JPH0729325B2 - Stock solution changer for mixing head for reaction injection molding - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial 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 reaction injection molding mixing head will be described with reference to FIGS.

First, the mixing head 1 will be described.

Reference numeral 2 denotes a head body, and a mixing chamber 3 is formed in the center of the head body 2 so as to penetrate therethrough.
A hydraulic cylinder 4 is attached to the lower part in the drawing, and a cleaning shaft 6 integrated with a piston 5 of the hydraulic cylinder 4 is fitted in the mixing chamber 3 so as to be able to slide forward and backward.

Further, three nozzle devices 11A, 11B and 11C are mounted on the upper part of the head main body 2 in the drawing with directivity orthogonal to the mixing chamber 3. Although not shown, each of these nozzle devices 11A, 11B, 11C has a supply port on the outer peripheral portion, and also has a discharge port, which is communicated with this supply port via a communication path, on the tip surface. The discharge port faces the mixing chamber 3. Further, the discharge port is closed by a nozzle needle valve urged by a spring so as to be openable and closable, and the nozzle needle valve is operated and opened by fluid pressure.

Then, as shown in FIG. 6, in the two nozzle devices 11A and 11B facing each other, the supply ports are respectively provided in the head main body 2
Via the supply passages 12A, 12B formed inside and the supply passages 13A, 13B outside the head body 2, they are connected to the outlets of the tank bodies 14A, 14B. Pumps 15A and 15B and strainers 16A and 16B are provided in the middle of the supply passages 13A and 13B. In addition, the return passages 17A and 17B formed in the head body 2 so as to face the mixing chamber 3
The tank body 14A, the inlet of the tank 14B is connected in communication via the return passage 18A, 18B outside the head body 2, the discharge port of the nozzle device 11A, 11B and the return passage 17A, 17B ,.
Grooves formed on the outer periphery of the cleaning shaft 6
Communication is established via 19A and 19B. In addition, different reactive stock solutions (hereinafter referred to as A solution and B solution) are stored in the two tank bodies 14A and 14B, respectively.

On the other hand, as shown in FIG. 5, in one nozzle device 11C orthogonal to the two nozzle devices 11A and 11B facing each other, a supply passage 21 and a head body 2 having a supply port formed in the head body 2 are provided. It is connected to three pigment coloring devices 23a, 23b, 23c as stock solution supplying devices via external supply passages 22a, 22b, 22c, respectively. The supply passages 22a, 22b,
On-off valves 24a, 24b, 24c are provided in the middle of 22c, respectively. The pigment coloring devices 23a, 23b, 23c are tank bodies 25a that store pigments such as red, blue, and black (hereinafter, referred to as Ca liquid, Cb liquid, and Cc liquid) as different raw materials.
25b, 25c, and these tank bodies 25a, 25
Pumps 27a, 27b, 2 having push-out pistons 26a, 26b, 26c in which b, 25c and the supply passages 22a, 22b, 22c are connected to each other.
Equipped with 7c.

In the following description, the subscripts a, b, and c in the reference numerals are omitted unless it is necessary to make a distinction.

Then, in the circulation state shown in FIGS. 5 and 6, hydraulic pressure is applied to the hydraulic cylinder 4 as indicated by the two arrows on the lower side of FIG. 6, the cleaning shaft 6 is moving forward, and mixing is performed. The chamber 3 is blocked. Then, as shown in FIG. 6, the liquid A and the liquid B are the tank bodies 14A and 14B.
From the supply passages 12A, 12B, 13A, 13B, the nozzle devices 11A, 11B, the groove portions 19A, 19B of the cleaning shaft 6 and the return passage 17
It circulates through the paths leading to the tank bodies 14A, 14B again via A, 17B, 18A, 18B. At this time, as shown in FIG. 5, the discharge port of the C liquid nozzle device 11C is blocked by the cleaning shaft 6.

Further, in the injection mixed state shown in FIGS. 7 and 8, hydraulic pressure is applied to the hydraulic cylinder 4 as indicated by the lower two arrows in FIG. 8, and the cleaning shaft 6 is retracted. Then, as shown in FIG. 8, the liquid A and the liquid B are supplied from the supply passages 13A, 13B, 12A, 12B through the nozzle devices 11A, 11B,
These nozzle devices 11A and 11B are respectively discharged into the mixing chamber 3 through the discharge ports, and while being mixed and collided in the mixing chamber 3, the tip opening thereof causes a mold (not shown) in which the mixing head 1 is mounted. It is discharged through the aftermixer and the gate into the cavity.

At that time, with one of the opening / closing valves 24a, 24b, 24c opened and the other two closed, the pushing piston 26 of the pigment coloring device 23 corresponding to the opened opening / closing valve 24 is lowered. As shown in FIG. 7, liquid C, which is a pigment of a desired color, is jetted into the mixing chamber 3 from the discharge port of the nozzle device 11C through the supply passages 22 and 21 and the nozzle device 11C. A molded product colored with a desired color can be obtained by mixing with the liquid and the liquid B.

