JPS5858155B2 - How to form a coating on a cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a coating on a high-temperature cooking device such as a hot plate, electric pot, or frying pan.

Some of these cookers are coated with non-adhesive, heat-resistant resin compositions such as fluororesin, but
These were those with an anodic oxide coating called bird coat (for example, an alumite finish on an aluminum base) applied to the surface of the base material, those with a hollow finish, or those coated with stainless steel sprayed.

All of these coatings are formed directly on the surface of the substrate chemically (chemical conversion treatment), physicochemically, or physically.
On this bird coat, a fluororesin composition such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, etc., which is a non-adhesive and heat-resistant resin composition, is applied. is coated as a film.

Since this fluororesin composition paint is a thermoplastic solution paint that is an aqueous suspension in which fluororesin composition particles are dispersed in a solvent, the fluororesin composition particles melt during baking after application, and the particles are separated. It fuses to form a continuous film layer, but because the fluid viscosity is high (for example, 10
10-1011 pOiSe/380°C, 104-105 pO for tetrafluoroethylene-hexafluoropropylene copolymer
1se/3000C), it is difficult to penetrate into the gaps between the alumite, hollow, and stainless steel particles of the bird coat, and there are air pockets, etc., and from the cross-sectional observation of the bird coat, it is difficult to anchor. If you try to cook with ozone in an electric pot, wok, etc., curry rice, boiled in water, etc. even though you expected the effect to be effective, the coating will blister several times from the interface of the bird coat, causing the whiteness of the base aluminum. The problem was that it rusted and became unsightly, and the non-adhesive film easily peeled off, resulting in a very short service life.

In addition, one additional step is required to apply the bird coat treatment to the surface of the substrate, and the formation treatment is performed using a method that requires time, equipment, and cost, and is unsuitable for use as a cooking utensil.

The invention is well suited for use as a cooker,
Moreover, the present invention provides a film forming method that is low in processing cost, easy to manage, and can ensure reliability.

In other words, hard inorganic particles of metal oxide are included in the undercoat as a bird coat, and a resin paint that closely adheres and blends with the base material and inorganic particles is used to achieve heat resistance, corrosion resistance,
It is characterized by the formation of a non-adhesive coating with wear resistance.

Now, we will mention double-sided cookers as targets for this implementation.

This is as shown in the external perspective view a and side view in Fig. 1.
One cooking surface 2 is a deep pot, and the cooking surface 6 on the other side is an electric cooking layer 1 that is shaped like a shallow dish so that it can be used as a hot plate. Cook in a pot or roast on a plate.

Therefore, 3 is the bottom of the cooking surface 2 on the chain side, 4 is its peripheral wall, and 5
is a power supply unit that supplies electricity to a heater 7 inserted between both cooking surfaces 2 and 6.

Of course, the cooker to which the present invention is applied is not limited to such an electric cooker.

FIG. 2 shows a partially enlarged sectional view of a cooking surface for explaining conventional film formation, and FIG. 3 shows a sectional view according to the present invention.

Assuming that the electric cooker 1 shown in Fig. 1 is used in the embodiment, the material of the cooking event 1' is JIS Al100P and aluminum alloy castings AC3A, AC7A, or steel, iron castings and forgings, etc. The cooking surface 2 is roughened by shot blasting, sandblasting, etc., and then the cooking utensil 1' is immersed in a 5-10% aqueous solution of caustic soda to degrease and etch it.

Wash with water, neutralize, dry thoroughly after washing with water, and then spray one of the paints A, B, C, or D listed in Table 1 below on cooking surface 2 to a thickness of 20±10 μm using a paint spraying device to remove the paint solvent. Immediately in a damp state that does not evaporate, use a separately prepared powder coating machine to spray silica (S i02 ), which is a hard metal oxide inorganic particle, with uniform particles of 10 to 30 microns.
Powder (alternatively, powder such as alumina: Al2O3 magnesia: Mgo may also be used.

) on the bottom 3 sides of cooking surface 2, and then spray the base coat several times on top of this by moving the device (approximately 5
(about μ) silica powder is included in the undercoat.

Next, set or force dry at the appropriate drying temperature for the undercoating paint you just used (after pre-drying at 100°C for 30 minutes): Baking at 280°C for 30 minutes B: 20 minutes at 180°C C: 18
0°C for 20 minutes D: 200°C for 20 minutes), and then, for example, if A's primer for polytetrafluoroethylene is used as the undercoat, then polytetrafluoroethylene (black) described in the same category is used. Used as a top coat, this was sprayed to give a finish of 20±10μ, and dried for one hour at the same temperature as the undercoat drying.

The top coats listed as B, C, and D were further baked at 250°C for 60 minutes to achieve a total film thickness of 4.
Forms a non-adhesive, heat-resistant, corrosion-resistant, and abrasion-resistant film as a bird coat in the range of 0±10μ.

Other film forming methods are common to the above-mentioned forming method, including forming a rough surface on the cooking surface, degreasing and etching, washing with water, neutralizing, and thoroughly drying after washing.The subsequent processing steps are as follows. It is done as follows.

That is, when spraying any of the undercoats A, B, and CD in Table 1 and the corresponding topcoat, first try using the undercoat (for example, the polyimide amide resin paint B).

) with a solid content of 10 to 20% (weight ratio) of silica (S
in2) The powder particles are uniformly mixed and sprayed onto the cooking surface 2. At this time, in order to prevent the silica powder particles from settling, the undercoat paint mixed with the silica powder particles is first uniformly stirred.
Just put it in the cup of a moving spray gun and spray.

