JP2994512B2 - Extrusion molding method and apparatus for multilayer parison - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for extruding a multilayer parison.

[0002]

2. Description of the Related Art A conventional multilayer parison extrusion molding apparatus is disclosed in Japanese Patent Application Laid-Open No. 62-104707. The multi-layer parison extrusion molding device shown in the figure includes an annular first resin passage through which the main resin forming the inner and outer layers of the parison flows, a main material extruder that supplies the main resin to the first resin passage, An annular second resin passage through which a barrier resin (sub-material resin) extruded between the inner and outer layers of the main resin flows, a sub-material extruder supplying the sub-material resin to the second resin passage, and the first resin passage; A first pressurizing means for pressurizing and extruding the main resin in the container, a supply source (second main extruder) for supplying the main resin to a portion corresponding to the pinch-off portion of the second resin passage, And a second pressing means for pressing and pressing the sub-material resin and the main material resin in the two resin passages. The pinch-off portion is formed by sandwiching the upper and lower ends and a part of the circumferential direction of the multilayer parison in the closed surface of the mold and bonding them together. Each of the resin passages is formed concentrically with the multilayer ring. The main resin is supplied from a supply source to a portion corresponding to the pinch-off portion of the second resin passage through which the barrier resin flows, and the sub-resin and the main resin in the second resin passage are separated by the first pressing means. A single-layer parison having no auxiliary material resin in a part of the circumferential direction (a portion corresponding to the pinch-off portion in the circumferential direction) because the main material resin is extruded before and after the main resin in the first resin passage is extruded by the second pressing means. A multilayer parison having a portion (actually, a two-layer main material resin is superposed and a single layer portion as viewed from the material side) is formed. As a result, the usage amount of the auxiliary material resin can be reduced.

[0003]

However, the conventional multi-layer parison extrusion molding apparatus as described above includes a secondary material extruder for forming the inner and outer layers of the parison, as well as a second extruder.
Since another supply source (second main material extruder) for supplying the main material resin to a portion corresponding to the pinch-off portion of the resin passage is required, there is a problem that the apparatus becomes expensive. Furthermore, since it is necessary to extrude the sub-material resin by the sub-material extruder and the main material resin by the second main material extruder so as not to be mixed with each other, the respective extrusion pressure and extrusion timing There is also a problem that the work of adjusting such as is troublesome. An object of the present invention is to solve such a problem.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by making the secondary material resin passage of the multilayer ring partially annular. In other words, according to the method for extruding a multilayer parison according to the first aspect of the present invention, a secondary material resin passage is formed concentrically with the first hole in the molten main material resin layer extruded from the annular first hole. second partial loop consisting of multi-layer ring that
Overlay sub wood resin layer of extruded molten state from the hole, which constitutes a non-existent portion of Fukuzai resin while moving through the resin passage towards the die slit, this
At this time, it is provided on the inner diameter side of the partial annular multilayer ring.
Sub-resin flows to the main resin due to the removed resin blocking member
It is characterized in that these are pushed out of the die slit while preventing them from being inserted. Invention of claim 2 of the present invention
Ring, a cylinder (10), a cylinder (10) axially movably disposed rods in the center of the (18), and linked core die (20) thereto, which is arranged on the outer peripheral side of this (22) and a multilayer ring (24, 26) disposed in the cylinder (10). An annular die slit (20a) is provided between the ring (22) and the core die (20). Formed, the multilayer ring (24,
26), a main material resin passage (36) is formed on the inner peripheral side, and the sub material resin passage (3) is formed in the multilayer ring (24, 26).
8), the main material extruder (52) for extruding the main material resin into the main material resin passage (36), and the sub material resin to the die slit (20a) via the sub material resin passage (38). press multilayer parison having a secondary timber extruder (54), the extruded
In the forming apparatus, the multilayer ring (24, 26)
Is fitted to the cylinder (10),
The sub-material resin passage (38) of the multilayer ring (24, 26)
Is formed in a partially annular shape, and the multilayer ring (24, 26)
Is composed of a multilayer ring member (24) and a ring member (26) arranged adjacent thereto, and the multilayer ring member (24) or the ring member (26) has a mating member thereof. An annular passage portion (26a) that is not in close contact with the mating member is formed on a surface facing the mating member.
The sub-material resin passage (38) is constituted by the sub-material resin passage (38), and the sub-material resin is mainly provided at the inner diameter side of the member (26) in which the partial annular passage portion (26a) is formed. Resin blocking member (2
8), characterized in that is provided. In addition, the code | symbol in a parenthesis shows the corresponding member of an Example.

