JPH07122501B2 - How to paint the inside wall of the microwave oven - Google Patents

Description

TECHNICAL FIELD The present invention generally relates to a method for coating an inner wall surface of an oven of a microwave oven, and particularly to a surface requiring heat resistance and non-adhesiveness. The present invention relates to a method for coating the inner wall surface of the oven of a microwave oven, which also has a surface to be coated.

[Prior Art] FIG. 4 is a perspective view of a microwave oven, and FIG. 5 is a perspective view of an inner box used in the microwave oven. The microwave oven 2 includes a main body portion 4 and a door 6. The inner box 8 is fitted into the body portion 4. Inner box 8 consists of left and right side walls 1
0, 10 ', a top plate 12, a bottom plate 14, a back plate 16 and a front plate 18.
The top plate 12 is provided with a high temperature heat irradiation hole portion 20 including a plurality of holes for introducing heat of a heater (not shown) provided on the top plate 12 into the inner box 8. . A heater (not shown) for sending warm air into the inner box 8 is also arranged on the rear side of the back plate 16.

By the way, a paint is applied to the inner wall surface of the oven 2 in order to make the appearance beautiful. Top plate 12, when selecting paint
Since the back plate 16 has a high temperature (400 to 800 ° C.), a heat resistant paint is required. Although the paint used for the left and right side walls 10 and 10 'and the bottom plate 14 is sufficient to have a heat resistance of 300 ° C or lower, a non-adhesive paint that can be easily cleaned even if the cooked food sticks to it is required. If there is a paint that satisfies all of these requirements, one kind of it may be applied on the entire inner wall surface of the oven, and there is no problem.However, there is no such paint at present, and there is no paint in each place. The current situation is to apply another type of paint that meets the requirements.

Next, a conventional coating method for the inner wall surface of the oven will be described.

In the first method, the assembled oven unit is first prepared. And, for example, in the part where heat resistance is required,
Mask the areas where heat resistance is not required and apply heat resistant paint. Then, after drying, the mask is removed. After that, the non-adhesive portion is masked in the non-adhesive portion, and the non-adhesive paint is applied. Then, after drying, the mask is removed. This method requires labor and manpower for masking.

The second method is to apply paint to each component in advance before assembling the oven. First, the end of each component is masked and the paint is applied. The reason why the edges are masked and the paint is not applied to this portion is because it is necessary to electrically connect metals to each other in this portion in order to prevent microwave leakage. In addition, when applying different paints to one part, the surface of a certain part is masked and the paint is applied to the other part. Then, the pre-coated product is assembled into an oven.

As a paint that can withstand a high temperature of 400 to 800 ° C., a paint using a borosiloxane as a binder and adding an inorganic pigment, which forms a heat-resistant ceramic coating film of black to chocolate brown is used. As the non-adhesive paint, for example, a tetrafluoroethylene resin-based paint is used.

[Problems to be Solved by the Invention] The conventional coating method is configured as described above, and in the first method, the time required for coating per oven is long, labor-intensive, and labor-intensive. However, there is a drawback that the cost is large and the productivity is low, and the equipment cost is enormous even if it is rationalized.

Then, the idea arises of implementing the first method without masking. In this case,
There are the following problems.

That is, the part where heat resistance is required (top plate 12, back plate 16)
The above-mentioned heat-resistant ceramic coating (coating using borosiloxane as a binder) is applied to a portion where heat resistance is not required and non-adhesiveness is required (side wall 10, 10 ', bottom plate 14,
When the front plate 18) is applied without being masked, the heat-resistant ceramic coating may be slightly sprayed on the portion where non-adhesiveness is required. In such a state, when a fluororesin coating material is applied to a portion where non-adhesiveness is required, the coating film after firing causes delamination (the fluororesin coating film is peeled off), and non-adhesiveness is required. The part will be poorly finished. In addition, heat-resistant ceramic coating parts (top plate 12, back plate 1
The fluorine coat sprayed on 6) also peels off, resulting in a poor finished appearance. Therefore, as long as the conventional paint is used, the masking method must be adopted in the first method.

