JPS61164531A - Heating cooker - 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 the Invention The present invention relates to a cooking device such as a hot plate, grill pan, electric pot, etc., which has an improved coating formed on the cooking surface.

BACKGROUND OF THE INVENTION Conventionally, these cooking utensils have been coated with a coating called furan coat for the purpose of non-stick properties and heat resistance. This is done by forming a hard coat layer on the surface of the base material, such as an anodized film called a hard coat layer, a enamel finish, or a material sprayed with an inorganic oxide such as alumina. In order to obtain high adhesion, a base film mainly composed of polytetrafluoroethylene is formed, and on top of that, polytetrafluoroethylene,
It is formed by forming an upper layer film of polyhexafluoropropylene, a copolymer of tetrafluoroethylene and hexafluoropropylene, a copolymer of tetrafluoroethylene and ethylene, or the like. In practical use, polytetrafluoroethylene has been used for the upper coating because of its high heat resistance and abrasion resistance. This polytetrafluoroethylene is usually coated with a dispersion type paint in which fine particles of polytetrafluoroethylene are dispersed in water in the presence of a surfactant, and then baked at a temperature of around 400'C to form a film. It is commonly used because of its adhesion to the base material, uniformity, and mass productivity.

Problems to be Solved by the Invention However, polytetrafluoroethylene has poor fluidity (melt viscosity at 380°C is 1011 to 10 poise), so the coating film obtained by the above method has a high Not only are there many holes, but there are also many voids in the coating film, and the surface is uneven, resulting in poor smoothness. Furthermore, since it has high crystallinity, microcrystals are formed on the surface, and the surface smoothness is poor. This is not the case with the above-mentioned coating method, but also with a sheet-like product obtained by cutting a heated and press-molded product, there are similarly many voids and the surface smoothness is poor. Therefore, when cooking in a cooker with an upper coating made of polytetrafluoroethylene, fats and other cooking materials seep in through pinholes and voids, solidify and carbonize, and even damage the surface. Since there are many irregularities and the cooked food remains there, the non-stick properties gradually decrease with repeated cooking, resulting in significant discoloration and the problem that the cooked food sticks to the surface. Furthermore, when sauce, salt water, cooked food, etc. enter through pinholes and voids and reach the base material, when the base material is made of aluminum etc., it corrodes and expands in volume, causing a phenomenon called spray, and finally reaches the upper layer. There were also problems such as peeling of the coating.

Furthermore, if a copolymer of tetrafluoroethylene and hexafluoropropylene or a copolymer of tetrafluoroethylene and ethylene is used as the upper layer coating, the coating will be difficult to coat because of its low heat resistance and low hardness when heated. There is a problem that thermal deterioration and wear tend to occur.

The present invention solves these conventional problems, and has a smooth surface with almost no pinholes or voids in the coating, which prevents deterioration of non-stick properties due to cooking, corrosion of the base material, and peeling of the coating. The purpose is to clean a heating cooker that has a non-adhesive coating with a small amount of adhesive.

Means for Solving the Problems In order to solve the above problems, the present invention forms a coating containing a perfluoroalkoxy resin or a copolymer thereof on the cooking surface of a heating cooker. The coating may be formed on a base coat of the cooker base material or may be applied directly to the cooker base material.

Effect The inventors analyzed the mechanism of decrease in non-adhesiveness in heating cookers such as hot plates and grill pans having a coating made of polytetrafluoroethylene. As a result, polytetrafluoroethylene coatings are usually made by spraying a dispersion type paint in which fine polytetrafluoroethylene powder is dispersed in water in the coexistence of a surfactant, and then heated to around 400°C. However, as mentioned above, polytetrafluoroethylene has poor fluidity at high temperatures, so even when baked at high temperatures, a uniform film is not formed, and the fine powder remains in some areas. Although it is only partially melted, there are many voids called voids, making it a very porous film as shown in Figure 1. Therefore, when cooking on such a film, the food will enter through the voids in the film and adhere to it, and will solidify and carbonize due to the high temperature during cooking, causing the film to become full of the food and its charcoal. It became clear that this caused the non-adhesive properties of this film to deteriorate.

Further, the surface of the coating has many irregularities, as is clear from FIG. 1 above. This is thought to facilitate the adhesion of the above-mentioned cooked food and its charcoal-grilled material.

As a result of research based on the results of this mechanism analysis, the inventors found that by forming a film containing a perfluoroalkoxy resin or its copolymer from among a number of seven resins, As shown in Figure 2, a homogeneous coating with almost no pinholes or voids and less unevenness on the surface can be obtained, and the decrease in non-adhesion that occurs with the polytetrafluoroethylene coating described above is extremely small. A heating cooker having the following properties is obtained.

The perfluoroalkoxy resin is represented by the general formula and has a molecular structure in which a perfluoroalkoxy group is bonded to a main chain consisting of carbon atoms and 7 non-atoms.

Similar effects can also be obtained with copolymers of perfluoroalkoxy and tetrafluoroethylene, copolymers of perfluoroalkoxy and hexafluoropropylene, and the like.

Example The present invention will be explained below based on Examples.

A hot plate was prepared using the following recipe.

(1) Material base material Nialuminum die-cast base coat: Polytetrafluoroethylene resin-based base paint (manufactured by Daikin Industries, Ltd.; for polyflon enamel base) Upper layer film: Barfluoroalkoxy resin (manufactured by Typon Corporation; PFM powder paint) ; MP-1o) (2) Manufacturing method The aluminum die-cast base material is roughened by sandblasting with a seven-random blasting agent,
Alumina was coated on the top surface by plasma spraying, a base paint was spray-painted, and it was dried at 150'C for 10 minutes.

