When early decal paper printing was just beginning to become popular, decals were applied to the glass and baked back to make the colored glaze on the flowers stick to the glass, but the effect was not ideal. Since the glass softening temperature is much lower than the ceramic sintering temperature, when the glaze powder on the decal is far from the melting temperature, the glass body has started to soften, and it is difficult to achieve the desired effect. {TodayHot}

After the 1970s, with the development of screen printing technology, the method of printing color glaze directly on glass with a screen was widely used.

First, glass printing ink

With screen printing on glass, its platemaking and printing are the same as ordinary screen printing. Glass printing is characterized by its ink. The glass printing ink is mainly composed of three components:

(1) Fusible glass frit. The glass frit used for making glass ink is generally composed of silica, boron trioxide, lead oxide and alumina.

(2) Glass pigments. The glass printing must be sintered at high temperature to fix the pigment on the glass. Therefore, the pigment of the ink cannot use organic pigments, and only inorganic metal oxides can be used. Once heated by {HotTag}, these metal oxides are integrated with the glass and the glass is colored. The inorganic pigments commonly used as glass inks are as follows:

Red: cadmium sulfide;

Yellow: lead chromate, cadmium sulfide, uranium salt;

Green: chromium oxide;

Blue: Aluminate drill;

Brown: iron oxide;

White: Calcium oxide, kaolin, etc.

Black: a mixture of cerium oxide, manganese oxide, etc.;

The color change on the screen is endless, and in order to display various different shades of transition and different brightness of light and shade, a variety of color materials are often used properly.

The fusible glass is mixed with a glass pigment and ground into a fine powder for use as an ink, and it is also referred to as a glass glaze powder.

(3) Diversion oil. The varnish is the link material for glass ink. It is made up of terpineol and turpentine, plus an appropriate amount of alkyd resin. A certain degree of fluidity is required on the side of the ink, so that the glass glaze powder can be well dispersed and has good printability; on the other hand, before the glass glaze is melted, it is necessary to perform gas flow before sintering. The combustion is clean and there is no adverse effect on the formation of the color glaze.

Second, glass printing

The screen printing method is used to directly print the color glaze ink on the glass. Different screen printing machines can be selected according to the shape of the glass substrate. The circular glass body, such as a glass cup or glass bottle, adopts the method of printing and printing on the printing object, and for the flat glass body, the printing method of the following is used.

Third, the glass glaze sintering

Sintering of glass glazes is also known as baking, and is generally performed in a baking oven. Sintering glass glaze, the key is to control the sintering temperature. Colored glaze inks are formulated with oily solvents and alkyd resins. The firing in the furnace takes about the following stages: First stage: from room temperature to 120°C, preheating, no change in printing ink; second Stages: From 120° to 250°C, light oil vaporizes and evaporates; Stage 3: From 250° to 500°C, heavy oil and resin are burned and gasified; Stage 4: From 500° to 580°C, in color glaze The glass powder begins to melt, and the surface of the substrate glass also softens slightly. In the fifth stage, from 580° to 620°C, the glass glaze powder is melted and melted, and the pigment powder is also melted in. The surface of the glass body is also completely softened. The glaze is combined with glass to complete the transfer and sintering of the glaze, and then slowly lowered to room temperature.

Reprinted from: Morning Art Printing