JPH05264045A - Surface treatment process for steel plate or stainless steel cooking equipment such as gas range - Google Patents

Abstract

PURPOSE:To improve anti-corrosion characteristics and strength against heat of a steel plate enamelled or stainless steel cooking equipment such as a conventional type gas range and to enable over-flown dew, soy source and oil stains to be easily wiped off. CONSTITUTION:A zinc coated surface of galvanized flat plate or a surface layer of stainless steel plate is applied with a sand blasting of 80 mesh at the first process, and then the plate is immersed by about 10 to 30 seconds in etching agents such as hydrofluoric acid, nitric acid, hydrochloric acid and aqueous phosphoric acid and the like with a concentration of about 0.1 to 30% as the second process. A fluorine resin film is layered on the surface of the plate and pressed against it, the plate and the film are applied by heat of about 340 deg.C to cause the film to liquified and the third process, the liquified film is press fitted into a concave part at a rough surface and replaced with residual air as the fourth process and then the film and the plate are released from their heated state as the fifth process, resulting in that the film is hardened and fixed to the plate.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Surface treatment method for kitchen appliances made of enamel steel plate or stainless steel such as gas stoves.

[0002]

2. Description of the Related Art Conventionally, the top plate of kitchen equipment such as a gas stove has been made of stainless steel or a steel plate, enameled. However, the problem remains that stains such as boiled spills, soy sauce, and oil cannot be easily wiped off.

On the other hand, there has been a fluorine resin-coated aluminum plate obtained by fusion bonding a fluorine resin to aluminum without an adhesive in the inner shell of an electric rice cooker. Therefore, when this is used as a top plate for a gas range, etc. It could not be used due to the mechanical strength of aluminum and the danger at high temperatures.

[0004]

[Problems to be solved] A conventional enamel-finished steel plate such as a gas stove or stainless steel kitchen equipment should be able to easily wipe off spills, soy sauce, oil and other stains while maintaining corrosion resistance and strength against heat.

[0005]

[Technical Means] The surface treatment method for kitchen equipment and the like of the present invention is as follows. As a first step, sandblasting of about 80 mesh is applied to the galvanized surface of a flat zinc steel plate or the surface of stainless steel.

In the second step, the substrate is dipped in an etching agent such as hydrofluoric acid, hydrochloric acid, sulfuric acid or phosphoric acid aqueous solution having a concentration of about 0.1 to 30% for about 10 to 30 seconds. If necessary, the immersed zinc steel plate or stainless plate is washed with water. Thus, the secondary recess r ₂ is formed.

In the third step, a fluororesin film is laminated on the surface of the plate, and the plate is heated to a temperature of 320 ° to 340 ° C at which the laminated fluororesin film is sufficiently softened,
Next, the fluororesin film is pressed against the plate.

In the fourth step, the plate and the film are heated to 340 ° C. inside and outside so that the softened film penetrates into the primary and secondary recesses r ₁ and r ₂ of the rough surface, and the film is liquefied, Replace with the air remaining in the rough surface. In the fifth step, the film and the plate are released from the heated state to cure the film and fix the film and the plate to the plate. In the fourth step, the inside of the furnace that heats the plate and the film is depressurized if necessary.

Finally, the plate body coated with the fluororesin film is formed into a desired shape.

[0010]

[Function] By immersing the sandblasted steel or stainless steel plate in an etching agent such as an aqueous solution of hydrofluoric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc., the first rough surface
A secondary deep recess is formed in the next recess. In particular, some of these secondary recesses are formed as lateral holes.

When the fluororesin film is brought into the melt-softened state, the softened film enters the lateral hole of the secondary recess and is replaced with air. Therefore, when the fluororesin film is solidified, it is difficult to separate it from the plate surface.

[0012]

EXAMPLES Examples of the case where the method of the present invention is applied to a zinc steel sheet ZnSt will be described below.

(A) As the first step, a zinc steel sheet ZnSt
Sandblast Sb using particles of about 80 mesh is applied to the zinc-plated Zn on the surface. Therefore, the primary recess r ₁ is formed on the surface of the steel sheet.

