JPH02169037A - Coated surface - Google Patents

Abstract

PURPOSE:To obtain a hardly scratchable coated surface decomposing oil by holding a fiber layer, which is formed by supporting a multiple oxide on a fibrous porous body, between a support and a reticular metal layer, and also supporting the same kind of multiple oxide on the surface of the metal layer. CONSTITUTION:A fiber layer 2 is held between a support 1 and a reticular metal layer 3 and a multiple oxide contg. Ce, Cu and Mn 1:X:(1-X) (0<X<1) molar ratio of Ce:Cu:Mn is supported on a fibrous porous body based on oxides such as SiO2 and Al2O3 to form the fiber layer 2. A metal oxide layer of the same multiple oxide is formed on the surface of the metal layer 3. Since the resulting coating layer has high void volume, a hardly scratchable coated surface for self-cleaning capable of feeding much oxygen and having high activity to the decomposition of oil is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a coated surface that has a catalytic action to decompose oil stains in cooking appliances such as ovens.

BACKGROUND ART Conventionally, when fats and oils adhered to the walls of such cooking appliances, it was difficult to remove them by washing with water, or to remove them mechanically if they were carbonized and stuck.

In order to eliminate this inconvenience, the surface to which leta will adhere is coated with a coating that has a catalytic effect. ]ff to decompose oil has already been attempted and put to practical use.

This is a method in which a catalyst is dispersed in a binder such as enameled flint or paint, which is applied and hardened by baking to form a film on the surface of the cooking chamber.It is applied to the heating chamber walls of various box-shaped cooking devices. has been done.

For example, an inorganic heat-resistant polymer such as an inorganic phosphate is used as a binder, and a layer obtained from a composition in which a solid acid or a metal oxide is dispersed is formed on the inside of the cooking chamber, or in enamel. There were techniques such as adding transition metal oxides to form a coating layer on the inside of the cooking chamber. In this case, solid acids and transition metal oxides are catalysts that oxidize and decompose oils above a certain temperature, and by forming a coating layer with such catalytic action, it is possible to eliminate oil stains that adhere to the inside of the cooking chamber. That is. There is also a method of eliminating oil stains using only thermal decomposition without using a catalyst.
In this case, 1 to 2 hours at a temperature of about 500"C is required.

Problems that the invention aims to solve However, the conventional technology has the following problems.

The basic structure of oil is triglyceride of higher fatty acids, but the solid acids and transition metal oxides mentioned above will not decompose the oil unless the temperature is raised above 450°C. By dispersing the catalyst in a binder or enamel, the catalyst surface is covered and the exposed area becomes smaller, which reduces the contact area between the oil and the catalyst surface, making it difficult to decompose the oil. In addition, oxygen diffusion becomes poor, which causes a decrease in activity. Also, the temperature of the oil itself is 450°C or higher and 500°C.
If it reaches a certain level, it will thermally decompose, making the effect of the coating layer unclear. When the temperature of the coating layer is maintained at about 400'C, carbonization of the oil progresses, and as a result, the surface of the coating layer is covered with tar-like material.

In order to obtain an enamellic coating layer, a high temperature of about 800° C. is required, and at such a high temperature, the surface area of the metal oxide decreases and its activity decreases.

As mentioned above, conventional coating layers have low activity and
There is a problem that oil stains cannot be completely decomposed at temperatures below 400'C, and this is due to the low activity of the catalyst itself.
Furthermore, this was because the catalyst surface was less exposed, the contact area between the oil and the catalyst surface became smaller, and the diffusion of oxygen into the coating was suppressed.

Furthermore, when such a coated surface is applied to the wall surface of a heating cooking device such as an oven, the surface needs to be hard to be scratched when there is a possibility that cooking utensils such as plates may come into contact with the wall surface.

The present invention solves the above problems and provides a coated surface that dissolves oil stains.

