JPS5848217B2 - Oil-degradable coating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is applied to the inner wall surface of a metal molded article, such as an electronic oven, an electric oven, a gas oven, and an electronic steam oven, to prevent the inside of the oven from being exposed to oily fumes generated from fats and oils during heating and cooking. The present invention relates to a fat-decomposable coating film that can effectively prevent wall contamination.

As is well known, the more frequently electronic ovens, electric ovens, and gas ovens cook poultry, beef, pork, and other oil-based products, the more oil-based fumes will be generated from the oil-rich products due to heating. The inner wall surface of the oven is usually contaminated by contamination, and the degree of contamination is proportional to the frequency of use of the oven, and sometimes this contamination builds up in the form of deposits over time.Moreover, when this deposit is remelted by heating, This flows along the inner wall surface of the oven, making the wall surface even more contaminated.

This has often been experienced in the past.

Therefore, in order to prevent this phenomenon from occurring on the inner wall surface of the oven, we introduced catalysts such as Fe, Co, Mn, and Cr, which are known as catalysts that have the function of decomposing oils and fats and hydrocarbon compounds (hereinafter referred to as decomposition catalysts). (a) Preparations of enamel-based materials such as silica, feldspar, silica, etc., (b) Preparations of aluminum-enamel materials such as lithium, boron-silicic acid, etc.; (
c) Kneading together with a preparation mainly containing a water glass-based substance such as alkali silicate, alkyl silicate, etc.
Several methods have been devised and known in which the desired inner wall surface of the oven is coated with this crosstalk in advance.

However, although such a method can prevent the contamination caused by heating of the oil and fat processed products, various drawbacks have been pointed out as follows.

In other words, in (a), 8
Since high temperature treatment of 00°C or higher is required, there are restrictions on the type and thickness of the base metal (hereinafter referred to as base material), and in case of O), the coating film formation temperature is 540 to 550°C.
Although it is practically advantageous because it requires much lower temperature treatment than (a) above, there are restrictions in terms of the base material, such as the base material must be aluminum, aluminum alloys, or steel plate coated with aluminum. .

Furthermore, regarding (c), as in (a) and @, there is no particular selectivity in terms of the substrate, and the desired coating film can be obtained by low-temperature treatment below 260°C, but it depends on the surface treatment conditions of the applied substrate. It has the drawback that the coating film does not adhere well and cracks occur in the coating film, causing the coating film to peel off.In addition, it has a drawback that the coating film is hydrolyzed due to its high water absorption.

Moreover, it also has the disadvantage of being inferior to the above two methods (A) and (0) in terms of coating hardness.

In addition to the above, methods (a), (b), and (c) all use water as a dispersant in the coating material during the coating process. Changes in temperature and humidity in the atmosphere make it difficult for the coating surface to become porous and evenly distributed. Therefore, in order to obtain a porous coating with even pores, it is necessary to always select the optimal coating conditions that correspond to the temperature and humidity in the atmosphere. They share the shortcomings of having to be.

Based on the above-mentioned points, the inventors of the present invention have conducted various studies to improve the above-mentioned points.
203 and ZrO2 or Al203, TiO2
, Fe203, ZrO2 to each of the three mixed powders.
By spraying a mixture of two or more powders selected from Co304, MnO2, and Cr203 onto the base metal surface, a coating film (porous coating film) with a desired uniform porous state can be obtained. The present invention was completed by experimentally discovering that oils and fats and water are easily absorbed, the absorbed oils and fats are decomposed by the presence of a decomposition catalyst, and the coating film has a good hardness (Mohs) of 9 to 12. Intimidated.

