JP2006312138A - Manufacturing method of coated stainless steel material molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of practically and economically manufacturing a coated stainless steel material molded article having excellent adhesiveness or slidability of a film, and corrosion resistance and heat resistance. <P>SOLUTION: In the method of manufacturing the coated stainless steel material molded articles, i.e. cooking appliances, shafts, or rollers, stainless steel materials formed in shapes of cooking appliances, shafts, or rollers are heat-treated, a coating surface of the stainless steel material is coated with a paint composition containing fluorocarbon resin and heat-resistant resin as a main component, and occasionally, a paint composition containing fluorocarbon resin as a main component is further painted thereon. The temperature for the heat treatment is preferably at 100 degrees or higher. Before applying heat treatment to the molded stainless steel material, the painting surface is preferably applied with defatting or grit blasting. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a corrosion-resistant and heat-resistant coated stainless steel molded article having excellent coating adhesion and sliding properties.

Iron, aluminum, and stainless steel, which are widely used as cooker materials, have advantages and disadvantages, respectively. Iron has a specific heat of about half that of aluminum and is easy to heat, but has the disadvantage of being heavy and easily rusted. Stainless steel is used in the manufacture of many cooking utensils because it has the lowest thermal conductivity, is difficult to cool, is durable and does not rust easily. Aluminum has been used in the manufacture of many cooking utensils such as frying pans because of its advantage of being light and easy to process, although it has the disadvantage of high specific heat and difficulty in heating.
In recent years, due to the diversification of food culture, there has been an increasing demand for easy cleaning of cooking utensils and for preventing the food from sticking to or sticking to the cooking utensil surface. In addition, with respect to aluminum cooking utensils, there is an increasing demand for processing a coating material having excellent mold releasability using a fluororesin as a main raw material on the cooking utensil surface from the viewpoint of Alzheimer's measures. For aluminum materials, the technology for processing coatings made mainly of fluororesin on the surface of cooking utensils is generally established, but non-adhesive coatings with excellent adhesion can be processed on iron and stainless steel materials. Is not easy, and this technology has not yet been established. The reason for this is that the non-adhesive coating film has poor adhesion to the stainless steel material, and the coating film swells while being repeatedly used for cooking, and eventually the coating film peels off, making it unusable. is there.
Conventionally, as a pretreatment of the stainless steel surface before coating, the surface of the stainless steel is activated by degreasing and grit blasting to increase the surface area, and further, the surface of the stainless steel is passivated by an acid such as a nitric acid solution. Attempts have been made to improve the corrosion resistance by increasing the chromium concentration of these materials, but in either case, it has not been possible to obtain adhesion that can withstand practical use.

  Until now, many cookware manufacturers have established a technology to process non-adhesive coatings mainly composed of fluororesin on the inside of stainless steel cooking utensils as stable coatings. However, the problem has not been solved yet.

  An object of the present invention is to provide a practical and economical method for producing a corrosion-resistant and heat-resistant coated stainless steel molded article having excellent coating adhesion and sliding properties.

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the object can be achieved by performing a heat treatment before coating the formed stainless steel material, and has completed the present invention.
That is, the present invention includes the following (1) to (10).

(1) Manufacturing a coated stainless steel product characterized by heat-treating the molded stainless steel material and then coating the surface of the stainless steel material with a coating composition mainly composed of a fluororesin and a heat-resistant resin. Method.
(2) The formed stainless steel material is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin, and further, a paint mainly composed of the fluororesin. A method for producing a coated stainless steel molded article, characterized by coating a composition.
(3) The method for producing a coated stainless steel molded article according to (1) or (2), wherein the temperature of the heat treatment is 100 ° C. or higher.
(4) The method for producing a coated stainless steel material molded product according to any one of (1) to (3), wherein the surface to be coated of the stainless steel material is degreased before heat-treating the molded stainless steel material.
(5) The method for producing a coated stainless steel material molded product according to any one of (1) to (3), wherein grit blasting of the surface to be coated of the stainless steel material is performed before heat-treating the formed stainless steel material.
(6) The method for producing a coated stainless steel material molded product according to (5), wherein the surface to be coated of the stainless steel material is degreased before grit blasting the molded stainless steel material.
(7) Painted stainless steel characterized by heat-treating a stainless steel material molded into the shape of a cooking utensil and then coating the coated surface of the stainless steel material with a coating composition mainly composed of a fluororesin and a heat-resistant resin. A method for producing steel cookware.
(8) A stainless steel material molded into the shape of a cooking utensil is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin, and further a fluororesin is coated thereon. A method for producing a cookware made of stainless steel, characterized by coating a paint composition comprising a main component.
(9) A coating characterized by heat-treating a stainless steel material molded into a shaft or roller shape, and then coating the surface to be coated of the stainless steel material with a coating composition mainly composed of a fluororesin and a heat-resistant resin. A method for producing a stainless steel shaft or roller.
(10) A stainless steel material molded into the shape of a shaft or roller is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin, and the fluororesin is further formed thereon. A method for producing a coated stainless steel shaft or roller, characterized in that a coating composition containing as a main component is applied.