L? ! Means for Solving the Problems In order to solve the above problems, the present invention comprises a support, a fibrous layer and a mesh metal layer, the fiber layer being bound by the support and the mesh metal layer. After 03
, Zr0z, a composite oxide of Ce, Cu, and Mn is supported on a fibrous porous body containing any one or more of the oxides as a main component, and the composite oxide Ce, C
The molar ratio of u and Mn is Ce:Cu:Mn=!
:X:1-X (however, 0<x<1) A metal oxide layer is provided on the surface of the silky metal layer, and the metal oxide layer has a ratio of Ce, Cu, and Mn. , Ce in molar ratio:
It supports a composite oxide in which Cu:Mn=1:X:1-X (however, 0<X<1).

action ” The action of the coated surface by means 2 will be explained.

In order to decompose oil stains, which is the objective of the present invention, it is necessary to increase the surface area of the catalyst and increase the supply of oxygen. is formed, and oxygen enters the interior of the coating l+i
It is easy to destroy and has a much larger surface area than conventional coatings. This makes it easier for the desired reaction to proceed more efficiently.

! Ceramink paper using iA machine fibers has a density of about 0.15 to 0.69 g/cJ and a porosity of about 70 to 90%. By supporting the catalyst on fibers having such a high porosity, the supply of oxygen can be improved and the catalyst activity can be fully exhibited.

The inorganic fibers have been described above, but the activity of the supported catalyst will be described below.
, Cu, Mn composite oxide, the ratio of Ce, Cu, Mn in molar ratio is Ce:Cu:Mn=l:X:I-X
(However, 0<x<1) Composite oxides exhibit higher activity for oxidizing hydrocarbons than composite oxides of a single element or two or more elements. This is Ce, Cu, M
This is because in the ternary oxide of n, the elements on the surface of the dioxide have many valences (for example, Mn has a valence of 3).
(Cu is monovalent, divalent, etc.), in other words, valence control is performed between different elements that cannot be seen in single or binary systems, creating a surface that is more suitable for reactions. . This is recognized by XPS (X-ray photoelectron spectroscopy). By supporting such a highly active catalyst on inorganic fibers, the oxidative decomposition activity is further improved, and a coated surface that decomposes oil and the like at an unprecedented low temperature can be obtained.

Furthermore, if such an inorganic fiber layer is applied to the wall of a cooking device such as an oven by sandwiching it between a support and a mesh metal layer, the surface will remain intact even if a cooking utensil such as a plate comes into contact with it. By making the metal mesh-like, it does not impede the diffusion of oxygen and impair the penetration of dirt such as oil, and by providing a metal oxide layer on the surface of the mesh-like metal layer, The metal oxide M includes Ce, Cu,
The molar ratio of Mn is Ce:Cu:Mn=l:X:1
By supporting a complex oxide of −X (0<X<1), oil stains and the like attached to the surface of the mesh metal can also be decomposed.

Example Examples of the present invention will be described below.

A test piece of the coating layer according to the present invention was prepared, and a salad oil oxidation decomposition test was conducted under heating conditions.

5US304 was used as the support, and stainless steel mesh (SUS304, wire diameter 0.05 body, hole diameter 0
．． 12■), and as the inorganic fiber, silica/alumina fiber (S i Oi : A Iz Os =53:
41, average fiber diameter 2.8 μm, porosity 92%, thickness 1.
, On) was used.

The test piece size was 50 x 50 mm.

The silica/alumina fibers were treated with a mixed aqueous solution of nitrates of Ce, Cu, and Mn (Ce: Cu: Mn = 1.0:
0.3: 0.7 mol/l), then 8
It was dried at 0°C, fired at 450°C, and sandwiched between 5US304 and the stainless steel nonche. The method of clamping is
As shown in FIG. 1, a metal bottle was provided between the support and the mesh metal, and each was joined by welding. The stainless steel mesh is formed by thermal spraying A1.03 to a thickness of 5 μm on the surface, and has an AI! A mixed aqueous solution of nitrates of Ce, Cu, and Mn (Ce:Cu:Mn=1.
0+ 0.3: 0.7mol/1. ) with a spray gun (DeVilbiss spray gun, nozzle diameter 1.4
mφ, Ajr pressure 1.5-2kg/cd), lo
It was prepared by applying ng/c-coating and baking at 450°C for 30 minutes.