Further, the second method also requires a lot of man-hours and requires expensive production equipment, and cannot be said to be an efficient coating method.

The present invention has been made to solve the above problems, and provides a method for coating the inner wall surface of an oven of a microwave oven, which has a good production efficiency and can obtain a coating film with a good finished appearance. With the goal.

[Means for Solving the Problem] The present invention relates to a method for coating an inner wall surface of an oven of a microwave oven, which has both a surface requiring heat resistance and a surface requiring non-adhesiveness. According to the present invention, first, an oven assembly having at least a first inner wall surface requiring heat resistance and a second inner wall surface requiring non-adhesiveness is prepared. Next, the first paint essentially consisting of polytitanocarbosilane varnish and a predetermined organic solvent is applied to the entire surface of the inner wall surface of the oven including the first inner wall surface and the second inner wall surface. Subsequently, a second paint essentially consisting of polytitanocarbosilane varnish, a predetermined organic solvent and fluororesin powder is applied to the second inner wall surface.

According to a preferred embodiment of the present invention, the method further comprises the step of applying a fluororesin paint to the second inner wall surface to which the second paint has been applied.

[Operation] According to the present invention, the first coating material essentially consisting of polytitanocarbosilane varnish and a predetermined organic solvent is applied to the first inner wall surface required to have heat resistance. On the second inner wall surface which is required to have non-adhesiveness, a second paint obtained by adding fluororesin powder to the first paint is overlaid on the first paint. When sintered, 40
A heat-resistant coating film that withstands a high temperature of 0 to 800 ° C is formed. Also, the second inner wall surface is heat resistant up to 400 ° C,
A coating film showing non-tackiness is obtained. In this case, in the coating film formed on the second inner wall surface, the coating film formed from the first coating material and the coating film formed from the second coating material do not cause delamination, and have excellent adhesiveness between them. . This is because polytitanocarbosilane which is the main component of the first paint and the main component of the second paint are the same, and a familiar layer is formed between the layers.

Further, according to the present invention, when the second coating material is applied to the second inner wall surface, the first inner wall surface is not masked. Therefore, the second paint may spray on the first inner wall surface, but this does not cause any problem. Because
Since the first inner wall surface rises to 400 ° C or higher during actual use, the tetrafluoroethylene resin powder (melting temperature 327 ° C, decomposition temperature 400 ° C or higher) contained in the second paint decomposes and evaporates during actual use. Will be discharged. As a result, on the first inner wall surface, the second paint becomes the same as the component of the first paint, adheres to the wall surface, and does not come off.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

First, the oven assembly shown in FIG. 5 is prepared. Since the top plate 12 and the back plate 16 reach 400 to 800 ° C., the paint used here is required to have heat resistance. However, because of the high temperature, non-stick properties are not needed. On the other hand, the side wall 10,1
0 ', the bottom plate 8 and the front plate 18 are required to have non-adhesiveness although heat resistance of about 400 ° C. is sufficient.

Referring to FIG. 1, FIG. 4 and FIG. 5, after preparing the oven assembly which requires the above requirements, the inner wall 21
A first paint 22 containing polytitanocarbosilane varnish, a heat-resistant pigment and toluene is applied to the entire surface of as a undercoat paint. The top plate 12 and the back plate 16 are sprayed to have a thickness of 20 to 30 μm, and the other parts are sprayed to have a thickness of 10 to 20 μm.

After that, by setting, toluene is naturally evaporated to dry the surface.

After the undercoat paint has dried, refer to FIG.
Parts other than the back plate 16, that is, the side walls 10, 10 ', the bottom plate 8,
The front plate 18 is provided with a second paint 23 containing polytitanocarbosilane varnish, a heat resistant pigment, a fluororesin powder and toluene.
Apply to a thickness of 10 to 20 μm. No masking is done. At this time, the periphery 13 and 15 of the high temperature heat irradiation hole portion 20 provided in the top plate 12 and the periphery 19 of the hole portion 17 provided in the back plate 16.
The second paint 23 may be sprayed on. Because the temperature around these holes 20 and 17 rises to a temperature of 400 ° C. or higher, the tetrafluoroethylene resin paint (melting temperature 327 ° C., decomposition temperature 400 ° C. or higher) contained in the second paint 23 is In actual use,
It decomposes and evaporates and is discharged. As a result, in this portion, the second paint becomes the same as the component of the first paint, has an affinity, and does not come off.

