JPS60172382A - Rust preventing treatment of thick metallic plate - Google Patents

Abstract

PURPOSE:To improve the performance, economy, and productivity by coating a rust preventive resinous paint on a thick metallic plate, and curing the coated film by the irradiation of an activation energy beam on-line between carrier rolls. CONSTITUTION:A thick steel plate 1 pretreated with rust preventive blasting is carried by on-line carrier rolls 2 and 2' in the direction as indicated by the arrow. And at least the lower surface, or both surfaces generally, is initially painted with a rust preventive paint to be cured by the irradiation of an activation energy beam such as ultraviolet rays and an electron beam in a painting device 3 provided immediately after the carrier roll 2. Before the thick steel plate 1 is sent to the carrier roll 2, the coated film on the lower surface is precedently and preponderantly irradiated with the activation energy beam and cured by an irradiation device 4 for curing the lower surface. Then the coated film on the upper surface is cured by an irradiation device 5 for curing the upper surface between the carrier rolls 2 and 2'.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objects of the Invention) The present invention relates to a method for rust-proofing a metal plate, and in particular to a method for rust-proofing a metal plate, which can be carried out online in solid and short interribs.

Conventionally, metal thick plates, such as J+7 for shipbuilding, plant use, etc.
．． The factory anti-corrosion coating of steel plates (that is, so-called cut plates) is
After spraying an air-drying paint diluted with a solvent, a room-temperature curing anti-rust oil or resin paint, or a thermosetting paint onto both the upper and lower surfaces of the metal plate held between the conveyor rolls, apply it to the bottom surface as much as possible) The paint is transported slowly without contact with squeezing rolls, and then, depending on the type of paint, it is forced dried or thermally cured in a heating oven.

However, since there is a certain limit on the interval between one general transport roll, the transport must be moved extremely slowly in order to allow sufficient drying or heat curing between the time the paint is applied and the time it contacts the next transport roll. This is a major hindrance to productivity.

In addition, because the curing time is insufficient, the bottom surface of the painted plate often comes into contact with the next transport roll in an uncured state, resulting in roll marks on the paint film and peeling of the paint film. It becomes necessary to repaint the product after it leaves the line, resulting in economic and time losses.

Furthermore, when using thermosetting paints, the paint film cannot be sufficiently dried and cured unless the base material is also raised to the curing temperature. It requires a lot of energy.

In particular, as the plate thickness increases, the surface area ratio (7 times the surface area) decreases, and even more energy is required. In such cases, the conventional method can be said to have an extremely large energy loss.

Therefore, the present inventors have conducted repeated studies in order to solve the problems in the conventional rust prevention treatment of thick metal plates and to find a rust prevention treatment method that is extremely excellent in terms of performance, scaleability, and productivity.

As a result, active energy-curable anti-corrosion resin paint is applied to the metal plate between the conveyor rolls, and active energy rays are irradiated immediately after application to completely coat the bottom surface of the metal plate before contacting the next conveyor roll. The present invention was completed based on the discovery that an excellent antirust treatment that solves all the productivity problems and energy cost problems of conventional methods can be achieved by hardening.

(Structure of the Invention) A method for applying anti-rust coating to a gold VvS thick plate during one general transport of the metal plate by a roll for transporting the thick plate, comprising:
Applying a rust preventive resin paint that hardens by irradiation with active energy rays to at least the lower surface of the metal plate, and irradiating the active energy rays to the lower face of the metal plate to harden the rust preventive resin paint. This is carried out between the conveyance roll 1 and the next narrowing roll 1'L.Continuous anti-corrosion treatment is carried out on the thick metal plate by on-line.Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the drawings. do.

The accompanying drawings are explanatory diagrams schematically showing an apparatus for performing rust prevention treatment on a thick metal plate according to the present invention, and FIGS. 1 and 2 are a plan view and a side view, respectively.

A thick steel plate 1 that has been subjected to rust removal by blasting as a general pre-treatment is conveyed online in the direction of the arrow by conveyor rolls 2.2° and 2''.Thick steel plate 1 is generally conveyed by the conveyor rolls. First, in a coating device 3 installed immediately after the conveyor roll 2, a rust-preventive paint that is cured by irradiation with active energy rays such as ultraviolet rays or electron beams is applied to at least the lower surface, generally both surfaces. A spray-type coating device is preferred, but other devices may be used as long as they can quickly and completely coat the coating.

