JPS6034506B2 - Manufacturing method for milky white glass enamel painted products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a milky white glass enamel coated product having a beautiful milky white baked coating of glass enamel on its surface.

It is already known to produce a product having a milky scale coating of glass enamel on the surface by phosphorizing a glass frit slip which becomes opalescent due to crystallization, such as Tj02 or Zr02, onto the substrate surface.

However, when using the above conventional method, the dawning temperature is generally as high as 800 to 85,000, and the minimum is about 75,000, so it cannot be applied to thin metal plates such as glass plates and thin iron plates, and there are limits to its application. .

This is because the above-mentioned base material is thermally deformed at the firing temperature. On this point, if it is possible to bake at low temperatures, it will not only be possible to solve the problems mentioned above, but also it will be possible to save a large amount of thermal energy, which is also economical. From this point of view, the inventors have conducted a series of studies to obtain a low melting point opalescent glass frit that can be fritted at low temperatures, and have achieved some results.

However, although this made it possible to bake at low temperatures, the problem remained that the baked glass enamel film could sometimes have a slight bluish-gray tinge, so it was still not fully satisfactory. There are various possible reasons why such a coloring phenomenon, which does not occur in conventional high-temperature printing, occurs during low-temperature baking. It is most appropriate to think that rearrangement of the glass structure occurs, resulting in lattice defects, which become a type of F center (color center) and cause the above-mentioned coloring phenomenon. Based on this assumption, the inventors considered various ways to eliminate the lattice defects and found that if an oxidizing agent is contained in the slip, the oxidizing agent will decompose during brazing and release oxygen. The inventors thought that this oxygen would eliminate the lattice defects mentioned above, and after conducting experiments and research, this prediction was confirmed to be correct, and this invention was finally completed.

That is, the present invention is a method for producing a product having a milky-white glass enamel baked coating on the surface by brazing a slip of glass frit that becomes opalescent due to crystallization onto the surface of the base material at a low temperature, and the slip includes:
The gist of this invention is a method for producing a milky white glass enamel coating product, which is characterized by using a product to which a certain amount of an oxidizing agent is added.

The glass frit used in this invention is Ti0
It is sufficient as long as the opacifying agent such as No. 2 and No. 2 of Z causes opacification by crystallization.

Not only a series of low-melting point crystallized glasses including one example of the composition of raw materials shown in the Examples below, but also known high-melting point crystallized glasses may be used. A well-known high-melting-point crystallized glass frit slip was heated to 7500
This is because when baking at a low temperature of 0 or lower, a coloring phenomenon still occurs. As an oxidizing agent, 0-sodium nitrate,
Nitrates such as potassium nitrate, lithium nitrate, and aluminum nitrate, chlorates such as lithium chlorate, sodium chlorate, and potassium chlorate, (3' perchlorates such as lithium perchlorate, sodium perchlorate, and potassium perchlorate) Acid salts, '4) Bromate salts such as lithium bromate, sodium bromate, potassium bromate, etc. are used, but are not limited to these.

It is desired that the oxidizing agent be water soluble in order to be uniformly dispersed in the slip. In addition, since it is necessary for oxygen to be generated and present during the low-temperature attaching of the slip, the oxidizing agent is 30%
Needless to say, it is desirable that the material decomposes at a temperature of 0 to 75,000, and that it does not cause coloring due to this. The amount of oxidizing agent used is
The amount is about several percent (based on weight) of the amount of glass frit used.

Specifically speaking, nitrates are 0.01 to 2.5%
, preferably 0.1 to 1.0%, chlorate and perchlorate alone or together 0.01 to 2.0%, preferably 0.1 to 1.0%, bromate 0.01~2.
0%, preferably 0.1 to 1.0%. If the amount of the oxidizing agent used is less than the above range, the effect of preventing coloring will be weakened, whereas if it is more than the above range, fine bubbles will tend to form in the glass enamel baked film. The oxidizing agent is not limited to chlorate and perchlorate, but a mixture of different types may be used. The timing of adding the oxidizing agent is free.

That is, in addition to adding it at the stage of crushing the glass frit or making the slip, it can also be added to the slip of the glass frit that has been made first. The slip is made by the usual method. At this time, it is common practice to use a thickener such as alumina sol. The particle size of the frit is 200 mesh, and the portion remaining in 320 mesh in 50 cc of slip is 0.5 to 0.5.
It is desirable to set it so that it is five evenings. In addition to glass plates, thin steel plates, aluminum plates, etc. are used as the substrate.

The slip coated on these substrates using a coating method such as spraying and dried is heated to a firing temperature of 450 to 7
5,000, most commonly 550 to 650, is applied to the substrate surface. Since the present invention is configured as described above, it is possible to produce a milky white glass enamel coated product having a beautiful milky white glass enamel coating on the surface even when fired at a low temperature.

Next, embodiments of this invention will be described.

[Examples 1 to 4 and Comparative Examples 1 to 5] Raw materials for producing glass frit were mixed in the following amounts.

