JPH0771B2 - Structure of coating for high temperature cooking equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a film structure formed on a base material such as a cooking surface of a high-temperature cooking device or a heating chamber wall surface,
In particular, the present invention relates to a film structure having improved heat resistance and non-adhesiveness.

[Prior Art] FIG. 9 is a perspective view of a microwave oven, and FIG. 10 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 is the left and right side walls
It is composed of 10, 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 having a plurality of holes for introducing heat of a heater (not shown) provided on the top plate 12 into the inner box 8. Has been.

FIG. 11 is a sectional view of an electric hot plate. The electric hot plate 24 comprises a plate plate 26 and a lid 28. A sheathed heater 30 is embedded in the plate plate 26. The plate plate 26 is formed of an aluminum alloy casting die-cast material.

Referring to FIG. 10 and FIG. 11, the inner box 8 of the high temperature cooking appliance
, And the cooking surface 25 of the plate plate 26 of the electric hot plate, heat-resistant stainless steel plate, enamel-finished steel plate, or tetrafluoroethylene resin, PES resin,
A heat-resistant steel sheet coated with a binder such as a silicone resin or a polysiloxane resin, an inorganic pigment, a heat-resistant polymer composition including a filler or the like or a ceramic is used.

[Prior Art Based on the Present Invention] Meanwhile, in the development of high-temperature and high-speed cooking equipment, there is a demand for shortening the cooking time in order to improve the taste of cooked food and to effectively utilize the time. There is. Therefore, it is necessary to treat food products at a high temperature, and as shown in FIGS. 10 and 11, the cooking surface 25, the inner wall of the inner box of the oven, and the inner surface of the door need to be heat resistant. . However, the above-mentioned conventional microwave oven and electric hot plate are insufficient in terms of high temperature heat resistance. Therefore, the applicant company has already prepared hot paints containing an organic solvent varnish containing polytitanocarbosilane as a binder, a heat-resistant pigment made of a heat-resistant metal oxide or a composite oxide, and a paint additive. Disclosed is a technique for baking on a cooking surface of a plate or a wall surface of an inner box of a microwave oven to improve heat and oxidation resistance, corrosion resistance and cleanability, and prevent burning of food.

[Problems to be Solved by the Invention] A coating film formed from the above-mentioned coating material containing polytitanocarbosilane as a main component is cured and sintered under a baking condition of 300 to 320 ° C. for 20 minutes, and the temperature is further increased. Then, the polymer of polytitanocarbosilane becomes ceramic at about 400 ° C.
By heating for a long time or further heating at a high temperature of 600 to 800 ° C., the polytitanocarbosilane polymer is completely ceramized. The ceramic coating thus obtained is unique in that it has high temperature heat resistance.

However, the cooking device using this ceramic coating also has the following problems. That is,
In an oven using an infrared heater that emits a high temperature of 800 ° C, the drip of meat and oil that is scattered from cooked food such as fish, beef, pork, and chicken adheres to the coating film, burning,
Carbonize and solidify. If the wall temperature at this time is 250 ° C or lower, or if the cooking time is within 30 minutes even if heated to 300 ° C, the solidified substances attached to the wall will be immediately peeled off, and there will be no problem in cleaning. Absent.

However, referring to FIG. 10, if the temperature inside the refrigerator is set to a high temperature of 300 ° C., the general wall surfaces (side walls 10, 10 and back plate 1
6) is heated to a high temperature of 280-300 ℃, and high temperature heat irradiation hole 20
The bottom surface 14 irradiated with the 800 ° C. heat ray from the surface becomes as high as 300 ° C. Further, in the microwave oven having a convection function in which warm air is circulated and the inside of the chamber is kept at 300 ° C, the temperature in the vicinity of the hot air outlet is about 400 to 450 ° C.
At such a high temperature, the oil droplets attached to the coating film have a very strong adhesiveness and cannot be easily removed by ordinary cleaning. Therefore, it will be used as it is, but if it is used for 7 to 100 hours, the adhered oil droplets solidify, carbonize, finally ash, erode the film, exposing the bare surface cause. Therefore, the coating film containing polytitanocarbosilane as a main component has been a practical problem.

The present invention has been made to solve the above problems, and retains the excellent feature of high temperature heat resistance of polytitanocarbosilane, and also has non-adhesiveness for high temperature cooking equipment. The purpose is to provide the structure of the coating.

