JPH0650179Y2 - Die head for blow molding machine - Google Patents

Description

[Detailed Description of Device] a. Purpose of the Invention <Industrial Field of Application> This invention is used for manufacturing a die head for a blow molding machine, particularly a hollow molded article composed of a plurality of different material parts.
It relates to a die head for blow molding machines with more than one layer.

<Prior Art> A die head for a blow molding machine of this type is disclosed in JP-A-60
-168625 gazette, there is a shutoff valve as a means for adjusting the flow rate of the molten resin flowing through each resin supply formed in the molding die in the die head for the blow molding machine, or the material flow. A mandrel having a ring-shaped protrusion that is reciprocally movable along the direction and that opens and closes one resin supply path at the lower end in the vicinity of the parison discharge port of this molding die is used.

<Problems to be Solved by the Invention> In the blow head for the blow molding machine of the above-mentioned prior art, by adopting this kind of means for adjusting the opening / closing degree of at least two kinds of resin supply paths provided in the blow molding die. ,
In addition to making the entire structure complicated, when shutting off the resin, the shutoff valve, which is the flow rate shut-off means on the resin side that has been supplied until now, is turned off, or one of the resin supply paths is discharged by the annular projection with the parison. Even if the screw of the extruder is stopped near the outlet and the screw of the extruder is stopped, the residual resin in the flow passage causes the resin to be supplied to the parison outlet of the molding die for a short period of time after the screw is stopped. This causes a phenomenon, and there is a problem that resin switching is not performed remarkably.

<Problems to be solved by the invention> In other words, due to the surface tension, the tip of a single parison made of a material discharged later is rounded and the tip of a single parison made of a different material ejected first is inserted. go. Further, since the material discharged earlier adheres to the wall surface, this material adheres to the surface of the material discharged later over a long range.

As a result, for example, when forming an automobile air duct,
The elastic resin used to absorb the vibration and displacement between the car and the engine, the hard resin such as polypropylene with small elasticity and small allowable elongation remains for a long range in the bellows part of the elastic body. In addition to being unable to do so, there is a possibility that a hollow molded product having a defect that the bellows portion is easily cracked during vibration or displacement is molded.

Also, in the case of a composite hollow molded product made of a resin of a different color,
The color at the switching point becomes unclear and the product value drops.

The present invention provides a die head for a blow molding machine in which resin is swiftly switched at a parison discharge port of a blow molding die to manufacture a hollow molded product in which a boundary (switching point) of different materials is highlighted. The purpose is to

B. Configuration of the Invention <Means for Solving the Problems> In order to achieve the above object, the present invention provides at least a double resin supply passage communicating with a single parison outlet of the molding die in the molding die. In a die head for a blow molding machine, the inner peripheral edge of the parison outlet is at the lower end peripheral edge of the mandrel core arranged at the center of the molding die, and the outer peripheral edge of the parison outlet is at the inner peripheral edge of the die ring. At least one annular sleeve that is formed concentrically with the mandrel core forms a partition wall of the at least double resin supply path, and the mandrel core and the die ring are attached to the innermost sleeve. A die head for a blow molding machine, characterized in that the die head is provided so as to come into contact with and separate from the lower end of the blow mold so as to be displaceable in the axial direction thereof.

In some cases, the mandrel core and the die ring may be selectively attached to and separated from the inner and outer inclined surfaces of the lower end of the annular sleeve formed in an acute angle.

This mandrel core is arranged so that the lower end edge of the mandrel core comes into contact with and separates from the lower end inclined inner surface of this innermost sleeve, and the innermost resin supply path can be opened and closed by the parison outlet.
In some cases, the inner peripheral edge of the die ring is brought into contact with and separated from the lower end of the sleeve, and the die ring is arranged so that the outermost resin supply passage can be opened and closed by the parison outlet.

The innermost sleeve is composed of two inner and outer movable sleeves, an inner working sleeve lower end is attached to and detachable from a lower end peripheral edge of the mandrel core, and an outer movable sleeve lower end contacts an inner peripheral edge of the die body. Equipped with a detachable inner movable sleeve for opening and closing the inner resin supply path,
In some cases, the outer movable sleeve is for opening and closing the outer resin supply passage.

In some cases, an accumulator type injection machine is connected to each resin supply path, and an extruder for feeding molten resin is connected to each accumulator type injection machine.

<Operation> The operation of the blow molding die head of the present invention thus constructed will be described below together with the method of use.

