JP2007044631A - Method of supplying aqueous two-liquid urethane coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the curing of a base resin with a curing agent during the interruption of coating in aqueous two-liquid urethane coating. <P>SOLUTION: The two-liquid urethane coating material obtained by charging the base resin and the curing agent alternately to a common supply passage 11 and mixing in a static mixer 13 (mixing apparatus) is supplied to a coating gun 14. When the coating is interrupted, the supply of the coating material to the coating gun 14 is stopped at a point of time when the base resin is finished to be charged to the common supply passage 11. In the state of stopping the coating material, the inside of the common supply passage 11 is occupied by the base resin because only the base resin is finally supplied direct before the stoppage of the coating and then, a small quantity of the base resin and a large quantity of the curing agent are not stayed as they are in contact with each other to prevent the curing of the base resin with the curing agent in a short time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for supplying an aqueous two-component urethane paint.

In Patent Document 1, as a means for supplying a paint composed of a main agent and a curing agent to a coating gun, this liquid agent is alternately supplied to a two-liquid mixing device, and the two liquid agents are mixed in the two-liquid mixing device. A method for delivering the obtained multi-component paint to the coating gun side is disclosed.
Conventionally, an oil-based two-component urethane paint is used as this type of paint, and a static mixer that stirs while alternately supplying the main agent and the hardener has been used as a means for mixing the main agent hardener.
JP 2004-141800 A

In recent years, considering the protection of the natural environment, the amount of aqueous two-component urethane paint used is increasing. However, when a static mixer is used as a mixing means for the aqueous two-component urethane paint, the following problems occur.
Water-based two-component urethane paint maintains a liquid state for a relatively long time (several hours) when the main agent and the curing agent are mixed at an appropriate mixing ratio, but the amount of the main agent is small and the amount of the curing agent is small. When both agents come into contact with each other in a large amount, there is a characteristic that they are rapidly cured in a short time (for example, about 20 minutes). Therefore, at the upstream end in the static mixer, that is, in the region where the degree of stirring is low, when the coating is interrupted, the large amount of the curing agent and the small amount of the main agent remain in contact with each other and harden during the coating interruption.
This invention is completed based on the above situations, Comprising: It aims at preventing that a main ingredient and a hardening | curing agent harden | cure while interrupting coating in aqueous | water-based two-component urethane coating.

  As a means for achieving the above object, the invention of claim 1 is characterized in that the main agent and the curing agent are alternately charged into the common supply path by a predetermined amount, and the main agent is mixed with the main agent by a mixing device provided at the downstream end of the common supply path. A method of supplying an aqueous two-component urethane paint obtained by mixing a curing agent to a coating gun, and when the coating is interrupted, when the main agent has been put into the common supply path, the coating gun It is characterized in that the supply of the aqueous two-component urethane paint to the is stopped.

  According to a second aspect of the present invention, in the first aspect of the present invention, the amount of the main agent introduced into the shared supply path in one input cycle is approximately the same as or larger than the volume of the shared supply path. However, it has characteristics.

<Invention of Claim 1>
In the state where the supply of the water-based two-component urethane paint to the paint gun is stopped, the main agent is mostly put into the common supply channel immediately before the stop, so the common supply channel is almost occupied by the main agent. . Therefore, the main agent and the curing agent can be prevented from curing in a short time without stagnation until a small amount of the main agent contacts a large amount of the curing agent in the shared supply path.

<Invention of Claim 2>
Since the amount of the main agent that is put into the common supply path at a time is almost the same as or larger than the volume of the common supply path, the remaining amount of curing agent in the common supply path when painting is interrupted Becomes almost zero, and the curing of the curing agent with the main agent can be more reliably prevented.

<Embodiment 1>
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The coating material supply apparatus of this embodiment supplies an aqueous two-component urethane coating material obtained by mixing a main agent and a curing agent to the coating gun 14, and includes a downstream end of the main agent supply path 10A dedicated to the main agent and a curing agent. The downstream end of the dedicated curing agent supply path 10 </ b> B is connected to a switching device 12 provided at the upstream end of the shared supply path 11, and a static mixer 13 for mixing the main agent and the curing agent at the downstream end of the shared supply path 11. (A mixing device that is a constituent of the present invention) is provided, and a coating gun 14 is connected to the downstream side of the static mixer 13.

  An upstream end of the main agent supply path 10A is connected to a known main agent pumping device 15A for pumping either the main agent or the cleaning agent as required. A total of 16A is provided. The upstream end of the curing agent supply path 10B is connected to a curing agent pumping device 15B having a well-known structure for pumping either the curing agent or the cleaning agent as required, and is in the middle of the curing agent supply path 10B. Is provided with a flow meter 16B. At the time of coating, the main agent and the curing agent are alternately put into the common supply path 11 at a predetermined ratio, and the added main agent and the curing agent are stirred while moving in the static mixer 13 to be aqueous two-component urethane. Become a paint.

Next, the switching device 12 will be described.
The switching device 12 is for switching between a state in which the curing agent supply path 10B is communicated with the common supply path 11 and a state in which the curing agent supply path 10B is blocked from the common supply path 11. In consideration of the property that the isocyanate, which is a curing agent of the urethane coating, is cured by contact with moisture, the curing agent can be prevented from contacting moisture in the outside air.