In the present invention, a hard and strong stable passive film can be formed on the surface of the stainless steel material to be coated by heat treatment of the stainless steel material formed into a shape such as a cooking utensil, a shaft, or a roller. As a result, a corrosion-resistant and heat-resistant non-adhesive coating with excellent coating adhesion and sliding properties can be formed practically and economically on the surface to be coated of stainless steel products such as cooking utensils, shafts and rollers. Became possible.
As a result, stainless steel cooking utensils such as a ryepan and a pan manufactured by the method of the present invention can be easily washed after use, have little sticking to the cooked product, and have a good decorative property. Furthermore, the stainless steel cooking utensil manufactured by the method of the present invention has improved the corrosion resistance, that is, the durability of the coating, by 2 to 10 times compared to the conventional cooking utensils.
The present invention can be applied not only to cooking utensils, but also to the manufacture of shafts, rollers and the like of machine parts composed of both end support portions and a cylindrical main body portion.

The present invention will be described in detail below.
In the present invention, first, a stainless steel material formed into a shape such as a cooking utensil or a shaft or roller of a machine part is preferably heat-treated at 100 ° C. or higher, more preferably 200 to 500 ° C., and most preferably 300 to 450 ° C. The shape of the cooking utensil is a specific shape such as a frying pan or a pan, and the shape of the shaft is composed of a cylindrical main body and is used as a shaft in machine parts. The shape of a roller consists of only a cylindrical main body part, or consists of a both-ends support part and a cylindrical main body part, and is used as a roller in a machine part. The heat treatment time is preferably 10 to 60 minutes. By this heat treatment, the concentration of Cr or Ni changes on the surface of the stainless steel material, and a hard and strong thin passive film is formed.
Before performing this heat treatment, it is preferable to degrease the coated surface of the stainless steel material with an organic solvent such as acetone or methyl ethyl ketone, or an aqueous solution of a detergent, if necessary.
Alternatively, before heat treatment of the stainless steel material, it is also preferable to perform grit blasting to form fine irregularities on the surface by spraying particles such as alumina powder together with air according to necessity or purpose.
Furthermore, it is also preferable to degrease the coated surface of the stainless steel material before performing appropriate grit blasting on the stainless steel material, if necessary.
After the heat treatment, when the temperature of the stainless steel material drops to near room temperature, a coating composition mainly composed of a fluororesin and a heat-resistant resin is applied to the surface to be coated and dried. Firing is performed according to the firing conditions.
When a high degree of non-adhesiveness is required, it is preferable to coat (top coat) a coating composition mainly composed of a fluororesin on a coated surface mainly composed of a fluororesin and a heat resistant resin. .

In the present invention, the fluororesin in the coating composition mainly composed of a fluororesin and a heat-resistant resin includes polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene. -A hexafluoropropylene copolymer (FEP) etc. are mentioned. Of these, polytetrafluoroethylene (PTFE) is preferred. Examples of the heat resistant resin include polyimide resin, polybenzimidazole resin, polyamideimide resin (PAI), polyethersulfone, polyphenylsulfone, epoxy resin, and polyorganosiloxane. Of these, polyamideimide resin (PAI) is preferred.
Any of these may be used alone or in admixture of two or more.
The fluororesin and the heat-resistant resin are usually used after being dispersed or dissolved in a solvent, and if necessary, other additives are blended.
Examples of the solvent include high-boiling and high-polarity solvents such as dimethylacetamide, dimethylformamide, and N-methyl-2-pyrrolidone, methyl isobutyl ketone, methyl ethyl ketone, toluene, water, and the like. It is preferable to use as.
Examples of other additives include various colorants such as pigments, surfactants, antifoaming agents, and fillers such as mica and silicon carbide.

