JPS6246587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for anticorrosive coating of narrow voids using a tubed antirust composition.

Doors, etc. of automobile bodies are designed to allow the windshield to be lowered and stored inside, to incorporate devices to raise and lower the windshield, and to reduce the weight of the vehicle as much as possible. Two steel plates are joined at the lower end using spot welding, etc.
It is sealed as plywood to form a narrow internal void. Each outer side of the plywood that forms such an internal void can be painted with a rust-preventive paint by conventionally known electrodeposition coating, etc., but the surface of the steel plate facing the internal void cannot be painted. In particular, the gap between the spot welded seal at the lower end is extremely narrow and cannot be painted. For this reason, in recent years, anti-rust compositions such as anti-corrosive oils, anti-corrosive waxes, etc. have been injected into such narrow gaps and coated with paint. One way to paint the narrow gap is to use a long, slender stick gun, or if necessary, a flexible stick gun, and move the tip of the gun to trace the area. This painting requires manpower and time, and the number of man-hours for painting is enormous.

The object of the present invention is to provide a rust-preventing composition by a coating method that overcomes the drawbacks of the conventional methods described above for coating narrow voids.

The rust preventive composition used in the present invention is a rust preventive composition enclosed in a tube, and the tube is made of polyolefin resin, is solid at room temperature, and melts when heated. , a tubed rust preventive composition which is stable at room temperature in the presence of the above rust preventive composition.

The present invention provides a rust preventive composition comprising heating the rust preventive composition contained in the tube to destroy the tube, and causing the rust preventive composition present in the tube to flow out and be applied onto the object to be coated with narrow gaps. The painting method is based on

As the rust-preventing composition that can be used in the present invention, any conventionally used rust-preventing composition can be used, such as vegetable oil, mineral oil, paraffin wax, synthetic wax, and bituminous wax. Paraffin waxes include petrolatum, carnauba wax, and waxes modified by oxidation, etc., and synthetic waxes include waxes made of low molecular weight polyethylene, polypropylene, polycaprolactone, polybutene, etc.
Vegetable oils include linseed oil, mineral oils include terpenes, various machine oils obtained through petroleum refining, liquid paraffin (JIS-K2231), and rust preventive oil (JIS-K2231).
K2246), and montan wax and its modified products by oxidation etc. can be used as bitiumen waxes.

According to the present invention, when these materials are placed in a tube to be described later and applied to the part of the object to be coated for rust prevention and heated, they are melted and spread when the tube melts and ruptures, and are applied appropriately to cover the object to be coated. Mix and use.

If necessary, the rust preventive composition may be dissolved in a volatile solvent, and after application, the solvent may be removed by evaporation to form a coating film. Hydrocarbons, halogenated hydrocarbons such as benzene, chlorobenzene, toluene, alcohols, ketones can be used as solvents. Such a hydrocarbon solvent acts as a plasticizer for the rust-preventing composition and at the same time effectively works as a plasticizer for the tube, giving the tube itself a function as a rust-preventing composition. The rust-preventing composition may contain amines to increase rust-preventing power, if desired.
A rust preventive agent such as NaNO ₂ may be added, and a coloring agent such as a pigment and a synthetic resin fine powder may also be added. Further, a partially curable resin component such as an epoxy resin or an isocyanate resin may be mixed.

The rust preventive composition of the present invention is enclosed in a tube made of polyolefin resin. The reason for this is that the rust-preventing composition has hydrocarbons as its main component, and by making the composition the same as these, it has good compatibility with these, and when melted, it becomes integrated with these, and the tube itself also acts as a rust-preventing composition. (Therefore, the effects of the present invention cannot be achieved with tubes made of incompatible vinyl chloride, etc.). As the polyolefin resin, medium or low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, polybutene, petroleum resin, etc. can be used.

The tube formed from the polyolefin resin needs to be solid at room temperature and stable at room temperature in the presence of the rust preventive composition. Note that being stable at room temperature in the presence of the rust preventive composition means that after the rust preventive composition is encapsulated in the tube,
It is sufficient that the composition is sufficiently stable during actual use in painting, and it is not necessarily necessary that the composition be stable for a long period of time after being encapsulated with the rust-preventing composition. This is because, at the time of use, a rust preventive composition may be put into the tube and applied as described below. Therefore, when a solvent is used in the rust preventive composition, or the components of the rust preventive composition themselves may have a certain degree of melting property for the polyolefin resin tube.