In the present invention, Al203 (powder) and Fe203,C
Using a mixture of two or more powders selected from o304, MnO2, and Cr203 (all powders) as a thermal spraying agent means (a) using Al203 alone and spraying it onto the base material surface (in a specified manner). temperature), the coating film becomes a porous coating film with a well-balanced hardness (Mohs) of 11 to 12, almost independent of changes in atmospheric temperature and humidity, and easily absorbs oils, fats, and water. The purpose is to effectively decompose fats and oils by interposing the decomposition catalyst therein.
Instead of 203 alone, A l2 0 3 + T s 02
If TiO2 is used alone and thermally sprayed onto the substrate in the same manner as in (a), a porous coating film can be obtained almost unrelated to atmospheric temperature and humidity changes, but Al20
3. In addition to being slightly inferior in hardness compared to when ZrO2 is used alone, it also has elasticity and pore formation per unit.
Since the amount is less than that of O2, Al203 is mixed to improve porosity and coating hardness (Mohs: 9 to 10). .

(c) In 0) above, using ZrO2 instead of TiO2 means that the coating film obtained by thermal spraying ZrO2 alone can be obtained almost unrelated to changes in temperature and humidity as described above, and there is no particular problem in terms of hardness. , A because it is unstable due to physical properties during thermal spraying.
This is due to the fact that 1203 is used in combination to supplement this and at the same time improve the decomposition of fats and oils.

(d) The use of a mixture of Al203, TiO2, and ZrO2 means that during thermal spraying, the special points of these three when used alone are mutually complemented, and the resulting coating film is resistant to changes in temperature and humidity as described above. It is an X-grade material that is designed to maintain the desired uniform porosity and hardness almost independently, to improve the absorption of fats and oils, and to improve the decomposition of fats and oils.

In addition, as a resolution catalyst used in the present invention, ,Fe203
2 selected from rCo304, MnO2, Cr203
The reason for using a mixed powder of two or more kinds of oxides is that the ability of these oxides to decompose fats and oils differs in terms of the type of fats and oils, decomposition temperature, decomposition time, etc. This is because the decomposition of absorbed fats and oils is made more effective by mixing them.

In this way, the present invention provides the above (a), (0), and (c).
A desired coating film can be easily obtained by any of the methods (d) (see examples and attached table).

As the base material used in the present invention, any known steel, stainless steel, aluminum or aluminum alloys, steel plate whose surface is coated with aluminum, etc. may be used.

However, in order to thermally spray the mixed powder of the metal oxide onto the corresponding metal surface, any known plasma method or gas method may be used, but it is preferable to use the plasma method, which can perform high-speed thermal spraying, in terms of efficiency. It is far more advantageous than the gas method.

Thermal spraying conditions include the particle size of the powder to be applied, the type of thermal spraying gas,
Needless to say, various requirements such as flow rate, flow rate and thermal spraying distance are taken into consideration, but unlike the previously known method (using a mixture of a decomposition catalyst and a binder), the present invention takes into consideration atmospheric temperature and humidity. Because it is completely unaffected by change,
It is possible to easily and efficiently obtain a uniform porous coating film that always corresponds to the thermal spraying conditions.

It is not theoretically clear why the coating film obtained by the present invention absorbs oils and fats and water easily, but according to the experiments of the present inventors, a certain particle size (10
When the mixed powder of the metal oxides (0 to 200 mesh) (see examples) is thermally sprayed onto the substrate surface, a uniform porous coating film is generated without being affected by changes in temperature and humidity. In this case, the absorption ability caused by the porosity of the coating film activated by metal oxides such as Al, Ti, and Zr in the thermal spray composition makes it easier to absorb oils, fats, and water onto the porous surface, and at the same time, the thermal spray agent It is thought that the fats and oils are effectively absorbed and decomposed one after another because the fats and oils are decomposed by the decomposition catalyst present therein.

In this way, the present invention uses a single powder of Al203, a combination of Al203 and TiO2, or a powder of Al203 as a thermal spray agent.
3 and ZrO2 or A 11 2 03 t
T ] 02 By spraying a mixture obtained by adding two or more powders selected from Fe203, Co304, MnO2, and Cr203 to each of the three mixed powders of tZrO2 onto the base material surface, the resulting coating film can be It is characterized and significant in that it makes it easier to absorb fats and oils and water, and also effectively decomposes fats and oils, thereby increasing the strength of the coating film.