In the present invention, as the fluororesin in the coating composition (top coat) mainly composed of a fluororesin, the fluororesin in the coating composition mainly composed of the fluororesin and the heat-resistant resin may be preferably used. it can. These can be used alone or in admixture of two or more.
This fluororesin can also be used usually with additives such as a solvent and other pigments if necessary.
As the solvent, a solvent that disperses and dissolves the coating composition containing the fluororesin and the heat-resistant resin as main components can be preferably used.

  The coating composition can be applied by an ordinary coating method using an airless sprayer, air sprayer, dipping, roll coater, brush, etc., dried and fired.

  The present invention will be described in more detail with reference to the following examples, but the present invention should not be construed as being limited to these examples. In the examples and comparative examples, “%” means “% by mass” unless otherwise specified.

Comparative Example 1
Polyamideimide resin (PAI, Torlon made by Solvay) and polytetrafluoroethylene (PTFE, made by Daikin) so that the dry film thickness is about 10 μm on the inner surface of a 30 cm diameter frying pan made of stainless steel plate (SUS304). ) Was spray-coated using a water-based paint with a resin solid content of 36% and a mass ratio of 1: 1 as a primer, and dried at 120 ° C. for 3 minutes.
When the temperature of the frying pan has dropped to near room temperature, 0.3% pigment and 0.5% mica with respect to PTFE (solid content) are added to a dispersion of resin solid content 30% in which PTFE is dispersed in water. Spray coating is performed so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm) with the paint obtained by dispersing as a top coat, dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after repeating this process 10 times, the paint surface of the frying pan did not stick to the mixture of the three kinds, and the contamination resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. The frying pan started to appear on the inner surface (painted surface) of the frying pan from the third cycle, and blisters were confirmed on the entire surface at the end of the tenth cycle.

Example 1
A 30 cm diameter frying pan made of a stainless steel plate (SUS304) was subjected to heat treatment (air baking) at 350 ° C. for 30 minutes.
Next, when the temperature is lowered to around room temperature, a polyamideimide resin (PAI, Torlon made by Solvay) and polytetrafluoroethylene (PTFE, made by Daikin) are mixed in a mass ratio of 1 so that the dry film thickness becomes about 20 μm. A water-based paint having a resin solid content of 36% contained in 1 was spray-coated, dried at 120 ° C. for 3 minutes, and then fired at 400 ° C. for 15 minutes.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after this process was repeated 10 times, there was no sticking of the mixture of the three kinds to the painted surface of the frying pan, and the stain resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. When this boiling / leaving was performed as one cycle and boiling / leaving was repeated for 10 cycles, no blisters were observed on the inner surface (painted surface) of the frying pan until the 8th cycle. Blister started to appear. In the adhesion test by the cross cut method, there was no loss of the coating film at 100/100.

  As described above, the stainless steel surface was greatly improved in adhesion and corrosion resistance by painting by simply performing a heat treatment, easy to clean after use, and difficult to adhere to the cooked food, and the durability was improved.

Example 2
A 30 cm diameter frying pan made of a stainless steel plate (SUS304) was subjected to heat treatment (air baking) at 350 ° C. for 30 minutes.
Next, when the temperature drops to near room temperature, a mass ratio of polyamideimide resin (PAI, Sollon Torlon) and polytetrafluoroethylene (PTFE, Daikin) is 1 so that the dry film thickness is about 10 μm. The water-based paint with a resin solid content of 36% contained in 1 was spray-coated as a primer and dried at 120 ° C. for 3 minutes.
When the temperature of the frying pan has dropped to near room temperature, a dispersion of 30% resin solids in which PTFE is dispersed in water, and 0.3% pigment and 0.5% mica with respect to PTFE (solids) Spray coating is performed using the paint obtained by dispersing as a top coat so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm), dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after this process was repeated 10 times, there was no sticking of the mixture of the three kinds to the painted surface of the frying pan, and the stain resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. No blisters were observed on the inner surface of the frying pan (painted surface) even after the end of 10 cycles, and there was no coating loss at 100/100 in the adhesion test by the cross-cut method.

  As described above, the stainless steel surface was greatly improved in adhesion and corrosion resistance by painting by simply performing a heat treatment, easy to clean after use, and difficult to adhere to the cooked food, and the durability was improved.