Silica stone [Si02] 7.2 parts by weight Boric anhydride [3B03] 17.0 Aluminum hydroxide [N(OH)3] 14.0 Soda carbonate [Na2C03] 5.7 Lithium carbonate [Li2C03] 4 .0 Potassium carbonate [K2C03] 7.4 Calcium carbonate [CaC03] 10.7 Titanium oxide [Ti
02] 5.3'' Then, the resulting mixture was placed in an alumina crucible, melted at 1200 to 1300 q○ for about 2 hours, clarified, and then poured into water and cooled to obtain glass frit A.

After drying and coarsely pulverizing this glass fiber IJ, it was used to make slips of Examples 1 to 4 and Comparative Examples 1 to 5 according to the slip formulations shown in Table 1.

That is, each formulation was ground and mixed using a pot mill or a vibration mill to form a slip. Each of the obtained slips was spray-painted onto a glass plate, dried, and then fired at a maximum temperature of 580 to 62,000.

The coloring state of the surface of each of these glass plates was as indicated by the first description Hagi. Note that no foaming was observed on the surface of each of these glass plates. Table 1 *1 The amounts are expressed in parts by weight.

*2 Alumina sol is an aqueous dispersion system with a solid content of approximately 1%.

As is clear from Table 1, in Examples 1 to 4 in which an oxidizing agent (nitrate) was added, a beautiful milky white color was obtained on the glass plate surface, whereas in the comparative example in which no oxidizing agent was added. In case No. 1 and in Comparative Examples 2 to 5 in which an additive other than an oxidizing agent was added, the surface of the glass plate was tinged with bluish gray.

[Examples 5-11] The slips of Examples 1-11 were made using the same glass frit used in Examples 1-4 and Comparative Examples 1-5 with the slip formulation of the second designation.

Each of these slips was spray-painted onto a glass slope, allowed to dry, and then fired at a maximum temperature of 580 to 620 o. The surface coloring state of each glass enamel coated product obtained was as shown in the second notation. Note that no foaming was observed on the surface of each of these glass plates. Table 2 *1 The amounts are expressed in parts by weight.

*2 Alumina sol is an aqueous dispersion system with a solid content of approximately 1%.

[Examples 12-17] The slips of Examples 12-17 were made using the same glass frit as used in Examples 1-4 and Comparative Examples 1-5 and with the slip formulation of the third designation.

Each of these slips was spray coated onto a glass plate, dried, and then fired at a maximum temperature of 580 to 62,000. The surface coloring state of each glass enamel coated product obtained was as shown in the second description. Note that no foaming was observed on the surface of each of these glass plates. Table 3 [Examples 18 to 27] Silica stone [Si02] 17.2 parts by weight Boric anhydride [Day 3B03] 12.0" Soda carbonate [Na2C03] 2.5 "Lithium carbonate [Li2C03] 2.0" Soda [
NaF] 3.5 Lithium fluoride [LiF
] 1.5 Titanium oxide [Ti02]
3.0 Zirconium oxide [Zr02]
9.5 After mixing with the above raw material composition, put it in an alumina crucible and heat it in a 120,000~130,000 furnace for about 2 hours.
Allowed time to melt and clarify.

Glass frit B was obtained by immersing it in water and cooling it. This glass frit B was dried and coarsely ground, and then made into a slip according to the slip formulation shown in Table 4. Silica stone [Si02] 20
．． 0 parts by weight Boric anhydride [Japanese 3B03] 12.0 ″Soda carbonate [Na2C03} 2.5 〃Lithium carbonate [Li2C03] 2.0 〃Soda fluoride [NaF] 3.5 〃Lithium fluoride [
LiF] 1-5 Zirconium oxide [Zr
02] 7.1 After mixing the above raw materials,
It was placed in an alumina crucible and melted in a 120,000 to 130,000 furnace for about 2 hours to clarify it.

Then, glass frit C was obtained by putting it into water and cooling it. This glass frit C was dried and coarsely ground, and then made into a slip according to the slip formulation shown in Table 4. Both slips B and C were spray-painted on the glass slope and after drying, the maximum temperature was 580-62
It was fired to a temperature of 0°C. The colored state of the surface of each of these glass plates was as in the fourth notation. Note that no foaming was observed on the surface of each of these glass plates. Table 4 *1 The amounts are expressed in parts by weight.

*2 Alumina sol is an aqueous dispersion system with a solid content of approximately 1%.

Claims (1)

[Claims] 1 A method for producing a product having a milky-white glass enamel baked coating on the surface by baking a slip of glass frit that becomes opalescent due to crystallization onto the surface of the base material at a low temperature, the slip being an opacifying agent TiO_2.
and/or SiO_2-B with ZrO_2
_2O_3-Al_2O_3R^1_2O-CaO-based frit to which a trace amount of oxidizing agent is added is used. A method for producing a milky white glass enamel coating product.