JPH02164732A - Method for forming plate glass - Google Patents

Abstract

PURPOSE:To easily bend plate glass by forming colored patterned coating films contg. inorg. pigment powder having specified properties on both sides of parts of the plate glass to be bent, heating and bending the plate glass and removing the coating films by washing. CONSTITUTION:Inorg. pigment powder having >=1,000 deg.C m.p. and <=5mum grain size, e.g., Fe2O3 or TiO2 powder is mixed with resin or an oily or fatty component such as rosin as a dispersive medium to prepare paste. Both sides of parts 2, 3 of plate glass 1 to be acutely bent are coated with paste contg. a black inorg. pigment such as Fe2O3 and both sides of a part 4 to be gently bent are coated with paste contg. a white inorg. pigment such as TiO2 to form coating films. The plate glass is then put on a metal mold 6 for bending, heated to a temp. between the strain point of the glass 1 and the softening point, bent, cooled and washed to remove the colored coating films.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for forming bent glass sheets that are often used in vehicles and other applications, and more specifically, forms a colored pattern coating on the surface of the glass sheet, and heats and bends the glass sheet. The present invention relates to a temporary glass forming method in which the coating film is then washed and removed.

[Prior art and its problems]

As a method of forming a colored coating film on a glass plate and then heating it, for example, as disclosed in Japanese Patent Publication No. 57-48498, a paste consisting of an inorganic pigment, a low melting point glass powder, a resin, and an oil-and-fat bone is used as the colored coating film. There is a method of baking a colored coating at the same time as hot forming, but when this is used for the above purpose, the coating adheres strongly to the slope glass and is difficult to peel off and remove. It is difficult to employ because it leaves traces on the temporary glass where the coating film is formed and tends to spoil the appearance.

Furthermore, as a method for manufacturing bent glass in which the local part of the plate glass is sharply bent, for example, in JP-A-5333211, a plate glass is placed on a bending mold, and a local heating line is arranged at the bending force. A method of softening and bending is disclosed by heating the whole body in a heating furnace and heating local parts to a higher temperature.

Alternatively, in JP-A No. 53-132016, a conductive paste consisting of silver or other conductive powder, a low melting point frit, and a resin component for dispersion and viscosity adjustment is applied in advance to the part to be bent, and then the chain is chained in a heating furnace. A method is disclosed in which the part is energized to a higher temperature to cause it to soften and bend.

In these known examples, it is necessary to place lead wires (members) inside the heating furnace and energize the heating medium. There are problems such as making it difficult to grow one mulberry.

In addition, in the prior art, it is difficult to remove paste baked-on parts because they are firmly adhered to the glass, and even if they are removed, metal ions such as silver will penetrate into the glass and become attached to the glass core. There is a problem in providing coloring.

The main purpose of the present invention is to solve these problems. For example, when a sharp bend is required in a local part of the plate glass, a black heat-absorbing coating is applied to the chain, and when a gentle curve is required, a white heat-reflecting coating is applied to the chain. By forming a coating film and heating the entire part in a heating furnace, the former is kept at a higher temperature than other parts by heat radiation, and the latter is maintained at a lower temperature to obtain the desired curved shape. The object of the present invention is to obtain curved glass extremely simply and easily without requiring special local heating operations.

[Means for solving problems]

The present invention forms a colored coating film on a desired part of a plate glass surface using a paste consisting of an i-free pigment powder with a melting point of 1000 degrees or more and a particle size of 5 μm or less, a resin as a dispersion medium, and an oil component.
Next, the plate glass is heated to a temperature above its strain point and below its softening point to curve into a desired shape, and after cooling, the colored coating film is washed and removed.

In the present invention, ordinary alkali-lime-based glass or aluminosilicate-based glass is used as the plate glass, and the softening point thereof is 750°C or lower.

Inorganic pigments include Cod, Cr2O, and FezO, which have a melting point of 1000°C or higher and do not easily react with glass below the softening point.
A compound containing one or more of x, MnO, ZnO, TiOz, ZrSiO4, etc. is used as appropriate.