Comparative Example 2
After grit blasting the surface of the cylindrical body of the shaft made of stainless steel (SUS304) having a diameter of 1 cm and having an average roughness Ra of 2 to 3 μm, the dry film thickness is about Sprayed with a water-based paint with a solid content of 36% containing a polyamideimide resin (PAI, Sollon Torlon) and polytetrafluoroethylene (PTFE, Daikin) at a mass ratio of 1: 1 so as to be 10 μm as a primer. Painted and dried at 120 ° C. for 3 minutes.
When the temperature of the shaft has dropped to near room temperature, a dispersion of 30% resin solids in which PTFE is dispersed in water with 0.3% pigment and 0.5% mica based on PTFE (solids) Spray coating is performed using the paint obtained by dispersing as a top coat so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm), dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of toner for a copying machine (manufactured by Sanyo Chemical Co., Ltd.) was dropped on 5 points on the painted surface of the shaft thus obtained, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified toner was gently wiped off with wet tissue paper. Even after this process was repeated 10 times, there was no toner sticking to the painted surface of the shaft and the contamination resistance was good.

  The obtained shaft was boiled for 8 hours in 10% saline (covered) and left for 16 hours in a state where boiling was stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. Blisters began to appear on the surface of the cylindrical main body (painted surface) of the shaft from the third cycle, and blisters were confirmed on the entire surface at the end of the 10th cycle.

  The obtained shaft was exposed to steam of mineral oil (Penzoil 10W-30) heated to 60 ° C. for 240 hours. Blisters occurred on the painted surface of the shaft in 120 hours.

Example 3
After performing grit blasting on the surface of the cylindrical main body of the roller composed of the both-ends support made of stainless steel (SUS304) and the cylindrical main body having a diameter of 1 cm so that the average roughness Ra is 2 to 3 μm, 400 Heat treatment (empty baking) was performed at 0 ° C. for 30 minutes. Next, when the temperature of the roller is lowered to near room temperature, polyamideimide resin (PAI, Torlon manufactured by Solvay) and polytetrafluoroethylene (polytetrafluoroethylene (PAI, Torlon made by Solvay) are used so that the dry film thickness is about 20 μm on the surface of the cylindrical body of the roller. A water-based paint having a resin solid content of 36% containing PTFE (manufactured by Daikin Co., Ltd.) at a mass ratio of 1: 1 was spray-coated, dried at 120 ° C. for 3 minutes, and then fired at 400 ° C. for 15 minutes.

  About 1 g of toner for a copying machine (manufactured by Sanyo Chemical Co., Ltd.) was dropped onto 5 points on the painted surface of the roller thus obtained, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified toner was gently wiped off with wet tissue paper. Even after repeating this process 10 times, there was no toner sticking to the painted surface of the roller, and the stain resistance was good.

  The obtained roller was boiled for 8 hours in 10% saline (covered) and left for 16 hours in a state where boiling was stopped. When this boiling / leaving was repeated for 10 cycles, boiling / leaving was repeated 10 cycles, and until the 9th cycle, no blisters were seen on the surface of the cylindrical body of the roller (painted surface). Blisters started to appear at the end of 10 cycles. In the adhesion test by the cross cut method, there was no loss of the coating film at 100/100.

  The obtained roller was exposed to steam of mineral oil (10W-30 manufactured by Penzoil) heated to 60 ° C. for 240 hours. No blisters were observed on the painted surface of the roller even after exposure for 240 hours.

  As described above, the stainless steel surface was greatly improved in adhesion and corrosion resistance by painting by simply performing a heat treatment, easy to clean after use, and difficult to adhere to the cooked food, and the durability was improved.

Example 4
After performing grit blasting on the surface of the cylindrical body portion of the shaft made of a stainless steel material (SUS304) having a diameter of 1 cm, the average roughness Ra is 2 to 3 μm, and then at 400 ° C. for 30 minutes. Heat treatment (empty baking) was performed. Next, when the temperature of the shaft is lowered to near room temperature, polyamideimide resin (PAI, Torlon produced by Solvay) and polytetrafluoroethylene (polytetrafluoroethylene) are used so that the dry film thickness is about 10 μm on the surface of the cylindrical body of the shaft. Spray coating was performed using a water-based paint having a resin solid content of 36% containing PTFE (manufactured by Daikin Co., Ltd.) at a mass ratio of 1: 1, and dried at 120 ° C. for 3 minutes.
When the temperature of the shaft has dropped to near room temperature, a dispersion of 30% resin solids in which PTFE is dispersed in water with 0.3% pigment and 0.5% mica based on PTFE (solids) Spray coating is performed using the paint obtained by dispersing as a top coat so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm), dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of toner for a copying machine (manufactured by Sanyo Chemical Co., Ltd.) was dropped on 5 points on the painted surface of the shaft thus obtained, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified toner was gently wiped off with wet tissue paper. Even after repeating this process 10 times, there was no toner sticking to the painted surface of the shaft, and the stain resistance was good.

