JPH03230947A - Manufacturing method of painted stainless steel plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a method for producing a coated stainless steel plate, which has a clear coating film formed on its surface to prevent fingerprints from adhering to the plate.

(Prior art) The main uses of stainless steel sheets in the past were for applications that required corrosion resistance, such as bathtubs and bathtub aprons, but in recent years, they have been increasingly used for interior materials from the standpoint of design. It has become to. In particular, this tendency has become more prevalent since the development of a chemical coloring method that forms an oxide film on the surface and colors it.

(Problem to be solved by the invention) However, when stainless steel plates are used for applications that are easily touched by human hands, such as interior materials, large amounts of fingerprints adhere to them in a short period of time.
The design quality deteriorates. In particular, since fingerprints are easily noticeable on colored stainless steel plates, preventing fingerprints from adhering has been a major problem in the past.

In general, stainless steel plates tend to attract fingerprints, and
Since it is easily noticeable, fingerprints cannot be avoided when it is used for applications that are easily touched, such as interior materials.

Therefore, various cleaning agents for the purpose of removing stains such as fingerprints have been commercially available. However, since fingerprints become more difficult to wash and remove as time passes after they have been deposited, they cannot be easily removed with cleaning agents and cleaning takes time. For this reason, there is a drawback that cleaning costs become high. In particular, when cleaning a colored stainless steel plate, if a cleaning agent is applied and rubbed vigorously with a cloth, the thickness of the oxide film in that area becomes thinner, which may result in color unevenness.

Because of these problems with fingerprint removal using cleaning agents,
Attempts have been made to coat stainless steel plates with clear paint to prevent fingerprints from sticking to them.

However, the conventional painting method, for example,
As shown in Publication No. 393, "Pre-painting method for stainless steel sheet with excellent paint film adhesion," the pre-painting treatment for clear paint is chromate treatment, so stainless steel sheet is not chromated.
The F film colors the stainless steel plate yellow, changing the appearance of the stainless steel plate from before the clear paint was applied. Particularly in the case of colored stainless steel sheets, this change in appearance seriously impairs the design.

The present invention provides a method for producing a coated stainless steel plate that does not cause the above-mentioned change in appearance when producing a stainless steel plate with excellent fingerprint stain resistance by coating with a clear paint.

(Means for Solving the Problems) The present invention provides that after phosphate treatment is applied to a stainless steel plate,
Paint by applying a water-based acrylic resin coating agent, drying to form an undercoat film with a dry film thickness of 0.3 to 5.0 μm, and then applying clear paint and baking to form a topcoat film. Started manufacturing stainless steel plates.

(Function) Since the pre-painting treatment in the present invention is degreasing and phosphate treatment for the purpose of cleaning, the stainless steel plate does not turn yellow unlike chromate treatment.

However, the adhesion of the clear coating film is poor with phosphate treatment alone, so a water-based acrylic resin coating agent is applied after the phosphate treatment to improve the adhesion of the clear coating film.

The stainless steel plates to be coated according to the present invention can be coated with various surface finishes, as well as colored stainless steel plates that have been colored by chemical coloring methods, physical coloring methods, etc., without causing discoloration.

The phosphate treatment can be performed using conventionally used treatment agents such as zinc phosphate treatment and iron phosphate treatment. Note that in this phosphate treatment, if oil is attached to the stainless steel plate, it is necessary to degrease and remove the oil before treatment.

This degreasing agent is an organic solvent, alkaline solution, surfactant, etc. Water-based acrylic resin coating agent has a carboxyl group in the molecule and neutralizes the resin whose acid value is 30 to 300 with a base component. It is an aqueous solution whose main component is a water-based resin.

Adding one or both of silica sol and epoxy resin to this coating agent can improve the adhesion of the clear coating film. For 100 parts by weight of water-based acrylic resin, the addition of these additives is 5 to 40 parts by weight in terms of solid content in the case of silica sol, and in the case of epoxy resin,
The amount should be 5 to 20 parts by weight in terms of solid content. If the amount added is outside the lower limit of these ranges, the adhesion of the clear coating film will not be improved, and if it is outside the upper limit, the storage stability of the coating agent will decrease.

The coating agent is applied by any method such as a dip squeeze method, a roll coater method, a spray method, etc. with the nonvolatile content adjusted to 5 to 50%, and then dried. The drying here may be performed to the extent that the water in the aqueous solution is evaporated. If the coating thickness after drying is less than 0.5μm, the coating cannot be made uniform, and if it exceeds 5μIff, it will be difficult to dry in a short time and the coating will easily yellow. .5~5
Set it to μm.

After forming the undercoat film as described above, a baking-type clear paint such as a thermosetting or thermoplastic resin coating is applied and baked and dried at an optimum temperature.

As the clear paint, various paints such as acrylic resins, alkyd resins, polyester resins, and fluorine resin paints can be used, but fluorine resin paints are preferred because they are less likely to attract fingerprints.

The clear paint may be applied by any method such as a roll coater method or a spray method.

(Example) Plate thickness 0.4+ow, width 200m+++, length 300m
5US304 stainless steel plate with 2D finish of
648, manufactured by Nippon Parriki Rising Co., Ltd.), and then washed with water. Subsequently, concentration 20 points (total acid points)
After adjusting the temperature to 65"C and treating with a zinc phosphate treatment agent (trade name Parbond R103, manufactured by Nippon Parriki Rising Co., Ltd.), it was washed with water and dried.

Next, a water-based acrylic resin coating agent having a composition as shown in Table 1 was applied, and after drying with hot air at 100°C for 60 seconds,
Apply fluororesin clear paint with a bar coater,
The steel plate was baked and dried for 60 seconds at a steel plate temperature of 230°C, and then cooled to room temperature.

The coated stainless steel plates produced as described above were subjected to a 180° bending test to evaluate coating film adhesion, and the state of discoloration in appearance was visually observed.

The results are shown in Table 1.

In addition, the coating film adhesion was evaluated based on the following criteria.

◎ No abnormality observed ○ Approximately 10% coating peeling Δ Approximately 10 to 50% coating peeling × Approximately 50% coating peeling 8 (Effects of the invention) As described above Secondly, the clear coating in the present invention is performed after pre-treating the stainless steel plate with a phosphate treatment that does not discolor the appearance and a water-based acrylic resin coating agent.
Unlike conventional coated stainless steel sheets, which are coated with clear paint after chromate treatment, the appearance does not change color.

Claims (2)

[Claims] (1) After applying phosphate treatment to a stainless steel plate, a water-based acrylic resin coating agent is applied and dried to form an undercoat film with a dry film thickness of 0.3 to 5.0 μm, and then,
A method for manufacturing a painted stainless steel sheet, which comprises applying a clear paint and baking to form a top coat. (2) As a water-based acrylic resin coating agent, the main component is a water-based resin that has a carboxyl group in the molecule and has an acid value of 30 to 300 and is neutralized with a base component, and one of silica sol and epoxy resin is used as the main component. Alternatively, the method for manufacturing a coated stainless steel sheet according to claim 1, characterized in that an aqueous solution containing both is used.