KR101388650B1 - An injection molding apparatus for urethane - Google Patents

Abstract

Disclosed is an injection apparatus for mold urethane by which a fixed quantity of a urethane material defoamed after being completely mixed using a batch tank is supplied to an injection machine. The injection apparatus for mold urethane according to the present invention includes: an injection machine for injecting a molten solution into a mold; a fixed quantity injection part having a piston vertically moving in a cylinder, wherein an outlet of the cylinder is connected to an inlet of the injection machine via an outlet tube; a batch tank to which an inlet of the cylinder is coupled via an inlet tube and in which mold urethane is stored; an inlet opening/closing valve and an outlet opening/closing valve which are installed at the inlet tube and the outlet tube, respectively, and perform reciprocal opening or closing operations; and a controller for controlling the injection machine, the fixed quantity injection part, the batch tank, the inlet opening and closing valve, and the outlet opening and closing valve. The batch tank is filled with nitrogen in order to prevent properties of the mold urethane from being changed and provide a jet pressure of the mold urethane. [Reference numerals] (130) Controller

Description

Injection method for casting urethane {An injection molding apparatus for urethane}

The present invention relates to an injection method for molding urethane, and more particularly, to an injection method for molding urethane that can be mass-produced using a newly developed new material so as not to quickly solidify when the main body of urethane and the curing agent are mixed.

Molding urethane generally refers to a method of casting by stirring the raw material and the curing agent.

The raw material and the curing agent of the mold urethane were stirred and poured into a mold preheated to an appropriate temperature (60 to 120 degrees), and the working time (curing time) was limited from 1 minute to 10 minutes. This reaction occurs when the raw material and the curing agent are stirred even though the temperature is not set, and there was a problem that the existing injection equipment and equipment to be equipped with mass production could not be used due to the hardening of the feeder line of the equipment.

Therefore, the method of pouring the mold into the mold within the predetermined curing time using the urethane casting machine for casting was the work method up to now, and the pulley and the oring were performed in the predetermined curing time using the hot plate press mold. Therefore, the urethane product for casting was not mass-produced, and the worker's work ability was an important variable factor in the physical properties.

On the other hand, the urethane that can control the curing time has recently been released, a material that does not cure for 4 to 24 hours instead of the current 1 to 10 minutes even after stirring the raw material and the curing agent has been released. There is a need to fabricate possible injection equipment.

Injection equipment generally refers to plastic injection devices such as PE, PP, and PC. Most of these materials are thermoplastic resins, which are one-component materials. Of course, there are also TPUs in the urethane series, but this material is only a one-component material that is melted at a predetermined temperature and injected into a mold.

Unlike the plastic injection device, the liquid silicone equipment called LSR is a silicone injection molding equipment using the concept of injection equipment. It supplies raw materials and hardeners to the equipment by using the dosing equipment, and then supplies the equipment to the injection equipment after stirring by using the STATIC MIXER. That's the way. This silicone injection equipment has already been developed and sold in foreign countries, and it is now time to localize and supply what was imported from foreign countries in Korea.

At this time, plastic injection is a method of melting raw material PALLET at a temperature of 200 to 250 degrees and dissolving it with a screw, and then cooling the material in a mold of 30 to 50 degrees. This material is a thermoplastic resin when the product is heated again. Reusable materials.

And LSR is a different concept from plastic injection. It is a method of supplying raw materials and hardeners at room temperature to equipment dosing, and then stirring them using a static mixer to supply them to the scourers to cure them in molds of 150 to 200 degrees. Though it is considered to be a temperature difference from plastic injection, the reaction structure and chemical formula are completely different concepts.

However, both the plastic injection equipment and the liquid silicone equipment were not available for injection of the molding urethane, and it was found that it is impossible to purchase and modify the current equipment. That is, the most important temperature control problem of urethane material could not be solved, and the mixed and degassed urethane should not be exposed to moisture and air in the air until it enters the mold of 40 ~ 70 degrees, and bubbles or foreign substances should never occur. Because it is. In addition, since the stirring must be much more sophisticated than conventional plastic injection equipment and liquid silicone equipment, a problem arises that the physical properties of the cast urethane cannot be maintained with the existing equipment.

