JP2580549Y2 - Multilayer blow molding machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer blow molding machine.

[0002]

2. Description of the Related Art In general, a hollow container made of resin is formed by blow molding in which pressurized air is blown into a parison inserted into a molding die to form the hollow container. In some cases, a multi-layer parison formed by laminating a plurality of resin layers is used in order to supplement characteristics that are not sufficient with a single resin. The cross section of the multilayer parison thus laminated formed a multilayer parison having a multilayer structure around the entire circumference for each layer.

[0003]

However, in the conventional multi-layer blow molding described above, depending on the use of the molded product, for example, it is sometimes desired to locally multiply only the resin for the outer layer of the skin material. In such a case, if the entire circumference is multi-layered, it is necessary to form a multi-layered structure even at an unnecessary portion, which has the disadvantage of increasing the amount of resin for the outer layer, and also has a disadvantage in that the separation at the time of recycling is difficult. The issue of impossibility was also raised.

An object of the present invention is to provide a multilayer blow molding machine capable of flexibly responding to a molding purpose, focusing on the above-mentioned conventional problems.

[0005]

In order to achieve the above object, a multi-layer blow molding machine according to the present invention comprises a multi-layer blow molding machine which forms a multi-layer by sandwiching a resin layer for an intermediate layer between a resin layer for an inner layer and a resin layer for an outer layer. In a blow molding apparatus, a plurality of resin passages are formed by inserting a split mandrel coaxially divided into a die housing, and a resin inlet from the extruder side is opened in the resin passage at a symmetrical position. A manifold is formed from the resin inlet to the surface of the land of the split mandrel in the left and right direction in the circumferential direction, the cross-sectional area of the passage is reduced, and a manifold that is curved in the extrusion direction is formed. The manifold end and the manifold end from the other resin inlet are separated from each other. They were joined to form a long manifold, and at least one was formed to a short manifold without the junction.

[0006]

According to the above construction, the outer layer resin, the intermediate layer resin, and the inner layer resin are charged from the outer layer extruder, the intermediate layer extruder, and the inner layer extruder toward the respective accumulators. When the plunger is driven under pressure, the resin for the outer layer, the resin for the intermediate layer, and the resin for the inner layer pass through respective long and short manifolds, and the resin flows down uniformly in each resin passage. At this time, the resin passing through the long manifold flows down from the end of the manifold and the junction, and the resin passing through the short manifold flows down only from the end of the manifold because there is no junction.
From the lower part of the die to the inner side in the thickness direction of the parison, a multilayer parison having a three-layer structure of a resin for a local outer layer, a resin for an intermediate layer, and a resin for an inner layer arranged all around is formed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the multilayer blow molding machine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a main part device applied to a multilayer blow molding method according to an embodiment, and shows an extruder, an accumulator and a parison injection die. First, the die 10 has a die housing 12 formed of a rectangular block, and a through-hole 14 having a substantially circular cross section is formed along a vertical center line thereof. Such a through-hole 14 is opened at the lower end surface of the die housing 12 in a state where the inner diameter is gradually reduced from the middle to the lower end surface of the die housing 12.

A mandrel 16 having a diameter smaller than that of the through hole 14 is inserted into the die housing 12. The mandrel 16 includes a circular main mandrel 16c located at the center of the die 10 and an inner ring mandrel 16b located at the outer periphery of the main mandrel 16c.
And the outer ring mandrel 16a located at the outermost layer,
It has a three-layer structure coaxially. That is, a cylindrical outer ring mandrel 16 a having a smaller diameter than the through-hole 14 is provided in the die housing 12, and is provided between the outer peripheral surface of the outer ring mandrel 16 a and the inner peripheral surface of the through-hole 14. Internal ring mandrel 16
A resin passage 18 having a length reaching the lower end of b is formed.

