JP2001322829A - Glass having high transparency, method for manufacturing glass having high transparency and frit for glass having high transparency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively and easily manufacture glass having high transparency from ordinary soda lime glass. SOLUTION: The frit prepared by compounding 5 to 45 parts cerium oxide and 0.1 to 10 parts coke with 100 parts silica sand and solidifying the mixture after melting is added to base glass in a fore hearth. The bivalent iron ions in the glass are turned to less color developing tervalent iron ions by the oxidation effect of cerium, by which the transparency is improved. The generation of foam in the glass is suppressed by compounding the coke with the frit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a highly transparent glass frit which can be manufactured by adding to a normal base glass (soda-lime glass) in a forehearth to produce a highly transparent glass. The present invention relates to a highly transparent glass used and a method for producing a highly transparent glass.

[0002]

2. Description of the Related Art When manufacturing glass tableware and high-grade glass products, highly transparent glass is required. Conventionally, when producing highly transparent soda-lime glass, sorted or refined silica sand or lime having a low iron content has been used as a raw material. That is, by using a raw material containing less iron, the amount of iron oxide in the glass was reduced, the yellow-green coloration due to iron was reduced, and the transparency was increased.

[0003]

The above-mentioned conventional high-transparency glass is made of silica sand or lime having a small iron content, which has been sorted or refined, so that the raw material cost is high. Further, since the compounded raw material is produced by melting it in a melting furnace, in the case of small-volume production, there are many losses and the cost is high. In addition, since ordinary glass products cannot be manufactured simultaneously in the same melting furnace, the process has great restrictions.

The present invention solves such a problem.
Developed a frit capable of imparting transparency to ordinary soda-lime glass, and by adding this frit to ordinary base glass (soda-lime glass) in the forehearth, it is possible to obtain highly transparent glass at low cost and easily. It is something that can be done.

[0005]

According to the present invention, 5-45 parts of cerium oxide and 0.1-10 parts of coke are used for 100 parts of silica sand.
This is a glass frit with high transparency, characterized by blending parts and solidifying after melting.

[0006] When a frit containing cerium is added to a base glass (soda-lime glass) in a forehearth, divalent iron ions in the glass are converted to trivalent iron ions by the oxidizing action of cerium. Since trivalent iron ions generate less color than divalent iron ions, transparency is improved. Therefore, according to the present invention, even a normal soda-lime glass containing 3% or more of iron can be a glass having high transparency.

The amount of cerium oxide in the frit is 5 to 45 parts per 100 parts of silica sand. If the amount of cerium oxide is less than 5 parts, the frit addition rate becomes high in order to obtain the required cerium oxide concentration in the final product, which causes a production problem associated with frit melting. If it is more than 45 parts, cerium tends to precipitate as crystals in the frit.

[0008] When a frit containing cerium is added to the base glass in the forehearth, a large amount of bubbles are generated, and as a result, defective products containing bubbles are significantly generated. This is because cerium oxide is a strongly oxidizing substance, and when the frit is melted in the base glass, oxygen gas is generated due to a change in the valence of cerium due to a redox reaction with the base glass as shown in the following equation. It is thought that it is.

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Therefore, by appropriately adding coke, which is a reducing agent, to the cerium-containing frit, the degree of redox is brought close to that of the base glass, and a change in the valence of cerium is suppressed, whereby the foaming of the glass can be prevented. The amount of coke added
If the amount is too small, the frit is too close to the oxidizing side with respect to the base glass (soda-lime glass), if too large, the frit is too close to the reducing side. Occurrence can be prevented.

In the present invention, silica sand 10 is used as a decolorizing agent.
Erbium oxide may be added in an amount of 1.3 to 4.0 parts or selenium in an amount of 0.02 to 0.4 parts with respect to 0 parts. The color development of erbium oxide and selenium is extremely stable,
It is hardly affected by changes in the atmosphere or an oxidizing agent such as cerium oxide, and a desired effect can be easily obtained. By blending the decoloring agent, the color of the glass can be made closer to colorless.