Some similarly disclosed is a method for producing a silicone molded product of Republic of Korea Patent Publication No. 10-2004-0019651 (published on June 6, 2004). This patent discloses a step of pumping a liquid silicone liquid 10 and a hardener liquid 20 to one supply line P, as shown in FIG. 1, and a liquid silicone liquid 10 to be transferred and Mixing the curing agent liquid 20 into the molding material through the mixer 24, receiving the mixed molding material through the mixer 24, and supplying the mixed molding material into the storage cylinder 30, and in the storage cylinder 30. Cooling the supplied molding material before supplying it to the mold, and quantitatively filling the molding material into the mold 40 by a forward operation of the hydraulic cylinder 32 installed at one side of the storage cylinder 30, and the mold 40 In the process of molding the molding material supplied to the) is heated to a predetermined temperature to form a shape of the product (A) and take out the molded product (A), and then sterilization and packaging and the like. .

Therefore, the inventors tried to supply the urethane material to the piston by using the injection equipment of the method for manufacturing a silicone molded product as described above, but the injection equipment of the disclosed patent was able to work at room temperature in a two-component type, but the newly developed urethane material was stored at room temperature. Because it is impossible to work.

The present invention has been made to solve the above problems, it is to provide an injection method for casting urethane that can be supplied to the piston a quantity of the defoamed urethane material after mixing completely using a batch tank.

The technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems.

In order to solve the above problems, the present invention, after storing the main material and the curing agent in a batch tank, mixing and defoaming to prepare a mold urethane (S10); Buffering the urethane mold injection unit (S20); Filling the mold urethane into the injection molding machine by operating a fixed quantity injection unit (S30); And injecting the mold urethane filled into the injection molding machine into the mold (S40); and, from step S10 to step S40, the mold urethane is 40 to 70 degrees Celsius by a heat retaining device. In addition to maintaining the temperature in step (S10) the mold urethane is stored for 4 to 24 hours.
Specifically, the mold urethane in step (S10) is injected into the metering unit by the pressure of nitrogen filled into the batch tank, the pressure of nitrogen is filled to have a relative pressure of 2 ~ 7bar.
Specifically, the fixed-quantity injection unit in step S20, the discharge port of the cylinder is connected to the injection port of the injection machine by the discharge pipe, the inlet of the cylinder is connected to the batch tank by the inlet pipe, the piston head and the vertical movement in the cylinder and The rod is built-in, and the mold urethane stored in the batch tank is filled into the cylinder while the piston head and the rod are raised upward when the inlet / opening valve disposed in the inlet pipe is opened while the discharge opening / closing valve mounted on the discharge pipe is closed.
Specifically, the mold urethane in step S30 is filled into the injection molding machine by a rod and a piston head which are pressurized under the state in which the inlet opening and closing valve is closed and the discharge opening and closing valve is opened.

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As described above, according to the injection method for casting urethane according to the present invention, it is possible to provide a new material urethane which has good physical properties but sensitive to environmental changes, so that mass production of the product can be provided. It will be possible to introduce mass production equipment, and the existing rubber market and silicone market, which are difficult to enter due to the inability to mass-produce molds and inconsistent quality, also have poor physical properties but cannot be used. It will be possible to enter the general injection market.

1 is an example showing a liquid-silicon injection equipment according to the prior art,
Figure 2 is a view showing the molding urethane injection equipment according to the present invention,
3 is a view showing a state in which the cast urethane is injected into the metering injection portion of the injection molding machine urethane according to the present invention, and
Figure 4 is a view showing a state in which the molding urethane is injected into the injection molding machine of the injection molding machine urethane according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are denoted by the same reference symbols whenever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Referring to FIG. 2, the mold urethane injection apparatus 100 according to the present invention includes an injection machine 10 for injecting a mold urethane into a mold 20, and a quantity for injection of a fixed amount of mold urethane into the injection machine 10. It comprises an injection unit 110, a batch tank 120 for supplying the mold urethane to the fixed-quantity injection unit 110, and a control unit 130 for controlling them.

