JPH1134108A - Molten resin kneading nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent unplasticized stocks from mixing with a molten resin without reducing a plasticizing capability and developing the pressure loss of the molten resin by a method wherein an X-like member connecting two collars each having an outer diameter slightly smaller than the inner diameter of a resin passage with each other, recessed parts and projected parts formed by the collars and resin feeding ports to the recessed parts opposing to each other and resin discharging ports from the recessed parts opposing to each other are provided. SOLUTION: A torpedo 4 has collars 7, the diameter of each of which is slightly smaller than the bore of a resin passage, at its both ends. A portion between both side collars 7 is a member, which has a near X-like section or in which four recessed parts 13 and four projected parts 18 are formed. The outer diameter of this projected part 18 is set to be smaller than the outer diameter of the collar 7 by a predetermined dimension. In the neighborhood of one collar 7 at the bottom parts of two recessed parts 13 opposing to each other, feed ports 9 and 10 communicating with an inlet 14 provided at the inlet edge face 16 of the collar 7. On the other hand, in the neighborhood of the other collar 7 at the bottom parts of the recessed parts 13 respectively having these feed ports 9 and 10, discharging ports 11 and 12 communicating with an outlet provided on the outlet edge face 17 of the collar 7 are bored. Further, if the inlet 14 and the outlet 15 are made reversed, the function remains the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for kneading a molten resin in order to improve color dispersion when forming a resin by coloring using a dry color or a master batch.

[0002]

2. Description of the Related Art Conventionally, a mixing head has been attached to the tip of a screw. As another means, as disclosed in Japanese Utility Model Laid-Open Publication No. 6-53120, there is a method in which a columnar portion for kneading the nozzle is inserted into the path of the molding material of the nozzle.

[0003]

However, in the above-mentioned mixing head, if the kneading effect is to be improved, the plasticizing ability at the time of plasticizing the raw material is reduced. In addition, in the case where the columnar portion is inserted into the nozzle, if a sufficient kneading effect is to be obtained, the pressure loss of the molten resin at the time of injection filling becomes large, and the resin pressure required for molding may be insufficient. It was.

[0004]

Therefore, a flange having an outer diameter slightly smaller than the inner diameter of the resin passage of the nozzle is provided at both ends, and both flanges are connected by a member having a substantially X-shaped cross section. The four concave portions long in the axial direction formed by the character-shaped member and the flange, the four convex portions forming the concave portion having an outer diameter smaller than the outer diameter of the flange by a predetermined dimension, and melting into the two opposite concave portions. A torpedo having a supply port for guiding the resin and a discharge port for discharging the kneaded molten resin from two opposite concave sections different from the concave section having the supply port is inserted into the nozzle, and the resin passage of the nozzle is inserted. By passing the molten resin through a narrow gap between the resin and the convex portion, a high-quality molten resin containing no unplasticized resin can be obtained.

[0005]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a torpedo 4 and the nozzle 1 equipped with the torpedo 4 is shown in FIG.

The nozzle 1 comprises a nozzle body 2 and a nozzle tip 3
Mainly composed of The base of the nozzle main body 2 is screwed to a not-shown front end surface of the heating cylinder. The base of the nozzle body 2 is provided with a resin passage 6 penetrating therethrough, and the nozzle tip 3 is screwed to the front end. A band heater 5 for heating and controlling the temperature of the nozzle body 2 is wound around the outer periphery of the nozzle body 2. A thermocouple for detecting the temperature is attached to an appropriate place (not shown), and the temperature is controlled by a separately provided control device. Is adjusted.

The torpedo 4 is mounted by removing the nozzle tip 3 and inserting it into the resin passage 6 of the nozzle body 2. The resin passage 6 has another step at a position slightly longer than the length of the torpedo 4 from the step of the mounting screw portion of the nozzle tip toward the base of the nozzle body 2.
Is held between the step and the bottom of the nozzle tip 3.

The torpedo 4 has flanges 7 at both ends, and its diameter is slightly smaller than the inner diameter of the resin passage 6. Between the flanges on both sides, a cross section is formed of a member having a substantially X-shape, and four concave portions 13 and four convex portions 18 are formed. The outer diameter of the projection 18 is smaller than the outer diameter of the flange 7 by a predetermined dimension. In a preferred embodiment,
When the torpedo 4 is inserted into the nozzle, the gap G between the resin passage 6 and the top of the projection 18 is 0.5 to 1.2 mm.
Since this size is smaller than the size of the raw material pellets, the unplasticized raw material cannot pass through, so that the unplasticized resin does not mix into the molten resin.

