Glass jar is a commonly used in food packaging, gift packaging, medicinal packaging of chemical containers.
Glass jar production process:
The production process of glass jar mainly includes raw material pre-processing. The lime raw materials (quartz sand, soda ash, limestone, feldspar, etc.) crushed, so that the wet raw materials dry, iron-containing raw materials for iron treatment to ensure the quality of glass. Preparation of mating materials. Glass batch material in the pool kiln or pool furnace for high temperature 1550 ~ 1600 degrees, heating, so that the formation of uniform, no bubbles, and meet the molding requirements of liquid glass molding. The liquid glass into the mold made of the required shape of glass products, such as flat, various utensils and other heat treatment. Through the annealing, quenching and other processes to eliminate or produce glass internal stress, phase or crystallization, and change the structure of the glass state. Glass jars are commonly used in food packaging, gift wrap, medicinal packaging, chemical utensils.
Materials and chemical composition Bottle glass material is generally composed of 7 to 12 kinds of raw materials. Mainly quartz sand, soda ash, limestone, dolomite, feldspar, borax, lead and barium compounds. In addition, there are clarifying agents, colorants, bleaching agents, opacifiers and other auxiliary materials (see glass). Coarse particles of quartz is difficult to melt completely; particles too fine in the melting process and prone to scum and dust, affecting the melting, easy to plug the furnace regenerator. Suitable particle size is 0.25 ~ 0.5mm. For the use of waste glass, generally also added broken glass, the amount is usually 20 to 60%, up to 90%.
Glass chemical composition of the glass, according to its use requirements, molding methods, molding speed, process characteristics and varieties of raw materials and other differences. The vast majority of bottles are made of soda-lime silicate glass. The main components of soda-lime silicate glass are SiO2, Na2O and CaO. The introduction of proper amount of Al2O3 and MgO can reduce the crystallization tendency of glass, enhance the chemical stability and mechanical strength of glass, and improve the forming performance of glass. Most countries in the world of sodium and calcium glass chemical composition of glass: SiO270 ~ 74%, CaO and MgO10 ~ 14%, Na2O and K2O13 ~ 16%, Al2O31.5 ~ 2.5%. When manufacturing a colorless glass jar, the content of Fe2O3 in quartz sand is very low (usually about 0.03%). In the ordinary soda lime glass, add Cr2O3 and Fe2O3, glass was emerald green, add sulfur - carbon or MnO2 and Fe2O3, glass was brown. Containers of pharmaceuticals are required to have high chemical stability and are made of borosilicate glass. Advanced cosmetic bottles, commonly used lead, barium or zinc crystal glass manufacturing, and some for the opaque glass, generally with fluoride as opacifying agent.
Quality requirements Glass bottles should have a certain performance and meet certain quality standards.
① glass quality: pure uniform, no gravel, stripes, bubbles and other defects. Colorless glass of high transparency; color glass color uniformity and stability, can absorb a certain wavelength of light energy.
② physical and chemical properties: a certain degree of chemical stability, not with the stuffing effect. Has a certain degree of shock resistance and mechanical strength, can withstand washing, sterilization and other heating, cooling process and bear the filling, storage and transportation, encountered general internal and external stress, vibration, shock, can be maintained without damage.
③ molding quality: to maintain a certain capacity, weight and shape, uniform wall thickness, mouth smooth, smooth to ensure good filling and sealing good. No distortion, the surface is not smooth, uneven and cracks and other defects.