[B] Concentration of 20 to 30% as the second step
The zinc steel plate ZnSt is immersed in an etching agent such as internal and external hydrofluoric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and an aqueous solution for about 10 to 30 seconds. Then, as shown in FIG. 2, the secondary recess r ₂ of the primary recess r ₁ is formed on the surface of the steel sheet by the etching action. A large number of lateral holes are formed in the secondary recess r ₂ .

If the zinc steel sheet ZnSt is washed with water as needed, a sharply roughened surface is obtained. (Figure 3)

(C) As the third step, a fluororesin film F · film, for example, a film of tetrafluoroethylene copolymer is placed on a zinc steel plate ZnSt washed with water. Then, heat of 320 ° C. to 340 ° C. is applied to the steel sheet to soften the fluororesin film F · film once. Thus, the fluororesin film F · film is caught in the primary recess r ₁ and the secondary recess r ₂ of the zinc steel plate ZnSt. (Figure 4)

(D) In the fourth step, the softened fluororesin film F · film is placed on the plate body while the furnace f is placed.
Insert inside. In the furnace f, heat of 340 ° C. inside and outside is applied to the plate body and the fluororesin film F · film, and the inside of the furnace is depressurized if necessary. Then the fluororesin film F ・ fi
The lm is liquefied, and the air remaining in the primary recess r ₁ and the secondary recess r ₂ on the rough surface of the plate passes through the liquefied fluororesin film F · film and is eliminated. Thus, the primary recess r _{1 and} the secondary recess r ₂ are replaced with air and filled with the liquefied fluororesin.

Next, the plate body and the fluororesin film F.film sent out from the furnace are cooled and the film F.f.
The ilm is cured and adhered to the plate. (Fig. 5)

As the fluororesin film, a tetrafluoroethylene copolymer such as silicon resin AFLON COP manufactured by Asahi Glass Co., Ltd. is used. The melting point of this silicone resin is within 340 ° C., and zinc plating and steel plate,
The adhesive strength with the stainless steel plate is extremely good, and the zinc steel plate ZnSt in the first to fifth steps is a stainless steel plate (S
T).

The tetrafluoroethylene copolymer is presumed to have the following chemical formula.

The properties are as follows. Physical properties Specific gravity 1.73 to 1.75 Melting point 255 to 270 ° C. Melt viscosity 10 ⁴ to 10 ⁵ poise

[0022] Mechanical properties Tensile strength (23 ℃) 410~470kg / cm ² yield strength (23 ℃) 190~220kg / cm ² elongation at (23 ℃) 420~440% tensile elastic modulus kg ^/ cm 2 5 to 8 × 10 ³ Friction coefficient (against stainless steel) 0.20

Thermal Properties Thermal Expansion Coefficient 9.4 × 10 ⁻⁵ C ⁻¹ Flammability Non-combustible Continuous heat resistant operating temperature 180 ° C.

Chemical properties Chemical resistance Excellent water absorption wheel (23 ° C) 0.01%>

Electrical Properties Short voltage 12 KV / 0.
1mm film Volume resistivity 10 ¹⁷ Oha · cm Arc resistance 120 sec

From the above physical, mechanical, thermal, chemical and electrical properties, in the present invention, tetrafluoroethylene copolymer is most suitable as a film to be attached to the surface of a zinc steel plate, ZnSt or a stainless steel plate (ST). Was chosen as the one.

In addition to the above-mentioned tetrafluoroethylene copolymer, a copolymer of pretemura fluoroethylene (PTFE) and perfluro-oroalkyl vinyl ether (P
A fluororesin film such as EA), a copolymer of precitra, fluorothien, hexa, fluoro, and propylene (FEP) may be used.

From the experimental results, it was confirmed that the fluororesin film did not deteriorate even if it was boiled over and that it could be easily wiped off with a cloth even after a lapse of time. In addition, soy sauce, oil, etc. do not penetrate into the film, so that a clean feeling can be maintained forever.

Further, the zinc steel plate and the stainless steel plate have a higher strength against heat than aluminum and have a degree of corrosion by heat comparable to that of aluminum, and as a result, are more durable than the case of using aluminum.

The fluororesin film F / film may be a two-layer film as shown in FIG. 7 or a three-layer film as shown in FIG. In the case of a two-layer film, the upper layer is a transparent film nc and the lower layer is a color film, and the two layers are integrally formed by extrusion.

