JPH01105714A - Stock liquid changing device of mixing head for reaction injection molding - Google Patents

Abstract

PURPOSE:To reduce the loss of stock liquid and time loss by a method wherein an exhaust passage having an on-off valve is provided in the communicating passage of a nozzle device and a pressurizing fluid supplying device, which exhausts the stock liquid in a supplying passage and in the communicating passage, and a stock liquid supplying device are selectively communicated by means of a change-over valve device. CONSTITUTION:The exhaust port of a nozzle device 11c is connected through an exhaust passage 41, which is formed within the head main body 2 of a mixing head 1 and an exhaust passage 42, which is provided outside the head main body 2, to a vessel 43. An on-off valve 44, which communicates or cuts of the exhaust port and the vessel 43 with or from each other, is provided in the midway of the exhaust passage 42. Further, a supplying passage 21 in the head main body 2 is communicatingly connected to the efflux port 52 of a 3-way change-over valve 51, to one influx port 53 out of two influx ports 53 and 54 of which three pigmenting devices 23a, 23b and 23c serving as stock liquid supplying devices are connected through on-off valves 24a, 24b and 24c respectively. Furthermore, an air supplying device 55 serving as a pressurizing fluid supplying device is communicatingly connected to the other influx port 54.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to a stock solution changing device for a reaction injection molding mixing head for switching stock solutions such as pigments in reaction injection molding (RIM). .

(Prior Art) An example of a conventional stock solution changing device for a mixing head for reaction injection molding will be described with reference to FIGS. 5 to 8.

First, the mixing head 1 will be explained.

Reference numeral 2 denotes a head body, and a mixing chamber 3 is formed through the head body 2 in the center thereof.
A hydraulic cylinder 4 is mounted at the bottom in the drawing, and a cleaning shaft 6 integral with a piston 5 of the hydraulic cylinder 4 is fitted into the mixer rung chamber 3 so as to be able to move back and forth in vibration.

Further, three nozzle devices 11^, 11B, and 11C are installed at the upper part of the head body 2 in the drawing, respectively, with directionality perpendicular to the mixing chamber 3. These nozzle devices 11A.

Although not shown, each of 11B and 11C has a supply port on the outer periphery and a discharge port connected to the supply port via a communication path on the distal end surface. It faces the mixing chamber 3. Also,
The discharge port is opened and closed by a nozzle needle valve biased by a spring, and is opened when the nozzle needle valve is actuated by fluid pressure.

As shown in FIG. 6, in the two opposing nozzle devices 11A and 11B, supply passages 128 each have a supply port formed in the head body 2.

12B and supply passage 13A outside the head main body 2, 1
3B, the tank bodies 148 are connected to the outlet of the tank body 14B. Note that the supply passages 13A, 1
In the middle of 3B are pumps 15^, 15B and sliders 1 to 16A.

16B is provided. Further, the tank body 14A is connected to the reflux passages 17A, 17B formed in the head body 2 facing the mixing chamber 3 via reflux passages 18A, 18B outside the head body 2.

The inlet of the nozzle device 11A and the discharge port of the nozzle device IIB are connected to the recirculation passage 17A.

17B are communicated with each other through grooves 19A and 19B formed on the outer circumference of the cleaning shaft 6. And both tank bodies 14A.

14B contains different reactive stock solutions (hereinafter referred to as A solution).
(referred to as liquid B) are stored respectively.

On the other hand, as shown in FIG. 5, in one nozzle device 11C orthogonal to the two opposing nozzle devices 11A and 11B, a supply port is formed in the head body 2 and a supply passage 21 is formed in the head body 2. Outer supply passage 22a
, 22b, 22c, three pigment coloring devices 23a, 23b, 23c as stock solution supply devices.
are connected to each. Note that the supply passage 22a
, 22b, and 22c are provided with on-off valves 24a, 24b, and 24c, respectively.