[0005]

A plurality of types of molten resin are extruded through respective resin passages, while the main resin passing through the annular main resin passage is extruded into a cylindrical shape, while the partial annular sub-assembly of the multilayer ring is extruded. The sub-material resin passing through the material resin passage is extruded into a partially cylindrical shape and is superimposed on the main material resin layer. Therefore, a partial cylindrical space having a shape corresponding to the partial cylindrical sub-material resin layer is formed on the surface of the main material resin layer, and flows into the partial cylindrical space from the adjacent main material resin passage. The main resin thus filled is filled. That is, a portion having a small number of superposed layers is formed in the multilayer parison. Thus, it is possible to extrude a multi-layer parison in which most of the parison is formed by the inexpensive main material resin and the expensive sub-material resin is formed only in necessary places. Since the multilayer ring is merely fitted to the cylinder, the replacement of the multilayer ring can be easily performed. In the case where the resin blocking member is provided in the member in which the partially annular passage portion is formed, even if the thickness of the sub-material resin is changed with respect to the thickness of the main material resin,
The boundary between the main resin and the sub resin in the circumferential direction can be made clear.

[0006]

1 to 5 show a first embodiment of the present invention. The cylinder 10 is formed with a cylinder hole 10a penetrating in the axial direction, a resin passage 10b formed at a lower right portion in FIG. 1, a resin passage 10c formed at an upper right portion in FIG. 1, and a heat medium passage 10d. The upper part of the cylinder 10 where the resin passage 10c is formed is formed thicker than the other parts. The heat medium can be circulated and supplied to the heat medium passage 10d of the cylinder 10 through a heat medium inlet and a heat medium outlet (not shown), so that the resin temperature in the cylinder 10 can be kept constant. A cylinder member 34 is arranged in the cylinder 10 in the cylinder hole 10a. The cylinder member 34 is fixed to a thick inner wall portion above the cylinder 10. As a result, the cylindrical member 34 is
Is divided into an annular hole 10e and a central hole 34a concentric with the annular hole 10e. A ring piston 12 is fitted in the annular hole 10e so as to be movable in the axial direction. Cylinder 1
The main material accumulator 50 is constituted by the 0, the ring piston 12, the cylindrical member 34 and the like. The piston rod 14 is connected to a piston rod of a fluid pressure cylinder 16. The fluid pressure cylinder 16 can drive the ring piston 12 of the main material accumulator 50 in the main material resin extrusion direction below in the figure. Center hole 34a of cylindrical member 34
Is provided with a rod 18 movably in the axial direction.
A thread portion is formed at the lower end of the rod 18 in the drawing. A core die 20 having a stepped hole is fitted on the rod 18 on the threaded portion side thereof, and a nut 40 is screwed into the threaded portion. The nut 40 is inserted into a stepped hole of the core die 20. Core die 20
, A snap ring 46 is attached to the snap ring groove. Thus, the core die 20, the rod 18, and the nut 40 are integrated. Core die 2
A ring 22 is arranged on the outer peripheral side of 0. Ring 2
2 is fixed to the outlet side of the cylinder 10. An annular die slit 20 is formed by the ring 22 and the core die 20.
a from which a multi-layer parison 48 can be extruded, as described below. By operating the rod 18, the core die 20 can move up and down in the figure with respect to the ring 22. Thereby, the die slit 20a