Since the color film c contains a pigment, the surface has little gloss, but if this is placed in the lower layer and the upper layer is made of a transparent film nc, the surface is glossy and can maintain its aesthetic appearance. Also, it can be removed quickly by wiping it against dirt. Also,
Contamination is not noticeable due to the color of the color film c.

When a three-layer film is formed as shown in FIG. 8, the middle is a color film c and the upper and lower parts are transparent films nc. By sandwiching the color film c in this way, the color is positioned in the middle of the extruded three-layer film at the time of melting, so that the color looks up from the plate body and looks beautiful. At the same time, dirt is not noticeable.

[0033]

【The invention's effect】

a. In the method of the present invention, the zinc steel plate ZnSt and the stainless steel plate ST are surface-treated with the fluororesin film F. film, compared to kitchen appliances such as a gas stove made of aluminum, whereby stains such as spillage, soy sauce and oil can be easily wiped off.
It also has high strength against heat.

B. Since the etching is performed with hydrofluoric acid, the secondary recess r ₂ is formed as a lateral hole in the primary recess r ₁ on the plate surface, so that it is perpendicular to the direction in which the fluororesin film peels off. To the secondary recess r ₂ .
Therefore, the fluororesin film is difficult to peel off.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first step,

FIG. 2 is an explanatory view of a second step,

FIG. 3 is an explanatory diagram of washing with water,

FIG. 4 is an explanatory diagram of a third step,

FIG. 5 is an explanatory view of a fourth step,

FIG. 6 is a perspective view of a gas range,

FIG. 7 is a side view of the two-layer film,

FIG. 8 is a side view of the three-layer film,

[Explanation of symbols]

Zn: Zinc plating, ZnSt: Zinc steel plate, F / fil
m: Fluororesin film, Sb: Sandblast, S
T: stainless steel, r ₁ : primary recess, r ₂ : secondary recess, f: furnace, c: color film, nc: transparent film, a: air.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 8, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Method for surface treatment of kitchen equipment made of steel plate or stainless steel such as gas cooker

[Claims]

Detailed Description of the Invention

[0001]

[Industrial application] Surface treatment method for kitchen appliances made of steel plates or stainless steel such as gas cookers.

[0002]

2. Description of the Related Art Conventionally, the top plate of kitchen equipment such as a gas stove has been made of stainless steel or a steel plate, enameled. However, the problem remains that stains such as boiled spills, soy sauce, and oil cannot be easily wiped off.

On the other hand, there has been an aluminum plate coated with a fluororesin, which is obtained by fusing a fluororesin to aluminum without an adhesive, in the inner shell of an electric rice cooker. It could not be used due to its mechanical strength and danger at high temperature.

[0004]

[Problems to be solved] A conventional enamel-finished steel plate such as a gas stove or stainless steel kitchen equipment should be able to easily wipe off spills, soy sauce, oil and other stains while maintaining corrosion resistance and strength against heat.

[0005]

[Technical Means] The surface treatment method for kitchen equipment and the like of the present invention is as follows. As a first step, sandblasting of about 80 mesh is applied to the galvanized surface of a flat zinc steel plate or the surface of stainless steel, or hairline processing is performed to make a rough surface. Thus, the primary recess r ₁ is formed.

As the second step, the substrate is dipped in an etching agent such as hydrofluoric acid, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid aqueous solution having a concentration of about 0.1 to 30% for about 10 to 30 seconds. If necessary, the immersed zinc steel plate or stainless plate is washed with water. Thus, the secondary recess r ₂ is formed.

In the third step, the plate and the fluororesin film are heated to a temperature at which the fluororesin film is sufficiently softened, the fluororesin film is laminated on the surface of the plate, and the laminated fluororesin film is pressed against the plate. The resin softened in this step almost penetrates into the primary recess r ₁ .

In the fourth step, the softened film is heated to a temperature at which the plate and the film are liquefied so that the softened film penetrates into the primary and secondary recesses r ₁ and r _{2 on the} rough surface, and the film is liquefied. Replace with the air remaining in the rough surface. In the fifth step, the film and the plate are released from the heated state to cure the film and fix the film and the plate to the plate. In the fourth step, the inside of the furnace that heats the plate and the film is depressurized if necessary.