Further, the pigment coloring devices 23a, 23b, 23
c is equipped with tank bodies 25a, 25b, and 25c that store pigments such as red, blue, and black (hereinafter referred to as Ca liquid, Cb liquid, and Cc liquid) as different raw materials, and these tank bodies 25a, 25b, 2
5c and the supply passages 22a, 22b, 22c are connected in communication with each other, and the extrusion pistons 26a, 26
b, pump 21a with 26c.

27b and 27c.

In the following description, the subscripts a, b, and c in the symbols will be omitted unless there is a need to distinguish them.

In the circulation state shown in FIGS. 5 and 6, hydraulic pressure is applied to the hydraulic cylinder 4 as shown by the two arrows at the bottom of FIG. 6, and the cleaning shirt 6 moves forward. , blocking the mixing chamber 3. and,
As shown in FIG. 6, liquid A and liquid B are stored in the tank body 14A.
, 14B to supply passages 12A, 12B, 1
3A, 13B, nozzle device 11^.

11B1 Groove portion 19A of cleaning shaft 6, 1
9B and reflux passages 17A, 17B, 18A
, 18B and then again to the tank bodies 14A, 14B, respectively. At this time,
As shown in FIG. 5, the discharge port of the nozzle device 11c for the C liquid phase is closed by the cleaning shaft 6.

In addition, in the injection mixing state shown in FIGS. 7 and 8, hydraulic pressure is applied to the hydraulic cylinder 4 as shown by the two arrows at the bottom of FIG. 8, and the cleaning shaft 6 is retracted. As shown in FIG. 8, liquid A and liquid B are supplied through supply passages 13^ and 13B.

12A, 12B to nozzle devices 11A, 11B
Then, the discharge is discharged from the discharge ports of these nozzle devices 11^ and 11B into the mixing chamber 3, and while colliding and mixing within the mixing chamber 3, the mold (see Fig. (not shown) through an aftermixer and gate.

At this time, by opening any one of the on-off valves 24a, 24b, and 24c and closing the other two, the extrusion piston 26 of the pigment coloring device 23 corresponding to the opened on-off valve 24 is lowered. , supply passage 22.
21 and the nozzle device 11c, this nozzle device 1
From the discharge port 1c, liquid C, which is a pigment of a desired color, flows into the seventh
As shown in the figure, it is injected into the mixing chamber 3 and mixed with liquid A and liquid B, thereby making it possible to obtain a molded article colored in a desired color.

When changing the coloring of the molded product, for example from red to blue, the on-off valve 24b is closed and the other on-off valves 24a and 24C are both closed. In this state, while lowering the extrusion piston 26b of the pigment coloring device 23b, the injection operation of the mixing head 1 is performed from 2 to 2.
Repeat 3 shots. This injection is empty discharge without an insert for the purpose of changing the color rather than cleaning the molded product, and thereby the supply passage 21 and the nozzle device 11C
The Ca liquid, that is, the red pigment is discharged, and the Cb liquid, that is, the blue pigment, eventually reaches the discharge port at the tip of the nozzle device 11C, and a blue-colored molded product can be obtained from the next shot.

At that time, if liquids A and B are stopped and only liquid C is discharged emptyly for color change, liquid C will not be able to solidify in the aftermixer, gate, or cavity and will remain in liquid form. It becomes difficult to remove. Therefore, the supply passage 21 and the nozzle device 1? C must appear for the first time from within c.
Even though there are only three liquids, it is necessary to combine liquids A, B, and C, empty discharge, wait for them to solidify, and then take them out. Therefore, liquids A and B are wasted.

By the way, in normal injection molding color changing, the nozzle device is separated from the mold and empty discharge is performed outside the mold, so there is no need for a solidification waiting time. On the other hand, in reaction injection molding, the nozzle device 11 is integrally provided in the mixing head 1, and the mixing head 1 and the mold are always in close contact with each other.
Unlike normal injection molding, the nozzle device and the mold do not come into contact with each other, so the mixing head 1 must be removed from the mold in order to discharge the unnecessary stock solution out of the mold. However, it is troublesome to attach and detach the mixing head 1, and when molding products with different colors in the same mold,
Rather than removing the mixing head 1, it is more advantageous to empty the mixture into the mold and release it after solidification.