Thereafter, a PF powder coating was applied using an electrostatic coating machine, and then baked at 380°C for 30 minutes.

This hot plate was compared with a conventional hot plate on which an upper coating film made of polytetrafluoroethylene was formed to see how the non-adhesiveness decreased due to cooking. The polytetrafluoroethylene upper layer was coated with a low coating until the base paint was baked, and the upper layer was electrostatically spray-coated with polytetrafluoroethylene dinuversion type enamel, and after baking at 380°C for 30 minutes, It was obtained by showering with water and quenching.

The cooking experiment method and non-stick measuring method are shown below.

(3) Cooking experiment method Set the hot plate to "high" temperature, add 6 to 7 slices of beef (approx. 1ooN), chopped cabbage, and a pinch (approx.
．． ! 9) and commercially available yakiniku sauce, 6 small spoons (approx.
Put the food on the cooking surface, cook for 15 minutes, then turn off the electricity, let it cool for 6 minutes, and then wash it with water and a neutral detergent. Repeat this process 60 times.

(4) Non-adhesion test method As shown in Figure 3, a base coat 2. An upper layer coating 3 is applied, and on the surface thereof, an inner diameter of 2Off and a height of 2
The off cylindrical tube 4 is placed, 5 g of Evokin adhesive 6 is injected into it and cured, a load is applied in the direction of the arrow in the figure at 5 fl from the cooking surface, and the shear peel strength is compared.

The results of the comparison under the above conditions are shown in the table below.

Table (Peel strength is average value of 6 points) As is clear from the results in this table, when the upper layer is coated with perfluoroalkoxy resin, the deterioration in non-adhesiveness due to the cooking experiment is less. (Small increase in peel strength) In this example, the upper layer film of perfluoroalkoxy resin was formed by painting, but it goes without saying that the same effect can be obtained by applying a film by heat-pressing. stomach.

Effects of the Invention As described above, according to the present invention, a non-adhesive coating that is homogeneous and has less surface irregularities can be obtained, and even after long-term use, there is little discoloration or sticking of cooked food, and the corrosion resistance is high. An electric cooker with less peeling can be obtained.

[Brief explanation of drawings]

Figure 1 is a scanning electron micrograph of the surface of a coating formed from a polytetrafluoroethylene dispersion paint (
The magnification is 2500 times). FIG. 2 is a scanning electron micrograph (magnification: 2500 times) of the surface of a coating made of perfluoroalkoxy resin according to the present invention. FIG. 3 is a sectional view showing a method for measuring non-stick properties of a cooking device. 3...Top coating film, 4...Cylindrical tube, 5
······glue. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4 --- PI cylinder pipe 5-z bottled material procedural amendment (method) % formula % 1 Display of case 1985 Patent Application No. 6941, Name of invention Heating cooker 3 Relationship with the case of the person making the amendment Patent Application Powdering Office 1006 Oaza Kadoma, Kadoma City, Osaka Name (582) Representative of Matsushita Electric Industrial Co., Ltd.
Toshihiko Yamashita 4th agent 〒57
1 Address: 7, Matsushita Electric Industrial Co., Ltd., 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Contents of amendment (1) The brief explanation column of the drawings in the specification will be amended as shown in the attached sheet. (2) Delete figures 1 and 2 of the attached drawings, and correct figure N3 as shown in the attached sheet. 4. A simple explanatory diagram of the drawings is a cross-sectional view showing a method of measuring non-stick properties of a heating cooker according to an embodiment of the present invention. 3... Top coating film, 4... Inner cylindrical tube, 5...
····glue. l-1 Amended Procedures for Shugo Sumishun Tomb May 37, 1985 Dear Commissioner of the Japan Patent Office - 1 Display of Case 1985 Patent Application No. 6941 2 Name of Invention Heating Cooker 3 Person Who Makes Amendment Case Relationship Patent Application Colonel Address 1006 Oaza Kadoma, Kadoma City, Osaka Name (582) Representative of Matsushita Electric Industrial Co., Ltd.
Toshihiko Yamashita 4 Agent 571 Address 6, Matsushita Electric Industrial Co., Ltd., 1006 Bold Kadoma, Kadoma City, Osaka Prefecture Subject of amendment 6, Contents of amendment (1) Lines 5 to 11 of page 5 of the specification r400″ is around 400″C.’ is corrected as follows. ``A method of baking at a temperature of around 400°C is used, but in the case of polytetrafluoroethylene, a scanning electron micrograph at 2500x magnification shows the surface of a coating formed from polytetrafluoroethylene dispersion paint. When I checked, I found that because of the poor fluidity at high temperatures as mentioned above, even when baked at high temperatures, a uniform film was not formed, and the fine powder was only partially melted, leaving gaps called voids. '2) On page 5, lines 17 to 18, ``The film was very porous.''
··many. ” is corrected as follows. ``Also, the surface of the coating was confirmed by the above-mentioned scanning electron micrograph at a magnification of 250 degrees, and there were many irregularities.'' 3) ``Perfluoroalkoxy resin...'' on page 6, lines 2 to 5. ...obtained,'' is corrected as follows. "Barfluoroalkoxy resin'! When I confirmed it with Kyodo, I was able to obtain a coating that was extremely homogeneous with no pinholes or voids, and had very little surface unevenness." (4) Specification No. Correct "As shown in Figure 3" in line 20 of page 8 to "As shown in the figure."

Claims (1)

[Claims] A heating cooker in which a coating containing a perfluoroalkoxy resin or a copolymer thereof is formed on the cooking surface.