The switching device 12 is for joining the main agent supplied through the main agent supply passage 10A and the hardener supplied through the hardener supply passage 10B, and is composed of an on-off valve mechanism 21 and a cylinder mechanism 34. The
First, the on-off valve mechanism 21 will be described.
A common inflow chamber 23 and a hardener inflow chamber 24 are formed vertically and in communication with each other at the lower end of the block body 22 made of a plurality of members. Similar to the cylindrical main agent charging port 25, a cylindrical curing agent charging port 26 is attached to the outer peripheral surface of the block body 22, and a main agent charging hole 25 a at the center of the main agent charging port 25 is formed at the upper end of the common inflow chamber 23. The curing agent charging hole 26 a at the center of the curing agent charging port 26 is communicated with the lower end portion of the curing agent inflow chamber 24. Although fluid movement from the outside to the inside of the block body 22 is allowed in each of the introduction holes 25 a and 26 a, the inside of the block body 22 (the common inflow chamber 23 and the hardener inflow chamber 24) and the outside of the block body 22 are allowed. Check valves 25b and 26b are provided for restricting the movement of fluid to the. Further, a cylindrical outflow port 27 is attached to the outer peripheral surface of the block body 22 in a state where the central outflow hole 27 a is communicated with the lower end portion of the common inflow chamber 23. The common supply path 11 is connected to the outflow hole 27a.

  A mounting hole 28 that communicates with the upper end of the common inflow chamber 23 is formed inside the block body 22, and the axial line extends in the vertical direction (the direction in which the common inflow chamber 23 and the curing agent inflow chamber 24 are arranged). A cylindrical support body 29 facing in a parallel direction) and a packing 30 with the axis line oriented in the vertical direction are attached side by side. A rod 31 having a circular cross section with the axis line directed in the vertical direction is passed through the central hole 29a of the support 29 and the central hole 30a of the packing 30 so as to be movable in the vertical direction. When the packing 30 is in close contact with the outer peripheral surface of the rod 31, the fluid (main agent and curing agent) in the common inflow chamber 23 is restricted from leaking to the support 29 side.

  A tapered valve seat 32 is formed at the boundary between the lower end of the common inflow chamber 23 and the upper end of the hardener inflow chamber 24. Further, the lower end portion of the rod 31 protrudes into the curing agent inflow chamber 24, and a valve body 33 that can be brought into contact with and separated from the valve seat 32 is fixed to the lower end portion of the rod 31. Has been. In the closed state in which the valve body 33 moves upward and contacts the valve seat 32, the fluid flow between the curing agent inflow chamber 24 and the common inflow chamber 23 is blocked, and the valve body 33 moves downward. In the open state separated from the valve seat 32, the fluid is allowed to flow from the curing agent inflow chamber 24 to the common inflow chamber 23.

Next, the cylinder mechanism 34 will be described.
A second pressurizing chamber 36B, which is a first pressurizing chamber 36A divided up and down by a piston 35, is formed at the upper end of the block body 22, and the upper end of the rod 31 is fixed to the piston 35. . A first fluid port 37A is connected to the first pressurizing chamber 36A, and a second fluid port 37B is connected to the second pressurizing chamber 36B. When the air is supplied from the first fluid port 37A to the first pressurizing chamber 36A and the air in the second pressurizing chamber 36B is discharged to the outside from the second fluid port 37B, the piston 35 and the rod 31 are lowered. Thus, the valve element 33 is opened from the valve seat 32. Further, when air is supplied from the second fluid port 37B to the second pressurizing chamber 36B and air in the first pressurizing chamber 36A is discharged to the outside from the first fluid port 37A, the piston 35 and the rod 31 are discharged. As a result, the valve body 33 comes into a closed state in which the valve body 33 abuts on the valve seat 32.

  Now, when painting, as shown in FIG. 3, the main agent and the curing agent are alternately put into the switching device 12 by a predetermined amount. When the main agent is charged, the on-off valve mechanism 21 is closed, the curing agent inflow chamber 24 and the common inflow chamber 23 are shut off, and the curing agent in the curing agent inflow chamber 24 flows into the common inflow chamber 23. Is regulated. In this state, the main agent flows into the common supply path 11 through the main agent charging hole 25a, the common inflow chamber 23, and the outflow hole 27a in this order. When the curing agent is charged, the on-off valve mechanism 21 is opened, and the curing agent sequentially passes through the curing agent charging hole 26a, the curing agent inflow chamber 24, the common inflow chamber 23, and the outflow hole 27a. Flow into. Further, when the curing agent is introduced into the common inflow chamber 23, the liquid in the common inflow chamber 23 is prevented from flowing into the main agent supply path 10 </ b> A by the check valve 25 b of the main agent input port 25.

  Then, the main agent and the curing agent that are alternately charged into the switching device 12 move in the common supply path 11 and are fed into the static mixer 13, and are stirred and mixed while passing through the static mixer 13. It becomes an aqueous two-component urethane paint. This aqueous two-component urethane paint is pumped to the coating gun 14 and discharged toward an object not shown.