[Means for Solving the Problems] With reference to FIG. 1B, the structure of the coating structure of the present invention will be described. With reference to FIG. 1B, reference numeral 32 represents a base material such as a cooking surface of a high-temperature cooking device or a heating chamber wall surface. On the base material 32, a ceramic layer 34 formed by converting polytitanocarbosilane as a main component into a ceramic is formed. Although the pigment particles 36 are embedded in the ceramic layer 34, the pigment particles 36 are not an essential constituent element. On the ceramic layer 34,
A non-adhesive resin layer 38 containing a non-adhesive resin is formed. Then, the ceramic layer 34 and the non-adhesive resin layer 38
At the interface with and, the ratio of the non-adhesive resin 40 and the polytitanocarbosilane continuously changes vertically. That is, the concentration of the non-adhesive resin 40 increases toward the upper layer portion of the ceramic layer 34, and the concentration of the non-adhesive resin 40 is 100% in the uppermost layer portion of the ceramic layer 34.

[Operation] In the film structure of the present invention, as described above, since the non-adhesive resin layer 38 made of a resin exhibiting non-adhesiveness is formed in the uppermost layer portion, even if oil droplets or the like are attached, it is easy. Can be removed. Further, since the main body portion of the coating structure is formed of the ceramic layer 34 made of polytitanocarbosilane to be ceramic, it has high temperature heat resistance. In addition, the ceramic layer
At the interface between 34 and the non-adhesive resin layer 38, the non-adhesive resin
Since the ratio of 40 and polytitanocarbosilane continuously changes up and down, the ceramic layer 34 and the non-adhesive resin layer 38
Adhesion with is good.

EXAMPLES Examples of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

1A and 1B schematically show the process of forming a film structure according to the present invention. FIG. 1A is a sectional view in a state before sintering, and FIG. 1B is a sectional view in a state after sintering.

First, referring to FIG.
Spray applied to a micron finish. paint
As 42, in an organic solvent varnish using polytitanocarbosilane (for example, Tyrannocoat manufactured by Ube Industries, Ltd.) as a binder, metal oxides or composite oxides of Fe, Co, Mn, Cr, etc. that can withstand high temperatures are used. A mixture of a heat resistant pigment, a fluororesin powder (Fostaflon # 9205 manufactured by Hoechst Japan Co., Ltd.), a thickener, silicone oil and an organic solvent was used. The general blending ratios are summarized below.

Organic solvent varnish containing Tyrannocoat …… 20 to 40 parts Heat resistant pigment ……………………………… 20 to 40 parts Fosterflon # 9205 ………… 3 to 20% by weight Thickener ……………… ...... 0.1 to 1.0% by weight Silicone oil ………… 0.1 to 1.0% by weight Organic solvent …………………………………………………………………… 20 to 40 parts The specific gravity of the paint is 1.1 to 1.8, and the nonvolatile content of the paint is 50-70
It is preferable that it is blended so as to be%.

Needless to say, the color of the paint can be black, brown, white or the like depending on the component of the heat resistant pigment.

The base material 32 is an aluminum-plated steel sheet that has been subjected to pretreatment such as degreasing, rust removal, chemical conversion treatment, and sandblasting in advance,
A 13 or 18Cr stainless steel plate was used.

Next, after pre-drying at 150 ℃ for 20 minutes, at 20
After baking for minutes and sintering, the coating film shown in FIG. 1B was formed.

Explaining the possible sintering mechanism, baking of 300 to 400 ° C (detailed conditions will be described later) causes the binder, polytitanocarbosilane, to ceramify, and the aggregate of sintered ceramic dense particles (ceramic Layer 34). At this time, at the same time, the powder of the fluororesin 48 melts, floats due to the difference in specific gravity, and penetrates between the ceramic particles. As a result, the structure is such that the fluororesin 48 is filled between the ceramic particles, and the uppermost layer portion of the film structure is formed of the high-concentration fluororesin film (non-adhesive resin layer 38). Although it has the same structure as the coating of the tetrafluoropolyethylene resin, the major difference from the coating of the tetrafluoride resin is that the interface between the ceramic layer 34 and the non-adhesive resin layer 38 goes to the upper layer portion of the ceramic layer 34. With this, the concentration of the non-adhesive resin 40 continuously increases. This improves the adhesion between the ceramic layer 34 and the non-adhesive resin layer 38. Also, inside the ceramic layer 34,
Since the fluororesin bonding layer is formed between the ceramic particles, it has excellent corrosion resistance and microcrack resistance, and acts to prevent the food from sticking at high temperatures (300 to 400 ° C).