(Problems to be Solved by the Invention) As described above, in the conventional stock solution changing device for a mixing head for reaction injection molding, when changing colors, for example, the injection operation of the mixing head must be repeated for 2 to 3 shots. Due to this, the old C liquid, that is, the pigment before color change, was discharged from the mixing chamber into the cavity, and the new pigment reached the discharge port of the nozzle device.
There have been problems in that there is a large loss of liquids A and B, ie, other raw materials, which occur when three shots are idly discharged, and there is a large time loss due to the waiting time for solidification of the raw materials idly discharged into the cavity. Particularly in the recent trend of high-mix, low-volume production, color changes are frequent, so it is disadvantageous in terms of productivity and economy to perform the above-mentioned dry discharge.

The present invention aims to solve the above-mentioned problems, and provides a stock solution changing device for a reaction injection molding mixing head that can reduce the loss of stock solutions other than the stock solution being switched and the time point loss when changing the stock solution. The purpose is to

(Structure of the Invention) (Means for Solving the Problems) The stock solution changing device for a mixing head for reaction injection molding of the present invention has a mixing chamber 3 and a discharge port 36 that can be opened and closed facing the mixing chamber 3. Mixing head 1 having a nozzle device 11C having a supply port 34 communicating with a discharge port 36 via a communication path 35
and a discharge port 3 of the communication path 35 of the nozzle device 11C.
A discharge passage 41, 42 having an on-off valve 44 is provided which communicates with the outside of the mixing head 1 from near the nozzle device 11G, and a supply passage 22a is provided at the supply port 34 of the nozzle device 11G.

At least two stock solution supply devices 23a, 23 supplying different stock solutions via 22b, 22c, 21
b, 23c are connected to a pressurized fluid supply device 55 that supplies pressurized fluid for discharging the stock solution in the supply passage 21 and the communication passage 35 of the nozzle device 11C, and further, the supply passage 22a , 22b , 22
c, the at least two stock solution supply devices 23a, 23b in the middle of 21;

23C and the pressurized fluid supply device 55 to the nozzle device 11.
A switching valve device 56 that selectively communicates with the supply port 34 of C is provided.

(Function) In the stock solution changing device for a mixing head for reaction injection molding of the present invention, when switching raw materials such as pigments for changing the color of a molded product, first, the opening/closing valve 44 in the discharge passage 41, 42 is
While opening the supply passages 21° 22a, 22b
, nozzle assembly M11C by the switching valve device 56 in 22c.
A pressurized fluid supply device 55 is communicated with the supply port 34 of the
The raw materials in the supply passage 21 and the communication passage 35 before switching are discharged from the vicinity of the discharge port 36 of the communication passage 35 of the nozzle device 11c through the discharge passages 41 and 42 that communicate with the outside of the mixing head 1.

Next, the switching valve device @56 connects the stock solution supply device 23 that supplies a new raw material to the supply port 34, and sends the new raw material into the supply passage 21, 22 and the communication passage 35 of the nozzle device 11C. It is filled up to the vicinity of the discharge port 36. Next, the on-off valves 44 in the discharge passages 41, 42 are closed to start molding, but at this time new raw materials are discharged into the mixing chamber 3 from the discharge port 36 of the nozzle device 11C.

(Example) Hereinafter, an example of the stock solution changing device for a reaction injection molding mixing head of the present invention will be described based on FIGS. 1 to 4. In the following description, parts having the same structure as those of the apparatus shown in FIGS. 5 to 8 will be denoted by the same reference numerals, and the description thereof will be omitted.

First, the nozzle device @11C for discharging liquid C, which is a pigment of red, blue, black, etc. as a raw material, will be explained with reference to FIG.

Reference numeral 31 denotes a cylindrical outer shell, and a cylindrical nozzle body 32 is fitted and fixed on the distal end side (left side in the drawing) of this outer shell 31. A nozzle needle valve 33 as a body is fitted so as to be able to slide forward and backward in the axial direction. A supply port 34 is provided on the peripheral surface of the outer shell 31.
On the other hand, the nozzle main body 32 has a communication passage 35 formed at its periphery that communicates with the supply port 34 , and a nozzle needle valve 33 that communicates with the communication passage 35 . A small hole-shaped discharge port 36 that can be opened and closed is formed at the tip. Further, the nozzle needle valve 33 is always biased by a spring (not shown) in the direction of closing the discharge port 36, but is opened by fluid pressure against the biasing force of the spring. ing.

