JP2010235357A - Method for molding sheet glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when molten glass is subjected to roll out molding, several visible stripes are generated easily in the traveling direction of a glass ribbon if the glass ribbon is widened. <P>SOLUTION: The method for molding the sheet glass, in which the molten glass falling from a molten glass feeder is made to pass through the space between paired rolls, comprises the steps of: forming the roll from a base material which consists of a material enough to involve a liquid therein or has a structure enough to do so; heating the molten glass and the glass ribbon and adjusting the temperatures of them; and rotating the rolls, which are arranged to be paired below the molten glass feeder, to roll the glass ribbon between the paired rolls while interposing a vapor curtain of the liquid between the glass ribbon and the roll. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a roll-out molding method for molten glass by a roll-out method.

  Various methods for forming molten glass into a plate shape are known. Particularly popular are the tin float method, the fusion method and the rollout method.

  The tin float method is currently most widely used as a mass production method for sheet glass, and is a method in which glass is floated on molten tin and stretch-formed. However, the metal tin that is solid at room temperature must be kept in a molten state at all times, so the energy required to keep the kiln warm is enormous. In addition, tin ions diffuse from the tin / molten glass interface into the glass, which may adversely affect the glass quality.

  The fusion method is a method in which molten glass flows down along both side surfaces of a refractory molded body, and the glass is joined at the lower part of the molded body. In this method, since the surface is kept in a non-contact state, a high-quality plate glass can be obtained. However, if devitrification occurs on the contact surface between the refractory and the molten glass, defects will occur continuously, so the refractory must be replaced, and the refractory increases as the glass width increases. The manufacturing cost of the system is enormous. Moreover, since it is necessary to consider the compatibility of a refractory and a glass composition in order not to cause devitrification, the glass composition which can be used is limited.

  The roll-out method is generally a method in which a molten glass is sandwiched between metal rolls and molded, and has an advantage that glass molding can be performed with a simple apparatus configuration at a lower cost than the tin float method and the fusion method. However, since the molten glass is rapidly cooled by contact with the metal roll, it is inevitable that contact marks, wrinkles, and undulations remain on the formed glass, and a polishing process is required to obtain a high-quality sheet glass product. It is essential.

  In view of these circumstances, a method has been proposed in which a roll base material that generates steam is used to impart conveying force to glass and roll-out molding to obtain high-quality glass that does not leave roll marks (Patent Documents). 1 and 2).

JP 2001-180949 A JP 2002-47019 A

  In the forming method described in Patent Documents 1 and 2 described above, a method of supplying molten glass between a pair of rotating rolls and adjusting the thickness by forming tension between the plurality of rolls in the glass traveling direction. Although it was taken, there was no description about the method of shape | molding a glass ribbon wide. As a method of widening the width of the glass, a method of narrowing between the rolls of a pair of rolls is considered to be effective, but if this method is used, several glass ribbons can be visually observed in the direction of travel. There is a need to solve this problem.

  As a result of earnestly studying the above problems, the present applicant has found that when the molten glass spreads in the width direction on the roll, the point where the temperature is lowered and difficult to spread in the width direction becomes the aforementioned streaks. Obtained. From the obtained knowledge, the molten glass is reheated on a roll, and when it is formed into a glass ribbon, it is formed into a width that does not cause streaking, and the formed glass ribbon end is further heated to adjust the temperature. Thus, a method for solving the above problem has been provided.

  That is, the present invention is a method of forming molten glass flowing down from a molten glass supply apparatus into a sheet glass by passing between paired rolls, and the base is made of a material or structure that can contain a liquid inside. The glass ribbon is rotated through a liquid vapor film between the rolls by rotating the rolls installed in pairs under the molten glass supply device while adjusting the temperature by heating the molten glass and the glass ribbon. It is a roll-out molding method of molten glass characterized by rolling.

  In the molten glass roll-out molding method of the present invention, the liquid that forms the vapor film is water.

  By this invention, it became possible to extend in the width direction without impairing the quality of the glass ribbon.

  The present invention relates to a method of forming molten glass flowing down from a molten glass supply apparatus into sheet glass by passing between paired rolls, and the base material is made of a material or structure that can contain a liquid inside. Rotating the rolls installed in pairs under the molten glass supply device while heating and adjusting the temperature of the molten glass and glass ribbon, and rolling the glass ribbon through a liquid vapor film between the rolls A molten glass roll-out molding method characterized by molding.

