JPH0372024B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Applicability) The present invention relates to a method for producing black glass using a color feeder. (Prior Art) It is well known that black glass is very useful for packaging containers, tableware, etc. A common method for manufacturing this black glass is the so-called batch method, in which a predetermined amount of coloring agent such as chromium or manganese is added to glass raw materials and then melted. On the other hand, in addition to the production method using the batch method described above, colored glass is produced using a so-called color feeder, in which colored glass is obtained by adding and mixing fritted glass containing a highly concentrated coloring component to molten glass in the feeder section of a melting furnace. Methods are also known. However, in the manufacturing method of black glass, large amounts of chromium, manganese, etc. are required as coloring agents, so when using the color feeder method, it is necessary to add a very large amount of colored frit glass. However, there was a drawback that the amount of outflow from the feeder was limited, making it impractical. In other words, there is a certain limit to the amount of chromium that can be contained in the frit, which is used as a coloring agent for black glass, and a very large amount of frit is required to supply the required amount of black glass. In order to melt the base glass sufficiently homogeneously in the color feeder, it is necessary to suppress the outflow amount as much as possible and stir and melt for a long time, making it impossible to maintain a sufficient outflow amount. Therefore, black glass is generally produced by the batch method, and the color feeder method has not been produced, and the development of this method has been awaited. (Object of the Invention) The object of the present invention is to provide a method for manufacturing black glass using a color feeder, and to provide a method for manufacturing black glass that can maintain a stable and high outflow amount. The object of the present invention is to provide a method for stably producing black glass using inexpensive raw materials by greatly reducing the use of expensive hexavalent chromium. (Structure of the invention) The structure of the present invention for achieving the above object is as follows:
In the method of manufacturing black glass using a color feeder, the dominant wavelength (λd): 545 ~ in CIE indication.
565nm, excitation purity (Pe): 40-85%, brightness (Y): 20-45% (measured value for 10mm thick glass), containing one or more of manganese, nickel, and cobalt. The gist of this is to add a coloring frit containing chromium to the above. (Examples) The present invention will be explained in detail below using examples. Composition of base glass (wt%) SiO ₂ 70.0 Al ₂ O ₃ 2.0 CaO 10.5 Na ₂ O ₃ +K ₂ O 15.0 CuO 0.03 CrO ₃ 0.15 <CIE display> Dominant wavelength (λd): 550.3 nm Excitation purity (Pe): 43.1 % Brightness (Y): 42.0% (Note: Measured value for 10 mm thick glass) Black glass was produced by adding colored frit to green base glass having the above composition using a color feeder. The composition of the coloring frit charged into the color feeder and the amount (wt%) of the frit charged relative to the amount of outflow of the base glass are as shown in Table 1. Further, the coloring frit was added and stirred and melted in a color feeder, and the color tone of the black glass obtained after 5 hours was measured (measured as CIE display), and the results are shown in the lower column of Table 1. The amount of coloring frit added to the amount of base glass flowing out is not limited to the examples, but is 0.5 to 5.0% by weight.
It is possible to arbitrarily select within the range of
If the amount is less than 0.5% by weight, a sufficiently deep color tone cannot be obtained as black glass, and if it is more than 5.0% by weight, it will take a long time to melt the frit, making it impossible to maintain a high flow rate.

【table】

[Table] Figure 1 shows the transmittance curve and CIE value of the black glass obtained in the example. In the figure, 1 is a 10mm thick base glass, 2 is a 3mm thick base glass, 3...
6 indicates a 3 mm thick black glass corresponding to Examples 1 to 4. According to an embodiment of the present invention, the color change of black glass can be changed in just 5 hours from the start of adding the coloring frit, whereas conventionally it took two days to change the color from white substrate to black glass. It has become possible to obtain good quality products that fall within the range. In addition, large amounts of potassium dichromate (K ₂ Cr ₂ O ₇ ) have traditionally been used in the chromium used as a coloring agent for black glass in order to obtain the color of hexavalent chromium. In order to maintain this state, it is necessary to strengthen the oxidizing properties of the molten glass, which results in poor clarification and reduces the amount of outflow. Potassium dichromate itself is extremely expensive, increasing production costs. It had the disadvantage of However, in the example, by using a green base glass, the use of potassium dichromate as a coloring agent can be minimized, so it is possible to eliminate all of the above drawbacks and maintain a high flow rate. Summer. Furthermore, it is now possible to use chromite (Cr ₂ O ₃ · FeO) as a coloring agent for green base glass.
This not only made it possible to significantly reduce raw material costs, but also made it possible to lower the temperature of the melting furnace by about 30 degrees Celsius to 1,550 degrees Celsius, compared to when large amounts of potassium dichromate were used. (Effects of the Invention) As described above, according to the method for manufacturing black glass using a color feeder according to the present invention, black glass can be manufactured using a color feeder, which was conventionally considered to be impractical due to the limitation of outflow amount. This allows production to be carried out while maintaining a high flow rate, and since it requires as little potassium dichromate as possible compared to conventional methods, it has good clarification and allows the temperature of the melting furnace to be significantly lowered. At the same time, it became possible to significantly reduce raw material costs. Furthermore, since the green base glass is used, there is no problem of color unevenness between the glass and the black glass, or any feeder out of a large number of feeders can be used for the production of black glass. It also has As described above, in the method for manufacturing black glass using a color feeder according to the present invention,
It has various effects and is extremely valuable in the glass manufacturing industry, making a great contribution to the development of the industry.

[Brief explanation of drawings]

Figure 1 shows the transmittance curve and CIE value of black glass according to an embodiment of the present invention, where 1 is 10
3 mm thick base glass, 2 represents 3 mm thick base glass, and 3 to 6 represent 3 mm thick black glass corresponding to Examples 1 to 4.

Claims (1)

[Claims] 1 In the method of manufacturing black glass using a color feeder, the dominant wavelength (λd): 545 in CIE indication.
~565nm, excitation purity (Pe): 40~85%, brightness (Y): 20~45% (measured value of 10mm thick glass), one or more of manganese, nickel, cobalt, etc. 1. A method for producing black glass, characterized by adding a coloring frit containing chromium and chromium.