After finishing the top and bottom coats, force dry at 150 ° C for 20 minutes. Then, baking is performed at 320 ° C to 400 ° C for 20 minutes to complete the finish.

On the finished inner wall surface of the oven, a heat-resistant ceramic coating film containing polytitanocarbosilane as a main component was formed on the top plate 12 and the back plate 16. A sectional view of the side walls 10, 10 ', the bottom plate 8 and the front plate 18 is shown in FIG. A two-layer non-stick coating was formed. In this case, the coating film formed from the first coating material 22 and the coating film formed from the second coating material 23 did not cause delamination and had excellent adhesion. this is,
Referring to FIG. 2, the coating film formed from the first coating material 22 and the second coating material
It is considered that the familiar layer 24 is formed between the coating film formed from the above paint.

Example 2 Since the steps up to the top coating of Example 1 are the same, the description thereof will not be repeated.

Then, by setting, toluene is naturally volatilized from the coated surface, and the surface is dried. When the surface is dried, refer to FIG. 3, and spray the tetrafluororesin-based black dispersion type paint 25 onto the top plate 12 and the back plate 16 except the holes 20 and 17. Coating, and finish so that the finished surface is a drizzle or a thin film continuous film of about 10 μm.

Then, after forced drying at 150 ℃ for 20 minutes, 400 ± 20 ℃
Then, sinter for 20 minutes. This resulted in a more tack-free coating. In this case, the coating film formed from the second coating material 23 and the coating film formed from the dispersion type coating material 25 did not cause delamination, and the adhesion between them was excellent. It is considered that this is because, as shown in FIG. 3, the familiar layer 26 is formed between the coating film formed from the second coating material 23 and the coating film formed from the dispersion type coating material 25.

In the present embodiment, even if the dispersion die 25 adheres to the periphery of the holes 20 and 17 of the top plate 12 and the back plate 16, no problem occurs due to the above reason.

The present invention is summarized as follows.

(1) The method according to the claims, further comprising a step of applying a fluororesin paint to the second inner wall surface applied with the second paint.

[Effects of the Invention] As described above, according to the present invention, a heat-resistant coating film and a non-adhesion film are applied to a part requiring high-temperature heat resistance and a part requiring stickiness by a coating method without masking, respectively. A protective coating film can be formed. As a result, the productivity can be greatly improved, and a low cost painting finish can be realized.

[Brief description of drawings]

1 and 2 are sectional views showing the steps of one embodiment of the present invention. FIG. 3 is a sectional view showing another embodiment of the present invention. FIG. 4 is a perspective view of the microwave oven. FIG. 5 is a perspective view of the oven of the microwave oven. In the figure, 2 is a microwave oven, 10 and 10 'are side walls, and 12
Is a top plate, 14 is a bottom plate, 16 is a back plate, 18 is a front plate, 21 is an inner wall, 22
Is the first paint and 23 is the second paint. In each drawing, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A method of coating an inner wall surface of an oven of a microwave oven, which has both a surface requiring heat resistance and a surface requiring non-adhesiveness, which is at least the first heat resistance required. The inner wall surface,
A step of preparing an oven assembly having a second inner wall surface which is required to be non-tacky, and the whole of the oven inner wall surface including the first inner wall surface and the second inner wall surface, A step of applying a first coating material consisting of polytitanocarbosilane varnish and a predetermined organic solvent, and subsequently, essentially, the second inner wall surface is essentially the polytitanocarbosilane varnish and the predetermined organic solvent. And a step of applying a second paint comprising a fluororesin powder, and a method of applying the inner wall surface of an oven of a microwave oven.