Temperature distribution of test piece, 300+1 (at 1℃,
When the salad oil was added at a rate of 10111 g/di and left for 60 minutes, the salad oil completely disappeared. On the other hand, the coated surface containing MnOx and CuOx was not completely burnt out even at 350±10°C. In addition, a composite oxide of Ce, Cu, and Mn (Cc:Cu:
Mn= 1.0: 0.3: 0.7+iol/
No matter how many times I repeated the salad oil test, the stain on the test piece 1) completely disappeared. In addition, the surface of the test piece was applied with a load of 40 g/cd (
When we performed a reciprocating abrasion test using a 50×50m test piece and applying a load of 1kg, there was little damage, the oil was decomposed even in the fully curved part, and no deterioration in catalyst performance in the fiber layer part was observed. Ta.

FIG. 1(a) shows a conceptual diagram of the cross-sectional structure of the coated surface of the present invention. Figures 1-) are conceptual diagrams of the cross-sectional structure of a wire-shaped metal supporting the composite oxide of the present invention.

Next, the effect of the amount of oxygen supplied to the catalyst was investigated.The oxidation activity of the salad oil of the composite oxide of Ce, Cu, and Mn, which is the catalyst of the present invention, was measured by DTA.

The measurement was based on the weight of commercially available salad oil and oxides being 2.5.
: Adjust to 1.0, mix thoroughly, and place in a quartz cell.D
A TA curve was obtained. Figure 2 shows the ratio of Ce, Cu, and Mn (
Ce:Cu:Mn=1.0:0.3:0
．． The results of measuring the composite oxide 7) in an oxygen atmosphere and a nitrogen atmosphere are shown. As can be seen from the figure, if the amount of oxygen supplied is large, the oil can be burned off at a lower temperature and the activity of the catalyst can be increased.

Next, silica/alumina fiber (SiO□, Alx 0
3=53:47, average fiber diameter 2.8 μm, J'7: Mi1
．． When the porosity of 0ffIIl) was changed from 68% to 94% and a burn-off test with salad oil was conducted, the results were as shown in Table 1.

(Item 16) Table 1 From Table 1, it can be seen that it is possible to burn off oil at a lower temperature than conventional self-cleaning. 8 in terms of porosity
If the change is about 5% or more, it is possible to burn off the oil at a low temperature of 300°C.

In addition, instead of silica/alumina fibers, zirconia fibers (ZrOx, Yz0s-89=6, average fiber f15.0μIl+, *0.5MA, porosity 84%) were used.
), using S[JS304 as a support and a mesh metal, stainless steel 1/S,' y , :z, (S U S
304, wire diameter 0.2 mm, hole diameter 0.2 M),
Similarly, a test piece was prepared and a salad oil burn-out experiment was conducted, and the burnout completely disappeared at 300'C160m1n, and no deterioration in performance was observed even after the abrasion test.

Further, although stainless steel mesh was used as the mesh metal, lath mesh or punched metal may also be used.

Further, as the metal oxide layer provided on the surface of the mesh metal layer, A1. Although O, is shown, any metal oxide that does not react with the composite oxide of Ce, Cu, and Mn may be used, such as silica/alumina, silica, and zirconia.

In addition, as an autumn wearing method using a support and a mesh metal layer,
Although we have shown how to weld with metal pins, caulking, etc. can also be used. Further, as a method for providing a metal oxide layer on the surface of the mesh-like metal layer, a thermal spraying method has been shown, but spraying a paint such as alumina sol may also be used.

Above, we have described the effect when the catalyst is supported on the inorganic fiber, the effect when the catalyst is supported by the support and the mesh metal, and the effect when the complex oxide is supported on the mesh metal. , Cu, and Mn.

Table 2 shows the surface area determined by the BET method. For comparison, single oxides of Ce, Cu, and Mn are also shown. Firing was performed at 450'C.