Further, a discharge port 38 is formed penetratingly in the outer peripheral portion of the tip of the outer shell 31 and the nozzle body 32 so as to communicate with a liquid reservoir 37 near the discharge port 36 at the tip of the communication path 35 . Note that an O-ring 39 for sealing is provided between the inner peripheral surface of the outer shell 31 and the outer peripheral surface of the nozzle body 32 with the discharge port 38 in between.

The discharge port 38 of the nozzle device 111c is the first
As shown in FIG. 3, a discharge passage 41 formed in the head body 2 of the mixing head 1 and the head body 2
It is connected to a container 43 via a discharge passage 42 provided outside. Note that the discharge passage 42 outside the head main body 2
An opening/closing valve 44 is provided midway between the discharge port 38 and the container 43 to communicate with or shut off the same.

Further, the supply passage 21 in the head body 2 that communicates with the supply port 34 of the nozzle device 11C is connected to the outlet 52 of the three-way switching valve 51. Further, one of the two inlets 53, 54 selectively communicating with the outlet 52 of the three-way switching valve 51 has three pigment coloring devices 23a and 23b as stock solution supply devices.
, 23c.

22b and 22c are opening/closing valves 24a and 22c, respectively.
24b.

It is connected via 24C. Furthermore, an air supply device 55 serving as a pressurized fluid supply device is connected to the other inlet 54 of the three-way switching valve 51 . Then, the three-way switching valve 51 and the three opening/opening valves 24
a, 24b, and 24c are the nozzle device 11
A switching valve device 56 is configured to selectively connect the air supply device 55 and any one of the three pigment coloring devices 123a, 23b, and 23c to the supply port 34 of C.

Next, a procedure for switching pigments for changing the color of a molded product will be explained. Here, an example will be described in which the color is changed from red to blue, that is, the case is changed from Ca liquid to CB liquid.

As shown in FIG. 1, the mixing chamber 3 is kept in a state where the cleaning shaft 6 is closed. At this time, as shown in FIG. 2, other reactive stock solutions A and B are being circulated. Then, as shown in FIG. 1, the on-off valve 44 in the discharge passage 42 is opened, and the inlet 54 connected to the air supply device 55 is communicated with the outlet 52 of the three-way switching valve 51. Then, air as a pressurized fluid is sent out from the air supply device 55 into the supply passage 21 in the head body 2 and the communication passage 35 of the nozzle device 11C, and the air remaining in the supply passage 21 and the communication passage 35 before switching is All of the Ca liquid is discharged to the outside of the mixing head 1 through the discharge port 38 and discharge passages 41 and 42 of the nozzle device 11c, and the on-off valve 44
After passing through, it flows into the container 43. In this way, the supply passage 21 and the communication passage 35 are cleaned.

Next, as shown in FIG. 3, pigment coloring devices 23a and 23b are installed at the outlet 52 of the three-way switching valve 51.

23c is connected to the inflow port 53, and
Open the on-off valve 24b in the cb liquid supply passage 22b,
Opening/closing valves 24a in other supply passages 22a, 22c
.

Close 24c. At the same time, the cb liquid pigment coloring device 23b
The extrusion piston 26b is driven to send out the CB liquid.

The sent out CB liquid flows through the supply passage 21 and the nozzle device J1.
There is a liquid reservoir 3 near the discharge port 36 in the communication path 35 of 1c.
7, and then begins to flow into the container 43 through the discharge passages 41, 42 and the on-off valve 44, completing the replacement of the Ca liquid with the CB liquid.

At this stage, close the on-off valve 44 in the discharge passage 42,
Molding begins. That is, the cleaning shaft 6
Liquid A, liquid B, and liquid CB are discharged from the nozzle devices 11A, 118, and 11C into the mixing chamber 3, respectively, and are mixed while being discharged into the cavity of the mold, forming a blue molded product. molded.