Next, the present invention is applied to the microwave oven shown in FIG. 9 and FIG. 10, and a suitable coating method, the addition amount of the fluororesin,
The firing conditions were determined. Left and right side walls 10, 10 of the inner box 8, bottom plate 1
4, the back plate 16, the front plate 18, and the back surface 22 of the door 6 that contacts the front plate 18 so as to withstand temperatures in the range of 250 to 450 ° C.
Aluminum plated steel sheet or SUS430, SUS410, SUS304
The stainless steel plate was used. Since the top plate 12 is provided with a heater (not shown) and the maximum temperature thereof reaches 800 ° C., a heat-resistant stainless steel plate such as SUS444 is used for the top plate 12.

Example 1 Fluorine resin powder (Hostaflon # 9205 manufactured by Hoechst Japan Co., Ltd.) was added in an amount of 3,6,8,15,20 in the above-mentioned general mixing ratio.
The paint was formed by changing the weight percentage. On the other hand, a fluororesin of 0% by weight (that is, a paint containing no fluororesin at all) was also prepared. A paint containing fluororesin powder,
Referring to FIGS. 9 and 10, the side walls 10, 10, the bottom plate 14,
The back plate 16, the front plate 18, and the back surface 22 of the door 6 were coated so as to have a finish of 10 to 40 microns. The coating method is as shown in FIG. That is, it is a method of spraying the coating material 50 on the base material 32. The top plate 12 was coated with the above-mentioned coating material containing no fluororesin powder to a thickness of 10 to 40 microns. Next, after pre-drying at 150 ° C. for 20 minutes, bake hardening was performed at 300 to 400 ° C. for 20 minutes.

Example 2 A coating material containing no fluororesin was prepared at the above-mentioned general blending ratio. The coating material containing no fluororesin was spray-coated on the side walls 10, 10, the bottom plate 14, the back plate 16, the front plate 18, and the back surface 20 of the door 6 so that the finish was 10 to 15 microns. On the top plate 12, paint containing no fluororesin 10-40
It was applied so as to have a micron finish. The coating method is as shown in FIG. That is, referring to FIG. 4, the coating material 52 containing no fluororesin was spray-coated on the base material 32. Then, it was left at room temperature to volatilize the organic solvent. The surface is matte, and 3-20% by weight (3,6,8,15,20% by weight is selected)
The coating material 50 containing the fluororesin powder in the range of 10 was applied so that the thickness after dry baking was 10 to 20 μm. After that, after pre-drying at 150 ℃ for 20 minutes, 300-400 ℃
It was baked and cured for 20 minutes.

Results and Discussion of Example 1 and Example 2 Coating Method As in Example 1 (FIG. 2), a coating material 50 containing a fluororesin was used.
When only this was applied to the base material 32, the coating material was not retained well on the finished surface, causing dripping, and it was not possible to apply it thickly. As a result, as shown in FIG. 1B, the fluororesin powder could not be floated on the upper layer portion, resulting in insufficient non-adhesiveness. Further, since the thickness is thin, peeling phenomenon and scratches occur, and there are problems in corrosion resistance and durability. In contrast,
With the two-layer structure as in Example 2 (FIG. 3), such inconvenience did not occur. That is, as shown in FIG. 1B, the fluororesin floated and the fluororesin layer 38 was formed on the uppermost layer of the coated surface. This is probably due to the following reasons. That is, when the paint 52 containing a fluororesin is overlaid on the undercoat paint 52, the organic solvent in the overcoat paint 52 permeates into the undercoat paint 52 to increase the tackiness and prevent dripping. . Therefore, thick coating is possible. Further, according to this method, the coating material 52 containing fluororesin
, So that the fluororesin powder can be sufficiently floated,
Furthermore, it becomes possible to dilute with thinner and spray. As a result, the fluororesin can be efficiently levitated as shown in FIG. 1B. This is also supported by the following facts. That is, the undercoat paint
When 52 is forcibly dried at 80 to 150 ° C and the top coating material 50 is applied, the fluororesin does not float. Also, after baking the undercoat paint 52 at a high temperature of 300 to 320 ° C, the overcoat paint 50
Is applied, delamination occurs.