, That is, the thickness of the parison 48 can be adjusted. Passage forming members 30 and 32 are arranged at a position above the position where the core die 20 is arranged in the figure. The rod 18 penetrates the passage forming members 30 and 32, respectively. A substantially ring-shaped multilayer ring member 24 is fitted to the cylinder 10. On the side of the multilayer ring member 24 facing the ring 22 side, a conical cylindrical portion 24a whose diameter decreases toward the lower end in the figure is formed. A tapered ring member 26 is disposed at a position facing the outer peripheral surface of the conical cylindrical portion 24a of the multilayer ring member 24. The tapering member 26 is fitted to the cylinder 10. The multilayer ring assembly is constituted by the multilayer ring member 24 and the taper ring member 26. The mounting position of the multilayer ring assembly in the axial direction is determined by being sandwiched between the ring piston 12 and the ring 22. As shown in FIG. 3, the tapered member 26 is formed such that the axial length of the right half in the figure is shorter than the axial length of the left half in the figure. In other words, the tapering member 26 is formed with a semicircular passage portion (tapered surface portion) 26a and a stepped passage blocking portion (tapered surface portion) 26c. Thus, when combined with the multilayer ring member 24 indicated by the phantom line in the figure, the sub-material resin passage 38 is formed in the right half of FIG. It is not formed. Secondary material resin passage 3
Reference numeral 8 communicates with the resin passage 10b. A step joining portion 26b is formed by a step between the passage portion 26a and the passage blocking portion 26c of the tapering member 26. The tapered ring member 26 has a resin blocking member mounting hole 26d formed at a position corresponding to the stepped joint 26b on the inner peripheral side of the cylindrical portion. As shown in FIG. 5, wedge-shaped resin blocking members 28 are mounted in the respective resin blocking member mounting holes 26d. The resin blocking member 28 will be described later. The main resin passage 36 is formed by assembling the passage forming members 30 and 32, the cylindrical member 34, and the multilayer ring described above.
Are formed. The main resin passage 36 communicates with the above-described die slit 20a at a downstream portion 36a thereof. A main material extruder 52 is attached to the cylinder 10 so as to communicate with the resin passage 10c. The main material accumulator 50 is connected to the resin passage 1 from the main material extruder 52.
The main resin extruded into the main resin passage 36 through Oc can be accumulated. A pipe 42 is connected to the cylinder 10 so as to communicate with the resin passage 10b. An auxiliary material extruder 54 is connected to an end of the pipe 42. The secondary material extruder 54 has its outlet side connected to a secondary material accumulator 56 via the pipe 42. The auxiliary material accumulator 56 can accumulate the auxiliary material resin extruded from the auxiliary material extruder 54. The accumulator 56 for the auxiliary material is
The piston rod is connected to the piston rod of the fluid pressure cylinder 58 via the piston rod. Fluid pressure cylinder 58
Can drive the sub-material accumulator 56 in the sub-material resin extrusion direction below in the figure. The pipe 42 is provided with a shut-off valve 44 downstream of the position where the auxiliary material accumulator 56 is provided. The shut-off valve 44 allows the auxiliary material resin to be pushed out to the downstream side when the built-in valve member is located at the open position, but the auxiliary material resin does not It can be prevented from being pushed further downstream. The main resin extruded cylindrically from the main material accumulator 50 through the downstream portion 36a of the main material resin passage 36 toward the inlet side of the die slit 20a is supplied from the sub material accumulator 56 to the pipe 42, the resin flow path. The sub-material resin extruded in a semi-cylindrical shape toward the entrance side of the die slit 20a through the semi-annular sub-material resin passage 38 of the assembly of the multilayer ring 10b and the multilayer ring. In order to make the shape and arrangement state of the resin blocking member 28 easy to understand, 4-4 in FIG.
FIG. 4 shows the section taken along the line rotated 180 degrees.
FIG. 5 shows a partial cross section taken along line 5-5 in FIG. The resin blocking member 28 has an inner diameter portion on the semi-peripheral side where the auxiliary material resin is not formed from the auxiliary material resin passage 38 of the multilayer ring assembly (the inner diameter portion of the portion where no grid line is provided in FIG. 2).
It can be prevented from flowing into. This makes it possible to make the boundary in the circumferential direction between the sub-material resin portion and the main-material resin portion of the parison 48 clear, as described later.

