JPH0489224A - Extrusion molding die - Google Patents

Abstract

PURPOSE:To manufacture a uniform molding polymer of superior quality by forming a constitution of polymer penetration resistance of a distributor in a manner of forming the difference of getting smaller from a central section to ward end sections. CONSTITUTION:A distributor 11 installed between a manifold 3 and a die 4 is constituted in a manner of forming the difference of polymer penetration resistance getting smaller as the same is away from a central section to ward end section. Pores 12 are disposed uniformly on a rectangular distributor 11, and the thickness of the distributor 11 is formed thick in the central section and thin at the end sections, by which polymer movement resistance is made smaller as the same is away from the central section to ward the end sections. The polymer is discharged out of the hole of a die nozzle 4 by setting the movement resistance of polymer at a choker bar 7 sufficiently larger compared with the resistance of discharge through a die nozzle 4, and a uniform molding polymer is manufactured.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a die for extrusion molding of molten polymer, and more particularly to an extrusion molding die capable of uniformly discharging the polymer from the entire die nozzle. .

(Prior Art) As shown in FIG. 12, a die for extrusion molding of molten polymer has a manifold 3 formed in a die head body 2 provided at the tip of a polymer passage 1, and a die nozzle fixed to the tip side of the die head body 2. Generally, a distributor 5 having a passage 6 is provided between the polymer passage 1 and the manifold 3, and the pre-melted polymer is guided to the die head body 2 through the polymer passage 1.

In the manifold 3, by providing the distributor 5 with a certain polymer passage resistance, the polymer passage 1
The structure is such that the polymer spreads and flows throughout the manifold 3, and the distributor 5 is
TIi! The polymer thus obtained is molded through a die nozzle 4 through a Chiyo cover 7, and after being discharged, it is cooled, solidified, and cut.

Conventionally, in extrusion molding dies such as those described above, the distributor 5 employs a perforated plate or a slit plate in order to provide resistance to passage of the polymer.

[Problems to be Solved by the Invention] By the way, the perforated plate or slit plate used in the conventional distributor 5 has a structure in which holes and slits are uniformly arranged over the whole, so The passage resistance of the polymer is constant regardless of the position in the radial direction, and it is difficult for the polymer to flow at the edges and outer periphery, and there is a difference in the discharge speed of the polymer between the center and the edges, and the polymer may remain in some parts of the manifold for a long time. Therefore, in the case of strands, the size of the strands becomes different, in the case of sorting, the thickness becomes non-uniform, and thermal deterioration adversely affects the quality of the molded polymer.

Therefore, in order to solve the above-mentioned problems, the object of this invention is to provide an extrusion molding die that can obtain uniformly molded polymer of excellent quality and can be operated continuously for a long time. .

(Means for Solving the Problems) In order to solve the above problems, the present invention adopts a structure in which the polymer passage resistance of the distributor is made smaller as it goes from the center to the ends. It is something.

[Effect]

When the molten polymer that has flowed into the distributor from the polymer passage passes through the distributor,
! Since the excessive resistance is large in the center and small at the ends, the molten polymer spreads over the entire manifold, and a sufficient amount of polymer flows also at the ends, eliminating the drawback that polymer near the walls of the manifold is difficult to flow. The polymer flowing more toward the ends moves from the ends toward the center in the choker, contrary to the manifold, so that the polymer is uniformly discharged from the entire die nozzle.

[Examples] Examples of the present invention will be described below with reference to FIGS. 1 to 11 of the accompanying drawings.
I will explain based on the times.

Note that the same parts as those in the conventional example shown in FIG. 12 are designated by the same reference numerals and will not be described.

As shown in FIG. 1, the distributor 11 provided between the manifold 3 and the die nozzle 4 has a structure in which the polymer passage resistance decreases from the center to the ends.

Note that 8 in the figure is a jacket.

1 to 6 show examples using a multi-hole distributor. First, in the first embodiment shown in FIGS. 1 to 3, holes 12 are arranged uniformly in a rectangular distributor 11. By making the thickness of the distributor 11 thick at the center and thin at the ends, the polymer passage resistance becomes smaller from the center to the ends.

The second embodiment shown in FIG.
The thickness of the holes 12 is kept constant, and the diameter of the holes 12 is small in the center and becomes larger toward the ends, thereby providing a difference in the resistance of polymer passage.

The third embodiment shown in FIG.
The thickness of the pores 12 is made constant, and the distribution density of the pores 12 is made coarser in the center and denser toward the ends, thereby creating a difference in the resistance to passage of the polymer.

The fourth embodiment shown in FIG. 6 is a combination of the first to third embodiments, in which the thickness of the distributor 11 is thicker at the center and thinner at the ends, and the diameter of the hole 12 is set at the center. The holes 12 are small at the edges and large at the ends, and the distribution density of the holes 12 is coarse in the center and becomes denser toward the ends.

Next, FIGS. 7 to 11 show examples using a slit distributor, and in the fifth embodiment shown in FIGS. 7 and 8, slits 13 are arranged in a distributor 11 at regular intervals. By making the thickness thicker in the center and thinner at the ends, the polymer passage resistance is differentiated.