When changing the coloring of the molded product, for example, when changing from red to blue, the opening / closing valve 24b is opened and the other opening / closing valves 24a and 24c are both closed. In this state, the injection operation of the mixing head 1 is repeated for 2 to 3 shots while lowering the extrusion piston 26b of the pigment coloring device 23b. This injection is a blank discharge without an insert for the purpose of color change, not for the purpose of obtaining a molded product.
The Ca liquid, that is, the red pigment is discharged from the supply passage 21 and the nozzle device 11C, the Cb liquid, that is, the blue pigment eventually reaches the discharge port at the tip of the nozzle device 11C, and a molded product colored in blue is obtained from the next shot. be able to.

At that time, if the liquids A and B are stopped and only the liquid C is discharged for color change, the liquid C cannot be solidified in the aftermixer, the gate, and the cavity, and remains liquid. It becomes difficult to remove. Therefore, although only the C liquid needs to be discharged from the supply passage 21 and the nozzle device 11C, the A, B, and C3 liquids should be combined and discharged in a blank state, and wait for the liquid to solidify. I have to. Therefore, the A and B liquids are wasted.

By the way, in the normal color change of the injection molding, the nozzle device is separated from the mold and the ink is discharged to the outside of the mold without any waiting time for solidification. On the other hand, in the reaction injection molding, the mixing head 1 is integrally provided with the nozzle device 11, and the mixing head 1 and the mold are always in close contact with each other.
Since the nozzle device and the mold do not come into contact with and separate from each other as in ordinary injection molding, the mixing head 1 must be removed from the mold in order to discharge the unnecessary stock solution outside the mold. However, attaching and detaching the mixing head 1 is troublesome, and when molding different colored products with the same mold,
It is more advantageous to perform idle discharge into the mold, wait for the solidification, and release the mold, rather than detaching the mixing head 1.

(Problems to be Solved by the Invention) As described above, in the conventional stock solution changing device for the reaction injection molding mixing head, for example, when the color is changed, the injection operation of the mixing head is repeated for 2-3 shots. Therefore, the old C liquid before color change, that is, the pigment is discharged from the mixing chamber to the cavity, and the new pigment reaches the discharge port of the nozzle device.
There has been a problem that the loss of liquids A and B, that is, other raw materials that occur during the three shots of idle discharge, and the time loss due to the solidification waiting time of the raw materials that have been idle discharged into the cavity are large. In particular, under the situation of high-mix low-volume production, which is a recent trend, the frequency of color change is intense, so performing the above-described blank discharge is disadvantageous from the viewpoint of productivity and economy.

The present invention is intended to solve the above-described problems, and provides a stock solution replacement device for a reaction injection molding mixing head, which can reduce loss of stock solution other than the stock solution to be switched and time point loss in stock solution replacement. That is the purpose.

[Structure of Invention]

(Means for Solving Problems) A stock solution changing device for a reaction injection molding mixing head according to the present invention has a mixing chamber 3 and an opening / closing discharge port 36 facing the mixing chamber 3, and is connected to the discharge port 36. A mixing head 1 having a nozzle device 11C having a supply port 34 communicating with a passage 35 is provided, and the nozzle head 11C communicates with the outside of the mixing head 1 from the vicinity of a discharge port 36 of the communication passage 35 to open and close. Discharge passages 41, 42 having a valve 44 are provided, and at least two stock solution supply devices for supplying different stock solutions to the supply port 34 of the nozzle device 11C via the supply paths 22a, 22b, 22c, 21.
23a, 23b, 23c and a pressurized fluid supply device 55 for supplying a pressurized fluid for discharging the stock solution in the supply passage 21 and the communication passage 35 of the nozzle device 11C are connected, and further, the supply A switching valve device 56 for selectively communicating the at least two stock solution supply devices 23a, 23b, 23c and the pressurized fluid supply device 55 with the supply port 34 of the nozzle device 11C in the middle of the passages 22a, 22b, 22c, 21. Is provided.