An outer peripheral surface from the middle to the lower end surface of the main mandrel 16c is engraved in a circular shape to form a resin passage 20 between the inner peripheral surface of the inner ring mandrel 16b. Further, the outer peripheral surface from the middle to the lower end surface of the inner ring mandrel 16b is engraved in a circular shape to form a resin passage 21 between the inner peripheral surface of the outer ring mandrel 16a. Between the reduced diameter portion 14a of the through-hole 14 below the die housing 12 and the mandrel 16, a hybrid resin passage 22 having a length reaching the resin discharge port 28 is formed.

A lower end of the mandrel 16 has a narrowed end corresponding to the diameter-reduced portion of the through-hole 14. A parison control core 16d is attached to the end of the mandrel 16 so as to be able to enter and exit the mandrel 16. At the tip of the parison control core 16d, a mandrel lip 29 is provided integrally with the opening of the through-hole 14, forming a circular ring-shaped resin discharge port 28 with the opening of the through-hole 14. I have. Therefore, by changing the amount of the parison control core 16d going in and out, the resin discharge port 28
Can be changed arbitrarily.

The die gap can be changed by using the die housing 1.
2 can be driven by the control cylinder 30 fixedly mounted on the support plate 24 erected on the upper surface of the main mandrel 1 and the rod 32 connecting the control cylinder 30 and the parison control core 16d.
6c.

On the other hand, an outer layer resin supply device 40 for supplying the outer layer resin 13a to the die 10 is provided.
An intermediate-layer resin supply device 50 for supplying b, and an inner-layer resin supply device 60 for supplying the inner-layer resin 13c are respectively attached. Since the resin supply devices 40, 50, and 60 have the same configuration, only the structure of the outer layer resin supply device 40 will be described, and description of the intermediate layer resin supply device 50 and the inner layer resin supply device 60 will be omitted.

The outer layer resin supply device 40 (50, 60) comprises an outer layer extruder 42 (52, 62) and an outer layer accumulator 44 (54, 64), and the outer layer accumulator 44 (54) is provided in the die housing 12. , 64)
Is installed. This accumulator 44 (54,
Numeral 64) is a plunger 44a (54a, 64a) interpolated. The outer layer accumulator 44 (54, 64) is driven by driving the plunger 44a (54a, 64a) by the outer layer injection cylinder 45 (55, 65). Outer layer resin 13a supplied inside with variable inner volume
The injection pressure of the parison 70 is generated by pressurizing (13b, 13c) and sending it to the die 10.

Outer layer accumulator 44 (54, 64)
To the die 10 from the outer layer resin 13a (13b, 13c)
To feed the outer layer accumulator 44 (54,
A nozzle portion 46 (56, 66) is provided at the tip of 64), which is flanged to the die housing 12, and the outer ring mandrel 16a (the inner ring mandrel 16a).
b, outer layer resin introduction passages 48 (58, 6) leading to an outer layer manifold 47 described later formed in the main mandrel 16c).
8) and the nozzle passage 49 (59, 69).
Further, in order to meter the outer layer resin 13a (13b, 13c) to the outer layer accumulator 44 (54, 64), the outer layer extruder 42 (52, 62) is connected to the extrusion passage 45 (5, 62).
5, 66). Extruder for outer layer 42
A screw 42a (52a, 62a) is provided inside (52, 62) so as to freely rotate and move back and forth in a loosely fitted state.

A resin inlet 71 for the outer layer is provided through a nozzle passage 49 (59, 69) for connecting the outer layer accumulator 44 (54, 64) provided on the peripheral wall of the die housing 12.
a (71b, 71c) supplied to the outer layer resin 13a
First, the outer ring mandrel 16 (13b, 13c)
a (16b, 16c), an outer layer manifold 47 having a semicircular cross-section that is branched in the circumferential direction to the middle in the circumferential direction and gradually reduces the cross-sectional area of the passage at a predetermined ratio while curving in the extrusion direction at a predetermined curvature. I have. Except for the outer layer manifold 47 which does not have the converging portion 72a, the other intermediate layer manifold 57 and the inner layer manifold 67 end are symmetrical with each other.
The inner layer and the inner layer manifold 67 are formed so as to merge at approximately 180 degrees from the intermediate layer and inner layer resin inlets 71b and 71c, respectively.