In addition, the inorganic pigment has a high surface energy because it is made into fine particles with a particle size of 5 μm or less, and when heated at a low temperature of 750"C or less, it causes gradual sintering, and it adheres moderately to glass, and also does not stick to glass when peeled off after heating. This is advantageous because it is difficult to visually recognize particle traces.On the other hand, if the particle diameter is 5 μm or more, particle traces become visible, and the adhesion is also poor, making it easy to peel off during the heating process.

Resins and oil components act as binders that adhere to inorganic pigments and glass when heated at low temperatures ranging from room temperature to several hundred degrees Celsius, and scatter and burn at higher temperatures. Add a viscosity modifier such as ethyl cellulose as required.

In addition, low melting point glass frit, alkali feldspar, borax, etc. that soften and melt at temperatures below 750°C and act as adhesives and binders for glass and inorganic pigments should be removed after the colored coating is heated and bent. The coexistence of these two methods must be avoided, as it makes it difficult to apply and leaves traces of the paint film easily.

〔Example〕

The present invention will be explained in detail with reference to Examples below.

FIG. 1 is a perspective view of a plain glass plate 1, and its sharply bent portion 2.3 has grains with a diameter of 0.3 to 5 μn on the front and back surfaces.
A paste in which a black inorganic pigment consisting of +Crz03, FezOz and CoO is dispersed in rosin and ethyl cellulose is applied by an appropriate means such as brush painting.

On the other hand, a paste in which a white inorganic pigment made of TiO2 and Zr5iO having a particle size of 0.3 to 4 μm is dispersed in a similar resin liquid is applied to the front and back surfaces of the portion 4 to be gently bent. Of course, the white inorganic pigment dispersion paste may also be applied to the non-curved portion 5.5'', taking heating conditions etc. into consideration.

Next, the plate glass 1 is placed on a bending mold 6 as shown in the perspective view of FIG. 2, and introduced into a heating furnace (not shown). For example, the heating furnace is equipped with metal resistance heating wires on the upper and lower inner surfaces of the furnace in order to make thermal radiation work efficiently. 500"C) and below the softening point (also 720"C), for example, 640°C.At this time, the temperature of the black paste coated area 2.3 of the plate glass 1 is raised to 670°C, and the gold is heated close to the softening point. Sharp bending along the mold becomes easy, and the white paste coated part 4 remains at about 620° C. and gently curves along the mold 6.

FIG. 3 is a perspective view of the plate glass 1 formed in this way, and the sharply bent portion 2.3 and the gently curved portion 4 are made of an inorganic material having a high melting point but an ultra-fine powder with high surface energy. The pigment is gently sintered and adheres to the plate glass l to an appropriate extent.

Then, by brushing and cleaning this, the coating film made of the inorganic pigment can be easily peeled off and removed. In this case, unlike when coarse inorganic pigments are used, they will not peel off during the heating process, or conversely, the pigment particles will not embed in the glass surface layer and leave traces, and when frit is mixed in. It does not become difficult to peel off and remove it as in the case of the above.

〔Effect of the invention〕

According to the present invention, since a colored film is applied to the glass, for example, an endothermic colored coating film is applied to the portion of the plate glass that is scheduled to be bent, thereby producing effects such as facilitating bending during heating. It can be widely and effectively applied to the field of sheet glass forming processing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a plain plate glass, FIG. 2 is a bending mold, and FIG. 3 is a perspective view of a molded glass. 1. Plate glass 2.3 m<bending part 4,
The part that bends gently

Claims (1)

[Claims] 1) A colored coating film is formed on a desired part of the surface of a plate glass using a paste consisting of an inorganic pigment powder with a melting point of 1000°C or more and a particle size of 5 μm or less, a resin as a dispersion medium, and an oil component, and then the plate glass is heated to a temperature above its strain point. 1. A sheet glass forming method, characterized in that the glass is heated to a temperature below its softening point to curve into a desired shape, and after cooling, the colored coating film is washed and removed.