JPH0354194B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a cracked enamel product with a beautiful appearance and a wide range of uses such as pots, sinks, kitchen panels, building material panels, etc. .

(Prior Art) Traditionally, enamel products have been manufactured with the aim of obtaining a uniform, unpatterned finished surface, and many studies have been conducted on manufacturing methods for patterned enamel products.
The method of producing cracked enamel products has hitherto been unknown.

(Problems to be Solved by the Invention) The present invention was completed in view of the above-mentioned circumstances in order to provide a method for manufacturing a cracked enamel product with a beautiful appearance.

(Means for Solving the Problems) The present invention for solving the above-mentioned problems includes externally adding one or more of hydrated borax, borax, and boric acid in an amount of 2 to 10% by weight during mill compounding. The added first glaze is wet-glazed on the surface of the substrate, and while the glazed surface is in an undried state, the softening temperature is higher than that of the first glaze and the difference in the body thermal expansion coefficient of the frit used is determined by 60 × 10 ^{- 7}
After applying a second glaze with a temperature below ^-1 ℃,
It is characterized by being fired using a conventional method to create a crack pattern.

In the present invention, first, a first glaze is wet-glazed on the surface of a base material such as an iron plate by a method such as wet spraying. As the first glaze, titanium glaze, titanium pastel glaze, underglaze, and other opaque glazes are suitable, and during the mill blending, 2 to 10% (by weight, the same shall apply hereinafter) of hydrated borax, borax, etc. , essentially containing at least one or more boric acids,
In addition, clay, sodium nitrite, potassium carbonate, water, pigments, etc. may be contained as necessary. It is thought that the above-mentioned hydrated borax, borax, and boric acid have the effect of increasing the dry strength of the glazed layer and improving the meltability during firing, which are effective in preventing the appearance of crack patterns. If these components are less than 2%, a stable crack pattern cannot be obtained, and if they exceed 10%, cracks will progress too much and the fired surface will deteriorate, so a range of 2 to 10% is appropriate. It goes without saying that this first glaze may be applied not only directly to the surface of the base material such as an iron plate, but also to the lower glaze firing surface and the upper glaze firing surface formed on the surface of the base material. While this glazed surface is in an undried state, a second glaze with a softening temperature higher than that of the first glaze is applied.
The glaze is applied in layers. The difference in softening temperature between the frit used for the second glaze and the frit used for the first glaze is preferably about 10 to 60°C,
Further, the difference in body thermal expansion coefficient between the two is preferably within the range of 60×10 ⁻⁷ ° C. ⁻¹ . If a combination outside these ranges is adopted, no cracks will occur or, conversely, excessive cracks will occur, making it impossible to obtain a beautiful crack pattern. It goes without saying that a glaze of any color can be used as the second glaze, and a transparent glaze may also be used. If the upper and lower layers are glazed in this way and then dried and fired using a conventional method, the first glaze, which has a lower softening temperature, will melt first and start flowing, causing expansion and leaving it in an unmolten state. By stretching the glaze on the upper layer side, almost uniform cracks or wrinkles are created over the entire surface, resulting in a beautiful-looking cracked enamel product. It goes without saying that the upper surface can be further coated with a transparent glaze or the like to protect the surface and improve its aesthetic appearance. It has been confirmed that if the first glazed surface is reapplied after it has dried, a spot pattern will appear and a beautiful cracked pattern cannot be obtained. It is thought that when coating is applied, the difference in dry strength and the difference in softening temperature between the first glaze and the second glaze work together to cause cracks in the second glaze layer during the firing process.

(Example) Next, preferred embodiments of the present invention will be shown.

Example 1 Titanium glaze 2 was wet-sprayed at a rate of 4.5 g/dm ² onto the surface of a Ni-treated thin steel plate 1 measuring 0.7 x 75 x 100 mm. This titanium glaze 2 is titanium frit
100%, 5% clay, sodium nitrite
0.2%, potassium carbonate 0.2%, hydrated borax 2.5%, water 45
The softening temperature of the titanium frit used is 530℃, and the coefficient of thermal expansion is 310.
×10 ^-7 ℃ ^-1 . While this glazed surface is in a wet state, 0.9 g/d is applied to its upper surface as shown in the drawing.
Transparent glaze 3 is overcoated at a ratio of m ² . Transparent glaze 3
is 100% transparent frit, 3% clay on the outside,
It is a mill blend of 0.2% sodium nitrite, 0.2% potassium carbonate, 0.2% bentonite, 0.5% blue pigment, and 45% water.The softening temperature of the transparent frit used is 580℃, and the coefficient of body thermal expansion is 363× 10 ^-7 ℃ ^-1 . If this is dried and fired at 830°C in a kiln, a beautiful cracked enamel product with white cracks appearing on the blue surface can be obtained.

Example 2 Hydrous borax in titanium glaze 2 used in Example 1 2.5
An enamel product with a cracked pattern was created in the same process as in Example 1 using a titanium glaze in which 5% of anhydrous borax was substituted, and a colorless and transparent glaze containing no pigment was applied to the top surface and fired. As a result, a beautiful cracked enamel product whose surface was protected by a transparent glaze was obtained.

(Effects of the Invention) As is clear from the above description, the present invention has succeeded in obtaining a cracked enamel product with a beautiful appearance that has almost uniform cracks or wrinkles on the entire surface, which is different from conventional products. Compared to non-patterned products, it is possible to obtain enamel products that are more interesting in terms of design and have properties such as surface strength, heat resistance, and chemical resistance that are comparable to conventional products. Therefore, the present invention greatly contributes to the development of industry as it solves the problems of the prior art.

[Brief explanation of drawings]

The drawings are cross-sectional views showing the steps of the first embodiment of the present invention. 2: Titanium glaze as the first glaze; 3: Transparent glaze as the second glaze.

Claims (1)

[Claims] 1 2 to 10% by weight of hydrated borax in the mill formulation,
A first glaze containing one or more of borax and boric acid is wet-glazed on the surface of the substrate, and while the glazed surface is in an undried state, the softening temperature is higher than that of the first glaze and the glaze is used. A method for manufacturing an enamel product, characterized by applying a second glaze with a difference in body thermal expansion coefficient of 60 × 10 ^-7 °C ^-1 or less between frits, and then firing in a conventional manner to create a crack pattern. .