The converging portions 72b and 72c are formed so that the converging symmetric intermediate layer manifold 57 and the inner layer manifold 67 are connected to each other by the inner ring mandrel 16b and the main mandrel 16c.
Are joined and joined so as to be in contact with a line along the axis of each. As a result, the intermediate layer resin 13 b flowing down the intermediate layer manifold 57 and the inner layer manifold 67.
The stream lines of the inner layer resin 13c and the inner layer resin 13c are parallel at the junctions 72b and 72c. The outer layer resin passage 18 (2) from the lower edge of the outer layer manifold 47 (57, 67) to the hybrid resin passage 22
0, 21) is the outer layer manifold 47 (57, 67)
A land portion 75 (76, 77) that forms a passage shallower than the passage cross-sectional depth of the portion is formed. By adjusting the shaving depth of the outer periphery of the outer ring mandrel 16a (16b, 16c) as described above. It was formed.

A multi-layer parison having three layers in the thickness direction is formed by using the blow molding machine having the above-described configuration. This is performed as follows.

First, the multilayer resin 13a (13b, 13b)
c) from the outer layer extruder 42 (52, 62) to the outer layer accumulator 44 (54, 64) using the plunger 44.
a (54a, 64a) is extruded and filled while being retracted. Next, the outer layer accumulator 44 (54, 64)
When the plunger 44a (54a, 64a) is advanced, the melted outer layer resin 13a (13b, 13c) flows from the nozzle passage 49 (59, 69) to the resin introduction passage 48 (58, 6).
8) through the outer layer resin inlet 71a (71b, 71b).
c), and flows into the outer layer resin 13a (13b, 13c).
Is the manifold 47 for the outer layer (57, 67) along with branching to the left and right at the manifold 47 for the outer layer (57, 67).
Overflows sequentially from the lower edge to the land 75 (76, 77),
The outer layer resin 13a flows uniformly in the resin passage. The resin 13b for the intermediate layer and the resin 13c for the inner layer are branched right and left by the manifold 57 for the intermediate layer and the manifold 67 for the inner layer, respectively, to reach the resin converging portion 72b for the intermediate layer and the resin converging portion 72c for the inner layer.

The outer layer manifold 47 (57, 57)
Since the groove cross-sectional area of 67) is set to be gradually reduced, the pressure distribution in the circumferential direction becomes uniform, and flows down the resin passage 18 (20, 21) as it is to reach the hybrid resin passage 22. In the hybrid resin passage 22, the outer layer resin 13 a flowing down the resin passage 18 flows down the reduced diameter portion 14 a side of the through-hole 14, and then flows down from the resin passage 21 on the way to the resin discharge port 28. The resin 13b flows down on the outer layer resin 13a. Furthermore, the resin 13c for the inner layer that has flowed down from the resin passage 20 near the resin discharge port 28 flows down on the resin 13b for the intermediate layer.
A so-called three-layer structure in which only the required width of the intermediate layer resin 13b and the inner layer resin 13c is locally set to the outer layer resin 13a, and the entire circumference is respectively set to the intermediate layer resin 13b and the inner layer resin 13c. Multi-layer parison 70
Is ejected from the resin discharge port 28. The cross section of the parison 70 thus laminated is formed as shown in FIG.

In the above description, the outer ring mandrel 1
Short manifold 47 having no confluence at the outer periphery of only 6a
Has been described, but a configuration (not shown) may be adopted in which a short manifold 57 having no junction is provided on the outer peripheral portion of only the inner ring mandrel 16b.
Outer ring mandrel 16a and inner ring mandrel 1
6b, the short manifold 47 having no merging portion on the outer peripheral portion,
57 may be provided (not shown). That is, when a short manifold having no confluence is provided on the outer periphery of only the inner ring mandrel, the cross section of the stacked parison 70 has a required intermediate layer portion as shown in FIG. Resin for intermediate layer 1 with only local width
3b. Further, in the case where short manifolds having no confluence are provided on the outer peripheral portions of the outer ring mandrel and the inner ring mandrel, respectively, the cross section of the stacked parison 70 is as shown in FIG. Only the necessary width of the outer layer and the intermediate layer is locally reduced to the outer layer resin 13a.
And the intermediate layer resin 13b.