1) In the case of "die head according to claim 1," first, the inner peripheral edge of the die ring is brought into contact with the lower end portion of the innermost annular sleeve, the peripheral edge of the mandrel core is separated from the lower end portion of the annular sleeve, and the innermost resin is supplied. Only the passage is opened, and the molten resin is extruded as a parison from the discharge port to a predetermined size through the innermost resin supply passage.

When the molten resin of different or different color from the previous one is extruded from the outer resin supply passage to the desired size as a parison from the discharge port, the lower edge of the sleeve is brought into contact with the peripheral edge of the mandrel core to completely complete the inner resin supply passage. And the inner peripheral edge of the die ring is separated from the lower peripheral portion of the sleeve, and the parison of different or different color is continuously extruded from this discharge port by a predetermined size.

A parison made of a different or different color resin thus molded is housed in a molding die and blow-molded to manufacture a hollow molded article having a composite material.

In the above description, the production of a hollow molded article in which different or different-colored resins do not overlap, but when producing a multilayer hollow molded article in which these resins are partially or completely overlapped, The mandrel and the die ring peripheral edge are separated from the lower end of the sleeve only in the portion where the different color resins overlap, and the different or different color resins are simultaneously extruded from the common discharge port from the inner and outer resin supply paths, and partially The multi-layer parison is dimensioned.

2) "The mandrel core and the die ring are arranged so that they can be selectively brought into contact with and separated from the inner and outer inclined surfaces of the lower end of the annular sleeve formed in an acute angle" (Claim 2) In this case, the switching of the inner and outer resin paths in this die head is performed as follows.

The inner peripheral edge of the die ring is moved away from the outer inclined surface of the sleeve tip, while the peripheral edge of the mandrel core is brought into contact with the inner inclined surface of the sleeve tip. In this state, the molten resin in the outer resin supply passage is extruded from the discharge port as a parison with a predetermined size. Subsequently, when a molten resin of a different or different color from the previous one is extruded as a parison from the innermost resin supply path to a desired size as a parison, the inner edge of the die ring is brought into contact with the outer inclined surface of the sleeve while the outer resin is supplied. The passage is blocked, and the discharge of the molten resin from this supply passage is completely cut off. At the same time, the peripheral edge of the mandrel core is separated from the inner inclined surface of the sleeve tip, and the innermost resin supply passage is opened.

Other functions are the same as those of the die head of 1) above.

3) "Die head according to claim 3 of utility model registration"
In the case of supplying one molten resin from the innermost resin supply path to the discharge port, the inner peripheral edge of the die ring is brought into contact with the lower end of the sleeve, and the outermost resin supply path is blocked by this discharge port, Further, while the other molten resin is being supplied from the outermost resin supply path to this discharge port, the lower end peripheral edge of the mandrel core is brought into contact with the lower inclined surface of the sleeve, and the innermost resin supply path is blocked by this discharge port. . Others are the same as those of the die head described in the item 1).

4) In the case of "die head according to claim 4" The difference from the operation of the 1) die head is as follows.

When the parison is molded by extruding a different or different colored molten resin from the ejection port of the adjacent outer resin supply channel following this extrusion from the ejection port of the molten resin of the innermost resin supply route, Lower the movable sleeve of the mandrel to contact the lower edge of the mandrel, lift the outer movable sleeve from the position of the contact point with the inner edge of the die ring, shut off the innermost resin supply passage, and adjacent the outer resin supply passage. Is opened, and a different or different molten resin is supplied to the discharge port from this outer resin supply passage.

To form a partially overlapped portion, both the inner resin and the outer resin are extruded in parallel at the same time.

5) In the case of the die head described in claim 5, in addition to the operation described in 1) above, the accumulator type injection machine and the corresponding extruder respectively connected to each resin supply path operate as follows.

First, each extruder is supplied with a resin having different types and characteristics, for example, one extruder is supplied with a hard resin (eg, HDPE resin), and the other extruder is supplied with a soft resin (eg, LDPE resin). The screw speed of the extruder is drive-controlled, and each molten resin melted in the extruder is extruded into the corresponding accumulator chamber of the accumulator-type injection machine, respectively, and temporarily retained therein, and first the accumulator on the resin side to be used. The injection plunger of the injection machine to the blow molding die by servo feed control, and the molten resin to be used first is supplied to the corresponding one resin supply path in the blow molding die, for example, the inner resin supply. It is supplied to the inside of the passage), extruded from the parison discharge port, and a parison of a predetermined size corresponding to one resin portion of the product is extruded from this blow molding die.