According to the above configuration, in order to switch the C liquid, the supply passage 21
Also, when replacing the C liquid before switching in the communication path 35 of the nozzle device 11C with a new C liquid, there is no need to discharge the A liquid and the B liquid as well. There is no loss. In addition, the C liquid is discharged through a dedicated discharge passage 41.
Since the mixture is discharged to the outside of the mixing head 1 via 42, unlike the case where the mixture is extracted into the cavity of a mold, there is no need for solidification time, and time loss is also reduced. Along with this, switching of liquid C is performed using valves 24a, 24b, 24.
c, 44. This can be done by the operation of 44.51, and the switching work can be simplified.

Furthermore, since the structure for switching the C liquid is simple and the number of equipment components is small, the switching work can be easily automated.

In the above embodiment, air was used as the pressurized fluid for discharging the C liquid in the supply passage 21 and the communication passage 35 of the nozzle device 11c, but depending on the concentration of C liquid, that is, the pigment, Freon or the like may be used instead of air. If it is discharged by this method, the discharge time can be shortened.

Furthermore, if the C solution is a reactive stock solution instead of a pigment, and the pigment coloring devices 23a, 23b, and 23c are stock solution supply devices that supply C solutions having different raw material components, depending on the selection,
Molded products with different physical properties can be obtained.

Even in this case, the stock solution can be replaced without empty discharge into the mold.

〔Effect of the invention〕

According to the present invention, a discharge passage having an on-off valve is provided to communicate with the outside of the mixing head from near the discharge port of the communication passage of the nozzle device to which a plurality of stock solution supply devices are connected to the supply port, and the discharge passage has an on-off valve. Since the pressurized fluid supply device that discharges the stock solution in the supply passage to the supply port and the communication passage through the discharge passage and the stock solution supply device can be selectively communicated by the switching valve device, when changing raw materials, There is no need to solidify the blankly discharged raw material, unlike when emptyly discharging it into a mold.Therefore, there is no loss of stock solutions other than the stock solution being switched, and time loss can also be reduced, simplifying the work of changing stock solutions. can be converted into

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of an embodiment of the stock solution change giM of the reaction injection molding mixing head of the present invention when pressurized fluid is supplied during stock solution change, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 of the same. , Fig. 3 is an explanatory cross-sectional view during the supply of the stock solution in the above stock solution replacement, Fig. 4 is a side view with a part of the same nozzle device in cross section, and Fig. 5 shows an example of a conventional mixing head for reaction injection molding. Explanatory sectional view, Figure 6 is vt-v of Figure 5 of the same
t sectional view, FIG. 7 is a yA sectional view at the time of injection and mixing as above, and FIG. 8 is a sectional view taken along the line -■ in FIG. 1. Mixing head, 3. Mixing tip v>bar, 11G -- Nozzle device, 23a, 23b. 23c...Pigment coloring device as stock solution supply device, 34
・・Supply port, 35・・Communication path, 36・・Discharge port, 41° 42・・Discharge path, 44・・Opening/closing valve, 55・・Air supply device as pressurized fluid supply device, 56・・Switching valve Device. -only 1- ``1hi''

Claims (1)

[Claims] (1) A mixing head including a mixing chamber and a nozzle device having a discharge port facing the mixing chamber that can be opened and closed and having a supply port communicating with the discharge port via a communication path, the communication path of the nozzle device A discharge passage having an on-off valve is provided that communicates with the outside of the mixing head from near the discharge port of the mixing head, and at least two stock solution supply devices supply different stock solutions to the supply port of the nozzle device via the supply passages. and a pressurized fluid supply device that supplies pressurized fluid for discharging the stock solution in the supply passage and the communication passage of the nozzle device, and the at least two stock solution supply devices are connected in the middle of the supply passage. A stock solution switching device for a mixing head for reaction injection molding, characterized in that a switching valve device is provided for selectively communicating the pressurized fluid supply device and the pressurized fluid supply device to the supply port of the nozzle device.