When the coating is temporarily stopped, the supply of the aqueous two-component urethane paint to the coating gun 14, that is, from the coating gun 14, when the main agent of the input amount of one cycle is completely supplied to the switching device 12. Stop the discharge of water-based two-component urethane paint. In this paint stop state, almost all of the inside of the common inflow chamber 23 and the inside of the common supply path 11 are occupied by the main agent, so that the main agent does not stagnate until a small amount of the main agent contacts a large amount of the curing agent.
Then, when restarting the coating, charging of the curing agent is started. With the addition of the curing agent, the supply of the aqueous two-component urethane paint from the static mixer 13 to the coating gun 14 is resumed, and the discharge of the aqueous two-component urethane paint from the coating gun 14 is resumed.

  Further, in the switching device 12 described above, air exists in the intermediate chamber 38 formed between the mounting hole 28 and the second pressurizing chamber 36B, and the lower end portion of the intermediate chamber 38 has a curing agent. A rod 31 protruding into the inflow chamber 24 passes therethrough. That is, the rod 31 penetrates between the space (the common inflow chamber 23 and the curing agent inflow chamber 24) in which the hardener flows and the space in which air exists (the intermediate chamber 38 and the second pressurizing chamber 36B). Yes. Here, in view of the characteristic that the isocyanate as the curing agent is cured by contact with moisture, the penetrating portion of the rod 31, that is, the sliding portion of the rod 31 (the inner periphery of the center hole of the packing 30 and the outer periphery of the rod 31). ), The curing agent is cured by contact with moisture, which may cause a problem in the sliding of the rod 31. However, in the present embodiment, since the common supply path 11 is interposed between the curing agent inflow chamber 24 and the packing 30 (the sliding portion of the rod 31), the gap between the center hole 30a of the packing 30 and the rod 31 is interposed. There is no possibility that the air will come into contact with the curing agent in the curing agent inflow chamber 24.

  In addition, since the main agent flow path from the main agent inflow chamber to the outflow hole 27a is formed between the hardening agent flow path from the hardener inflow chamber 24 to the outflow hole 27a and the packing 30, the common inflow Even if the chamber 23 is temporarily filled with the curing agent, the curing agent does not remain in the common inflow chamber 23 by quickly charging the main agent after the completion of the charging of the curing agent. And contact with air is prevented.

  As described above, in the present embodiment, when the coating is interrupted, the supply of the aqueous two-component urethane paint to the coating gun 14 is stopped when the main agent has been introduced into the common supply path 11. In other words, in the state where the supply of the aqueous two-component urethane paint to the coating gun 14 is stopped, since the main agent was last added to the shared supply path 11 immediately before the stop, the inside of the shared supply path 11 is Almost occupied by the main agent. Therefore, it does not stagnate until a small amount of the main agent and a large amount of the curing agent come into contact with each other in the common supply path 11, and is cured in a short time due to the contact of the small amount of the main agent and the large amount of the curing agent. Can be prevented.

  Further, in the present embodiment, the amount of the main agent introduced into the common supply path 11 in one input cycle is set to be approximately the same as or larger than the volume of the common supply path 11. Therefore, in the state where the coating is interrupted, the residual amount of the curing agent in the shared inflow chamber 23 and the shared supply path 11 becomes almost zero, and the curing of the curing agent with the main agent can be more reliably prevented.

<Other embodiments>
The present invention is not limited to the embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, the mixing device provided at the downstream end of the common supply path is a static mixer. However, according to the present invention, instead of the static mixer, even when the supply of the aqueous two-component urethane paint is stopped You may provide the stirring apparatus which can stir the main ingredient and the hardening | curing agent.
In addition, this stirring device may be provided upstream of the static mixer.

(2) In the above embodiment, only the static mixer is used as the mixing device. However, according to the present invention, the main agent and the curing agent are stirred upstream of the static mixer even when the supply of the aqueous two-component urethane paint is stopped. A stirrer that can be used may be provided.
(3) In the above embodiment, the amount of the main agent to be charged into the common supply path in one input cycle is the same as or larger than the volume of the common supply path. The amount of the main agent introduced into the shared supply path may be smaller than the volume of the shared supply path.

Overall configuration diagram of Embodiment 1 Cross-sectional view of a switching device for switching between charging of the main agent and curing agent Graph showing the charging cycle of main agent and curing agent

Explanation of symbols

11 ... Common supply path 13 ... Static mixer (mixing device)
14 ... Paint gun

Claims (2)

Put the main agent and curing agent alternately into the common supply path by a predetermined amount,
A method of supplying an aqueous two-component urethane paint obtained by mixing a main agent and a curing agent to a coating gun by a mixing device provided at a downstream end of the common supply path,
A supply method of an aqueous two-component urethane paint characterized in that when the coating is interrupted, the supply of the aqueous two-component urethane paint to the coating gun is stopped when the main agent has been introduced into the common supply path. 2. The aqueous two-component urethane paint according to claim 1, wherein the amount of the main agent introduced into the shared supply path in one charging cycle is substantially the same as or larger than the volume of the shared supply path. Supply method.

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