The above-mentioned frit of the present invention is added to a base glass (soda-lime glass) in a forehearth. An appropriate amount of the frit is about 1 to 3% by weight based on the base glass. If it is less than 1%, the desired transparency of the glass cannot be obtained, but if it is more than 3%, not only the effect is small, but also a production problem associated with frit melting occurs.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The composition of the frit of the embodiment of the present invention is shown in Table 1. Cerium oxide having a purity of 90% is used. Soda ash and anhydrous borax are added to promote melting, and calcium carbonate is added for vitrification.

[Table 1]

The frit of the example was added to a base glass (soda lime glass) having the composition shown in Table 2 in a forehearth to produce a colorless and highly transparent example glass. The base glass obtained by melting the prepared batch in a melting furnace flows through the forehearth and is supplied to a glassware forming machine. The foreheart is a shallow groove-shaped temperature control section for controlling the glass to a viscosity and temperature suitable for molding. A feeder is provided at the tip of the forehearth, and glass is supplied to the forming machine from the feeder.

The base glass having the composition shown in Table 2 is
It is a very common soda-lime glass with an iron content of 0.03% or more. The addition of the frit is performed in the fore hearth, and the addition amount is 1.7% by weight of the base glass amount.
And FIG. 1 shows light transmittance curves of the glass of this embodiment and the base glass. As is clear from the figure, in the visible light range (420 to 720 nm), the glass of the example has a higher transmittance than the base glass.
The glass of the example has a brightness Y = 88.8 and a main wavelength λ = 56.
The stimulus purity was 5.4 nm, Pe = 0.3 (converted to a thickness of 10 mm). The base glass has a brightness Y = 87.0 and a dominant wavelength λ.
= 566.8 nm, and the stimulation purity Pe = 0.8 (converted to a thickness of 10 mm). Compared to the base glass, the glass of the example has higher transparency because of its higher lightness, and has lower stimulus purity, indicating that it is more colorless. Further, since the dominant wavelengths are almost the same, the color of the glass is hardly changed.

[Table 2]

[0015]

According to the frit of the present invention, a glass having high transparency can be obtained by adding the frit to a normal base glass in a forehearth, so that even in the case of small-scale production, the frit can be easily manufactured at low cost and with high transparency. Glass can be manufactured. Also, since ordinary soda-lime glass is melted in the melting furnace, normal glass products can be manufactured simultaneously in the same melting furnace, and there is no restriction on the process. By using erbium oxide or selenium as the decoloring agent, it is possible to obtain a colorless and highly transparent glass at low cost and easily.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of light transmittance of a glass and a base glass of an example.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G062 AA01 AA09 BB01 BB03 CC02 CC04 DA06 DA07 DA08 DB01 DC01 DD01 DE01 DF01 EA01 EA10 EB01 EC01 ED01 EE01 EF01 EG01 FA01 FA10 FB01 FC01 FD01 FE01 FF01 FL01 FL01 GC02 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH12 HH13 HH15 HH17 HH20 JJ01 JJ02 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK06 KK07 KK10 MM01 NN01

Claims (7)

[Claims] 1. Cerium oxide 5 to 4 per 100 parts of silica sand
Highly transparent glass frit characterized by blending 5 parts and coke 0.1 to 10 parts and solidifying after melting 2. The frit of claim 1, wherein the silica sand
A highly transparent glass frit characterized by blending 1.3 to 4.0 parts of erbium oxide with respect to 0 parts. 3. The frit of claim 1, wherein the silica sand is
Highly transparent glass frit characterized by blending 0.02 to 0.4 parts of selenium with respect to 0 parts 4. A highly transparent glass obtained by adding the frit according to claim 1, 2 or 3 to a base glass (soda lime glass) with a forehearth. 5. The glass according to claim 4, wherein the concentration of iron in the glass is 0.03% or more, the lightness (Y) is 88 or more in CIE display converted to a thickness of 10 mm, and the stimulating purity (P
e) the glass having high transparency, wherein 0.6 or less. 6. A method for producing highly transparent glass, comprising adding the frit according to claim 1, 2 or 3 to a base glass (soda lime glass) with a forehearth. 7. The production method according to claim 6, wherein the highly transparent glass produced has an iron concentration of 0.03% or more, a lightness (Y) of 88 or more in CIE display converted to a thickness of 10 mm, and an excitation purity. A method for producing highly transparent glass, wherein (Pe) is 0.6 or less.