Further, the tube used in the present invention needs to melt when heated. This is so that when the tube containing the anticorrosive composition of the present invention is placed in the area to be coated and heated, it will be melted and destroyed, causing the encapsulated composition to flow out and spread to the target area of the object to be coated. It is. The tube only needs to be melted at the heating temperature used when coating using the coating method described below.
Such temperature is 80℃ or higher, preferably 90℃~
The temperature is 130℃.

The tube may be of any size as long as it can be inserted into a narrow gap in the object to be coated. Further, the shape includes any shape that can be adapted to the structure of the site of use.

The tube-filled rust preventive composition of the present invention can be produced by enclosing the rust preventive composition in the tube. Any method known in the art can be used to encapsulate the tube.

When using the tubed anticorrosive composition of the present invention to coat a target object, such as the narrow gap in the above-mentioned automobile door, the tubed anticorrosive composition is poured into the gap, The tube is heated to a temperature at which it melts and breaks. In this way, the encapsulated antirust composition also melts and flows out, and can be applied to the part of the object to be coated. When carrying out the coating method of the present invention, if the other parts of the object to be coated are coated with a conventionally used coating material and used at the same time to form a coating film by heating and curing it, This is preferable since the narrow gaps can be coated with antirust coating at the same time as the other coating films mentioned above are formed. Furthermore, the coating method of the present invention includes:
Of course, it can be done separately from other parts of the object to be coated.

The present invention will be explained below with reference to Examples.

Example 1 Ethylene-vinyl acetate resin (melting point 91°C:
Misolan 27) manufactured by Mitsui Polychemical Co., Ltd. (trade name) was molded into a tube with a thickness of 500μ, a diameter of 10mm, and a length of 700mm with one side sealed on one side by a conventional method, and the following antirust composition was heated to 50℃ to melt it. and inject it with a dropper,
Enclosed.

Parafine wax (manufactured by Kanto Kagaku Co., Ltd., melting point 44-46
℃) 50 parts by weight Bebicon oil (manufactured by Hitachi Chemical Co., Ltd.) 30 parts by weight Mineral terpene 10 parts by weight Aluminum silicate (Kaolin ASP-200 manufactured by Hayashi Kasei Co., Ltd.) 2 parts by weight Two steel plates treated with zinc phosphate by a conventional method The lower part of the car body door was spot welded and sealed, and the outer panel was painted with a regular cationic electrodeposition paint and baked to harden. Next, the above-mentioned tube-filled anticorrosive composition was poured into the narrow gap inside the door, and the outer panel was spray-coated with an intermediate coating by a conventional method. Thereafter, the entire door was baked in a furnace at 135°C for 20 minutes. Through this heat treatment, the intermediate coating film on the outer panel part was baked and hardened, and at the same time, the narrow gap was completely coated and sealed with the rust preventive composition.

The rust-preventive coated area thus formed showed no rust in the welded area even after 240 hours in a salt spray test according to JIS-Z-2371.

Example 2 A straw-shaped tube with a thickness of 300μ, a diameter of 10mm, and a length of 500mm was made using a conventional method using medium-density polyethylene (manufactured by Asahi Kasei Co., Ltd., Miutetsu, M500R, softening point 110°C), and a straw-shaped tube was made using low-density polyethylene wax. Tsukusu (Mitsui Hiwatukusu)
220P, manufactured by Mitsui Petrochemical Co., Ltd.) 50 parts by weight of Noxlast #366 (rust preventive oil, manufactured by Nippon Parkerizing Co., Ltd.) 100 parts by weight of mineral spirits (hydrocarbon solvent) A rust prevention composition consisting of 50 parts by weight was heated to 120°C. Warm and mix evenly. Thereafter, the tube is cooled to 70° C., one end of the tube is immersed in the rust preventive composition, and a negative pressure is applied from the other end to suck up a predetermined amount. Thereafter, both ends are sealed in a conventional manner to form the tube of the present invention. A rust preventive composition was obtained.

Next, using the usual method, the tube is placed inside the door of a car which has undergone the following steps: pre-treatment → electrodeposition coating → baking → intermediate coating → baking. After that, a top coat is applied and baked at 140℃ for 30 minutes to dry. did. The rust-preventing coated area thus formed was immersed in 3% saline and the state of rust was observed, and no rust was observed after 240 hours of immersion.

Claims (1)

[Claims] 1 The tube is made of polyolefin resin,
A rust-preventing composition contained in a tube, which is solid at room temperature, melts under elevated temperature, and is stable at room temperature in the presence of the rust-preventing composition, in which a rust-preventing composition is enclosed in a tube, A method for rust-preventing coating in a narrow gap with a rust-preventing composition, which comprises destroying the tube by heating and causing the rust-preventing composition inside the tube to flow out and apply onto the object to be coated.