Finally, the plate body coated with the fluororesin film is formed into a desired shape.

[0010]

[Function] By immersing the sandblasted steel or stainless steel plate in an etching agent such as an aqueous solution of hydrofluoric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc., the first rough surface
A second small recess is formed in the next recess. In particular, some of these secondary recesses are formed as lateral holes.

When the fluororesin film is brought into the melt-softened state, the softened film enters the lateral hole of the secondary recess and is replaced with air. Therefore, when the fluororesin film is solidified, it is difficult to separate it from the plate surface.

[0012]

EXAMPLES Examples of the case where the method of the present invention is applied to a zinc steel sheet ZnSt will be described below.

(A) As the first step, a zinc steel sheet ZnSt
Sandblast Sb using particles of about 80 mesh is applied to the zinc-plated Zn on the surface. Therefore, the primary recess r ₁ is formed on the surface of the steel sheet.

[B] As the second step, the concentration is 10 to 20%
The steel plate ZnSt is immersed in an etching agent such as hydrofluoric acid, sulfuric acid, hydrochloric acid, phosphoric acid, and an aqueous solution inside and outside for about 10 to 30 seconds. Then, as shown in FIG. 2, a secondary recess r ₂ is formed in the primary recess r ₁ on the surface of the steel sheet by the etching action. A large number of lateral holes are formed in the secondary recess r ₂ .

If the zinc steel plate ZnSt is washed with water as needed, a rough surface having double recesses can be obtained.
(Figure 3)

(C) As the third step, a fluororesin film F · film, for example, a film of tetrafluoroethylene copolymer is placed on a zinc steel plate ZnSt washed with water. Then, the inside and outside heat is applied to the steel sheet, and once the fluororesin film F
・ Press the film. Thus, the fluororesin film F
A part of the film penetrates into the primary recess r ₁ and the secondary recess r ₂ of the zinc steel plate ZnSt. (Figure 4)

(D) In the fourth step, the softened fluororesin film F · film is placed on the plate body while the furnace f is placed.
Insert inside. In the furnace f, heat of 340 ° C. inside and outside is applied to the plate body and the fluororesin film F · film, and the inside of the furnace is depressurized if necessary. Then the fluororesin film F ・ fi
The lm is liquefied, and the air remaining in the primary recess r ₁ and the secondary recess r ₂ on the rough surface of the plate passes through the liquefied fluororesin film F · film and is eliminated. Thus, the primary recess r _{1 and} the secondary recess r ₂ are replaced with air and filled with the liquefied fluororesin.

Next, the plate body and the fluororesin film F.film sent out from the furnace are cooled and the film F.f.
The ilm is cured and adhered to the plate. (Fig. 5)

As the fluororesin film, a tetrafluoroethylene copolymer such as the fluororesin AFLON COP manufactured by Asahi Glass Co., Ltd. is used. The melting point of this fluororesin is within the range of 255 to 270 ° C., and the adhesive strength with zinc plating, steel plate and stainless steel plate is extremely good. The zinc steel plate ZnSt in the first to fifth steps is replaced with a stainless steel plate (ST).

The tetrafluoroethylene copolymer is presumed to have the following chemical formula.

The properties are as follows. Physical properties Specific gravity 1.73 to 1.75 Melting point 255 to 270 ° C. Melt viscosity 10 ⁴ to 10 ⁵ poise

[0022] Mechanical properties Tensile strength (23 ℃) 410~470kg / cm ² yield strength (23 ℃) 190~220kg / cm ² elongation at (23 ℃) 420~440% tensile elastic modulus kg ^/ cm 2 5 to 8 × 10 ³ Friction coefficient (against stainless steel) 0.20

Thermal Properties Thermal Expansion Coefficient 9.4 × 10 ⁻⁵ c ⁻¹ Flammability Non-combustible Continuous heat resistant operating temperature 180 ° C.

