having a thickness.
2.A water absorption rate calculation circuit 11 based on the output from the extrusion pressure setting device 112
Subtractor 113, Subtractor 11 configured to reduce the output of 1
Function generator 1 that outputs the target extrusion pressure based on the output of 3
14. A servo amplifier 115 for controlling the second proportional pressure servo valve 107 based on the output of the function generator 114.

The sub-material / adhesive control circuit 102, from the main material control circuit 101,
When the operation signal of the extrusion operation of the main material is input, the extrusion pressure correction signal output by the water absorption rate sensor 110 is subtracted from the extrusion pressure signal output by the extrusion pressure setting unit 112,
13, the target extrusion pressure is subtracted by the function generator 114, and based on the target extrusion pressure, the second single-acting hydraulic cylinder 26 pushes down the plunger 20 of the second extruder 12. Then, the operation of the second electromagnetic proportional pressure servo valve 107 is controlled. Therefore, when the water absorption of nylon is high, the target extrusion pressure is set low, while when the water absorption of nylon is low, the target extrusion pressure is set relatively high and the plunger 26 is extruded, Accumulator 20
The nylon stored therein is fed to the annular resin passage 32 at an extrusion pressure corresponding to the water absorption.

Further, the sub-material / adhesive control circuit 102 is
When the operation signal is input from the controller, the plunger 23 is pushed out by the third single-acting hydraulic cylinder 27 after a predetermined time elapses by a control circuit (not shown), and the accumulator
The third electromagnetic proportional pressure servo valve 108 is operated and controlled such that the adhesive stored in 22 is fed from the third extruder 13 to the annular resin passage 32 at a predetermined pressure. In this way, by causing the third extruder 13 to start extruding the adhesive with a delay of a predetermined time from the first and second extruders 11 and 12, the lower burr 70 allows the high density polyethylene layer 2, 6 and the nylon layer 4, only the lower burr 70
The separation of the high-density polyethylene and the nylon layer in the recycling step of the above becomes easy, and the recycling step of the lower burr 70 is simplified.

When a predetermined time has elapsed since the extrusion of the adhesive by the third extruder 13 was started and the multilayer parison excluding the upper burr 71 was extruded from the annular extrusion member 40, the auxiliary material / adhesive control circuit 10
2 controls the third electromagnetic proportional pressure servo valve 108 so as to stop the extrusion of the adhesive by the third extruder 13; Is extruded from the extrusion device 10, the main material control circuit
101 controls the first electromagnetic proportional pressure servo valve 107 so as to stop the single-acting hydraulic cylinder 24 from pushing down the plunger 25, and the high-density polyethylene to the annular resin passage 32 by the first extruder 11. Stop pumping.

The main material control circuit 101 also outputs a stop signal of the main material extruding operation to the sub-material / adhesive control circuit 102 simultaneously with the stop of the high-density polyethylene pumping. Secondary material / adhesive control circuit 102
Stops the extrusion of nylon from the second extruder 12,
As a result, the control device of the extruder 10 is the extruder 11,
12 and 13 stop the extrusion of the resin, and complete the extrusion process of one cycle. Since the extrusion of the adhesive from the third extruder 13 is stopped relatively early, the upper burr 71 also
It is formed only of the high-density polyethylene layers 2 and 6 and the nylon layer 4, and the step of reusing the upper burr 71 is facilitated.

As described above, according to the present embodiment, the extrusion molding apparatus 10 measures the water absorption rate of nylon as an auxiliary material in the water absorption rate sensor 10 for measuring in the material supply system and the water absorption rate of nylon detected by the water absorption rate sensor 110. And an auxiliary material / adhesive control circuit 101 configured to variably set a target extrusion pressure of the second extruder 12 based on the auxiliary material / adhesive control circuit 101.
When the melt viscosity of the molten nylon in the accumulator 20 is low, the second
The target extrusion pressure of the extruder 12 is set low to operate and control the second electromagnetic proportional pressure servo valve 107, thereby suppressing excessive extrusion of nylon, while reducing the water absorption of nylon. When the melt viscosity of the nylon in the accumulator 20 is high, the target extrusion pressure of the second extruder 12 is set to be high, and the operation of the second electromagnetic proportional pressure servo valve 107 is controlled. It prevents shortages.

Accordingly, the extrusion molding apparatus 10 can always keep the nylon extrusion amount at a desired extrusion amount regardless of the fluctuation of the water absorption of nylon, and extrudes the sub-material resin layer 4 to a desired thickness to form the main material. Merge with the resin layers 2, 6 and the adhesive layers 3, 5,
Multi-layer parisons can be extruded with a uniform barrier layer throughout.

The multilayer parison thus extruded is a molded product because nylon, which is a sub-material forming the barrier layer, is always extruded with a uniform thickness from the start to the end of resin extrusion. In the fuel tank 1, a portion where the barrier layer is not formed, or the barrier layer is formed thicker than necessary, so that the thickness of the main resin layer can be reliably prevented from being insufficient. Thus, the fuel tank 1 can surely prevent gasoline from permeating the wall and being released to the outside.

The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention described in the claims, which are also included in the scope of the present invention. Needless to say.

For example, the water absorption sensor 110 may use a water absorption sensor that detects the dielectric loss and temperature of the resin and outputs the detected value as an electric signal.

Further, in the above-described embodiment, the water absorption rate calculation circuit is provided in the auxiliary material / adhesive control circuit. However, a water absorption rate measurement device provided with a calculation circuit for calculating the water absorption rate may be used.