Next, the operation of the first embodiment will be described.
A heat medium of a predetermined temperature is circulated in the heat medium passage 10d of the cylinder 10 in advance. This allows cylinder 1
0 is maintained at a constant temperature. The main resin extruded from the main extruder 52 is supplied to the resin passage 10 c and the main resin passage 3.
6 and accumulated in the accumulator 50 for the main material. The sub-material resin extruded from the sub-material extruder 54 is accumulated in the sub-material accumulator 56. After the accumulation of both resins is completed, the pistons of both accumulators 50 and 56 are moved downward in the figure by driving the fluid pressure cylinders 16 and 58, respectively. As a result, the main material resin is extruded into a cylindrical shape toward the annular die slit 20a of the main material resin passage, and the sub material resin is extruded into the pipe 42 and the resin
b and the secondary material resin passage 38, and is extruded in a semi-cylindrical shape toward the die slit 20a. That is, in the downstream portion of the assembly of the multilayer ring, a semi-cylindrical sub-material resin is superimposed on the outer peripheral side of the cylindrical main material resin. For this reason, the semi-cylindrical portion on the side from which the sub-material resin is not extruded becomes a space, but while moving toward the die slit 20a, the semi-cylindrical space portion is filled with the main material resin on the inner peripheral side. As a result, a multi-layer parison 48 having the same thickness is extruded from the die slit 20a over the entire circumference. The parison 48 is sandwiched between the molds of a hollow molding machine (not shown), and at the same time as the mold is closed, the upper part thereof is cut by a cutter device (not shown).
Is blown into the hollow molded article to form a hollow molded article as shown in FIG. As shown in FIG. 7, the hollow molded article has a sub-material resin portion provided with a grid line covering a half circumference of the outer surface. For example, when the half-circumferential portion of the bottle-shaped hollow molded article is exposed to high temperatures, the amount of expensive heat-resistant resin can be reduced by using a resin having high heat resistance as the auxiliary material resin.

Next, FIG. 8 shows a second embodiment of the present invention.
The same members as those of the first embodiment are denoted by the same reference numerals. A passage member 11 is attached to the cylinder 10 at the upper part in the drawing. In the passage member 11, a resin passage 10c is formed. The main member extruder 52 is connected to the passage member 11 at the right end in the figure, and the fluid pressure cylinder 13 is attached to the upper part in the figure. The extrusion port of the main material extruder 52 communicates with the resin passage 10c. The rod 18 passes through the axis of the passage member 11. The piston of the fluid pressure cylinder 13 is connected to the rod 18. A double cylindrical member 15 is arranged on the outer peripheral portion of the cylinder 10 on the side where the passage member 11 is attached. The opening on one end side of the double cylindrical member 15 is closed by the lower end surface of the passage member 11, and the opening on the other end side is
Is closed by the upper end face of the step. Double cylindrical member 1
Although not shown in FIG. 5, an inlet and an outlet for injecting and discharging the heat medium are formed. The passage forming member 30 is
As shown in FIG. 9, it is held on the cylinder 10 via four bridge members 17. The passage forming member 19 is attached to the upper part of the passage forming member 30 in the drawing. The rod 18 described above penetrates the passage forming member 19. In the second embodiment, the accumulators for accumulating the main resin and the sub resin are not provided. In the multilayer ring assembly including the multilayer ring member 24 and the tapered ring member 26, the axial mounting position of the multilayer ring assembly is determined by being sandwiched between the upper inner step portion of the cylinder 10 and the ring 22. Other configurations are
This is the same as that of the first embodiment.

Next, the operation of the second embodiment will be described.
In the second embodiment, the main resin extruded from the main extruder 52 is continuously pushed out of the resin passage 10c of the passage member 11 into the main resin passage 36 without being accumulated in the accumulator. After being superposed on the sub-material resin continuously extruded from the sub-material extruder 54 through the resin passage 10b, it is extruded from the die slit 20a. The cylinder 10 has a double cylindrical member 15
It is adjusted by the heat medium circulated through the inside. Other operations are the same as those of the first embodiment.

In the description of the first embodiment,
Although the passage portion 26a is formed in the tapered ring member 26, the passage portion may be formed on the multilayer ring member 24 side. In this case, the resin blocking member 28 may be attached to the multilayer ring member 24. In the description of the first embodiment, the multilayer ring member 24 and the tapered ring member 26 are arranged in the axial direction. However, they are formed in a ring shape having no tapered surface and arranged concentrically. You can also. further,
In the description of the first embodiment, the auxiliary material resin passage 38 is constituted by the multilayer ring member 24 and the tapered ring member 26. However, the multilayer ring member and the tapered ring member 26 are integrally formed by one member. It can also be formed. In the description of the first embodiment, the sub-material resin passage 38 is formed over a semicircle. However, the stepped portion 26c that blocks the resin at a plurality of locations on the circumference.
May be provided. Thereby, the auxiliary material resin can be extruded from the plurality of partial annular portions. That is, the sub-material resin can be extruded in a stripe shape. By replacing the tapering member 26 with a member having no stepped portion 26c, a multi-layer parison 48 in which the sub-material resin layer is formed over the entire circumference can be obtained. Further, in the description of the first and second embodiments, the parison 48 is composed of the two layers of the main material layer on the inner peripheral side and the sub-material layer on the outer peripheral side. Along with the formation, a sub-material layer can be formed on the inner peripheral side, and the number of layers can be increased. Further, in the description of the first embodiment, the resin blocking member mounting hole 26b is formed in the tapered ring member 26, and the resin blocking member 28 is mounted therein. If it is low and there is no risk of entering the main resin side, the resin blocking member 28 may not be provided.