  The obtained shaft was boiled for 8 hours in 10% saline (covered) and left for 16 hours in a state where boiling was stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. There was no blistering on the surface of the cylindrical body of the shaft (painted surface) even after the end of 10 cycles, and the coating loss was 100/100 even in the adhesion test by the cross-cut method. There wasn't.

  The obtained shaft was exposed to steam of mineral oil (Penzoil 10W-30) heated to 60 ° C. for 240 hours. No blisters were observed on the painted surface of the shaft even after 240 hours of exposure.

  As described above, the stainless steel surface was greatly improved in adhesion and corrosion resistance by painting by simply performing a heat treatment, easy to clean after use, and difficult to adhere to the cooked food, and the durability was improved.

Comparative Example 3
After the inner surface of a frying pan made of stainless steel plate (SUS304) having a diameter of 30 cm is washed with methyl ethyl ketone and degreased, polyamideimide resin (PAI, Torlon made by Solvay) and polytetra A water-based paint having a resin solid content of 36% containing fluoroethylene (PTFE, manufactured by Daikin) at a mass ratio of 1: 1 was spray-coated, dried at 120 ° C. for 3 minutes, and then fired at 400 ° C. for 15 minutes.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after repeating this process 10 times, the paint surface of the frying pan did not stick to the mixture of the three kinds, and the contamination resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. The frying pan started to appear on the inner surface (painted surface) of the frying pan from the third cycle, and blisters were confirmed on the entire surface at the end of the tenth cycle.

Comparative Example 4
The inner surface of a frying pan made of stainless steel plate (SUS304) having a diameter of 30 cm is washed with methyl ethyl ketone and degreased, and then grit blasted so that the average roughness Ra becomes 3 to 4 μm, and then 10% nitric acid solution is added. It was heated to 50-60 ° C. and left for 15 minutes. A 10% nitric acid solution was emptied, washed thoroughly with water and then dried. Resin solid content containing a polyamide-imide resin (PAI, Solvay Torlon) and polytetrafluoroethylene (PTFE, Daikin Corp.) at a mass ratio of 1: 1 so that the dry film thickness is about 10 μm on the inner surface. Spray coating was performed using 36% water-based paint as a primer and dried at 120 ° C. for 3 minutes.
When the temperature of the frying pan has dropped to near room temperature, a dispersion of 30% resin solids in which PTFE is dispersed in water, and 0.3% pigment and 0.5% mica with respect to PTFE (solids) Spray coating is performed using the paint obtained by dispersing as a top coat so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm), dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after repeating this process 10 times, the paint surface of the frying pan did not stick to the mixture of the three kinds, and the contamination resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. In the frying pan, blisters started to appear on the inner surface (painted surface) of the frying pan from the fifth cycle, and blisters were confirmed on the entire surface at the end of the tenth cycle.

Example 5
The inner surface of a frying pan having a diameter of 30 cm made of a stainless steel plate (SUS304) was washed with methyl ethyl ketone and degreased, followed by heat treatment (blank baking) at 400 ° C. for 30 minutes. Next, when the temperature of the frying pan is lowered to near room temperature, polyamideimide resin (PAI, Torlon made by Solvay) and polytetrafluoroethylene (PTFE, made by Daikin) are massed so that the dry film thickness becomes about 20 μm. A water-based paint having a resin solid content of 36% contained in a ratio of 1: 1 was spray-coated, dried at 120 ° C. for 3 minutes, and then fired at 400 ° C. for 15 minutes.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after this process was repeated 10 times, there was no sticking of the mixture of the three kinds to the painted surface of the frying pan, and the stain resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. When this boiling / leaving was performed as one cycle and boiling / leaving was repeated for 10 cycles, no blisters were observed on the inner surface (painted surface) of the frying pan until the 9th cycle. Blister started to appear. In the adhesion test by the cross cut method, there was no loss of the coating film at 100/100.