Further, in the above embodiment, both the inner main resin layer 2 and the outer main resin layer 6 are formed of a high-density polyethylene layer, and the inner adhesive layer 3 and the outer adhesive layer 5 are both formed of modified polyethylene. Is formed by
A different material may be used as a main material for forming the inner main resin layer 2 and the outer main resin layer 6, and as an adhesive for forming the inner adhesive layer 3 and the outer adhesive layer 5,
Different materials may be used. For example, when the main material is formed as a layer, a material that imparts rigidity, drop strength, and water resistance to the multilayer hollow molded container, such as low-density polyethylene, polystyrene, polybutene, ethylene-vinyl acetate copolymer, and polypropylene , Polycarbonate,
A resin such as polyester can be used, and the adhesive is a material capable of adhering a main resin layer made of a main material and a barrier resin layer made of a sub material, for example, an ionomer resin, ethylene-vinyl acetate copolymer. Coalescing, acrylic resin,
Resins such as a vinyl chloride-vinyl acetate copolymer and a polyolefin-modified resin can be used. Here, the polyolefin-modified resin is obtained by chemically modifying a polyolefin by Kraft reaction, alcoholysis reaction, copolymerization, and the like.Specifically, an unsaturated carboxylic acid such as maleic anhydride or its anhydride is used. Examples thereof include a product obtained by crafting a product into a polyolefin, a product obtained by partially saponifying EVA and then performing a partial esterification reaction with a carboxylic anhydride, and a product obtained by copolymerizing an α-olefin and an olefin.

Further, in the above-described embodiment, a description has been given of the case where the fuel tank 1 of the vehicle containing gasoline is manufactured. However, the present invention is not limited to this.
It goes without saying that the present invention can also be applied to the case of manufacturing a multilayer hollow molded container for storing other fuels and a multilayer hollow molded container for storing chemicals.

Further, in the above-described embodiment, nylon is used as the molding resin. However, those skilled in the art will appreciate that the extrusion molding apparatus according to the present invention is not limited to polyamide resins such as nylon, but has relatively high hygroscopicity and a high water absorption rate. It can be appreciated that other types of multi-layer parison extrusion using a resin whose variation in melt viscosity can affect melt throughput can also be effective.

Effects of the Invention According to the present invention, a plurality of resins are supplied respectively, a plurality of extruders configured to extrude the supplied resins at a predetermined pressure are included, and the resins extruded from the respective extruders are merged. In a multi-layer parison extrusion molding apparatus configured to form a multi-layer parison composed of a predetermined resin layer, when a resin having a relatively high hygroscopicity is used, a desired resin layer having no unevenness over the whole is obtained. It is possible to provide a multilayer parison extrusion molding apparatus capable of forming a multilayer parison having the following.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of an extrusion molding apparatus for a multilayer parison constituting a production apparatus for a fuel tank of an automobile according to an embodiment of the present invention, and FIG. 2 is a schematic view of a blow molding apparatus constituting the production apparatus. FIG. 3 is a schematic longitudinal sectional view of the annular extrusion member shown in FIG. 1, FIG. 4 is a schematic configuration diagram of a control device of the extrusion molding apparatus, and FIG. FIG. 3 is a block circuit diagram partially showing a configuration of a material / adhesive control circuit. DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 2 ... Internal main resin layer, 3 ... Internal adhesive layer, 4 ... Sub-material resin layer, 5 ... External adhesive layer, 6 ... External main resin layer, 10 ... ... Resin extrusion molding equipment, 11 ... First extruder, 12 ... Second extruder, 13 ... Third extruder, 14 ... Accumulator head, 15 ... Cylinder, 16 ... Core, 17 ... Annular main resin passage, 18 Main resin storage chamber, 19 Annular piston, 20, 22 Accumulator, 21, 23 Plunger, 24, 26, 27 Single-acting hydraulic cylinder, 24a, 26a, 27a ... piston, 24b, 26b, 27b ... hydraulic chamber, 25 ... plunger, 30 ... die, 31 ... core support 32 ... annular resin passage, 33 ... core, 34 ... die slit, 35 …… Rod, 40 …… Annular extrusion member, 41 …… Sub-material resin passage, 42 …… Adhesive passage, 43a, 43b …… Branch adhesive passage, 44, 45, 46 …… Lit, 47, 48, 49… Annular nozzle, 50… Support member, 60… Die, 61… Upper resin cutting part, 62… Lower resin cutting part, 70… Lower burr, 71… Upper burr, 101: Main material control circuit, 102: Sub-material / adhesive control circuit, 103: Piston position detection sensor, 104: Hydraulic supply device, 106, 107, 108: Electromagnetic proportional pressure servo valve 110, water absorption sensor, 111, water absorption calculation circuit, 112, extrusion pressure setting device, 113, subtractor, 114, function generator, 115, servo amplifier.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B29C 49/78 B29C 49/78 // B29L 9:00

Claims (3)

(57) [Claims] A plurality of extruders each supplied with a plurality of resins, and configured to extrude the supplied resins at a predetermined pressure, wherein the extruded resins are combined. In a multilayer parison extrusion molding apparatus configured to form a multilayer parison composed of a predetermined resin layer, a water supply rate detection unit that detects a water supply rate of the resin, and a water supply rate detection unit that detects the water supply rate of the resin. An extrusion pressure control means for variably setting an extrusion pressure of the extruder based on a water supply rate. 2. The multi-layer parison extrusion molding apparatus according to claim 1, wherein said water supply rate detecting means irradiates the resin with a beam and detects a reflected beam to detect a water supply rate. 3. The multi-layer parison extrusion molding apparatus according to claim 1, wherein said extrusion pressure control means sets the extrusion pressure to be large when said water supply rate is small.