As can be seen from the above description, the present invention has the above-mentioned characteristics and fully exhibits the desired effects.
For example, when pre-coating this on the inner wall surface of an electronic oven, electric oven, gas oven, or electronic steam oven, it can effectively remove oily fumes and water generated during cooking of oil and fat processed products in the oven. While absorbing the oil, it also decomposes the oil and fat content during absorption, thereby preventing contamination of the inner wall surface of the oven by oily fumes.

This is particularly effective in cases where oil-based processed products are frequently cooked in the oven, etc., and there is no accumulation of contaminants caused by oil-based fumes that occur in the past, and the inner wall surface of the oven is always clean. can be maintained.

Therefore, the practical effects from this aspect are large, and the scope of its application is also large.

The present invention will be explained in more detail below with reference to Examples.

Example 1 Stainless steel plate (100mmX100mmX
1. The surface of the J'2m) was degreased by a conventional method, then blasted with #60 Morundum (product name: Showa Denko), and then a metal oxide powder mixture consisting of the following composition was applied using a plasma spraying machine ( Plasma Dyne Co., Ltd.) was used to thermally spray the plasted surface using argon-helium gas to a film thickness of 100 microns to obtain a uniformly porous coating (average pore diameter of approximately 10 microns).

Next, this stainless steel plate was heated and held at 250°C, and a drop of vegetable oil (safflower oil) was dropped onto the appropriate place on the surface. After 1.5 minutes), the oil smudge that had appeared during the absorption of the oil droplets had completely disappeared, and the area looked exactly the same as the non-droplet area, which was satisfactory as it was indistinguishable.

(Composition) Al203 (100 mesh) 100 parts (weight MnO2
(120〃) 60〃Co304 (120〃) 40ll Example 2 30 micron aluminized steel plate (100imX10
0milF'! After degreasing the surface of (m) using a conventional method and polishing it with a lace buff, a metal oxide powder mixture having the following composition was sprayed onto the surface using a plasma method to a film thickness of 120 microns to obtain the desired porosity (average pore diameter of approximately 8. micron) to obtain a coating film.

Next, this aluminized steel plate was subjected to the same test under the same conditions as in Example 1.

As in Example 1, the results were extremely satisfactory.

(Composition) Al203 (150 mesh) 40 parts Tt02 (120 't) 40ttMn
02 (120 tt) 70uCo 3
04 (1 2 0 tt) 2 0
ttFe203 (120〃) 10〃 Example 3, 2. Te7 Ress board (100mm x 100m
m×i. J'! After treating the surface of m) in the same manner as in Example 1, a metal oxide powder mixture having the following composition was thermally sprayed in the same manner as in Example 1 to coat the surface with 70 micron porosity (average pore diameter of approximately 10 microns). Obtain a membrane.

This stainless steel plate was then subjected to the same test under the same conditions as in Example 1, and very satisfactory results similar to those of the previous example were obtained.

(Composition) Al203 T i0 2 Z r 0 2 MnO2 Co304 Same below) 100 parts 2 1 5 tt 1 0 0 u 50 (180 mesh) (180 tt ) (180 u) (100 n) (100 u) Implementation Example 4 30 micron F luminized steel plate (100 mix 1
0 0mm x 1. mm) was treated in the same manner as in Example 2, and a metal oxide powder mixture having the following composition was thermally sprayed using a plasma method to a film thickness of 140 microns to obtain the desired porosity (average pore diameter of approximately 10 microns). Obtain a coating.

Next, this aluminized steel sheet was subjected to the same test under the same conditions as in Example 1, and the oil droplets were completely absorbed into the porous coating film in 1 minute and 50 seconds, and after 54 seconds, the oil droplets were completely absorbed into the porous coating. The oil smear completely disappeared and was seen as the same as the non-dropped area, indicating a satisfactory result.

