JPH04134450U - Electrostatic coating equipment for conductive paint - Google Patents

Abstract

(57) [Summary] [Purpose] When performing electrostatic painting with water-based paints such as water-soluble resin paints that can be applied without solvent or with a small amount of solvent, conductive water-based paints are atomized using a rotating atomizer head. It eliminates the trouble of applying insulation measures to prevent high voltage leaks in the paint sprayer and its paint supply system, and improves paint application efficiency.
It also improves the operability of the coating machine. [Structure] The atomizer 1 is connected to the ground, and a high voltage is applied to multiple needle-like electrodes 3 arranged in an electrically insulated state along the periphery of the atomizer 1, and the rotating atomizing head 2 of the atomizer 1 produces fine particles. By charging the atomized particles of conductive paint, it is possible to eliminate the trouble of taking insulation measures for the paint sprayer 1 and its paint supply system, and to move the rotary atomizing head 2 along the outer periphery of the tip from the outer periphery to the tip. A bulge 8 was formed to give a rounded shape.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is an electrostatic coating method that performs electrostatic painting using conductive paints such as water-based paints and metallic paints. Regarding electric coating equipment.

0002

[Conventional technology]

In June 1976, the Paint Department of the Chemical Council announced resource-saving and low-pollution measures for paints and coatings. Since the Council's report to the Minister of International Trade and Industry, the paint industry has taken steps to eliminate or reduce the use of organic solvents. Therefore, multi-component paints such as two-component urethane paints, water-based paints such as water-soluble resin paints, etc. Progress has been made in the development of paints that can be applied without solvent or with a small amount of solvent. However, multi-component paints have complicated paint supply systems and short pot lives. Due to problems such as difficulty in handling, it is not widely used. In addition, conductive paints such as water-based paints are electrostatically charged using a paint sprayer that applies high voltage. Any attempt to paint will cause a high voltage leak to the paint sprayer and all of its paint supply systems. It is necessary to take insulation measures to prevent electrostatic painting equipment that does not take such measures. It is not possible to apply conductive paint to the area.

0003 In other words, the electrostatic coating equipment currently used in automobile paint factories uses organic solvents. A high voltage of DC-80 to 120 KV is applied to the insulating resin paint diluted with the agent. An electrostatic atomizer that atomizes paint particles with a rolling atomizer head and charges the paint particles negatively. The cathode is the cathode, and the grounded object is the anode, and an electrostatic field is formed between them. Negatively charged paint particles are sprayed from the atomizing head and are attracted to the object by electrostatic attraction. The mainstream method is to adsorb onto the surface of If you want to paint with conductive paint such as - It is necessary to take troublesome insulation measures such as those described in Publication No. 141869. stomach. However, like multi-color electrostatic coating equipment for car painting, dozens of colors of paint can be changed. Insulating all the huge number of paint tanks and paint piping installed in painting equipment. is nearly impossible.

0004 In addition, connect the paint sprayer and paint supply system to ground, and connect the paint A high voltage is applied to needle-shaped electrodes that are electrically insulated along the By charging the paint particles sprayed from the rotating atomizer head, troublesome insulation measures are no longer required. (U.S. Pat. No. 3,393,662), but in this case, the distance between the needle electrode and the paint sprayer is If it is close, as will be described later, the entire path will be destroyed at the tip of the needle electrode and the tip of the rotating atomizing head. - At the same time, electrical discharge occurs and the coating efficiency of the paint on the surface of the workpiece decreases significantly. However, there was a risk of dangerous arc discharge. In addition, to prevent this, if you widen the gap between the needle electrode and the paint sprayer, the entire area The structure becomes larger and the operability of the coating machine deteriorates.

[0005] For this reason, in the painting industry, static paints using insulating resin paints that consume large amounts of organic solvents are being used. There is a shift from electrical painting to resource-saving and pollution-free painting using water-based paints such as water-soluble resin paints. The current situation is that this cannot be planned. However, recently there has been an increase in the global environmental conservation movement, and efforts are being made to change this trend. is considered an urgent need.

