JPS61137534A - Heat resistant painted steel plate for food heating processing tool - 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 [Field of Industrial Application] The present invention relates to a heat-resistant coated steel plate that is a material for food heating processing tools such as so-called bakeware, oven top plates, and heating plates.

[Conventional technology and its problems]

So-called bakeware (baking mold) for baking bread and cakes
In general, oven top plates, etc. are used under high temperature conditions of around 200℃ and food is directly scattered, so corrosion resistance and heat resistance are highly required.
Further, it is preferable that the material has so-called non-adhesive property (mold releasability), which means that stains can be easily removed. Steel sheets with excellent corrosion resistance include steel sheets coated with corrosion-resistant paints, such as steel sheets coated with epoxy resin for the undercoat and acrylic, polyester, vinyl chloride resin, etc. for the topcoat, but the continuous heat resistance temperature of these coatings is The temperature is only about 120 to 130° C. at most, and it is difficult to avoid deterioration of coating film performance when used in a high temperature range.

Moreover, such conventional coated steel sheets have the disadvantage that they have insufficient non-stick properties, insufficient press formability, and easily crack when subjected to drawing processing.

In addition, for example, frying pans and heating plates, etc., are made by applying fluororesin processing to steel plates, but the non-stick properties and corrosion resistance are insufficient, and since they are manufactured by press molding and resin processing, press processing of steel plates In this case, there is a problem similar to the above-mentioned problem of poor moldability. In addition, tools treated with resin-treated foods generally have the disadvantage of requiring oiling with edible vegetable oil or the like prior to first use to ensure non-stick properties.

[Means to solve the problem]

In view of these conventional problems, the present invention has been developed as a steel plate for food heating processing tools, which has a heat resistance of 200°C or higher, has excellent non-stick properties and press formability, and has been commercialized. It is an object of the present invention to provide a heat-resistant coated steel sheet that does not require initial oil application in cases where the surface of the stainless steel sheet or plated steel sheet is coated with oil.
Its basic characteristics are that it forms a coating film mainly composed of a mixture of tetrafluoroethylene resin and other heat-resistant resins, and that the coating film is impregnated with edible vegetable oil.

The present invention also provides a two-coat, two-bake coated steel sheet in which a heat-resistant polyphenylene sulfide resin, a polyether sulfon resin, or a mixture of a polyphenylene sulfide resin and a polyether sulfon resin is applied to the surface of a stainless steel sheet or a plated steel sheet. A primer coating film made of resin is formed, and a coating film mainly composed of a mixture of tetra7tethylene resin and other heat-resistant resin is formed on top of the primer coating film, and the coating film is impregnated with edible vegetable oil. are the other basic characteristics.

The present invention will be explained in detail below.

The present invention relates to a heat-resistant coated steel plate for food heating processing tools such as so-called bakeware, and stainless steel plates and various plated steel plates can be used as the raw steel plate. The plated steel sheets mentioned above include Zn-plated steel sheets, At-plated steel sheets, Zn-At alloy plated steel sheets, Ni-plated steel sheets, and Z-plated steel sheets.
n-NL alloy plated steel plate, stainless steel plated steel plate, C
There are r-plated steel sheets (so-called tin-free steel sheets), etc. Among these steel plates, Tin 7 Lee steel plate is preferred when emphasis is placed on paint adhesion and durability under high temperature conditions.

This steel plate is made by subjecting the steel plate to electrolytic chromate treatment to form a coating consisting of metallic chromium and chromium oxide, and has extremely good oxidation resistance at high temperatures.
It hardly oxidizes even in an atmosphere around 0°C, and has superior paint adhesion compared to Zn-plated steel sheets and the like.

In addition, if painting adhesion is important, ζ is a stainless steel plate (stainless steel plate and stainless steel plated steel plate), Zn
-At-based alloy-plated steel sheets, zn-Ni-based alloy-plated steel sheets, and Nt-based alloy-plated steel sheets are preferred. These steel plates have superior corrosion resistance and paint adhesion compared to ordinary cold-rolled steel plates, Zn-plated steel plates, Sn-plated steel plates, and the like. Paint adhesion largely depends on the removability of the oxide film that forms on the surface of the steel plate (or the plated surface in the case of plated steel sheets), and peeling off of this oxide film is one of the main causes of inhibiting paint adhesion. In this respect, each of the steel plates described above has a property that the formed oxide film is less likely to peel off compared to other steel plates such as Zn-plated steel plates, and therefore excellent paint adhesion can be obtained.

In addition, when using a plated steel plate as the material, it is necessary to form a coating by phosphate treatment or chromate treatment.
This can improve paint adhesion, for example, At
- It can be said that this method is particularly effective when the At% is low in the case of Zn alloy plating.

Further, it is possible to add other elements to the above At-Zn-based plating, Zn-Ni-based plating, and Ni-based plating in consideration of corrosion resistance and the like.

The present invention applies high temperature (200°C or more) to the surface of such a steel plate.
Forms a heat-resistant coating film that has heat resistance for regular use.