[0011]

As described above, according to the present invention, it is possible to extrude a multilayer parison having no auxiliary material layer formed at a desired position on the circumference by a simple mechanism. Accordingly, the apparatus for extruding the multilayer parison can be made inexpensive, and the adjustment work of the apparatus can be simplified. Further, since the multi-layer ring is merely fitted to the cylinder, the multi-layer ring can be easily replaced, and the setup change time of the apparatus can be shortened.

[Brief description of the drawings]

FIG. 1 is a view showing a multi-layer parison extrusion molding apparatus (first embodiment) of the present invention.

FIG. 2 is a plan view of a tapering member.

FIG. 3 is a sectional view of a tapering member.

FIG. 4 is a view showing a section taken along line 4-4 in FIG. 1 rotated 180 degrees.

FIG. 5 is a view showing a resin blocking member.

FIG. 6 is a view showing a molded product.

FIG. 7 is a sectional perspective view taken along line 7-7 in FIG. 6;

FIG. 8 is a view showing a multilayer parison extrusion molding apparatus (second embodiment) of the present invention.

FIG. 9 is a sectional view taken along line 9-9 in FIG. 8;

[Explanation of symbols]

 Reference Signs List 10 cylinder 10b, 10c resin passage 12 ring piston 14 piston rod 16 fluid pressure cylinder (ring piston driving device) 18 rod 20 core die 20a die slit 22 ring 24 multilayer ring member (multilayer ring) 26 taper ring member (ring member: multilayer ring) ) 28 resin blocking member 36 main material resin passage 38 sub material resin passage 40 parison 52 main material extruder 54 sub material extruder

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FIB29L 9:00 22:00 (56) References JP-A-58-18232 (JP, A) JP-A-62-284721 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29B 11/00-11/16 B29C 47/00-47/96

Claims (2)

(57) [Claims] 1. A molten state extruded from an annular first hole.
In the main resin layer in the state, the secondary material resin passage is concentric with the first hole.To
ConstitutePush through the partial annular second hole made of the multilayer ring
The extruded molten sub-material resin layer is superimposed and moved in the resin passage toward the die slit.
Where no auxiliary material resin is presentConstitute At this time, it is provided at the inner diameter side of the partial annular multilayer ring.
The secondary resin flows to the main resin side due to the
While preventing that These from the die slit
Extrusion method of multilayer parison characterized by extrusion
Law. 2. A cylinder (10) and a cylinder (10).
Rod (18) arranged movably in the axial direction at the center of the rod
And a core die (20) connected thereto and an outer periphery thereof
Ring (22) arranged on the side and inside the cylinder (10)
And a multi-layer ring (24, 26) arranged at
Between the ring (22) and the core die (20)
Die slit (20a) is formed.
The main material resin passage (36) is formed on the inner peripheral side of the plug (24, 26).
Formed on the multi-layer rings (24, 26)
A resin passage (38) is formed, and the main material resin passage (3) is formed.
6) a main material extruder (52) for extruding a main material resin, and a sub material
The resin is supplied to the die slit (2) through the secondary material resin passage (38).
0a) to extrude a secondary material extruder (54).
In the parison extrusion molding apparatus, the multilayer ring (24, 26) is connected to the cylinder (1).
0) and a multilayer ring (24, 2)
6) The secondary material resin passage (38) is formed in a partially annular shape.
Re, The multilayer ring (24, 26) is a multilayer ring member (2
4) and a ring member (26) disposed adjacent thereto.
And is composed of In the multilayer ring member (24) or the ring member (26),
A part that does not adhere to the mating member on the surface facing the mating member
A split annular passage portion (26a) is formed,
(24, 26) forms the sub-material resin passage (38).
Has been established, The member (2) in which the partial annular passage portion (26a) is formed
In 6), the sub-material resin is placed on the inner resin
Resin blocking member (28) for preventing inflow Provided
Re Extrusion molding apparatus for multi-layer parison
Place.