Since the mold 20 and the injection machine 10 can be understood by anyone skilled in the art, detailed description thereof will be omitted.

The fixed quantity injection part 110 injects the molding urethane injected into the injection molding machine 10 into the injection molding machine 10 by the vertical action of the piston, and the piston head 116 embedded in the cylinder 112 and the piston head ( A rod 118 connected to the 116 and extending out of the cylinder 112, and an inlet 113 and an outlet 114 through which the mold urethane enters and exits the cylinder 112 are formed.

An inlet tube 140 and an outlet tube 150 are coupled to the inlet 113 and the outlet 114 of the fixed quantity injection unit 110, respectively, and the inlet tube 140 is a batch tank in which mold urethane is mixed and stored. It is connected to the 120, the discharge pipe 150 is connected to the injection port 11 of the injection machine 10.

In this case, the inlet and outlet valve 140 and the discharge tube 150 are respectively equipped with an inlet opening and closing valve 145 and a discharge opening and closing valve 155 to control the inlet and outlet of the casting urethane. That is, the inlet opening and closing valve 145 and the discharge opening and closing valve 155 are injecting and quantifying the mold urethane into the cylinder 112 of the metering injection unit 110 while opening and closing the opposite operation. Urethane is to be injected into the injection molding machine 10 in a quantitative manner. More detailed operation will be described below.

Next, the batch tank 120 is completely mixed and defoamed by the stirring mixer 122 after the main body and the curing agent of the mold urethane are stored to have a constant mixing ratio. The batch tank 120 is configured to prevent the change in the physical properties of the urethane when exposed to the local heat by installing a heat retaining device 124, and prevents hardening by reacting with moisture and oxygen in the air Nitrogen is charged. Several experiments have shown that nitrogen filling pressure is appropriate to maintain a relative pressure between 2 and 7 bar.

The reason for filling nitrogen into the batch tank 120 is to maintain the nitrogen without changing the physical properties of the material, but to supply the mold urethane injection unit 110 using the nitrogen pressure. Therefore, the batch tank 120 maintains a high pressure to buffer the urethane in the injection molding unit 110 when the inlet opening and closing valve 145 of the inlet pipe 140 is connected to the batch tank 120 is opened. It will be possible.

On the other hand, the mold urethane must be maintained at a predetermined temperature of 40 to 70 degrees Celsius (different for each material), the thermal insulation holding device for all parts of the injection molding apparatus for injection molding urethane 100 of the present invention connected while the mold urethane is supplied It was installed, using the heating block and heat protection cable fruit oil can be maintained to maximize the physical properties of the urethane.

Finally, the controller 130 controls the batch tank 120, the inlet opening and closing valve 145, the metering injection unit 110, the discharge opening and closing valve 155 and the injection machine 10 in accordance with each condition. That is, when the nitrogen pressure filled in the batch tank 120 is lower or higher than the reference value, it is controlled, and the inlet opening and closing valve 145 and the discharge opening and closing valve 155, the fixed quantity inlet 110 and It is to control the injection machine 10 in a time or sensing manner.

Hereinafter, the operation of the mold urethane injection device 100 configured as described above will be briefly described with reference to the drawings.

3 and 4 is a view showing the flow of the branch to be cast to the injection molding machine urethane stored in the batch tank.

