|
Existing methods of glass matting - description of different methodologies.
Matt drawing on glass can be received in two widespread ways.
Way №1 is the processing with the help of sandblaster. The surface is processed by air stream with presence of the smallest parts of sand or other materials.
In this case the expensive equipment is required. Consumables (certain kinds of carbides) also aren't cheap. As glass during the processing undergoes, as a matter of fact, the blows of high frequency, it is necessary to count with high percent of waste - glass, especially if it contains microcracks or the rests of thermal stress, just breaks.
The mat surface, received by processing with sandblaster tool, strongly fixes fatty stains of finger prints, which are very difficult to remove. Therefore insistently it is recommended to cover such glasses with special polymeric compounds, that always leads to rise in price of end-products.
Among other things, processing by means of abrasive materials is not considered safe manufacture. The glass dust, which is formed during the processing of the glass surface, is dangerous for respiratory apparatus.
Way №2. To make glass matting is possible also with a help of chemical influence of acid steams, which is called - hydrofluoric acid. As the method is toxic, it is used in practice seldom. The matter is that inhalation of concentrated steams of this acid can lead to a fatal outcome.
It is necessary to notice, that there are also other ways of chemical processing of glass.
The following composition is considered well known: sodium fluosilicate, hydrochloric acid, hydrofluoric acid, water. Disadvantage of the given method is its toxicity, caused by evaporation of hydrofluoric acid during the glass matting procedure.
Other chemical composition, invented in Japan, includes: melt of salts of alkaline metal, nitrate or sulphate of one- or bivalent cation. Then hydroxide, a carbonate or bicarbonate of monovalent or bivalent cation are added to the melt of salts. The lack of this method is complexity of technology and complicated working conditions while working with the melt of salts.
We also know that there is a mat paste, which gives a chance to get matted drawing on the glass surface. Its composition: sodium acetate, barium sulphate, fluoric acid, sulfuric acid. The matting paste imperfection - its high toxicity as it includes acids, that adversely affect environment and the human's health.
In 2002 scientists have developed another multicomponent reactant, which could make the surface matted. Structure: potassium nitrate, barium sulphate, barium fluoride, lithium nitrate, dimethyl sulfoxide. Again, disadvantage of the method is complexity of the compound preparation. Besides, glass, which is covered with this mat paste, should be held in the furnace at temperature of 300 degrees in the course of an hour. It considerably limits the sizes of manufactured products with parameters of the furnace, and also reduces productivity and raises percent of waste in production.
That's why we can make some important conclusions: the above-stated methods (and also similar to them) are very sticky in usual conditions. The special equipment, professional skills and big financial investments are required.
|
|
|
