JPS5936569A - Drying method of paint - Google Patents

Abstract

PURPOSE:To make a heating area small and to dry a paint at high speed, by passing an object to be treated on which the paint containing volatile solvent is coated through an air heating furnace and the heat area to be radiated by a heat radiation lamp. CONSTITUTION:A metallic plate M on which a paint containing volatile solvent is coated is carried by a carrying roll 2 through an air heating furnace and heated by hot air to liberate the solvent. Then, this metallic plate M is passed through a heating furnace 20 provided with a heat radiation lamp such as a halogen lamp, etc., and the paint is dried by radiation heat. In this way, the length of an area necessary for heating can be shortened and the paint can be dried at high carrying speed.

Description

[Detailed description of the invention] The present invention relates to a paint drying method.

Generally, metal plates, such as steel plates used in the construction of automobile bodies, need to be painted to prevent corrosion. Such a coating process for a metal plate is performed by applying a paint containing a volatile solvent such as toluene to the metal plate using, for example, a coating roller, drying it, and cooling it by draining water or the like. In order to dry the paint here, the surface of the steel plate,
A temperature sufficient for the paint to harden and dry, e.g.
It is necessary to heat to 0°C (2). As shown in Fig. 1, a typical conventional method for drying paint includes a blower tube 11 for sending hot air from a hot air source such as a heavy oil burner, and a tube for discharging the hot air. Wind exhaust pipe 12
A hot-air drying method in which a metal plate M coated with paint is conveyed along a conveyance path P inside the hot-air stove by a conveyance roller 2 using a hot-air stove connected to the hot-air stove, and the paint is dried with hot air. It has been known.

However, in such a hot air drying method,
In order to raise the temperature of the surface of the metal plate M to a temperature higher than that required for drying the paint, it is necessary to heat the inside of the hot air stove 1 to a temperature higher than that temperature. Assume that the surface temperature of plate M is short.
If the temperature of the hot air is increased for this purpose, a large amount of heat will be wasted, and the hot air stove l will need a heat insulating structure with high heat insulation efficiency. For this reason, in practice it is not a good idea to increase the temperature of the hot air, so it is necessary to make the contact time of the surface of the metal plate M with the hot air sufficiently long. In this way, the area required for heating is increased in order to increase the contact time and thickness of the Kanatsuki plate.
In other words, the length of the thermal stable furnace 1 must be made large,
A large area is required.

On the other hand, it is conceivable to use a heat radiation lamp to dry the paint, but since the solvent is usually flammable, it may be necessary to use a spark at the electrical contacts of the heat radiation lamp or to remove the glass cover of the heat radiation rung. When it is shattered by some kind of impact, an explosion occurs due to the arc. In order to prevent this, the terminal parts should be of explosion-proof construction, and the lighting equipment should be constructed with an explosion-proof structure. A special structure for protecting the enclosure gas 2 may be used, but this would require a device with a considerably complicated structure, and would also cause the problem of sacrificing the heat radiating area.

The present invention was made based on these circumstances, and it is possible to dry the paint at a rough conveyance speed while reducing the length of the area required for heating. 8. The purpose is to provide a paint drying method that does not require such drying, and its characteristics are as follows: A workpiece coated with a paint containing a volatile solvent is conveyed through hot air ft, a step of escaping the volatile solvent from the paint using hot air; and a step of transporting the object to be treated through a heated radiant area by a heat radiant lamp and drying the paint by the radiant heat of the heat radiant lamp. Including points.

Examples of the method of the present invention will be described below.

In one embodiment of the method of the present invention, as shown in FIG. 2, a hot stove is connected to a blower tube 11 for sending in hot air from a KN oil burner or the like and an exhaust tube 12 for discharging hot air. ■Feeded out from the feed roll 60 using
Compressed air is injected from the outer circumferential surface β of the metal plate M, which has been coated with a paint containing a volatile solvent on both sides by the coating roller 61. The surface of the metal plate M is heated in the hot blast furnace 1 by the hot air from the blast tube II, and the surface temperature is increased to, for example, 110° C. (5). During this time, the solvent was applied to the metal plate M.
It is then introduced through this metal plate M5 air curtain Ai into a heating furnace 20 having a heat radiation rung, for example a heat radiation rung.