  As described above, the stainless steel surface was greatly improved in adhesion and corrosion resistance by painting by simply performing a heat treatment, easy to clean after use, and difficult to adhere to the cooked food, and the durability was improved.

Example 6
The inner surface of a frying pan made of stainless steel plate (SUS304) having a diameter of 30 cm is washed with methyl ethyl ketone, degreased, and then subjected to grit blasting so that the average roughness Ra becomes 3 to 4 μm, and then heated at 400 ° C. for 30 minutes. Processing (empty baking) was performed. Next, when the temperature of the frying pan is lowered to near room temperature, polyamideimide resin (PAI, Sollon Torlon) and polytetrafluoroethylene (PTFE, Daikin) are used so that the dry film thickness is about 10 μm. A water-based paint having a resin solid content of 36% contained at a mass ratio of 1: 1 was spray-coated as a primer, and dried at 120 ° C. for 3 minutes.
When the temperature of the frying pan has dropped to near room temperature, a dispersion of 30% resin solids in which PTFE is dispersed in water, and 0.3% pigment and 0.5% mica with respect to PTFE (solids) Spray coating is performed using the paint obtained by dispersing as a top coat so that the dry film thickness is about 15 μm (total dry film thickness is about 25 μm), dried at 120 ° C. for 3 minutes, and then baked at 400 ° C. for 15 minutes. went.

  About 1 g of a liquid (three kinds of mixtures) in which the same amount of soy sauce, sugar, and eggs was mixed onto the painted surface of the frying pan thus obtained was dropped at 5 points, and this was placed in an oven at 200 ° C. and dried for 15 minutes. When the temperature dropped to near room temperature, the solidified three-kind mixture was lightly wiped with wet tissue paper. Even after this process was repeated 10 times, there was no sticking of the mixture of the three kinds to the painted surface of the frying pan, and the stain resistance was good.

  The obtained frying pan was filled with 10% saline solution up to 2 cm from the top, covered and boiled for 8 hours, and allowed to stand for 16 hours with the boiling stopped. This boiling / leaving was defined as one cycle, and the boiling / leaving for 10 cycles was repeated. No blisters were observed on the inner surface of the frying pan (painted surface) even after the end of 10 cycles, and there was no coating loss at 100/100 in the adhesion test by the cross-cut method.

  In this way, the stainless steel surface is safer than nitric acid treatment, and by simply performing a heat treatment, adhesion and corrosion resistance by coating are greatly improved, cleaning after use is easy, and cooking is difficult to adhere, and durability is improved.

Claims (10)

  A method for producing a coated stainless steel material molded product, comprising: heat-treating a molded stainless steel material, and then coating a coated surface of the stainless steel material with a coating composition mainly composed of a fluororesin and a heat-resistant resin.   The formed stainless steel material is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin, and a coating composition mainly composed of the fluororesin is further formed thereon. A method for producing a coated stainless steel molded product, characterized by being coated.   The manufacturing method of the coated stainless steel material molded product of Claim 1 or 2 whose temperature of heat processing is 100 degreeC or more.   The manufacturing method of the coated stainless steel material molded product as described in any one of Claims 1-3 which degreases the to-be-coated surface of this stainless steel material, before heat-processing the shape | molded stainless steel material.   The method for producing a coated stainless steel material molded product according to any one of claims 1 to 3, wherein grit blasting of the surface to be coated of the stainless steel material is performed before heat-treating the formed stainless steel material.   The method for producing a coated stainless steel material molded product according to claim 5, wherein the surface to be coated of the stainless steel material is degreased before grit blasting the formed stainless steel material.   Cooking made of stainless steel characterized by heat-treating a stainless steel material molded into the shape of a cooking utensil and then coating the surface of the stainless steel material with a coating composition mainly composed of a fluororesin and a heat-resistant resin Instrument manufacturing method.   A stainless steel material molded into the shape of a cooking utensil is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin. A method for producing a coated stainless steel cooking utensil, characterized in that a coating composition is applied.   A stainless steel material formed in the shape of a shaft or a roller is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin. Manufacturing method of shaft or roller. A stainless steel material molded into the shape of a shaft or roller is heat-treated, and then the coated surface of the stainless steel material is coated with a coating composition mainly composed of a fluororesin and a heat-resistant resin, and further a fluororesin as a main component thereon. A method for producing a coated stainless steel shaft or roller, characterized in that a coating composition is applied.