Next, when switching to the other resin, the injection plunger of the accumulator-type injection machine on the side (for example, the inner side) that had previously supplied one resin into the molding die is fed into the molding die. A sufficient distance for the resin to stay in the accumulator chamber and a backward movement corresponding to the resin extrusion amount of the accumulator type injection machine, and the screw rotation of the corresponding extruder is set to a low speed, and one of the molten resin molding dies Supply to the corresponding resin supply path (inner resin supply path) is stopped, the residual stress of one molten resin in this molding die is absorbed in this accumulator chamber, and extruded from the discharge port of the blow molding die. To stop. Further, since the other resin (outer side) stays in the corresponding accumulator chamber during extrusion of the one resin (inner side), the corresponding other resin supply (outer resin supply) of the molding die is advanced by the advance of the plunger. (Passage) A predetermined amount is supplied into the passage, extruded from the discharge port, and a different parison of a predetermined size corresponding to the other resin (outside) portion of the product is extruded integrally from the molding die following the parison.

<Example> Next, a typical example of the present invention will be described.

<First Embodiment> In FIG. 1, A is a die head for a blow molding machine, and double resin supply passages 12, 13 communicating with a single parison outlet 11 of a molding die 10 in this die head A are It is provided in the molding die 10.

The inner peripheral edge 16 of the parison discharge port 11 is at the lower end peripheral edge 15 of the mandrel core 14 arranged at the center of the molding die 10, and the outer peripheral edge 19 of the parison discharge port 10 is at the inner peripheral edge 18 of the die ring 17, respectively. One annular sleeve 20 that has been formed and is provided concentrically with the mandrel core 17 forms the partition walls of the double resin supply passages 12 and 13, and the mandrel core 14 and the die ring 17 are formed on the sleeve 20. Are selectively attached to the inner and outer inclined surfaces 21 and 22 at the lower end of the annular sleeve 20 formed in an acute angle so as to be able to contact and separate in the axial direction of the molding die 10.

The operation of this embodiment is the same as the operation of the die head according to the second aspect of the present invention, and the description thereof will be omitted.

<Second Embodiment> The components having the same reference numerals as those in the first embodiment have the same configuration, and different items are as follows.

The lower end peripheral edge 15 of the mandrel core 14 contacts and separates from the lower end inclined inner surface 21a of the sleeve 20, and the mandrel core 14 is provided so that the inner resin supply passage 12 can be opened and closed by the parison outlet 10. The inner peripheral edge 18a of the die ring 17a comes into contact with and separates from the 20a, and the outer resin supply passage 13 is connected to the parison discharge port 1
This means that the die ring 17a is openable and closable at 0 (see FIG. 2).

The operation of this embodiment is the same as the operation of the die head according to the third aspect of the present invention, and the description thereof will be omitted.

<Third Embodiment> The same reference numerals as those in the first embodiment have the same configurations as those in the first embodiment, and the different matters are as follows.

The sleeve 20 includes inner and outer double movable sleeves 20b and 20c. A lower end 20b of the inner movable sleeve 20a is attached to and detachable from a lower end peripheral edge 15 of the mandrel core 14, and a lower end 20c of the outer movable sleeve 20c. ′ Is attached to the inner peripheral edge 18 of the die ring 17 so that it can freely come into contact with and separate from the inner movable sleeve 20.
b is for opening and closing the inner resin supply passage 12, and the outer movable sleeve 20c is for opening and closing the outer resin passage 13 (see FIG. 3).

The operation of this embodiment is the same as the operation of the die head according to the fourth aspect of the present invention, and a description thereof will be omitted.

<Other Embodiments> When the accumulator type injection machines 23 and 24 are connected to the resin supply paths 12 and 13, respectively, and the extruders 25 and 26 for feeding the molten resin to the accumulator type injection machines 23 and 24 are connected. (See FIG. 7).

The operation of this embodiment is the same as the operation of the die head according to the fifth aspect of the present invention, and the description thereof is omitted.

C. Effects of the Invention The effects of the invention constructed and operated as described above are as follows.

In the die head for the blow molding machine according to claim 1, the mandrel core and the die ring are provided so as to come into contact with and separate from the innermost sleeve near the lower end of the sleeve and are displaceable in the axial direction thereof. As a result, the supply of the innermost resin and the outer resin adjacent to the innermost resin to the parison discharge port can be reliably interrupted at the time of this discharge port, and at least two layers of the innermost resin and the outer resin adjacent to each other The boundary area between the innermost resin and at least a single-layer portion where the outermost resin is not present can be formed at right angles to the axis of the parison without sagging, and if the inner and outer resins have different colors, the difference in color The borderline of can be made to stand out.