(Composition) Al203 (150 mesh) 100 parts Mn02
(120 tt) 70ttCr203 (
150 〃 ) 70〃ZrO2 (150 〃
) 35 The above description is given as a representative embodiment of the present invention, and the present invention is not limited to this embodiment.

Below, in order to compare the coating film effects of the present invention product and conventional product,
Both of them were subjected to the required tests under the same conditions below.

(1) Example 1 (base material stainless steel, film thickness 100, am), Example 2 (base material aluminized steel plate, film thickness 120 μm) and Example 3 (base material stainless steel, film thickness 120 μm) according to the present invention as test pieces
5 each of 4 (base material aluminized steel plate, film thickness 140 μrrL), and the corresponding conventional products listed in Appendix ■ (base material stainless steel, film thickness 100 μm), same ■ (base material aluminized steel plate, Five pieces each (dimensions are the same as in the corresponding example) were used.

(2) In the test, each specimen of the present invention product and the conventional product was heated to a predetermined temperature (
After heating and holding at 250℃, add a drop of safflower oil (using a pipette) to the coating surface, and check the time required from the time of dropping until it is fully absorbed into the coating, and the size of the safflower oil mark that remains after absorption ( φ) and decomposition of safflower oil after absorption (by decomposition catalyst)? The main purpose of this study was to measure and confirm the time from the generation of fume (pale purple smoke) until its end, as well as the subsequent state of the coating surface and coating hardness.

According to the results of this test, the coating film of each test piece that ultimately became the present invention did not leave any traces after oil decomposition after dropping safflower oil on the surface, and it was possible to pass the test. No trace was observed even when the same spot on the same specimen was repeatedly tested 16 times.
In addition, while it shows a good coating hardness (Mohs) of 9 to 12, in the case of the conventional product (■) listed separately, drops of safflower oil were repeatedly applied to the same place on the same specimen 16 times in the same way as the inventive product. As a result, a carbon film was observed every time in ■.Although no visible film fall was observed in ■, it was confirmed that oil drip marks remained in the form of stains every time.

Furthermore, in the case of ■, in the same repeated test as above, 5
After repeating this process, it became clear that the oil had no absorption capacity at all and remained on the coating surface as oil droplets, so we had no choice but to stop dropping the oil after the 6th time.

Moreover, the coating film hardness (Mohs) is 3 to 7, and the inventive product is 34 to 7.
It was confirmed that the amount was only 58% (see attached table "Presence or absence of absorption marks and coating film hardness").

By the way, if we talk about the manufacturing method (outline) and precepts of the conventional products ■~■ above, ■■ is made of SiO2, K20, B2 on the steel surface.
03, Al203, CaO, NaSiF, BaO, T
Frit containing i02 etc. and Fe203, MnO
2 and other mixtures were applied and annealed at 750 to 800°C.
iO, B203, Na20, Al203, L i2 0
A mixture of a frit containing tK20sC a O, etc., and Fe203, MnO2, etc. is applied53.
It was calcined at 0 to 570℃, and () is a viscous liquid mainly composed of alkali silicate, mixed powder of ZnO, CaO, Fe203, MnO, etc., which is a curing agent for the alkali silicate, is added and stirred. The liquid was applied to a metal plate via a spray gun and fired at 260 to 300°C.

As is clear from the above table, the product of the present invention exhibits excellent effects that eliminate the drawbacks of conventional products, and therefore, the practical benefits it brings to related industries are particularly highly evaluated.

Claims (1)

[Claims] 1 person l203 single powder or Al203 and T t
F e2 o3) Co3 04 t M
An oil/fat decomposable coating film characterized in that a mixture of two or more powders selected from n021 C r203 is thermally sprayed onto the surface of a base metal.