Painting is done with one coat and one bake or two coats and two bakes. First, in the case of 1-co) L-bake, a heat-resistant coating film is formed that is mainly composed of a mixture of polytetrafluoroethylene resin (PTFE) and other heat-resistant resins. Other heat-resistant resins that can be mixed with PTFE include polyphenylene sulfide (PPS) and polyether sulfonate (PKS).
etc., PTFE + PPS paint, PTFFI: +
Used in the form of PES-based paints.

Tetrafluoroethylene resin has heat resistance and processing lubricity, so it has excellent press workability, and therefore also has excellent non-adhesive properties (R-type properties).

Such coatings can be applied using continuous strip coating equipment under normal coating conditions.

After painting, steel plates are generally baked at a temperature of 350°C or higher.

In addition, in the case of 2 coats and 2 bakes, first use polyphenylene sulfide resin CF'PS as the primer coating.
Alternatively, a coating film is formed using polyether sulfone resin (PES) or a mixture of both resins (PPS+PE5) as a heat-resistant resin. This primer coating film is exposed to high temperatures (2
It has general heat resistance at temperatures above 00°C. Examples of such primers include the following food paints.

(a) Solvent = 60-70% CNMP + Tsurpets) Heat-resistant resin: 20-30% (pF:s) Rust-preventing pigment: 1% st, Cr, m fat content 佽) Solvent 26
5% (NMP + Nrupetsun) Heat-resistant resin: 20-30% (
(PES) Rust-inhibiting pigments, At 10, and inorganic pigments.Such a primer is subjected to a baking treatment after its coating is formed. This baking temperature is lower than the baking temperature after topcoating, and is generally carried out in a temperature range of 200 to 400°C.

A top coating (finishing) coating is formed on the primer coating, but this coating is made of ethylene tetrachloride resin (P) as a heat-resistant resin, as in the case of the 1-coat 1-baked steel sheet described above.
TFE) is an essential component, and the main component is a mixture of tetra7tethylene resin and other heat-resistant resins.

After the coating film is formed, the steel plate is subjected to a second baking process in a heating furnace. This baking temperature is about 350 to 400°C.

Of the above two-coat coatings, it is preferable that the primer coating contains a rust-preventive pigment in order to place emphasis on corrosion resistance.As this rust-preventive pigment, strontium-based Inorganic pigments such as On the other hand, from the viewpoint of ensuring lubricity and non-adhesiveness during press working, the finish coating film does not contain anti-rust pigments that would impair these properties. However, a pigment for gloss (for example, At) may be included.

Furthermore, in the present invention, the coating film as described above is impregnated with edible vegetable oil. As the edible vegetable oil, appropriate ones such as cottonseed oil, soybean oil, and corn oil can be used. The edible vegetable oil impregnated into a film in this way improves the press formability of the steel plate, and also improves the non-stick properties when manufactured into a product, making the usual oil application before use unnecessary.

Such a coating of edible vegetable oil is applied to the coated film after the spot treatment by an appropriate method such as a one-way coater, and is impregnated into the coated film.

〔Example〕

The coated steel plates shown in Table 1 were manufactured, and their press formability (non-adhesiveness has a correlation with press formability and can be evaluated by press formability), corrosion resistance, and heat resistance were investigated.

These results are shown in Table 2.

The test conditions for each characteristic test are as follows.

0 Press formability test (lubricity) Dice: 40.9 dar 3R, punch = 40 dar 4R.

Wrinkle holding plate: In a deep drawing test using 40.50, the wrinkle holding pressure was increased until it reached its limit, and the wrinkle holding pressure was measured. 0 Corrosion resistance test Red rust (TFS), white rust (Zn
-At) generation time ◎: 500: more than 01240 hours or more △2 50 hours or more ×: less than 24 hours
ad + tape peeling ◎: No peeling ○: Peeling △: Peeling about 10 degrees ×: Peeling @ about 20 degrees
It has excellent corrosion resistance as well as general heat resistance under the above), and also has extremely excellent press formability and non-adhesive properties, and does not require the application of press oil or oil during use after product production. This makes it unnecessary, and it is extremely useful as a coated steel plate for food heating processing tools such as bakeware, open top plates, and heating plates.

Patent applicant Nippon Kokan Co., Ltd. Inventor Takashi Shimomura Ryodo
Shidong Jame Tatsu
Takashi Yamachi, Patent Attorney, Sho Yoshihara, Dou Sando
Kiyoshi Takahashi procedural amendment (voluntary) February 21, 1939 6Q

Claims (2)

[Claims] (1) Food heating processing in which a coating film mainly composed of a mixture of tetrafluoroethylene resin and other heat-resistant resin is formed on the surface of a stainless steel plate or a galvanized steel plate, and the coating film is impregnated with edible vegetable oil. Heat-resistant painted steel plate for tools. (2) Forming a primer coating film on the surface of a stainless steel plate or a galvanized steel plate using a heat-resistant resin made of polyphenylene sulfide resin, polyether sulfon resin, or a mixture of polyphenylene sulfide resin and polyether sulfon resin. A heat-resistant coated steel sheet for food heating processing tools, further comprising forming a coating film mainly composed of a mixture of tetrafluoroethylene resin and other heat-resistant resin thereon, and impregnating the coating film with edible vegetable oil.