In this embodiment, the parison 70 has a three-layer structure, but may have a single-layer structure, a two-layer structure, or a four-layer structure by increasing the number of divisions of the mandrel 16.

[0023]

As is apparent from the above description, the multilayer blow molding machine according to the present invention is a multilayer blow molding machine that forms a multilayer by sandwiching a resin layer for an intermediate layer between a resin layer for an inner layer and a resin layer for an outer layer. In the molding apparatus, a plurality of resin passages are formed by inserting a coaxially divided mandrel into a die housing, and resin inlets from the extruder side are opened in the resin passages at symmetric positions. A manifold is formed from the inflow port to the land surface of the split mandrel in the left and right direction in the circumferential direction, the cross-sectional area of the passage is reduced, and a manifold that is curved in the extrusion direction is formed. The manifold end and the manifold end from the other resin inflow are joined respectively. To form a long manifold, and at least one of them is formed in a short manifold that does not have the merging section. Since it is possible to multi-layered,
Recycling becomes possible without mixing foreign materials (sub-materials) into the burrs. Furthermore, there is no resin stagnation in the resin flow path in the die head, which improves color change and resin changeability, and makes it easier to disassemble and assemble by dividing the mandrel into multiple layers, which is effective for color change and resin change cleaning. Therefore, it is possible to flexibly cope with the diversification of the number of layers of the molded article.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view of a blow molding machine showing an embodiment according to the present invention.

FIG. 2 is an enlarged sectional view of a lower part of a die.

FIG. 3 is a perspective view of an inner ring mandrel.

FIG. 4 is a cross-sectional view illustrating a three-layer parison according to an embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 dice 12 dice housing 13a resin for outer layer 13b resin for intermediate layer 13c resin for inner layer 16 mandrel 16a external ring mandrel 16b internal ring mandrel 16c main mandrel 18, 20, 21 resin passage 22 hybrid resin passage 28 resin discharge port 40 (50, 60) Outer layer resin supply device (intermediate layer resin supply device, inner layer resin supply device) 42 (52, 62) Outer layer extruder (intermediate layer extruder,
Extruder for inner layer) 44 (54, 64) Accumulator for outer layer (accumulator for intermediate layer, accumulator for inner layer) 44a, 54a, 64a Plunger 45, 55, 65 Extrusion passage 47 (57, 67) Manifold for outer layer (for intermediate layer) Manifold, inner layer manifold) 48, 58, 68 Resin introduction path 49, 59, 69 Nozzle passage 70 Parison 71a (71b, 71c) Outer layer resin inlet (intermediate layer resin inlet, inner layer resin inlet) 72b intermediate Resin junction for layer 72c Resin junction for inner layer 75 (76, 77) Land

Continuation of the front page (56) References JP-A-6-305003 (JP, A) JP-A-6-218798 (JP, A) JP-A-6-182856 (JP, A) JP-A-4-234623 (JP) JP-A-63-262212 (JP, A) JP-A-4-316808 (JP, A) JP-A-1-275120 (JP, A) JP-A-5-200838 (JP, A) (58) Surveyed field (Int.Cl. ⁶ , DB name) B29C 49/22 B29C 49/04

Claims (1)

(57) [Scope of request for utility model registration] 1. A multi-layer blow molding apparatus for forming a multilayer by sandwiching a resin layer for an intermediate layer between a resin layer for an inner layer and a resin layer for an outer layer. A resin passage is formed, and a resin inlet from the extruder side is opened at a symmetrical position in the resin passage, and each resin inlet is branched right and left in the circumferential direction to a land surface of the split mandrel to reduce a passage cross-sectional area. A manifold that decreases and curves in the extrusion direction is formed, and the manifold end and the manifold end from the other resin inlet are respectively joined to form a long manifold, and at least one of the short manifolds does not have the junction. A multi-layer blow molding machine characterized by being formed into a.