JPH0343474A - Heat-resistant coating film and heating cooker coated with the same film - Google Patents

Abstract

PURPOSE:To obtain the subject coating film suitable for coating in the interior of heating cooker such as oven, having high hardness and slipperiness of surface, comprising a polyborosiloxane, etc., as a binder, a compound having a lamellar structure, and containing complex oxide of Ni or Mo, etc. CONSTITUTION:The objective coating film comprising a polyborosiloxane and/or polyborotitanosiloxane as a binder, a compound having a lamellar structure, a complex oxide of Ni or Mo and, if necessary, a porcelain enamel component or glass powder. The coating film is applied to the inner wall of cooking chamber for preparation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a heat-resistant coating that is applied to the inside of a heating cooker such as an open cooker or a grill, and has the function of decomposing and removing dirt generated during cooking under heating. The present invention relates to a cooking device provided with the heat-resistant coating.

Conventional technology There are two main types of coatings: coatings that decompose and remove dirt that adheres to the inner walls of cooking appliances under heat when cooking meat, fish, etc., and cooking utensils coated with the coatings, as follows: .

The first method is to raise the internal temperature of the enamel so that the coating heats up from the enamel and the surface temperature of the enamel reaches approximately 450° C. or higher, thereby decomposing dirt on the enamel surface using heat.

Second, the coating uses inorganic metal phosphate, silicate, or enamel as a binder, and Mn and Cu.

This is the case of porous vII# in which transition metal oxides such as Fe, Co, and Ni and alkaline earth oxides are dispersed.

This kind of coating used the catalytic action of metal oxides to burn and decompose oil stains at low temperatures.

Problems to be Solved by the Invention However, the above conventional techniques have the following problems. In enamel, cracks occur and peeling occurs when the temperature reaches soo'c or higher. As a result, the iron base material corrodes and becomes unusable as a cooker.

In addition, for porous membranes using phosphates or silicate as a binder, the coating must be made as porous as possible to increase the contact area between the oil and the catalyst and to improve oxygen diffusion within the coating to ensure complete combustion of oil stains. Must be.

However, if the material is made porous, its hardness decreases and it may peel or be damaged, which poses a practical problem. Furthermore, burning causes residual tar components and ash to enter the porous spaces and settle there, which may gradually reduce purification performance.

As mentioned above, there are some problems with the conventional technology, but the present invention deals with a structure that cleans oil stains on a dense and hard coating.

Means for Solving the Problems In order to solve the above 11 problems, the present invention uses one type or a mixture of two of polyborosiloxane and polytitanosiloxane as a binder, and a compound having a layered structure and Ni, M
A heat-resistant coating made of a composite oxide of o, which is dense and smooth, and has the ability to oxidize and decompose oil stains, and the heat-resistant coating is applied to the inner wall of the cooking appliance, and the heat-resistant coating is applied to the inner wall of the cooking appliance to prevent the particles from scattering from the food during cooking. To provide a heating cooker that cleans dirt adhering to food.

action The oil stain purifying effect of the film according to the present invention will be explained.

For stains, triglycerides of higher fatty acids such as oil,
Examples include protein, carbohydrates, salt, ash, etc.
Here, the action will be explained using oil as a representative example.

If the structure of oil is given by formula (1), the reactions necessary for purification are the breaking of carbon bonds and oxidation to carbon dioxide and water.

R3-C-0-CH.

1 (R+, Rt, and Rs are saturated and unsaturated alkyl groups) When heat is applied to oil, dehydrogenation and tar formation occur.

High temperatures of 450°C or higher are required to oxidize and decompose tar.

Therefore, conventional porous coatings incorporate a catalytic action into the thermal decomposition process to decompose tar at a relatively low temperature.

However, in practical use, porous coatings have problems such as being easily peeled off and easily damaged. Furthermore, if complete combustion is the goal, there will inevitably be a limit to the purification ability in terms of the amount of dirt that can be processed.

Therefore, the present invention first focuses on weakening the bonding force between the tar component and the coating surface.

When the semi-organic polyborosiloxane and polyborotitanosiloxane used as the binder in the present invention are fired at 450° C. or higher, they become free of #9 and can form a very dense thin film.

For example, conventional porous coatings have pores on the order of tens to hundreds of microns, but the pores of the thin film using polyborosiloxane or the like as a binder are at most on the order of several microns.

Furthermore, by incorporating a layered compound, the releasability of the tar component from the coating surface was improved.

Second, we focused on oxidatively decomposing oil stains in the surface layer of the coating, and mixed a composite oxide of Ni and MO as a catalyst.

A composite oxide of Ni and Mo is known as a highly active catalyst for hydrogenolysis of petroleum, gasoline, etc.