[0006] Therefore, from the viewpoint of saving resources and preventing pollution, this invention was developed using electrostatic painting using water-based paints. In order to make this practical, the troublesome insulation of the paint sprayer and its paint supply system was removed. Measures should be taken to enable electrostatic coating of conductive paint without any special measures, and By taking these measures, we will ensure that no adverse effects such as a decrease in paint application efficiency occur. The technical challenge is to make this possible.

[0007]

[Means to solve the problem]

In order to solve this problem, the electrostatic coating device for conductive paint according to the present invention was developed by Bell. A paint sprayer that atomizes conductive paint with a rotating atomizing head in the form of a cup-shaped or cup-shaped atomizer is connected to earth. Then, a plurality of needle-shaped electrodes arranged in an electrically insulated manner along the periphery of the paint sprayer, The rotating atomizer head charges the atomized spray paint particles and creates an electrostatic field between them and the object to be coated. A high voltage is applied to form a It is characterized by the formation of a rounded bulge towards the tip.

[0008]

[Effect]

According to the present invention, the conductive material is atomized by the rotating atomizing head of the paint sprayer connected to ground. Sprayed paint particles are charged with a needle-like electrode to which a high voltage is applied, and the needle-like electrode The Coulomb force of the electrostatic field formed between the object and the surface of the object to be coated attracts and It is adsorbed. Therefore, high voltage is not applied to the paint sprayer, and the needle The electrodes are installed in an electrically insulated state, so do not use the paint sprayer or the conductive paint on the paint sprayer. Insulating the paint supply system to prevent high voltage leaks There's no need.

[0009] In addition, if the tip of the rotating atomizing head is thin and angular as is the case in the past, high voltage may not be applied. The entire air gap between the needle electrode and the applied voltage is likely to be destroyed. When broken, a glow discharge is generated not only from the tip of the needle electrode but also from the tip of the rotating atomizing head, resulting in needle-like Charges of different polarity are generated on both the electrode and the rotating atomizer head, and these charges collide with each other. They are then electrically neutralized, reducing the charging effect of the needle-shaped electrode on the sprayed paint particles. As a result, the efficiency of coating the paint onto the surface of the object to be coated may deteriorate. In addition, the glow discharge that destroys all circuits is a transitional phenomenon that progresses to the next arc discharge. This is a very dangerous sign, so increase the distance between the rotating atomizing head of the sprayer and the needle electrode. It has to be spread out wide, making the overall structure larger and impairing the operability of the coating machine. There is a risk of being exposed.

0010 On the other hand, as in the present invention, along the outer circumference of the tip of the rotating atomizing head, By forming a rounded bulge toward the tip, the distance between the needle electrode and the needle electrode can be narrowed. Even a partial glow discharge ( Corona discharge) only occurs, but glow discharge occurs at the tip of the rotating atomizing head due to complete path destruction. This can be prevented from occurring. Therefore, by narrowing the distance between the paint sprayer and the needle-shaped electrode and making the whole machine smaller, The operability of the paint sprayer can be improved, and the paint application efficiency can be improved even if the spacing is narrowed. There is no risk that the rate will worsen.

[0011]

【Example】

Embodiments of the present invention will be specifically described below with reference to the drawings. Figure 1 is a diagram showing an example of an electrostatic coating device according to the present invention, and Figure 2 is a partial cross-section of a rotating atomizing head. It is a front view.

0012 The electrostatic coating device of this example uses the rotation of a bell-shaped or cup-shaped rotating atomizing head 2 to dissolve water. A coating machine 1 that atomizes water-based paint such as plastic paint is connected to ground, and the coating machine A plurality of needle-like electrodes 3 are arranged in parallel along the periphery of the electrode 1 at predetermined intervals. Each needle electrode 3 is attached to the body of the paint sprayer 1 with an electrically insulating material 4 and is electrically connected. DC-40 to A high voltage of 100KV is applied.