As shown in FIGS. 3(a), 3(b), and 4, this heating furnace 20 includes a conveying roller 2 along a conveying path PLL, from which compressed air is injected from its outer peripheral surface. On the other hand, a total of 8 lamps 3 are arranged in parallel along the transport path Pvc, 4 lamps each, so as to face each other via the transport path Pi. As shown in FIG. 6, a plurality of halogen rungs 4 are arranged in two rows in the width direction of the conveyance path P so as to extend along the conveyance path P, respectively.
A reflection mirror 5 equipped with a mirror cooling pipe 51 is provided on the opposite side of the transport path P of each halogen rung 4, and air for cooling the reflection mirror 5 and the base of the halogen rung 4 is supplied as indicated by the arrow in FIG. A mechanism for air supply and exhaust should be connected to each lamp 3 so that the air flows smoothly. After entering the heating furnace 20 having such a configuration, the metal plate M7 is conveyed in a floating state by the conveyor rollers 2 (6). The metal plate M is caused to pass through a heat radiation region Qv, and the surface temperature of the metal plate M is raised to, for example, 250° C. by the radiant heat, thereby drying the paint. Then metal plate M
It is cooled by passing through a water-cooled furnace 62, and then wound up by an additional roll 63 of the coated metal sheet MY. Here, it is important to dissipate the solvent in the hot air stove 1 so that the concentration of solvent vapor in the heating furnace 20 becomes lower than the explosion limit.

According to the above method, the surface temperature of the metal plate M is raised by passing it through a hot air stove and then passing through the heat radiation area Qv of the halogen rung 4 to dry the paint. In the furnace 20, it is not necessary to heat the atmosphere Z around the metal plate M to a high temperature (・, so it is possible to heat the metal plate Mg while gaining a rough thermal efficiency, and there is no need for a furnace body with a complicated structure, and therefore the output (approximately) 10 gen/pu 4 By providing the unit (7) close to the conveyance path P, the amount of heat given to the surface of the metal plate M over time can be reduced to a large value. By increasing the rate of temperature rise on the surface of the metal plate M, the length g4 of the area required for heating as a whole can be reduced and the paint can be dried at a high transport speed. Moreover, hot stove 11
Cj'6, the hot air causes the solvent to flow from the interface of the metal plate M into the heating furnace 20? In order to dissipate the solvent vapor to a concentration lower than the explosive limit, it is necessary to enter the heating furnace 20. On the electrical contact of the 10gen lamp 4? Due to the snow cracking, there is no risk of an explosion caused by the arc igniting the solvent vapor when the enclosure glass is shattered by some kind of impact, and there is no need for a complicated explosion-proof device. .

Here, according to the method of the above embodiment,
A steel plate with a thickness of 0.711111 and coated with paint on one side is conveyed at a conveyance speed of xzoo-/min, and the different surface temperature is raised to 30' using hot air at a temperature of about 250°C in a hot air oven.
CC' is heated to 110°C, and the temperature of the steel plate is raised to 110°C, and then the temperature of the steel plate is raised to 250°C from 110°C in an L heating furnace to dry the paint. The length of the hot stove is approximately 20
771. It is sufficient if the length of the heating furnace is about 8 m, and the length of the area required to heat the whole is about 28 m.
It is. In contrast, the conventional hot air drying method
In order to dry the paint by using hot air 2 with a temperature of 250 to 300°C and conveying the same steel plate as described above at the same conveyance speed, the length of the area necessary for heating, that is, the length of the hot air oven. is required to be about 60 to 70 m, so from this example,
Assuming that the conveyance speed of the steel plate remains the same, it is understood that in the method of the above embodiment, the length of the area required for heating is significantly smaller than in the conventional hot air drying method.

As described above, the present invention includes the steps of transporting a workpiece coated with a paint containing a volatile solvent through a hot air stove, and causing the volatile solvent to escape from the paint using the hot air from the hot air stove. The present invention is characterized in that it includes a step of transporting the object to be treated through a heat radiant area by a heat radiant lamp and drying the paint by radiant heat from a heat radiant lamp. It is possible to dry the paint at a high transport speed while keeping the length of the required area small, and it is possible to provide a method for drying the paint without explosion.

[Brief explanation of the drawing]

FIG. 1 is an explanatory longitudinal cross-sectional side view showing an example of an apparatus used in a conventional hot air drying method for paint drying, FIG. 2 is an explanatory view showing an example of an apparatus used in the method of the present invention, and FIG. (A) and Figure 3 (B) respectively show 8 of the heating furnaces shown in Figure 2.
The explanatory diagram and partially enlarged diagram shown in Fig. 4 are for the heating furnace shown in Fig. 2? An explanatory perspective view showing the arrangement of the lighting fixtures, No. 5
6 are an explanatory partially cutaway side view and a plan view thereof, respectively, of the lamp l shown in FIG. 3(A). 1...Hot stove 2--Conveyance roller 20...
Heating furnace 3 - Lamp 4... Halogen/U/G
5... Reflection mirror 60... Feed roll 61.
..., application roller 62... water-cooled furnace 63...
Winding roll (10) M Metal plate agent Patent attorney Masahiko Oi

Claims (1)

[Claims] ■) A step in which the object to be treated coated with a paint containing a volatile solvent is conveyed through a hot air oven, and the volatile solvent is evaporated from the paint by the hot air from the hot air oven; A paint drying method characterized by comprising the step of transporting the paint through a heat radiated area by a heat radiation lamp and drying the paint by the radiant heat of the heat radiation lamp.