JP2002255575A - Device for manufacturing sheet glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for manufacturing sheet glass capable of manufacturing the sheet glass with little defect for many hours stably, by enabling to coat the body of the device for manufacturing the sheet glass with platinum alloy and using the device body regardless the composition of the sheet glass. SOLUTION: In this invention, the device body 1 is constituted with a construction material having a coefficient of linear expansion larger than that of the platinum alloy, and at least both surfaces of the device body 1 are coated with the platinum, alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a thin glass used for a glass sheet for a liquid crystal display display substrate.

[0002]

2. Description of the Related Art As a method for continuously forming a glass ribbon from a molten glass and manufacturing a glass plate having an extremely small thickness, a manufacturing method of drawing a glass ribbon downward, that is, a fusion method is known.

[0003] This fusion method uses a manufacturing apparatus comprising a main body having a cross-sectional shape converging downward and side end members provided on both side surfaces of the main body. This is a manufacturing method in which the glass ribbon is made to flow down along the surface and integrated at the lower edge of the main body.

The main body is made of a refractory material such as alumina or zirconia. However, the main body is eroded by contact with the molten glass, so that the usable time of the main body is short due to deterioration of the distribution of streaks, stones and wall thickness with time. There were difficulties. Also,
It was necessary to change the material of the main body to an optimum one according to the glass composition to be molded.

[0005] In order to solve such difficulties, a method of coating the main body surface with a platinum alloy has been proposed, but it has been difficult to solve the deformation of the platinum alloy plate due to thermal expansion.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, to make it possible to coat a platinum alloy on the main body, to use the same main body regardless of the glass composition, and to obtain a thin glass sheet with few defects. It is an object of the present invention to provide a thin glass manufacturing apparatus that can be manufactured stably for a long time.

[0007]

According to the present invention, there is provided a main body having a cross-sectional shape converging downward, a molten glass flowing down on both surfaces at a converged lower edge, and a ribbon-forming body. In a manufacturing apparatus for a thin glass comprising: a side end member for regulating a width of a molten glass provided on both side ends of a main body, the main body is made of a material having a linear expansion coefficient larger than that of a platinum alloy, and at least both surfaces of the main body are formed. Is provided with a platinum alloy.

In the present invention, unless otherwise specified,
The linear expansion coefficient means an average linear expansion coefficient in a temperature range between a normal temperature and an actually used temperature.

In the present invention, the main body is made of a material having a linear expansion coefficient larger than that of the platinum alloy. This is because a tensile stress is generated in the platinum alloy coated on the surface at the temperature actually used. In addition, the thickness distribution is prevented from being deteriorated due to the loosening of the platinum alloy.

[0010] Regarding the coefficient of linear expansion, if the difference in linear expansion coefficient from the platinum alloy is too large, the platinum alloy may be damaged, and if it is too small, the above-mentioned effects may be insufficient. A preferable material of the main body has a coefficient of linear expansion 0.5 × 10 −6 / ° C. to 5 × 10 −6 / ° C. higher than that of the platinum alloy. Examples of the refractory having such a linear expansion coefficient and having heat resistance include magnesia refractories, magnesia-chromium refractories, high chromium refractories, zirconia refractories, and siliceous refractories.

Of these, the siliceous refractory reacts with the molten glass and is easily eroded, so that the entire body must be coated with a platinum alloy. Depending on the composition of the molten glass, a magnesia-based refractory containing magnesia as a main component [about 13.8 × 10 -6 /
C. (20.degree. C. to 1800.degree. C.)] and a zirconia refractory containing zirconia as a main component [about 11.0.times.10@-6 /.degree.
C.-1000.degree. C.)], magnesia-chromium refractories and high chromium refractories are not easily eroded by molten glass, so it is not necessary to cover the entire body with a platinum alloy, only the necessary parts are covered. Alloy savings. As for the thickness of the platinum alloy coated on the surface of the main body, if the thickness is too thin, cracks or breakage may occur due to insufficient strength, and if it is too thick, workability deteriorates, adhesion to the main body deteriorates, and cost increases Are not preferred. Desirably, the range is 0.3 to 2.0 mm.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a front view of the thin glass manufacturing apparatus of the present invention,
FIG. 2 is a perspective view of the main body 1 of the manufacturing apparatus shown in FIG.