The sixth embodiment shown in FIG.
The thickness of the slit 13 is kept constant, and the width of the slit 13 is narrow at the center and widened toward the ends, thereby providing a difference in polymer passage resistance.

The seventh embodiment shown in FIG. 10 is a combination of the fifth and sixth embodiments, in which the thickness of the distributor 11 is thicker at the center and thinner at the ends, and the slit 130 is
The width is narrower in the center and wider toward the ends (this creates a difference in polymer passage resistance).

The eighth embodiment shown in FIG. 11 is constructed with -1 slits 13, and the thickness of the distributor 11 is made thicker at the center and thinner at the ends, or the width of the slit 13 is made narrower at the center. By making the slit 13 wider toward the end, or by combining the two in an open-and-open manner, the polymer passage resistance of the slit 13 is made different between the center and the end.

In addition, in any of the embodiments, the central part and the end part ii! i
It is preferable that the ratio of a resistance is set to about 2 to 10 at the center part, with the end part being 1.

Moreover, although each embodiment shows a rectangular distributor, the present invention can also be applied to a circular distributor.

The extrusion molding die of this invention has the above configuration,
Since the polymer passage resistance of the distributor 11 is made to be large at the center and small at the ends, the polymer flowing into the manifold 3 from the polymer passage 1 does not flow straight to the center, but is distributed throughout the manifold 3. It will spread out and a sufficient amount of polymer will flow to the edges as well.

When the distributor 11 makes the flow rate faster at the ends than the center and more polymer is allowed to flow, the polymer moves from the ends to the center in the choker bar 7, contrary to the manifold 3, so the polymer in the choker bar 7 The pressure in the plane direction becomes uniform.

If the resistance to movement of the polymer in the choker 7 is set to be sufficiently larger than the resistance to discharge through the die nozzle 4, the polymer is uniformly discharged from the entire die nozzle 4, and a uniformly molded polymer can be obtained.

〔effect〕

As described above, according to the present invention, the polymer passage resistance of the distributor in the extrusion molding die is made smaller as it goes from the center to the ends, so that the polymer can be uniformly discharged from the entire die nozzle, resulting in a uniform A shaped polymer can be obtained.

Further, there is no local retention of the polymer in the manifold for a long time, there is no quality deterioration of the molded polymer due to thermal deterioration, and continuous operation for a long time is possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an extrusion molding die according to the present invention, FIG. 2 is a perspective view showing a first embodiment of a distributor used in the above, the third is a longitudinal sectional view of the same, and FIG. 4 is a longitudinal sectional view of the same. FIG. 5 is a longitudinal sectional view showing the second embodiment, FIG. 5 is a longitudinal sectional view showing the third embodiment, FIG. 6 is a longitudinal sectional view showing the fourth embodiment, and FIG. 7 is a longitudinal sectional view showing the fifth embodiment. 8 is a longitudinal sectional view of the same as above, FIG. 9 is a longitudinal sectional view showing the sixth embodiment of the same, and FIG. 10 is a longitudinal sectional view of the same as the seventh embodiment.
FIG. 11 is a perspective view showing the eighth embodiment, and FIG. 12 is a longitudinal sectional view showing a conventional extrusion molding die. 1... Polymer passage, 2... Die head body, 3... Manifold, 4...
...Die nozzle, 7...Cho cover 11...Distributor, 12...
- Hole, 13...Slit. Patent applicant Asuriki Kogyo Co., Ltd.

Claims (8)

[Claims] (1) In an extrusion molding die in which a die nozzle is provided on the outlet side of a manifold formed in the die head body and a distributor is built into the manifold, the polymer passage resistance of the distributor is made smaller as it goes from the center to the ends. An extrusion molding die that is characterized by its unique features. (2) The extrusion molding die according to claim 1, wherein the distributor is a porous distributor, the thickness of which is thicker at the center and thinner at the ends to provide a difference in polymer passage resistance. (3) The extrusion molding die according to claim 1, wherein the distributor is a porous distributor, and the pore diameter is small in the center and large in the ends to provide a difference in polymer passage resistance. (4) The extrusion molding die according to claim 1, wherein the distributor is a porous distributor, and the distribution density of the holes is coarse at the center and dense at the ends to provide a difference in polymer passage resistance. (5) A porous distributor whose thickness is thicker in the center and thinner at the edges, the pore diameter is smaller in the center and larger at the edges, and the distribution density of the pores is coarser in the center and denser at the edges. The extrusion molding die according to claim 1, wherein the extrusion molding die has a difference in polymer passage resistance. (6) The extrusion molding die according to claim 1, wherein the extrusion molding die is a slit distributor, the thickness of which is thicker in the center and thinner at the ends to provide a difference in polymer passage resistance. (7) The extrusion molding die according to claim 1, wherein the extrusion molding die is a slit distributor, and the width of the slit is narrow at the center and wide at the ends to provide a difference in polymer passage resistance. (8) A slit distributor in which the thickness is thicker at the center and thinner at the ends, and the width of the slit is narrower at the center and wider at the ends to create a difference in polymer passage resistance. Item 1. The extrusion molding die according to item 1.