JPH042010Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Purpose of the invention] (Industrial application field) The invention involves collision-mixing multiple liquid synthetic resin components at high pressure and feeding them into a mold to form synthetic resin products through a chemical reaction. This invention relates to a mixing head for reaction injection molding.

(Prior Art) Conventionally, as a mixing head for reaction injection molding, the one shown in Japanese Utility Model Application Publication No. 157211/1983 is known. This conventional one
As shown in FIG. 1 and FIG. 4, injection ports 4 of a plurality of injection nozzles 3 each inject different liquid synthetic resin components (hereinafter referred to as raw materials) toward a cylindrical mixing chamber 2 in the head body 1. are provided at positions facing each other, and a circulation port 6 of the circulation path 5 is provided close to the upper position in the figure of each of the injection ports 4. Also,
A spool 7 is provided in the mixing chamber 2 so as to be able to move forward and backward in the axial direction, and the injection port 4 of each of the injection nozzles 3 and the circulation port 6 of the corresponding circulation path 5 are provided on the outer periphery of the tip side of the spool 7, respectively. A communicating groove 8 is formed. Further, a small diameter protrusion 9 is integrally provided at the tip of the spool 7.

Although not shown in the above publication, usually a second mixing chamber 10 communicating with the mold is orthogonally installed at the tip of the mixing chamber 2, and inside this second mixing chamber 10, A cleaning spool 11 is provided so as to be movable forward and backward.

In the non-injection state shown in FIG. 3, the spool 7 is located at its lower limit, and is cut off from the injection port 4 and the tip of the mixing chamber 2, which communicates with the cavity of the mold. At this time, the injection port 4 of the injection nozzle 3 and the circulation port 6 of the circulation path 5 are communicated via the circulation groove 8 of the spool 7, and each raw material is circulated separately through the circulation path 8.

Next, in the injection state shown in FIG.
and the tip of the mixing chamber 2 are communicated with each other. The raw material injected from each injection port 4 is
While colliding and mixing in the mixing chamber 2,
It is discharged from its tip.

Further, at the end of injection, the spool 7 is advanced downward in the figure, and the cleaning spool 11 is advanced rightward in the figure, so that the spool 7 and the cleaning spool 11 are returned to the position shown in FIG. 3.

At this time, in the process of advancing the spool 7 to stop the injection of raw materials from each injection port 4, the protrusion 9 at the tip of the spool 7 is interposed between each injection port 4, so that the raw materials directly collide. I am trying to prevent this.

In other words, the raw material injected from one injection nozzle 3 is prevented from entering and remaining in the injection port 4 of the other injection nozzle 3, and this prevents the raw material from hardening and causing pressure fluctuations or causing problems such as clogging of the injection nozzle 3. I try not to let this happen.

(Problems to be Solved by the Invention) According to the above-mentioned conventional mixing head, the material is prevented from entering between the injection ports 4 of each injection nozzle 3 only when the spool 7 opens and closes as the spool 7 moves up and down. Therefore, it is inconvenient when measuring each raw material.

That is, before injection molding, there is a measuring operation in which each stock solution is individually discharged and the desired discharge amount is measured. inject it.

In this case, with the spool 7 retracted,
Since the raw materials injected from the plurality of injection nozzles 3 arranged at positions facing each other collide head-on, one is injected at high pressure, while the other is in a no-load state. Therefore, the raw material ejected from one injection nozzle 3 at high pressure enters the injection port 4 of the other injection nozzle 3 under no load and reacts with the other component, causing pressure fluctuations as described above. In addition to causing or clogging,
It enters the stock solution circulation circuit and reacts in the stock solution circulation hose, causing problems in molding.

In addition, when the mixing chamber 2 is directly connected to the aftermixer, the protrusion can be removed by advancing the tip of the spool 7 to the end of the mixing chamber 2. Since the mixed raw material remaining around the protrusion 9 can be completely discharged to the outside of the mixing chamber 2, this part can be removed together with the runner gate after the mold is opened, but even in that case, there is a thin wall near the base of the protrusion 9. The cured product tends to adhere to the mold and is fed into the mold during the next injection, causing defects.

On the other hand, if the second mixing chamber 10 is provided perpendicularly to the mixing chamber 2, the tip surface of the spool 7 cannot be advanced to the end of the mixing chamber 2. If this is done, the protrusion 9 will protrude into the second mixing chamber 10, so the mixed raw material around the protrusion 9 will remain in the mixing chamber 2, harden at that position, and be used for the next injection. becomes an obstacle.