First, as described above, the main body and the curing agent are stored to have a constant mixing ratio, and then mixed and degassed to prepare a mold urethane (step S10). And nitrogen is filled in the batch tank 120. Referring to FIG. 3, since the batch tank 120 is filled with nitrogen as described above, the mold urethane stored in the batch tank 120 is always ready to be discharged.
Next, the mold urethane is buffered in the fixed quantity injection part 110 in the batch tank 120. The discharge of the casting urethane is automatically introduced into the metering injection unit 110 by opening the inlet opening and closing valve 145. At this time, in order to fill the mold urethane (U) in the cylinder 112 of the metered dose injection unit 110 in a quantitative manner, the piston head 116 and the rod 118 must be lifted up by the inflow pressure of the mold urethane (U). For this, the discharge port 114 of the cylinder 112 must be blocked. Therefore, when the inlet opening and closing valve 145 is opened, the discharge opening and closing valve 155 is controlled to be closed so that the mold urethane (U) is a cylinder in which the piston of the fixed quantity injection unit 110 is lifted up to the maximum from the batch tank 120 ( 112) the inner and the discharge opening and closing valve 155 is fully buffered.

When the molding urethane U is buffered in the metering injection unit 110 as described above, the metering injection unit 110 is operated to fill the molding urethane U in the injection machine 10 (step S30). As shown in FIG. 4, the urged rod 118 is pressed to push the mold urethane U filled in the cylinder 112 into the injection machine 10. At this time, in order for the mold urethane (U) to be transferred to the injection molding machine 10, the discharge port 114 must be opened and the inlet 113 must be closed, so that the inlet opening and closing valve 145 is closed while the discharge opening and closing valve 155 is opened. The control unit 130 to control.

The mold urethane U filled with the injection molding machine 10 is injected into the mold 20 to complete the injection (step S40).
As described above, the mold urethane is maintained at a temperature of 40 to 70 degrees Celsius by a heat retaining device mounted to each part through which the mold urethane (U) is distributed, and thus, the mold urethane in the batch tank 120 is 4 to 24 degrees. It is stored without time hardening.

The present invention is not limited to the configuration and operation of the embodiments described above. The embodiments may be configured so that all or some of the embodiments may be selectively combined so that various modifications may be made.

100: Injection molding machine for casting urethane
10: injection molding machine 20: mold
110: fixed quantity injection unit 112: cylinder
113: inlet 114: outlet
116: piston head 118: rod
120: batch tank 122: stirring mixer
124: heat retaining device 130: control unit
140: inlet pipe 145: inlet opening and closing valve
150: discharge pipe 155: discharge opening and closing valve

Claims (6)

After storing the casting material and the curing agent in a batch tank, mixing and defoaming to prepare a mold urethane (S10);
Buffering the mold urethane to the injection unit (S20);
Filling the mold urethane into an injection molding machine by operating the metering injection unit (S30); And
And injecting the mold urethane filled in the injection machine into a mold to complete injection (S40).
The mold urethane is maintained at a temperature of 40 to 70 degrees Celsius by the heat retaining device in the step S10 to the step S40, and the mold urethane is stored for 4 to 24 hours in the step S10. Injection molding method for casting urethane, characterized in that.
The method according to claim 1,
The mold urethane in the step (S10) is injected into the metering unit by the pressure of nitrogen filled into the batch tank,
The pressure of the nitrogen is injection method for molding urethane, characterized in that the filling to have a relative pressure of 2 ~ 7bar.
The method according to claim 1,
The metered dose injection unit in the step (S20),
The discharge port of the cylinder is connected to the injection port of the injection machine by the discharge pipe, the inlet of the cylinder is connected to the batch tank by the inlet pipe, the cylinder has a piston head and rod for vertical movement
The mold urethane stored in the batch tank is filled into the cylinder while the piston head and the rod are lifted up when the inlet / opening valve disposed in the inlet pipe is opened while the discharge opening / closing valve mounted to the discharge pipe is closed. Injection molding method for cast urethane characterized in that.
The method of claim 3,
The mold urethane in the step (S30),
Injection method for the cast urethane, characterized in that the inlet opening and closing valve and the discharge opening and closing valve is opened in the injection molding machine by the rod and the piston head is pressurized.
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