Next, in the die head for a blow molding machine according to claim 2, the mandrel core and the die ring are selectively attached to and detached from the inner and outer inclined surfaces of the lower end so as to be adjacent to the innermost resin. The outer resin to be used, and the supply of the adjacent outer resin to the parison discharge port can be reliably and selectively blocked at this discharge port, and a single-layer parison made of the innermost resin,
The boundary area with the single layer parison made of adjacent outer resin,
Can be clarified at right angles to the axis of the parison without dripping,
When the inner and outer resins have different colors, a ring-shaped color pattern can be formed on the hollow molded article by selecting the innermost resin and the outer resin. Therefore, in the case of a hollow molded product such as an automobile air duct with a bellows part, this bellows part is made of only soft resin, both ends of this air duct are made of hard resin, and the vibration of the air duct can be sufficiently absorbed by this bellows part. , The bellows can be fully absorbed, and at the boundary between the bellows and both ends, the molten hard resin will drip back and remain coated on the peripheral surface of the soft resin forming the bellows, which may impair its softness. It can be resolved, and the breakage from the bellows can be avoided.

Further, also in the die head for the blow molding machine according to claim 3, the mandrel core and the die ring are selectively moved up and down to selectively communicate the inner and outer resin passages with the parison discharge port. Can be surely shut off.

Also in the die head for the blow molding machine according to claim 4, the movement of the inner and outer movable sleeves allows the parison made of at least two layers of resin inside and outside to be discharged from the parison discharge port, as well as the inside and outside thereof. Inner and outer resins are alternately supplied to the parison outlet through the resin supply passage, and the inner resin parison and the outer resin parison are butted in the axial direction.
The abutment surface may form a single parison formed at right angles to its axis.

Next, in the die head according to claim 5, while one resin is being extruded from the discharge port as a single layer parison, another resin of different type or different color is temporarily retained in the accumulator type of the corresponding accumulator type injection machine. Therefore, it is possible to more reliably prevent the above-mentioned sagging, and quickly prepare for the next use.

[Brief description of drawings]

The figure relates to this invention, and FIG. 1 shows the first of this invention.
FIG. 2 is an enlarged schematic half sectional view showing an embodiment, FIG. 2 is an enlarged schematic half sectional view of a die head discharge port portion showing the second embodiment, and FIG. 3 is a schematic view of a main part of the third embodiment, FIG. 5 and 6 are partial cross-sectional views of the parison manufactured in each example, and FIG. 7 is a schematic view of a main part of another example. Description of main symbols in the figure A: Die head.

Claims (5)

[Scope of utility model registration request] 1. A die head for a blow molding machine, wherein at least double resin supply paths communicating with a single parison outlet of a molding die are provided in the molding die, and the die head is arranged at the center of the molding die. At least one annular sleeve provided concentrically with the mandrel core is formed with an inner peripheral edge of the parison outlet at the lower end peripheral edge of the mandrel core and an outer peripheral edge of the parison outlet at the inner peripheral edge of the die ring. A partition wall of the at least double resin supply path is formed, and a mandrel core and a die ring are provided so as to come into contact with and separate from the innermost sleeve near the lower end of the sleeve and are displaceable in the axial direction thereof. A die head for blow molding machines. 2. The utility model registration claim, wherein the mandrel core and the die ring are arranged so that they can be selectively brought into and out of contact with the inner and outer inclined surfaces of the lower end of the annular sleeve formed into an acute angle. A die head for a blow molding machine according to item 1. 3. The mandrel core is arranged such that the lower end peripheral edge of the mandrel core is in contact with and separated from the inner inclined surface of the lower end of the innermost sleeve, and the innermost resin supply passage can be opened and closed by a parison discharge port. The blow molding according to claim 1, characterized in that the inner peripheral edge of the die ring is in contact with and separated from, and the die ring is provided so that the outermost resin supply passage can be opened and closed by the parison outlet. Die head for machine. 4. The innermost sleeve is composed of an inner and outer double movable sleeve, the lower end of the inner movable sleeve is attached to and detachable from the peripheral edge of the lower end of the mandrel core, and the lower end of the outer movable sleeve is the die. Claim 1 of the utility model characterized in that the inner movable sleeve is provided on the inner peripheral edge of the ring so as to be able to come in contact with and separate from the inner movable sleeve for opening and closing the inner resin supply path, and the outer movable sleeve is for opening and closing the outer resin supply path. A die head for a blow molding machine according to the item. 5. A utility model registration claim characterized in that an accumulator type injection machine is connected to each resin supply path, and an extruder for sending molten resin to each accumulator type injection machine is connected. A die head for a blow molding machine according to claim 1.