(Function) In the stock solution changing device for the mixing head for reaction injection molding of the present invention, when switching the raw materials such as pigments for changing the color of the molded product, first, the opening / closing valve 44 in the discharge passages 41, 42 is opened. At the same time, the pressurized fluid supply device 55 is connected to the supply port 34 of the nozzle device 11C by the switching valve device 56 in the supply passages 21, 22a, 22b, 22c, and the pressurized fluid is connected to the supply passage 21 and the nozzle device 11C. The supply passage 21 and the communication passage are sent out into the passage 35.
A discharge passage through which the raw material inside the 35 is communicated from the vicinity of the discharge port 36 of the communication passage 35 of the nozzle device 11C to the outside of the mixing head 1.
Discharge via 41, 42. Next, the stock solution supply device 23 that supplies new raw material to the supply port 34 is made to communicate by the switching valve device 56, and the new raw material is sent into the supply passages 21 and 22 and the communication passage 35 of the nozzle device 11C to discharge the nozzle device 11C. Fill up to near exit 36. Next, the on-off valve 4 in the discharge passages 41, 42
Although molding is started by closing 4, the new raw material is discharged into the mixing chamber 3 from the discharge port 36 of the nozzle device 11C at this time.

(Example) An example of a stock solution changing device for a reaction injection molding mixing head according to the present invention will be described below with reference to FIGS. 1 to 4. In the following description, the parts having the same structures as those of the device shown in FIGS. 5 to 8 are designated by the same reference numerals, and the description thereof will be omitted.

First, the nozzle device 11C that discharges the C liquid, which is a pigment such as red, blue, or black as a raw material, will be described with reference to FIG.

Reference numeral 31 is a tubular outer shell, and a tubular nozzle body 32 is fitted and fixed to the tip side (left side in the drawing) inside the outer shell 31. A nozzle needle valve 33 as a body is fitted so as to slide forward and backward in the axial direction. A supply port 34 is formed on the peripheral surface of the outer shell 31, while the nozzle body 32 has the supply port 34.
Is formed in the peripheral portion, and a small-hole-shaped discharge port 36 communicating with the communication passage 35 and closed by the nozzle needle valve 33 so as to be openable and closable is formed at the tip. There is. Further, the nozzle needle valve 33 is always biased by a spring (not shown) in the direction of closing the discharge port 36, but it is designed to be opened by fluid pressure against the biasing force of the spring. ing.

Further, on the outer peripheral portions of the tips of the outer shell body 31 and the nozzle body 32, a liquid pool portion near the discharge port 36 at the tip portion of the communication passage 35.
A discharge port 38 is formed so as to communicate with 37. The inner peripheral surface of the outer shell 31 and the nozzle body are sandwiched by the discharge port 38.
An O-ring 39 for sealing is provided between the outer peripheral surface of 32 and the outer peripheral surface of 32.

The discharge port 38 of the nozzle device 11C is, as shown in FIGS. 1 and 3, a discharge passage 41 formed inside the head body 2 of the mixing head 1 and a discharge passage provided outside the head body 2. It is connected to the container 43 via 42 and.
An opening / closing valve for connecting or disconnecting the discharge port 38 and the container 43 is provided in the discharge passage 42 outside the head body 2.
44 are provided.

Further, the supply passage 21 in the head main body 2 that communicates with the supply port 34 of the nozzle device 11C is communicatively connected to the outflow port 52 of the three-way switching valve 51. Furthermore, one of the two inflow ports 53, 54 selectively communicating with the outflow port 52 of the three-way switching valve 51 has one of the three inflow ports 53, 54 with three pigment coloring devices 23a, 23b, Supply passages 22a, 22b, 2 connected to 23c
2c are connected via open / close valves 24a, 24b, 24c, respectively. Further, the other inlet of the three-way switching valve 51
An air supply device 55 as a pressurized fluid supply device is communicatively connected to 54. Then, the three-way switching valves 51 and 3
One opening / closing valve 24a, 24b, 24c is provided for the air supply device 55 and the three pigment coloring devices 23 to the supply port 34 of the nozzle device 11C.
A switching valve device 56 that selectively communicates any one of a, 23b, and 23c is configured.

Next, a procedure for switching the pigment for changing the color of the molded product will be described. Here, the case where the color is changed from red to blue, that is, the case where the Ca liquid is changed to the Cb liquid will be described as an example.

As shown in FIG. 1, the mixing chamber 3 is kept closed by the cleaning shaft 6. At this time, as shown in FIG. 2, other reactive undiluted liquids A and B are circulating. Then, as shown in FIG. 1, the opening / closing valve 44 in the discharge passage 42 is opened and the air supply device is provided to the outflow port 52 in the three-way switching valve 51.
The inflow port 54 to which 55 is connected communicates. Then, the air as the 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 remains in the supply passage 21 and the communication passage 35 before switching. The Ca liquid is entirely discharged to the outside of the mixing head 1 through the discharge port 38 and the discharge passages 41, 42 of the nozzle device 11C, passes through the opening / closing valve 44, and then 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, in the three-way switching valve 51, the outflow port 52 is connected to the inflow port 53 to which the pigment coloring devices 23a, 23b, 23c are connected, and the Cb liquid supply passage 22b is opened and closed. The valve 24b is opened, and the open / close valves 24a, 24c in the other supply passages 22a, 22c are closed. At the same time, Cb liquid pigment coloring device 23b
The Cb liquid is sent out by driving the extrusion piston 26b of. The Cb liquid sent out is supplied to the supply passage 21 and the communication passage 3 of the nozzle device 11C.
The liquid 5 is filled up to the liquid reservoir 37 in the vicinity of the discharge port 36, and then starts to flow into the container 43 through the discharge passages 41 and 42 and the opening / closing valve 44, and the replacement of the Ca liquid with the Cb liquid is completed.