Chemical properties Chemical resistance Excellent water absorption (23 ° C) 0.01%>

Electrical Properties Short voltage 12 KV / 0.
1mm film Volume resistivity 10 ¹⁷ Oha · cm Arc resistance 120 sec

From the above physical, mechanical, thermal, chemical and electrical properties, in the present invention, tetrafluoroethylene copolymer is most suitable as a film to be attached to the surface of a zinc steel plate, ZnSt or a stainless steel plate (ST). Was chosen as the one.

In addition to the above-mentioned tetrafluoroethylene copolymer, a fluororesin film such as a copolymer of precitra, fluorothien, hexa, fluoro, and propylene (FEP) may be used.

From the experimental results, it was confirmed that the fluororesin film did not deteriorate even if it was boiled over and that it could be easily wiped off with a cloth even after a lapse of time. In addition, soy sauce, oil, etc. do not penetrate into the film, so that a clean feeling can be maintained forever.

Further, the zinc steel plate and the stainless steel plate have a higher strength against heat than aluminum and have a degree of corrosion by heat comparable to that of aluminum, and as a result, are more durable than the case of using aluminum.

The fluororesin film F / film may be a two-layer film as shown in FIG. 7 or a three-layer film as shown in FIG. In the case of a two-layer film, the upper layer is a transparent film nc and the lower layer is a color film, and the two layers are integrally formed by extrusion.

Since the color film c contains a pigment, the surface has little gloss and is liable to become dirty, but this is placed in the lower layer,
If the upper layer is a transparent film nc, the surface is glossy and the appearance can be maintained. Also, it can be removed quickly by wiping it against dirt. Alternatively, the transparent film may be pressed against the color film c fused in the fourth step to form a transparent film on the surface.

When a three-layer film is formed as shown in FIG. 8, the middle is a color film c and the upper and lower parts are transparent films nc. By sandwiching the color film c in this manner, it is possible to eliminate the difficulty of the pigment of the color film infiltrating into the small recesses during melting. At the same time, there is a transparent film layer on the surface, so stains can be removed easily.

[0033]

Effects of the Invention a. In the method of the present invention, the zinc steel plate ZnSt and the stainless steel plate ST are surface-treated with a fluororesin film F / film to easily wipe off spills, soy sauce, oil, etc., compared to the conventional steel plate enamel finish or stainless steel kitchen appliances. Can be taken. Further, it has sufficient strength against heat.

B. The secondary recess r ₂ is formed as a lateral hole in the primary recess r _{1 on} the surface of the plate made by sandblasting, hairline processing, etc., especially when the solution is used. Into the secondary recess r ₂ at a right angle to. Therefore, the fluororesin film is difficult to peel off.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first step

FIG. 2 is an explanatory diagram of a second step

[Fig. 3] Explanatory drawing when washing with water

FIG. 4 is an explanatory diagram of a third step.

FIG. 5 is an explanatory diagram of a fourth step

FIG. 6 is a perspective view of a gas range,

FIG. 7 is a side view of the two-layer film,

FIG. 8 is a side view of the three-layer film,

[Explanation of symbols] Zn: zinc plating, ZnSt: zinc steel plate, F-fil
m: Fluororesin film, Sb: Sandblast, S
T: stainless steel, r ₁ : primary recess, r ₂ : secondary recess, f: furnace, c: color film, nc: transparent film, a: air.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 7]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 8]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area C23F 1/28 8414-4K

Claims (3)

[Claims] 1. A galvanized surface of a flat zinc steel plate or a surface layer of a stainless steel plate is sandblasted with about 80 mesh as a first step, and a density of 0.
Immerse it in an etching agent such as 1 to 30% hydrofluoric acid, hydrochloric acid, phosphoric acid aqueous solution for 10 to 30 seconds, and as a third step, laminate and press a fluororesin film on the surface of the plate,
And, the plate and the film are liquefied by applying heat at 340 ° C. inside and outside, and as the fourth step, the liquefied film is press-fitted into the recess of the rough surface and replaced with the remaining air, and as the fifth step. A surface treatment method for kitchen equipment made of steel plate enamel finish or stainless steel, characterized in that the film and the plate are released from a heated state to cure the film and fix the plate. 2. The surface treatment method for kitchen equipment according to claim 1, wherein a tetrafluoroethylene copolymer is used as the fluororesin film. 3. The method according to claim 1, wherein a color film as a fluororesin film is laminated with a transparent film.