[0013] As a result, each needle-like electrode 3 generates a corona discharge from its tip, and the rotating atomizing head 2 generates negative ions that charge the atomized spray paint particles, and An electrostatic field is formed between the substrate 7 and the object 7 connected to the base.

[0014] In addition, the rotary atomizing head 2 has a circular shape along the outer periphery of the tip, from the outer periphery to the tip. A bulge 8 is formed to give a bulge. This bulge 8 extends from the outer periphery of the rotating atomizing head 2 to the tip, as the cross section is shown in FIG. It is rounded in an arc shape with a radius of curvature r of about 2 to 5 mm.

[0015] However, when starting the application of water-based paints such as water-soluble resin paints with the electrostatic painting equipment described above, Then, the spray paint particles of the water-based paint atomized by the rotary atomizing head 2 of the coating machine 1 are -Main produced by corona discharge of needle electrode 3 to which high voltage of 40 to 100 KV is applied. As well as being charged with a negative charge due to the attachment of inus ions, The electrified spray paint particles use the needle electrode 3 as a cathode and the object 7 connected to ground as a positive electrode. Coating is efficiently attracted and adsorbed to the surface of the object to be coated 7 by the Coulomb force of the electrostatic field as a pole. be done.

[0016] In this way, it is possible to prevent high voltage leakage to the coating machine 1 and its paint supply system. Electrostatic coating with conductive water-based paint can be performed without taking complicated insulation measures. can. Further, the rotary atomizing head 2 of the coating machine 1 has a bulge 8 formed along the outer periphery of the tip. The bulge 8 makes the tip thick and rounded, making it needle-like. Even if the air gap between the needle electrode 3 and the electrode 3 is made small, the tip of the needle electrode 3 still remains in between. Produces a partial cathodic glow discharge called a corona discharge that is necessary to charge the spray paint particles Only partial destruction occurs, and the tip of the rotating atomizing head 2 also produces an anodic glow discharge. Since destruction is unlikely to occur, the different polarities generated by cathodic glow discharge and anodic glow discharge The charge effect on the spray paint particles is reduced by the collision between the charges and the neutralization of the charges. There is no risk that the fruit will be damaged. Therefore, the distance between the sprayer 1 and the needle electrode 3 is narrowed to improve the operability of the sprayer 1. Even if the interval is narrowed, the coating efficiency of the paint on the surface of the object 7 will decrease. There is no risk of it happening.

[0017]

[Effect of the idea]

As described above, the present invention prevents high voltage leaks from paint sprayers and their paint supply systems. Electrostatic painting with conductive paints such as water-based paints without the need for troublesome insulation measures to prevent Moreover, the operability of the paint sprayer that sprays the conductive paint and the The paint is applied efficiently to the surface of objects, so it is suitable for insulation that requires large amounts of organic solvents. Enabling the switch from electrostatic painting using resin paint to resource-saving and pollution-free painting using water-based paint. It has a very good effect and is easy to achieve.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of an electrostatic coating device according to the present invention.

FIG. 2 is a partial cross-sectional view of a rotating atomizing head.

[Explanation of symbols]

1...Painting machine 2...Rotating atomization head 3...needle electrode 4... Electrical insulation material 5...High pressure generator 6...High voltage cable 7...Object to be coated 8...Bulge

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Toru Omura Torini 1-9 Kakimotocho, Toyota City, Aichi Prefecture Within Tei Kogyo Co., Ltd.

Claims (1)

[Scope of utility model registration request] Claim 1: Bell-shaped or cup-shaped rotating atomizing head (2)
A paint sprayer (1) that atomizes conductive paint is connected to ground, and a rotating A high voltage is applied to charge the atomized spray paint particles at the atomizing head (2) and to form an electrostatic field between the coating material and the object to be coated (7). An electrostatic coating device for a conductive paint, characterized in that a rounded bulge (8) is formed from the outer periphery to the tip along the .