The coated thick steel plate 1 is then sent to the next conveyor roll 2', but the irradiation device 4 for hardening the bottom surface is installed prior to this, and the bottom surface of the thick steel plate that comes into contact with the first general feed roll is first focused in advance. The coating film is cured by irradiating the active energy ray. The coating film on the top surface of the thick steel plate is then coated with an irradiation device 5 for hardening the top surface, which is installed between the transport roll 2'' and the 1st transport roll 2''.
The above-mentioned active energy rays are irradiated and cured. The reason for arranging the positions of the irradiation device 4 for bottom hardening and the irradiation device 5 for hardening the second side (see the second side view) is that generally the thick steel plates being conveyed are cut intermittently. Therefore, the thickness of the flame t after −· thick steel plates have passed.
There is a period of time during which there is no steel plate in the irradiation cloth for 2.2° between the transport rolls until the liW plate arrives. At this time, if the upper and lower irradiation devices are in the same position, the active energy rays will directly hit each other, shortening the life of the source. To prevent this, the positions of the upper and lower irradiation devices should be changed. It shifts it. Therefore, if the steel plate is processed continuously without any breaks,
Or, if the lifespan of the irradiation force I is not an issue] - There is no problem even if the commercial and upper surface irradiation devices 4 and 5 are placed in the same position and the upper and lower surfaces of the steel plate are hardened at the same time. It also includes cases.

Furthermore, in the case of ultraviolet rays, the active energy rays used in the present invention refer to those with a wavelength of 1,800 to 5,000 keV, and in the case of electron beams, those emitted from a power source of 300 KeV or more.

The irradiation time varies depending on the paint, ranging from clear paints such as anti-corrosion oils where irradiation for a short time of 1 to 2 seconds is sufficient, to paints with anti-rust pigments that require irradiation for up to 30 seconds. However, the processing time is much shorter than the 10 to 20 minute processing times found when using conventional oven drying or baking ovens.

Therefore, by adjusting the conveyance speed, the interval between conveyor rolls, and the width of the irradiation device for curing the upper and lower surfaces according to the paint used, it is possible to completely cure the paint from one conveyor roll to the next without reducing productivity. The paint can be cured to give an excellent product without roll marks or paint peeling.

Next, specific examples will be shown.

Rust prevention treatment according to the present invention was carried out under the following conditions using the apparatus shown in Figures 1 and 2.

Row A thick steel plate: Width 4rn-, length 10m, thickness 10mm (rust removed by blasting) Painting 2 Painted on both top and bottom surfaces using a spray method.

Paint; epoxy unsaturated acrylate]-based external radiation curing paint red iron (Fe 203) and titanium white (Ti
Contains 20% by weight of anti-corrosion pigment with tit 02) (Feeding speed: 4 m/min. Both the upper and lower surfaces of the irradiation device are irradiated with ultraviolet rays with a lamp output of 120 W/cm. The irradiation length in the direction of line movement is 1 m0. Irradiation time : 15 seconds (one side) Distance between the rolls: 2rn The cured coating film is uniformly coated on the entire surface with a film thickness of 18 to 20μrn, and there are no roll marks (;J' j
No iff or peeling of the paint film was found, and the distance was 4m/
The conveyance speed was also excellent in terms of productivity.

(Results of the Invention) As is clear from the above explanation, according to the method of the present invention, the anti-corrosion coating can be completely cured in just 11.5 seconds, Roll marks caused by rolls and coating films are eliminated.

■Since roll mark scratches and paint peeling are effectively prevented, sleeve repair painting, which was previously required, is no longer necessary.

■Improvement of productivity, uniformity of quality, and improvement in quality will be achieved.

■Since we use a paint that causes a curing reaction by absorbing active energy, there is no energy loss to the matrix, and even if the object is coated with a large heat capacity, there is no need to heat it. The improvement in process economy is significant.

■Can be installed by simply adding light equipment to a conventional anti-corrosion painting line.

This is an extremely practical rust prevention treatment method.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are a schematic plan view and a side view, respectively, of an apparatus for rustproofing a thick metal plate used in the method of the present invention. 1: Thick steel plate 2.2'', 2'': Conveyance roll 3: Coating device 4: Irradiation device for hardening the bottom surface 5: Irradiation device for hardening the top surface Applicant Sumitomo Kinku Industries Co., Ltd. Agent Patent attorney Akira Hirose −

Claims (1)

[Claims] A method of applying a rust-preventing coating treatment to a thick metal plate when the metal plate is transported by a roll for transporting the thick metal plate, the method comprising applying a rust-preventing resin paint that hardens by irradiation with active energy rays to at least the lower surface of the metal plate. and irradiating the lower surface of the metal plate with the active energy rays to cure the rust-preventing resin coating.