One of the flanges 7 at the bottom of the two opposing concave portions 13
Are provided with supply ports 9 and 10 communicating with an inlet 14 provided on an inlet end face 16 of the flange 7. On the other hand, the outlet end face 1 of the flange 7 is provided near the other flange 7 at the bottom of the two concave portions 13 opposite to the concave portion having the supply ports 9 and 10.
Discharge ports 11 and 12 communicating with an outlet 15 provided in 7 are provided. Note that the inlet 14 and the outlet 15 are designated for convenience, and the functions are the same even if reversed.

Next, the flow state of the molten resin will be described. The molten resin flowing out of the heating cylinder flows into the resin passage 6 of the nozzle body 2 and reaches the torpedo 4. The molten resin entering the inlet 14 is diverted to the supply port 9 and the supply port 10,
As shown in FIG. When the concave portion 13 is filled with the molten resin, the molten resin flows through the narrow gap G between the convex portion 18 and the resin passage 6 to the concave portion adjacent on both sides as indicated by an arrow b. At this time, the molten resin is satisfactorily kneaded, and the gap G prevents the passage of the unplasticized raw material. The molten resin flowing into the adjacent concave portion is supplied to the supply port 1
0, and flows into the discharge port 11 as shown by the arrow d, further merges with the molten resin from the other discharge port 12, reaches the nozzle tip 3 from the outlet 15, and molds. Is filled.

A seat 8 is provided at an appropriate position on the top of the projection 18, and its outer diameter is the same as the outer diameter of the flange 7. That is, the height of the seat 8 is equal to the predetermined dimensional difference between the outer diameter of the projection and the outer diameter of the flange. The seat portion 8 is effective in maintaining the core of the torpedo 4 and preventing breakage. For example, if one supply port is closed with an unplasticized raw material or the like, resin pressure is applied only to the concave portion communicating with the other supply port, and if there is no seat portion, a substantially X-shaped member in cross section Breaks.

The length of the torpedo 4, that is, the distance between the inlet end face 16 and the outlet end face 17, is preferably 3 to 7 times the diameter of the flange 7. The length of the torpedo 4 greatly contributes to the pressure loss of the resin pressure. As the length of the torpedo 4 increases, the passage cross-sectional area of the gap G increases, and the pressure loss decreases, but the flow length increases. There is an optimal length that combines both. The pressure loss in the nozzle of the present invention is 400 to 500 kgf / cm ² in terms of resin pressure, and the necessary cavity pressure in normal molding is 500 kgf / cm ^2.
/ Cm ² , which is sufficient since the maximum injection pressure of an injection molding machine is generally 1500 kgf / cm ² or more.

[0013]

As described above, in the molten resin kneading nozzle according to the present invention, the kneading state of the molten resin can be improved without reducing the plasticizing ability and excessively increasing the pressure loss of the molten resin. This makes it possible to prevent defective phenomena such as mixing of an unplasticized raw material into a molded article and occurrence of color unevenness. Further, the nozzle of the present invention does not require a relatively large modification such as a screw change unlike the conventional mixing head, and can achieve the object by a relatively small change of only the nozzle portion.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a nozzle of the present invention.

FIG. 2 is a perspective view of a torpedo fitted into the nozzle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Nozzle main body 3 Nozzle tip 4 Torpedo 5 Band heater 6 Resin passage 7 Flange 8 Seat 9, 10 Supply port 11, 12 Discharge port 13 Depression 14 Inlet 15 Outlet 16 Inlet end face 17 Exit end face 18 Protrusion

Claims (3)

[Claims] A flange having an outer diameter slightly smaller than an inner diameter of a resin passage of a nozzle is provided at both ends, and the two flanges are connected by a member having a substantially X-shaped cross section. Four concave portions that are formed in the axial direction and four convex portions that form the concave portion having an outer diameter smaller than the outer diameter of the flange by a predetermined dimension, and a supply port that guides the molten resin to the two opposing concave portions. A molten resin kneading nozzle for inserting a torpedo having a discharge port for discharging the kneaded molten resin from two opposing concave portions different from the concave portion provided with the supply port. 2. The nozzle for kneading molten resin according to claim 1, wherein the gap between the top of the convex portion having a predetermined dimension lower than the outer diameter of the flange and the resin passage is 0.5 to 1.2 mm. . 3. The nozzle for kneading molten resin according to claim 1, wherein a seat having a height corresponding to a predetermined dimension for lowering the projection than the outer diameter of the flange is provided at the top of the projection.