As shown in these figures, side end members 2 and 3 are engaged with the side end of the main body 1, and the side end member 2 is provided with an introduction hole 4 for molten glass. Although not shown in the drawing, the introduction hole 4 is connected to a tank kiln containing the clarified molten glass, and is for supplying the molten glass to the groove 5 of the main body 1 from the tank kiln. The main body 1 has a groove 5, and the cross-sectional shape of the main body 1 converges downward. The molten glass supplied to the groove 5 flows from left to right along the groove 5 in FIG. The overflowed molten glass flows down along both surfaces 7 of the main body 1 and is integrated at a lower edge 8 to form a glass ribbon. A downward pulling force is applied to the glass ribbon, thereby forming the glass ribbon to a target thickness.

The main body 1 has an average linear expansion coefficient of about 11 × 10 −6.
/ Magnesium chrome refractory. The surface of the main body 1 has a thickness of about 0.5 m by a platinum alloy (average coefficient of linear expansion: about 9.1 × 10 −6 / ° C.) film 10 containing Rh 10%.
m. The platinum alloy coating 10 may be provided only on the surface 7, but is preferably provided on all surfaces of the main body 1 and the side end members 2, 3 which come into contact with the molten glass. The reason is that the body 1 and the like are eroded by contact with the molten glass,
This is because it is possible to prevent the shape of the main body 1 or the like from being substantially deformed due to the deformation of the shape or the intrusion of the molten glass into the minute gap between the refractory and the platinum alloy. Reference numeral 11 denotes a gas vent pipe for discharging gas generated from the main body 1 or the like into the atmosphere. Although the pipe 11 is not always necessary, it is desirable to provide the pipe 11 because when the platinum alloy film 10 is coated on the entire surface of the main body 1 and the like, the platinum alloy film 10 can be prevented from being deformed by the gas.

According to the present invention, the platinum alloy film 10 coated on the main body 1 generates tensile stress due to a difference in thermal expansion with the main body 1 and maintains close contact with the main body 1, thereby maintaining dimensional accuracy.

[0016]

EXAMPLE Using the manufacturing apparatus shown in FIGS. 1 and 2, thin glass sheets having a normal window glass composition were continuously manufactured. That is, clear molten glass (up to 1300 ° C.)
From the upper surface 6 of the main body 1,
A drawn glass ribbon was produced downward at a speed of 150 to 300 mm / Hr. Cooling after one month of continuous use, 1
We used for months, but there was no problem.

[0017]

According to the present invention, the main body is made of a material having a coefficient of linear expansion larger than that of the platinum alloy, and at least both surfaces of the main body are coated with the platinum alloy. Can be produced with good yield. In addition, the main body can be reused without replacing the main body when the work is stopped.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the device of the present invention.

FIG. 2 is a perspective view including a partly broken portion of the main body shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Upstream side end member, 3 ... Downstream side end member,
4 ... Introduction hole, 6 ... Top surface, 8 ... Bottom edge, 10 ... Platinum alloy film

Claims (5)

[Claims] 1. It has a sectional shape converging downward,
A thin glass manufacturing apparatus comprising: a main body forming a ribbon by integrating molten glass flowing down on both surfaces at a converged lower edge, and side end members provided on both side ends of the main body to regulate the width of the molten glass. In the above, the main body is made of a material having a linear expansion coefficient larger than that of a platinum alloy,
An apparatus for producing thin glass, wherein at least both surfaces of the main body are coated with a platinum alloy. 2. The apparatus according to claim 1, wherein the main body is made of a material having a coefficient of linear expansion 0.5 × 10 −6 / ° C. to 5 × 10 −6 / ° C. greater than that of a platinum alloy. An apparatus for manufacturing the thin glass according to the above. 3. The production of a thin glass according to claim 2, wherein the platinum alloy is made of a platinum alloy containing gold, platinum, rhodium, or iridium as a main component of platinum and platinum. apparatus. 4. The apparatus according to claim 2, wherein the main body is made of a magnesia refractory. 5. The apparatus according to claim 2, wherein the main body is made of a zirconia refractory.