As described above, the heat-resistant coating of the present invention oxidizes and decomposes oil stains due to the oxidizing action of the Ni-Mo composite oxide, and furthermore, since the coating is dense and has good surface slipperiness, the remaining tar components and ash are removed. Since it can be easily peeled off and wiped off, when used on the inner wall surface of an open or grill cooking appliance, oil stains scattered from food and attached to the wall surface can be cleaned by applying heat.

Example An embodiment of the present invention will be described below.

First, the manufacturing method of the film will be explained.

Binder and filler, layered compound and Ni.

Mo complex oxide and solvent are dispersed in an attritor for 24 hours, and the resulting paint is sprayed with a spray gun (DeVilbiss spray gun, nozzle diameter 1.4 mm, air pressure 2 to 2.5 k).
g/c+a) onto a stainless steel (SO3304430> base material) and sequentially fired at 500°C to 1600°C to form a film.

For the NiMo composite oxide, starting materials were a nitrate for Ni and an ammonium salt for Mo, and the aqueous solutions of each were mixed, the resulting precipitate was filtered, washed with water, dried, and incinerated at 450°C. The analysis result of the product is NtO:MoO,ζ
It was 35:36.

Next, a certain amount of salad oil was dropped onto the film, and the film was left in an oven set at a certain temperature to conduct an oil purification test.

The formulation of the paint used to form the film and the results of the oil purification test are summarized in the table below.

All formulations are shown in weight ratios.

The margin oil purification test below was conducted at 380'C, and the time required for purification is shown. The films of Nα■ to Shai■ containing Mo St, WSz, and BN and using polyborosiloxane or polytitanosiloxane as a binder have good slipperiness, and
[l [phase], No. 2 membrane was porous.

MoS2. Among WS and BN, the film containing MoS had a very high pencil hardness of 9H.

Next, we investigated the addition of MoS and an oxidation catalyst. Nα■, N
The results are shown in α■ and Nα■. Transition metal oxides such as CuMnOx, which are commonly used in oil decomposition, such as Nα■, have dense membranes and poor oxygen diffusion, making it impossible to combust oil, resulting in poor purification performance.

In addition, discoloration of the coating film due to reduction of metal oxides was noticeable. N
When C e Ot, which is a rare earth oxide like α■, is added, the oil purification performance is high, but a yellow and shiny discoloration remains on the membrane surface.

As shown in Nα■, when N i OMo O3 was added, the purification performance was high and there was almost no discoloration of the coating film. Unlike transition metal oxides, NtO-MoO does not change color due to reduction, and it is thought that dehydrogenation and decomposition of oil stains occur in the surface layer of the coating.

From the above results, we added Mob and NtO-MoO,
Furthermore, it was found that a film of Nα■ to which a small amount of Fe, ○, .CuO.MnxO3 was added as a black pigment was the most excellent in both hardness and purification performance.

Note that Alz○ is added to equalize the total amount of fillers, and changing only the binder from polyborosiloxane to polytitanosiloxane or mixing the two will affect the physical properties and purification ability. Not having it is a hindrance, Nα
■I understand more.

Also, inhibitors using phosphates or silicates as binders [
In phase 1 and 2, the PH of the membrane was biased toward acid or alkali, resulting in poor oil purification performance, and since the membrane was porous, tar was deposited within the pores.

As described above, the heat-resistant coating of the present invention can dehydrogenate and decompose oil stains, and further weaken the binding force between the coating surface and tar, making it a heat-resistant coating suitable for practical use on the inner wall surface of a cooking appliance. be.

As described in the detailed description of the invention, the heat-resistant coating of the present invention has high hardness,
It has good surface slipperiness and also has the ability to decompose oil stains, making it possible to obtain a coating that is excellent in cleaning stains inside the cooking appliance.

By applying it to the inner wall of the cooking appliance and heating the coating after it becomes dirty, the dirt will disappear, and the remaining ash and deposits can be easily peeled off and wiped off.
The inner walls of the cooking cabinet can be kept clean forever.

Claims (2)

[Claims] (1) A heat-resistant material containing polyborosiloxane, polyborotitanosiloxane, or a mixture of the two mentioned above as a binder, a compound with a layered structure, a composite oxide of Ni and Mo, and optionally an enamel component or glass powder. sex capsule. (2) A heat-resistant product containing polyborosiloxane, polyborotitanosiloxane, or a mixture of the two mentioned above as a binder, a compound with a layered structure, a composite oxide of Ni and Mo, and optionally an enamel component or glass powder. The heat-resistant coating is coated on the heat-resistant coating and the inner wall of the cooking chamber, and the heat-resistant coating is provided with a heater for heating the cooking chamber.