  FIG. 1 is a side view schematically showing an example of a roll-out molding apparatus for a sheet glass product for carrying out the present invention, and FIG. 2 is a front view. The forming apparatus comprises a pair of rolls 3 having a base material capable of containing water on the surface, a device 4 for supplying liquid thereto, and a device 5 for heating the molten glass 2 or the glass ribbon 6.

  Above the roll-out molding apparatus, there is a molten glass supply apparatus 1, which is an apparatus that can supply molten glass 2 that has been melted from the raw material over a sufficient time at a desired temperature. The molten glass 2 is supplied onto a pair of rolls 3 and spreads in the width direction on the rolls 3. The molten glass 2 spread to a desired width on the roll 3 passes between the rolls 3 while being formed into a plate shape by the roll 3.

  At this time, the distance of the roll 3 to the molten glass supply device 1, the roll rotation speed, the temperature of the molten glass supplied onto the roll, and the flow rate of the supplied molten glass are appropriately set according to the desired glass ribbon. It is desirable. In particular, since the width of the glass ribbon formed by the roll 3 is affected by the molten glass temperature and the flow rate of the molten glass, it is desirable that the distance between the rolls can be set freely. Furthermore, if the gap between the rolls is too narrow, the molten glass may not flow out, or there may be frequent streaks on the glass ribbon to be molded, and on the other hand, if the gap between the rolls is too wide, roll molding may not be possible. It is desirable that the distance between the rolls is set appropriately.

  As for the roll base material that can contain the liquid on the roll surface, examples of the material include porous inorganic materials, metal materials, carbon materials, paper, and fibers. The properties required for these materials are heat resistance against radiant heat from the molten glass 2 and the heating device 5 received through the vapor film, water content capable of holding a sufficient amount of liquid on the rotating roll, For example, water absorption speed and surface flatness.

  The liquid supply device 4 to the roll substrate is a device that can supply a sufficient amount of liquid to the rotating roll. In addition to the water tank type as shown in FIGS. It is done. Alternatively, one more roll containing sufficient liquid may be installed, and the liquid may be supplied to the base material of the roll 3 by contacting it somewhere on the roll 3.

  Further, the liquid supplied to the roll base material is preferably a gas that forms a vapor film on the roll surface, not a gas near room temperature, but a gas at least above the glass transition point. The liquid is vaporized by the high heat of the molten glass 2 and the glass ribbon 6, and forms a vapor film between the glass and the roll. The liquid should have low toxicity, be non-flammable at the temperature used, and should not react chemically enough to cause the vaporized vapor to adversely affect the glass and roll, to increase water and hydrophilicity. An aqueous solution to which an alcohol is added, an aqueous solution to which a surfactant is added, or the like can be given.

Molten glass 2 or glass ribbon 6 is heated by heating device 5 and the temperature is adjusted.
At this time, the number of the heating devices 5 does not have to be as shown in FIG. 1, and one or more pairs may be installed in the vertical direction according to the desired width of the glass ribbon. It is desirable that the position of the heating device 5 can be set freely in both the width direction and the height direction. Heating is performed using a burner, a heater, etc. Also, as shown in FIG. 1, the heating device does not have to be installed so as to heat from the end of the glass ribbon toward the center, and is installed so as to face the glass ribbon. The glass ribbon surface may be heated.

It is a side view of the example of an apparatus for carrying out the present invention. It is a front view of the example of an apparatus for carrying out the present invention.

1: Molten glass supply device 2: Molten glass 3: Roll 4: Liquid supply device 5: Heating device 6: Glass ribbon

Claims (2)

A method of forming molten glass flowing down from a molten glass supply apparatus into a sheet glass by passing between a pair of rolls, the roll comprising a base material made of a material or structure capable of containing a liquid therein, While the glass and glass ribbon are heated to adjust the temperature, the rolls installed in pairs under the molten glass supply device are rotated, and the glass ribbon is rolled and formed between the rolls through a liquid vapor film. A roll-out molding method for molten glass, which is characterized. The method for roll-out forming molten glass according to claim 1, wherein the liquid that forms the vapor film is water.