The overall surface area in Table 2 is approximately 70~+20r+ (7g), which is large because the firing temperature is 450'C, which is a low temperature for an oxide.Also, compared to a single oxide, a composite Oxide has a large surface area. This is thought to be due to the effect of Cent. In fact, Ce/CuOxid
The surface areas of e'PCe/Mn 0xide were larger than those of Cub, Mn, and O in Table 2, respectively. Table 2 shows that Ce Cuo, 5 Mno, and s Oy have large surface areas, but Ce, Cu, and Mn91 composite oxide (
The dependence of the molar ratio Ce, Cu, Mn-1:X:1X) on the surface area is shown in FIG.

From FIG. 3, it was found that the peak of the surface area was located near X=0.3.

The above ratio of Ce, Cu, Mn (Ce:CuMn-
The oxidation activity of the salad oil of the composite oxide (1,0:X:1-X) was measured by DT8. For the measurement, commercially available salad oil and oxide were thoroughly mixed at a weight ratio of 2.5:1.0, and the mixture was placed in a quartz cell to obtain a DTA curve. Figure 4 shows the TG of the four types of oxides shown in Table 2.
showed a curve. In Figure 4, weight 5 + decreasing speed is large,
It can be said that a substance whose weight loss is completed at a lower temperature side has a high oxidation activity. Therefore, CeCuo, sM mouth. 1. O
It is clear that y has high activity and is effective as an oxidation catalyst. Figure 5 shows the ratio of Ce, CuSMn (Ce
: Cu :Mn= 1.0:x:1-X (however, o<
It shows the dependence of the TO curve of the composite oxide on X of X<]). When X=0.3, the activity seems to be the most important.

This is considered to correspond to the dependence of surface area on X.

Effects of the Invention As explained above, the self-cleaning coating surface of the present invention can form a coating layer with a high porosity by using inorganic fibers, and can supply more oxygen. It has a high oxidative decomposition activity for triglycerides, and if applied to equipment that generates oil stains, such as the inner wall of a cooker, it can eliminate oil stains by raising the temperature to around 300'C. , and when such an inorganic fiber layer is sandwiched between a support and a mesh metal layer and applied to the wall of a cooking device such as an oven, even if a cooking device such as a plate comes into contact with it,
The surface is less likely to be scratched, and by making the metal mesh-like, it does not impede the diffusion of acid, and also prevents dirt such as oil from penetrating. A metal oxide layer is provided, and the metal oxide layer contains Ce, Cu,
By supporting the composite oxide of Mn, oil stains and the like attached to the surface of the mesh metal can also be decomposed.

This allows the cooker to be used in a clean state at all times. In addition, AI is possible for oil lη at around 300°C, so in the design of the cooker, the insulation structure can be reduced (if the catalyst cannot be used, a thermal decomposition temperature of around 500°C is required) and the capacity of the heater. It also saves energy because it does not need to be large.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional view of the coated surface of an embodiment of the present invention, FIG. 1(b) is a cross-sectional view of the mesh metal supporting the composite oxide on the same coated surface, FIGS. 4 and 5 are the same characteristic diagrams. 1...Support, 2...Inorganic fiber layer, 3
, 7... Front opening metal, 4... Inorganic fiber, 5, 9... Composite oxide, 6... Metal bottle, 8... ...Al2O3 layer. Name of agent: Patent attorney Shigetaka Awano Idiot 1/-X y
T-Muz - Inorganic vomiting 3, 7-・Mesh 1 Gluttony 2 Wings 4-゛Kumayari G Kishiba Uoka 2 Zugin (min) (a, ε・-AJLtθ31 1ゝ〜〜− I regret the call of Noboru 58'Da1 - 1 number 4

Claims (1)

[Claims] Consisting of a support, a fiber layer, and a mesh metal layer, the fiber layer is sandwiched between the support and the mesh metal layer, and contains at least one oxide of any one of SiO_2, Al_2O_3, and ZrO_2. It is made by supporting a composite oxide of Ce, Cu, and Mn on a fibrous porous body as a main component, and the ratio of Ce, Cu, and Mn in the composite oxide is Ce:Cu:Mn in molar ratio. = 1:
, the molar ratio of Mn is Ce:Cu:Mn=1:X:
1-X (however, 0<x1) The coated surface supports a composite oxide.