This 10 to 15 μm spraying is then dried, and a corresponding top coat that does not contain inorganic particles (a paint made by homogeneously mixing 13% Hostaflon powder in an organic solvent solution with a polyimide amide resin paint solid content of 26%) is applied for 20 to 15 μm. The 30μ spraying is for sufficient firing to form a hard coat with a total film thickness of 40±10μ.

In the electric cooking device 1 manufactured by this method, the bottom 3 of the cooking surface 2 is sufficiently hard coated as shown in FIG. 3, and the peripheral wall 4 is also hard coated, although slightly less than the bottom 3. The paint of base coat 11 is firmly applied to the base of cookware 1' (
The silica particles 10, which are in close contact with the shot-blasted rough surface 1'a of the aluminum (aluminum) and have a sufficient anchoring effect, are firmly coated with the undercoat 1.
Since the finish of the top coat 12 is applied to the paint 1, the physical and chemical effects of the cooking liquid are not applied to the cooking surface 2.It has sufficient heat resistance and corrosion resistance, and is ideal for preventing peeling. A cooker for high-temperature heating can be manufactured.

In addition, the paints used in the above two forming methods include polyimide amide resin paints, silicone-polyester resins, silicone-acrylic resins, and other silicone resin paints that have heat resistance, corrosion resistance, and a finish with few pinholes other than conventional fluororesin paints. Paint and polyphenylene sulfide resin paint are used as the undercoat paint, and a paint mixture of 10 to 30% fluororesin powder in these resin paints is used as the top coat paint, and this is applied and baked to finish, non-stick, heat resistant, It may also be made corrosion resistant.

As shown in Fig. 2, in the conventional coating structure, a hard coat 13 applied to a cooking utensil 1' is treated with an undercoat 11 degree and a top coat 12. Resin coating (base coat 11, top coat 1
2) Treated products have the problem of electrolytic corrosion due to pinholes and penetration of cooking liquid from the tip of the hard coat, which corrodes the base aluminum and expands into aluminum oxide, lifting the fluororesin coating and causing it to peel off. Furthermore, even if a primer with good adhesion was used as the undercoat 11 for the hard coat 13 made of alumite, boiling of the cooking liquid caused poor adhesion.

Similarly to alumite, enamel also has a smooth surface (when viewed microscopically), so it is easy to peel off due to penetration and lifting from the fluororesin coating when boiling. According to the present invention, these drawbacks have been completely solved.

To clarify this through an experiment, the cooking utensil 1' of the electric cooker 1 coated with the above coating was subjected to a JIS salt water spray test of 240 hours, boiled water of 240 hours, and ozone stock mix of 2.
Boil 5g/1200cc water 8 Hr t 16 H
5 cycles with r rest as 1 cycle, undiluted soybean oil,
All passed the test of immersion in sauce at 60℃ for 240 hours, immersion in 3% saline solution at room temperature for 10 days, and the conventional hollow finish
Stainless steel thermal spray hard coat fluororesin coating, double and triple layer finish thick film 40-50 without hard coat
For μ fluororesin coating, salt water spray JIS24
Hr ~ 48 Hr white rust, 1 cycle to 2 cycles with ozone stock mix, flaking, soybean oil, sauce 6
Blisters and white rust occur when immersed at 0℃ for 48 to 72 hours, 3
A test result showed that white rust occurs after 2 to 3 days of immersion in saline solution at room temperature.

In addition, in an abrasion resistance test, the coating sufficiently withstood a load of IJg and 5,000 to 10,000 rotations using a stainless steel wire scrubbing brush, but the stainless steel wire showed more significant wear and tear, indicating good hard coat performance.

In the above example, silica (S i 02) particles were used as hard metal oxide powder particles, but silica balloon particles, which mix well with glass powder and paint and do not settle, are also highly effective.

Since the present invention is constructed as described above, the surface after the undercoating resin paint is applied and dried becomes rough due to the hard inorganic particles mixed inside, and the top coat and the undercoat are made of the same material. Since the resin paint is used, it has good mutual adhesion and the non-adhesive coating does not peel off easily.

In other words, even if the top coat is worn down by long-term use, the base coat is mixed with hard inorganic particles and has an uneven surface, so the top coat exists between the uneven surfaces and is non-adhesive. Sexuality is not impaired.

In addition, to roughen the surface of the undercoat in order to achieve the above effects, it is sufficient to apply and dry the undercoat resin paint mixed with hard inorganic particles on the cooking surface of metal utensils, so it is not necessary to use the conventional hard coat. In this way, the workability is improved, the material cost is low, and since it is flexible, it can have a remarkable effect of being highly durable.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view a and a side view of an electric cooking appliance to which the film forming method of the present invention has been applied, Fig. 2 is a partially enlarged sectional view illustrating conventional film formation, and Fig. 3 is a side view. FIG. 2 is a partially enlarged cross-sectional view illustrating film formation of the present invention. DESCRIPTION OF SYMBOLS 1...Electric cooker, 1'...Cooking utensil, 9...Coating layer, 10...Silica particles, 11...Undercoat , 12... Top coat, 13
・・・・・・Conventional bird coat.

Claims (1)

[Claims] 1. Topcoat as an undercoat in cooking utensils where the roughened cooking surface of metal clothing is coated with a heat-resistant, corrosion-resistant, and abrasion-resistant non-stick resin paint to form a non-stick coating. Using a resin paint made of the same material as the base coat, mix hard inorganic particles of metal oxide into the base coat resin paint, apply to the roughened cooking surface, and after drying, apply the above non-stick resin paint as the top coat. A method for forming a film on a cooking device.