At this stage, the opening / closing valve 44 in the discharge passage 42 is closed and molding is started. That is, the cleaning shaft 6 is retracted so that the A liquid, the B liquid, and the Cb liquid are separated from each other by the nozzle devices 11A and 11A.
B and 11C are respectively discharged into the mixing chamber 3 and mixed, and then discharged into the cavity of the mold,
A blue molded product is molded.

According to the above configuration, in order to switch the C liquid, the A liquid and the B liquid are also discharged when the C liquid before switching in the supply passage 21 and the communication passage 35 of the nozzle device 11C is replaced with new C liquid. Since there is no need to do so, there is no loss of undiluted solution A and solution B. Further, since the C liquid is discharged to the outside of the mixing head 1 through the exclusive discharge passages 41 and 42, unlike the case where it is discharged into the cavity of the mold, the solidification waiting time is not required and the time loss is reduced. It Along with this, switching of the C liquid can be performed by operating the valves 24a, 24b, 24c, 44, 51,
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, the supply passage 21 and the nozzle device 11
Air was used as the pressurized fluid for discharging the C liquid in the C communication passage 35, but if the liquid is discharged by Freon instead of air according to the concentration of the C liquid, that is, the pigment, the discharge time can be shortened. it can.

Further, if the liquid C is used as a reactive stock solution instead of the pigment and the pigment coloring devices 23a, 23b, and 23c are stock solution supply devices for supplying the C solution having different raw material components, molded articles having different physical properties can be obtained by selection. You can Even in this case, the stock solution can be changed without performing idle discharge into the mold.

〔The invention's effect〕

According to the present invention, a discharge passage having an opening / closing valve is provided which communicates with the outside of the mixing head from the vicinity of the discharge port of the communication passage of the nozzle device in which a plurality of stock solution supply devices are connected to the supply port of the nozzle device. Since the pressurizing fluid supply device for discharging the stock solution in the supply passage and the communication passage to the supply port through the discharge passage and the stock solution supply device can be selectively communicated by the switching valve device, when changing the raw material, There is no need to solidify the raw material that has been discharged in a blank as in the case of empty discharge into the mold. Therefore, there is no loss of undiluted solution other than the undiluted solution to be switched, and time loss can be reduced, simplifying the undiluted solution replacement work. Can be converted.

[Brief description of drawings]

FIG. 1 shows an embodiment of a stock solution changing device for a reaction injection molding mixing head according to the present invention, and is an explanatory sectional view when supplying pressurized fluid during stock solution replacement, and FIG. 2 is a sectional view taken along line II-II of FIG. ,
FIG. 3 is an explanatory cross-sectional view at the time of supplying undiluted solution in diluting undiluted solution,
FIG. 4 is a side view showing a cross section of a part of the above nozzle device, FIG. 5 is an explanatory cross sectional view showing an example of a conventional reaction injection molding mixing head, and FIG. 6 is a cross section taken along line VI-VI of FIG. Figure,
FIG. 7 is an explanatory sectional view of the same jet injection mixing, and FIG. 8 is a sectional view taken along the line VIII-VIII of FIG. 1 ... Mixing head, 3 ... Mixing chamber, 11c ... Nozzle device, 23a, 23b, 23c ... Pigment coloring device as stock solution supply device, 34 ... Supply port, 35 ... Communication passage,
36 ... Discharge port, 41, 42 ... Discharge passage, 44 ... Open / close valve, 55 ... Air supply device as pressurized fluid supply device, 56
...... Switching valve device.

Claims (1)

[Claims] 1. A mixing head comprising: a mixing chamber; and a nozzle device having an opening / closing discharge port facing the mixing chamber and having a supply port communicating with the discharge port via a communication path. A discharge passage having an opening / closing valve is provided so as to communicate with the outside of the mixing head from the vicinity of the discharge port of the communication passage, and at least two stock solutions that supply different stock solutions to the supply port of the nozzle device via the supply paths. A supply device is connected to a pressurized fluid supply device that supplies a pressurized fluid for discharging the stock solution in the supply passage and in the communication passage of the nozzle device, and the at least two stock solutions are provided in the middle of the supply passage. A switching valve device for selectively communicating the supply device and the pressurized fluid supply device with the supply port of the nozzle device is provided. A stock solution replacement device for reaction injection molding mixing heads.