Section V glass printing
the so-called glass printing refers to the printing method with glass as the main product. The use of glass has a long history. Even in modern times, glass is also an indispensable material, especially all kinds of glass products have penetrated into all aspects of social life. Large enterprises with relatively mature technology in China's polyurethane industry will generally control the cost at 1600 yuan per cubic meter. Since the 20th century, industrial glassware and food glassware have been able to be produced in large quantities. It is transparent and colorless, and can realize multi-color printing and low-cost production. Now, the production of glass products is developing in the direction of diversification of shapes and exquisite printing
the printing of glass products can adopt silk printing, inkjet printing and transfer printing, etc. at present, silk printing is mostly used. The advantages of using thread towel on glass products are:
① the glass surface is smooth and hard, and most of its products are transparent, so it is suitable to use soft contact silk printing to complete color printing
② glass is an inorganic material with good chemical stability. It has little adhesion with the organic synthetic resin of the binder in the ink, which does not meet the basic requirements of adhesion and durability. Therefore, after printing, the pressure transmission is better and the shrinkage force is reduced. To carry out sintering treatment, it requires that the ink layer should have a certain thickness and heat resistance, and the silk printing method can meet this requirement
it can be seen that the fundamental problem of glass printing is how to correctly select special inks and carry out necessary post-treatment in order to improve the adhesion of the glass surface to the ink, and at the same time, adopt a reasonable silk printing method to realize the exquisite printing of glass products
I. composition, structure and surface properties of glass
(I) chemical composition and structure of glass
1 Chemical composition of glass
glass is an amorphous solid. There is no constant proportional relationship between the chemical components that make up the glass. Glass is generally made by heating raw materials into a molten state and then cooling. The main raw material for making all kinds of glass is the oxide of some elements. For example: SiO2, Al2O3, Fe2O3, Cai, MgO, Na2O, K2O, PbO, B2O3, P2O3, etc. These oxides can be divided into three categories. First, those that can independently form glass complexes, such as SiO2, B2O3, etc., are called "glass producer oxides"; Second, it cannot form glassy state by itself, but it can form complexes with some oxides, such as Al2O3, V2O5, etc., which are called "intermediate oxides"; Third, oxides that can break the complex, such as Na2O, K2O, etc., are called "complex multibody oxides". The percentages of various oxides in main industrial glasses are shown in the table
table composition of various practical glasses
type
oxide glass bottle glass bulb with/% plate
glass electrical appliances
glass crystal
glass optics
glass fluorescent lamp
glass physical and chemical hardness
glass alkali free
glass high silicic acid
glass sio 056.853.069.5868.880.6253.596.3Al2O. 91.. 00.5--0.041.362.014.70.4Fe2O.. 00.2--0.010.060.16--CaO. The rotation of 0--0.077.250.2217.5-m lead screw completes the beam displacement go 0---0.360.294.5-Na2O. 04.. 4416.473.. 02K2O. 72.08.370.600.. 02BaO----5.02.54----PbO--1.031.431.. 5---B2O3----9.09.. 910.02.9
2. Chemical structure of glass
from the perspective of chemical structure, silicate and other melts that have been developed for too long contain a variety of negative ion groups when they are cooled into glass. With the decrease of temperature, these anion groups polymerize into large anion groups and form complex structures. The melt of silicate glass contains negative ion groups such as [sio4]-4, [si2o7]-6, [si6o18]-12, [sio3]n-6n, [si4on]n-6n. In the complex structure formed by the agglomeration of these negative ions, each silicon atom and the surrounding four oxygen atoms form a tetrahedral cone. Silicon atom is in the center of the cone, and oxygen atom is in the four vertex angles, which are shared with the adjacent cone. Si+4 is called "complex forming agent ion". The na+, k+ plasma contained in the melt has a large radius and less charge, and the bond formed between them and oxygen is much smaller than that of silicon oxygen. Therefore, the oxygen ions connected with it are easy to be pulled away by si+4, thus making the oxygen bridge between two silicon atoms
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