JPS621780B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention can be used on the walls of various ovens and interior parts near the combustion chambers of oil heaters, etc., to remove dirt and tar from organic oils from fish, meat, etc., proteins and carbohydrates, and to remove combustion gases. It relates to a self-cleaning wall that facilitates oxidation of unburned components therein. Conventionally, for example, various types of oven walls have been coated with an enamel coating mixed with a metal oxide catalyst or a coating of water-soluble completely inorganic paint in order to easily remove dirt adhering to the wall surface, but the former enamel finish The processing process is complicated and difficult, resulting in high costs and very low yields.
In particular, as the material, a steel plate for enamel must be used, and a surface-treated steel plate cannot be used. Recently, aluminum-plated steel sheets have also been made available for enameling, but these also have poor adhesion and require thorough pre-treatment before application to obtain a uniform coated surface. It has the disadvantage that it is difficult to control to maintain a constant quality due to the repelling phenomenon. Furthermore, since enamel processing is a slurry-like liquid based on aqueous solvent, pre-treatment cleaning must be thoroughly controlled, and two treatments, an undercoat and a topcoat, are required to improve adhesion. The processing process is complicated, such as the need for glaze firing (heating at a high temperature of 400 to 600℃ for 20 to 30 minutes) to form the enamel coated surface, and the formed coated surface is glass-like and hard. However, it has the disadvantage that it is easily chipped or peeled off due to deformation of the equipment, impact, drop, or cold/hot shock, and its quality is unstable. On the other hand, in the case of completely inorganic water-soluble self-cleaning paints, the two components are mixed together with a hardening agent and a water glass solution and diluted with water before coating with metal oxide catalyst powder. Spray with a spray gun with an attachment nozzle and apply 100%
A paint film can be obtained by finishing a thick film of ~200 μm and baking it for 20 to 30 minutes in a high-temperature atmosphere of 300 to 400°C, but it has serious practical problems and is not of sufficient quality. In other words, when processing a two-component mixture, the mixing process is troublesome, and because it is water-soluble, it must be thoroughly pretreated, and even if you think it has been completely treated, when spray painting it, a repellent phenomenon occurs and the painted surface is not uniform. . In addition, in order to achieve a uniform coating surface, the painted object must be preheated to 80 to 100℃, and even if a uniform appearance can be achieved, it is not only difficult to obtain good adhesion, but also the finish The quality of the painted surface was not of a quality that would be durable for practical use, and it had drawbacks such as peeling in the cross-cut adhesion test, and poor impact resistance, flexibility, corrosion resistance, and cold and hot shock properties. The present invention has been devised in view of the above matters,
The aim is to provide products that are superior to conventional products in terms of quality, processing, and cost. First, the paint used in the present invention will be explained.
The maximum temperature used for this paint is 600℃.
The above heat-resistant paints, ie, organic solvent solution paints having the components shown in Table 1, are used.

[Table] That is, using an organic solvent solution paint with a solid content of 60 to 80% [heat resistant paint described in Table 1 above] which is a mixture of silicone resin and a heat-resistant inorganic pigment as the main component, in this organic solvent solution paint 0.1 to 0.5 cordierite (alumina) impregnated or coated with platinum.
The self-cleaning paint used in the present invention is prepared by homogeneously mixing (60±20) micron particles of the platinum-supported powder. (60% solid content refers to the residual distillate (weight ratio) when the solution paint in Table 1 above is heated at 250°C for 3 hours.) In addition, in the above (Table 1), special auxiliaries are It is generally added to heat-resistant paints to maintain the paint's viscosity, anti-sagging properties, and high-temperature adhesion. The composition of the heat-resistant organic solvent solution paint and the catalyst powder will be described later. Next, the coating method will be explained. First, parts or assemblies machined from cold-rolled steel plates (SPCC steel plates), aluminum-plated steel plates, galvanized steel plates, stainless steel plates, iron castings, etc., are degreased with organic solvents or with weak alkali, neutral, etc. After degreasing in the emulsion degreasing process, it is washed with water and dried. Then, the above-mentioned self-cleaning heat-resistant paint was diluted with an organic solvent, adjusted to an appropriate coating viscosity, and sprayed onto the above-mentioned object.
Dry in an atmosphere at 40°C for 1 coat and 1 bake.
Finish to a film thickness of 120μ or more. If left as is, the catalyst particles will be covered with silicone resin and will prevent activation, so pass it through a furnace at 300-400℃ for 5-10 minutes to carbonize and bake the silicone resin until no smoke is emitted, converting it into a SiO ₂ film. . The paint film created in this way has porous, catalytically active adhesion, hardness,
It has excellent durability and reliable performance. Also, since it is an organic solvent-based product, there are no defects due to insufficient degreasing. As mentioned above, the paint film made by adding a catalyst to the 600℃ heat-resistant paint, which is a mixture of silicone resin and heat-resistant inorganic pigment, can be processed with unprecedented ease of work and simple management, and has excellent paint film performance and low cost. You can get cheap ones. Figures 1 and 2 show an embodiment of the self-cleaning heat-resistant wall of the present invention using the above-mentioned paint, in which an oven wall 3 is formed of an aluminized steel plate 2 having aluminum plating layers 1 and 1' on its surface. The self-cleaning heat-resistant paint film 4 described above is formed to a thickness of about 100 μm on the aluminum plating layer 1' on one side of the aluminized steel plate 2, thereby forming a self-cleaning heat-resistant wall 5. The thickness of the coating film 4 of 40μ to 120μ is extremely excellent in terms of durability. Next, the performance of the self-cleaning heat-resistant wall in the above example is shown in Table 2. Table 2 shows the solution paint (solid content 60%) in Table 1.
Alumina with 0.5% or 0.2% platinum (diameter 40
μ) Powder weight ratio: 2, 5, 8, 12, 15, 20,
The self-cleaning properties and durability of the coating film 4 were comprehensively evaluated when each of the self-cleaning paints formulated at 30% and 40% was used as the coating film 4.