Regarding the amount of fluororesin powder added and the firing conditions, referring to Example 2, the amount of fluororesin powder added was 3, 6, 8,
A test panel was prepared by changing the content to 15, 20% by weight, and three firing conditions of 300 to 320 ° C, 330 to 360 ° C and 370 to 400 ° C were selected and tested.

In baking at 300-320 ℃, even if the amount of fluororesin powder added was changed, oil droplets scattered from fish and meat burned to the coating film in cooking in a convection grill oven. The degree of sticking was the same, and no significant difference was observed in the cleaning property. However, as the amount of the fluororesin powder added increased, the cleaning property tended to improve.

Similar results were obtained even under baking conditions of 330 to 360 ° C.

In baking at 370-400 ℃, the one with 6,8,15% by weight of fluororesin showed the best performance in terms of long-term heat resistance, corrosion resistance and durability. Even when 20% by weight was added, although the powder tended to be pulverized in the uppermost layer, a powder having no problem in practical use was obtained.

In the above examples, the non-adhesive resin is exemplified by a thermoplastic fluororesin (tetrafluoropolyethylene resin), but the present invention is not limited to this, and thermoplastic engineering plastic powder such as PPS and PES. Even if it is, the same effect is realized.

The embodiment shown in FIGS. 4 to 8 is one in which the present invention is applied to the cooking surface of the electric hot plate shown in FIG. The cooking surface of the electric hot plate to which the present invention is applied is 250 to 4
It showed good non-stickiness and cleanability in high temperature cooking in the temperature range of 50 ℃. The method for producing the coating film will be described below.

Example 3 Referring to FIG. 4, the cooking surface of base material 32 was oil-baked at 400 ° C. and then shot-blasted. After the obtained rough surface 54 was cleaned and cleaned, a fluororesin-free paint 52 for undercoating was applied to the rough surface 54 so that the finish was 10 to 20 microns. Then, after leaving it at room temperature to evaporate the organic solvent, 10 to 10 parts of the coating material 50 containing 8 to 15% by weight of fluororesin is applied.
It was applied to give a 30 micron finish. The paint was the same as that prepared in Example 1. The same applies to the examples described below. After that, it was dried at 150 ° C. for 20 minutes and then baked and cured at 370 to 400 ° C. for 20 minutes. The resulting cooked surface showed good non-stick and cleanability.

Example 4 With reference to FIG. 5, the cooking surface of the substrate 32 was oil-baked at 400 ° C. and then shot-blasted to make the surface uneven. After cleaning and cleaning the obtained rough surface 54, ceramic alumina-titania 56 was sprayed on the rough surface 54. After that, paint 52 that does not contain fluorocarbon resin for undercoating
It was applied so as to have a finish of 10 to 20 microns. Next, after leaving it at room temperature to volatilize the organic solvent, a coating material 50 containing 8 to 15% by weight of a fluororesin was applied to a finish of 30 to 30 microns. In this example, since the ceramic alumina-titania 56 is sprayed onto the rough surface 54,
Good adhesion between the base material 32 and the coating film can be obtained.

Example 5 Referring to FIG. 6, the cooking surface of substrate 32 was oil-baked at 400 ° C. and then shot-blasted to make the surface uneven. After cleaning and cleaning the obtained rough surface 54, ceramic alumina-titania 56 was sprayed on the rough surface 54. Then, a coating 50 containing 8 to 15% by weight of fluororesin powder is added to 20 to
It was applied to give a 40 micron finish. Even in such an example, good performance was exhibited in non-adhesiveness and cleanability. In this case, since the undercoat paint is not used, there is an effect that the manufacturing cost is reduced.

Example 6 Referring to FIG. 7, the cooking surface of substrate 32 was oil-baked at 400 ° C. and then shot-blasted to make the surface uneven. After cleaning and cleaning the obtained rough surface 54, ceramic alumina-titania 56 was sprayed on the rough surface 54. After that, silver heat resistant primer paint 58 mixed with aluminum powder with polytitanocarbosilane as a binder
It was applied to give a 5 micron finish. Then, after drying at room temperature to evaporate the solvent, a coating material 50 containing 8 to 15% by weight of a fluororesin was applied so as to have a finish of 20 to 40 microns. In this embodiment, since the primer paint 58 is used, there is an effect that the corrosion resistance is improved.