The present invention attempts to solve such problems, and aims to prevent the raw material injected from one injection port from entering the opposite injection port when measuring each raw material. It is something.

[Structure of the idea]

(Means for Solving the Problems) The present invention provides a plurality of injection ports 4 at opposing positions of the mixing chamber 2 for injecting different liquid synthetic resin components that react with each other, and In a mixing head for reaction injection molding, a mixing head for reaction injection molding is provided with a spool 7 that can move forward and backward to open or close the injection port 4 with respect to the mixing chamber 2 in the mixing chamber 2. A movable projecting body 13 is provided so as to be freely movable back and forth in the axial direction.

(Function) In the present invention, when measuring the raw material and discharging the raw material from either of the injection ports 4, the projecting body 13 is advanced to protrude from the tip of the spool 7, and
It is interposed between the plurality of injection ports 4 to prevent raw materials from directly entering.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

Since the basic configuration of this mixing head is the same as that shown in FIGS. 3 and 4, corresponding parts are designated by the same reference numerals and detailed explanation will be omitted.

A cylindrical collision prevention protrusion 13 having a smaller diameter than the outer diameter of the spool 7 is provided coaxially in the axial direction of the center of the spool 7 of the mixing chamber 2 so as to be movable forward and backward.

And in mixing chamber 2,
The protruding body 13 retreats into the spool 7 and the spool 7 moves forward with their tip surfaces flush with each other, and the circulation groove 8 of the spool 7 connects the injection port 4 of the injection nozzle 3 and the circulation port 6 of the circulation path 5. and the injection position where the spool 7 is retracted with the protruding body 13 retracted into the spool 7 and the injection port 4 of the injection nozzle 3 is opened to the mixing chamber 2 (Fig. 1). ),
Three states are possible: a metering operation position (FIG. 2) in which the spool 7 is retracted and the protrusion 13 is advanced.

Then, during circulation, the raw material is circulated at the circulation position as in the conventional case.

Further, during injection molding, as in the conventional method, as shown in FIG. 1, the spool 7 and the projecting body 13 are moved back, and different raw materials are caused to collide head-on from the injection port 4 of each injection nozzle 3.

Next, when measuring the raw material prior to injection molding, as shown in FIG. 2, the spool 7 is moved backward, and the protrusion 13 is moved forward to be interposed between the injection ports 4. By performing the metering operation in this state, the raw material on the side of the injection nozzle 3 that is injecting is prevented from directly entering the injection port 4 of the other injection nozzle 3 in the no-load state that is not injecting, and the raw material is A metering operation can be performed by being guided outside the mixing chamber 2.

Regarding cleaning, if the mixing chamber 2 is directly connected to the after mixer, the protrusion 13 is moved back so that it is flush with the tip surface of the spool 7, and the tip surface of the spool 7 is cleaned. By advancing the mixing chamber 2 to the end, the mixed raw material can be completely discharged out of the mixing chamber 2. Furthermore, when the second mixing chamber 10 is provided perpendicularly to the mixing chamber 2, In this case, the tip surface of the spool 7 can be advanced to the end of the mixing chamber 2 with the protrusion 13 retracted in the same manner as above, so that the mixed raw material does not remain around the protrusion 13. , it will not harden at that location and will not interfere with the next injection.

[Effect of idea]

According to the present invention, when discharging the raw material, the spool of the mixing chamber is moved back and the protruding body is moved forward and interposed between each injection port, so that the raw material on the injection port side is injected into the other injection port. The material does not directly enter the injection port in an unloaded state, and the raw material can be measured without any trouble.

[Brief explanation of the drawing]

1 and 2 are sectional views showing one embodiment of the mixing head of the present invention, and FIGS. 3 and 4 are sectional views of a conventional mixing head. 2... Mixing chamber, 4... Injection port,
7... Spool, 13... Projection.

Claims (1)

[Claims for Utility Model Registration] A mixing chamber is provided with a plurality of injection ports at opposing positions for injecting different liquid synthetic resin components that react with each other, and the injection ports are provided within the mixing chamber. In a mixing head for reaction injection molding in which a spool that can be opened or closed with respect to a bar is provided so as to be able to move forward and backward, a protrusion that can come out and go in and out from the tip of the spool is provided in the spool so that it can move back and forth in the axial direction. A mixing head for reaction injection molding with special features.