[Table] The above performance is based on the condition after coating film 4 treated on the inner wall of a gas range oven is sprinkled with 3 c.c. of salad oil and used for 8 hours at a temperature of 250°C to 300°C, which is the actual operating temperature. It is something. As is clear from Table 2 above, 5% catalyst powder
Coating film 4 using a paint compounded at a ratio of ~20% has very good self-cleaning properties and durability. If the ratio is less than 5%, it will be durable but the self-cleaning effect will be weakened, and if the ratio is more than 15%, the self-cleaning property will be good but the coating will be soft and brittle, resulting in poor durability. become. The diameter of the above alumina powder is optimally between 40μ and 80μ; if less than 40μ is used, the contact area of the oil to be purified will be small and the permeability of the oil will be poor, resulting in poor self-cleaning properties. On the other hand, if particles larger than 80μ are used, the particles are too coarse and the surface of the coating film 4 becomes rough, causing wear and peeling of the coating film 4, both of which are unsuitable for practical use. In addition, the adhesion of organic solvent solution paint as a coating film,
As mentioned above, the amount of catalyst powder that can be added is in the range of 5% to 20% by weight without impairing heat resistance. Therefore, within this range, metal oxidation catalysts exhibiting sufficient self-cleaning properties are limited, and platinum and palladium (Pd) are particularly preferred. The required amount of metal oxide catalysts other than those mentioned above is several times that of platinum, and the adhesion hardness and abrasion resistance of the coating film 4 are extremely deteriorated. However, if platinum is added in an amount of 30% or more, the performance of the coating film 4 will be greatly degraded and the cost will increase. As explained above, the self-cleaning heat-resistant wall of the present invention fully satisfies the three points of durability, self-cleaning performance, and cost, and is optimal as a heat-resistant wall for various types of equipment. As described above, the self-cleaning heat-resistant wall of the present invention is produced by mixing platinum or palladium with alumina powder having a diameter of (60±20)μ in a heat-resistant organic solvent solution paint made by mixing a heat-resistant inorganic pigment with a silicone resin. Since this is a self-cleaning heat-resistant paint coated on the wall surface with a solid content of 5% to 20% catalyst powder impregnated or coated with 0.1% to 0.5%, it is a coating film containing an oxidation catalyst. Not only is it extremely easy to form on a wall surface, but the coating film has excellent adhesion to the wall surface, hardness, and durability. Therefore, according to the present invention, it is possible to provide a self-cleaning heat-resistant wall that has excellent self-cleaning properties and durability and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of an inner box of a gas oven embodying the present invention, and FIG. 2 is a partially enlarged sectional view of FIG. 1. 4: Heat-resistant paint film for self-cleaning, 5:
Self-cleaning heat-resistant wall.

Claims (1)

[Claims] 1. For self-cleaning heat-resistant walls of equipment, platinum or palladium is added to alumina powder with a diameter of (60 ± 20) μ in a heat-resistant organic solvent solution paint containing a heat-resistant inorganic pigment mixed with silicone resin in a weight ratio.
A self-cleaning heat-resistant paint containing 5% to 20% solid content of catalyst powder impregnated or coated at 0.1% to 0.5% is provided, and the self-cleaning heat-resistant paint is applied to the wall surface to form a coating film. The self-cleaning heat-resistant wall is characterized by forming a coating film in a high-temperature atmosphere and carbonizing the resin to form a porous surface.