Example 7 Referring to FIG. 8, the cooking surface of substrate 32 was oil-baked at 400 ° C. and then shot-blasted to make unevenness. After cleaning and cleaning the obtained rough surface 54, a ceramic alumina-titania 56 was sprayed on the rough surface 54. After that, a silver-colored heat-resistant primer paint 58 mixed with aluminum powder containing polytitanocarbosilane as a binder was applied to a finish of 3 to 5 microns. After that, it was dried at room temperature, the solvent was volatilized, and then the coating material 52 containing no fluororesin was applied so as to have a finish of 10 to 15 microns. After that, it is dried at room temperature, and the coating material 50 containing 8 to 15% by weight of fluororesin is applied so as to have a finish of 10 to 30 microns, dried at 150 ° C for 20 minutes, and then baked at 370 ° C to 400 ° C for 20 minutes. Tied up. According to this example, the corrosion resistance and the adhesion are further improved.

In addition, although the microwave oven and the electric hot plate are illustrated in the above-described embodiments, the present invention can be applied to other high-temperature cooking appliances.

The present invention is summarized as follows.

(1) In the invention described in the claims, the non-adhesive resin layer is formed of a fluororesin.

(2) The method for producing a film structure according to the claims includes: a step of adding a non-adhesive resin to an organic solvent varnish containing polytitanocarbosilane as a binder and mixing them to form a coating material; The method includes a step of applying the coating material on the base material and a step of sintering the coating material applied on the base material.

(3) In the method described in the above item 2, the sintering is 37
A method performed by heating in the range of 0 to 400 ° C.

(4) The method according to the above (2), wherein the non-adhesive resin is a thermoplastic fluororesin powder.

(5) The method according to (4) above, wherein the amount of the fluororesin powder added is 6 to 15% by weight based on the total weight of the organic solvent varnish.

[Effects of the Invention] As described above, according to the film structure of the present invention, since the non-adhesive resin layer made of the resin exhibiting non-adhesiveness is formed in the uppermost layer portion, oil droplets and the like do not adhere. . Also,
Since the main body of the coating structure is formed of the ceramic layer in which polytitanocarbosilane is made into ceramic, it has high temperature heat resistance. Further, at the interface between the non-adhesive resin layer and the ceramic layer, since the ratio of the non-adhesive resin and polytitanocarbosilane continuously changes up and down, the non-adhesive resin layer and the ceramic layer The adhesion is great. When such a film structure is formed on the inner wall surface of a microwave oven, which is a high-temperature cooking device, the cooking surface of an electric hot plate, etc.,
Excellent performance in terms of heat resistance and non-adhesiveness.

[Brief description of drawings]

FIG. 1A is a sectional view showing a state before sintering of a film structure according to an example of the present invention. FIG. 1B is a sectional view of a film structure according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a method for manufacturing a film structure according to the present invention. FIG. 3 is a cross-sectional view showing another example of the method for manufacturing the film structure of the present invention. FIG. 4 is a sectional view of still another embodiment of the present invention. FIG. 5 is a sectional view of still another embodiment of the present invention. FIG. 6 is a sectional view of still another embodiment of the present invention. FIG. 7 is a sectional view of still another embodiment of the present invention. FIG. 8 is a sectional view of still another embodiment of the present invention. FIG. 9 is a perspective view of a microwave oven. FIG. 10 is a perspective view of an inner box fitted into a microwave oven. FIG. 11 is a sectional view of an electric hot plate. In the figure, 2 is a microwave oven, 6 is a door, 10 is a side wall, 12 is a top plate, 14 is a bottom plate, 16 is a back plate, 18 is a front plate, 22 is a back surface of a door, 24 is an electric hot plate, and 25 is cooking. The surface, 32 is a base material, 34 is a ceramic layer, and 38 is a non-adhesive resin layer. In each drawing, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A film structure formed on a base material such as a cooking surface of a high-temperature cooking appliance or a wall surface of a heating chamber, wherein polytitanocarbosilane which is a main component is made into a ceramic, An ceramic layer formed on the ceramic layer; and a non-adhesive resin layer formed on the ceramic layer, the resin including a non-adhesive resin, and an interface between the non-adhesive resin layer and the ceramic layer. In the structure of the coating for a high-temperature cooking device, in which the ratio of the non-adhesive resin to the polytitanocarbosilane continuously changes in the vertical direction.