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Glass Jar Chemical Composition

Oct 13, 2017

Glass can is a chemical utensil which is used for food packaging, gift wrapping and medicine packaging.

Production process of glass can:

The production process of glass can mainly includes raw material preprocessing. The block material (quartz sand, pure alkali, limestone, feldspar etc.) is crushed to dry the wet raw materials and iron raw materials are treated with iron to ensure the quality of the glass. Preparation of melting system. The glass compound is made in a pool kiln or a pool furnace for 1550~1600 degrees, heating to form a uniform, non-air bubble, and meet the liquid glass forming requirement. The liquid glass is put into the mould to make the glass products of the desired shape, such as the plate, various utensils and other heat treatment. Through annealing, quenching and other processes, the stress, fracturing, or crystallization of the glass are eliminated or produced, and the structural state of the glass is changed.

Glass jars are often used in food packaging, gift wrapping, pharmaceutical packaging, chemical utensils.

Glass jars are packaged containers for food and beverage and many products, and are widely used. Glass is also a very historical packaging material. In the case of many kinds of packaging materials coming into the market, the glass container still occupies an important position in the beverage packaging, which is inseparable from the packaging characteristics which it has no substitute for other packaging materials

The chemical composition of glass bottle glass is different according to its use requirement, forming method, forming speed, technological characteristics and raw material varieties. The vast majority of bottles are made of sodium calcium silicate glass. The main components of sodium calcium silicate glass are SiO2, Na2O and CaO. The introduction of proper amount of Al2O3 and MgO can reduce the crystal tendency of glass, enhance the chemical stability and mechanical strength of the glass, and improve the molding property of glass. The chemical composition of sodium calcium bottle glass in most countries of the world is: SiO270 ~ 74%,CaO and MgO10 ~ 14%, Na2O and K2O13 ~ 16%, Al2O31.5 ~ 2.5%. When making colorless glass bottles, the content of Fe2O3 in quartz sand is very low (usually about 0.03%). In regular sodium calcium glass, add Cr2O3 and Fe2O3, glass is emerald green, add sulfur - carbon or MnO2 and Fe2O3, and glass is brown. The bottle can be made with high chemical stability and borosilicate glass. High-grade cosmetic bottle, commonly contain lead, barium or zinc crystalline glass manufacture, some is milky glass, commonly use fluoride as the milky turbidity agent.

The quality of the glass can be required to meet certain quality standards.

Quality of glass: pure and uniform, without sand, stripe, bubble etc. The transparency of colorless glass is high; The color of the color glass is uniform and stable, which can absorb light energy of a certain wavelength.

Physical and chemical properties: it has certain chemical stability, and does not function with the contents. Have certain shock resistance and mechanical strength, can withstand washing, sterilization, such as heating, cooling and filling, storage and transportation, meets the general internal and external stress, vibration, impact, can keep intact.

Quality of molding: maintain a certain capacity, weight and shape, the wall thickness is uniform, and the mouth is smooth and smooth to ensure that the filling is convenient and well sealed. No distortion, smooth surface, uneven surface and crack.

Manufacturing process glass jar manufacturing mainly includes preparation, melting, molding, annealing, surface treatment and processing, inspection and packaging.

Preparation of materials: including the storage, weighing, mixing and feeding of raw materials. It is required to mix the mixture evenly and the chemical composition is stable.

Melting system: the melting of the glass can be carried out in continuous operation flame pool kiln (see glass melting kiln). The daily output of the fire pool is generally more than 200t, and the large scale reaches 400 ~ 500t. The daily output of horseshoe flame pool kiln is more than 200t. Glass melted temperature up to 1580 ~ 1600 ℃. The melting energy consumption accounts for about 70% of the total energy consumption. It can be used to effectively save energy through the comprehensive insulation of the kiln, increasing the capacity of the storage room lattice, improving the distribution of the material pile, improving the combustion efficiency and controlling the convection of the glass liquid. In the melting pool, the bubbling can improve the convection of the glass, strengthen the clarification process and increase the amount of material. It can increase the output and improve the quality without increasing the melting furnace.

Molding: mainly adopt molding method, apply blow - blow molding small mouth bottle, press - blow molding wide mouth bottle (see glass manufacturing). Less control is adopted. The production of modern glass jar is widely used in automatic bottling machine. The weight, shape and evenness of the bottle are required to control the temperature in the feeding trough. There are many types of automatic bottle making machines, which are most commonly used in the bottle machine. This kind of bottle blowing machine is expected to drop to bottle blowing machine, rather than bottle blowing machine obey the gob, and therefore no rotating parts, work safety, and any branch can separate parking for repair without affecting the other branch operations. The bottle mechanism of the determinant system is wide and flexible. It has been developed into 12 groups, double drops or three drops forming and microcomputer control.

Annealing: the annealing of the glass jar is to reduce the permanent stress of glass residue to the allowable value. Annealing is usually done in continuous annealing furnace mesh belt type, high annealing temperature is about 550 ~ 600 ℃. Mesh belt type annealing furnace (figure 2) using forced air circulation heating, uniform furnace temperature distribution in cross-section and form air curtain, limit vertical airflow movement, guarantees the furnace temperature uniformity in each zone stability.

Surface treatment and processing: the surface treatment of glass bottles can be treated by means of hot end and cold end coating on annealing furnace. Hot end coating is after forming in hot condition (500 ~ 600 ℃) bottles in gasification of stannic chloride, titanium tetrachloride and stannic chloride butyl ester of environment, make these metal compounds in hot bottles after oxidation decomposition into the oxide film on the surface, to fill the glass surface microcrack, prevent the formation of surface cracks at the same time, improve the mechanical strength of glass bottles. Cold end coating is with single stearic acid salt, oleic acid, polyethylene emulsion, silicone or silane etc., in the annealing furnace outlet temperature of about 100 ~ 150 ℃ bottles surface spraying, form a layer of lubrication film, in order to improve the resistance to wear and tear on the surface of the bottles, lubricity, and impact strength. In production, cold end coating and hot end coating are used in combination. For large capacity bottles with more than 1l, some foam polystyrene or polyethylene film sheath on their surface. The sheath has a heat contraction, the sleeve is heated and then the bottle body is tightly wound. It is resilient and resilient. When the jar is broken, no debris can fly out when the jar is broken, so as to avoid personal injury.

The reagent bottle, sample bottle, perfume bottle and so on are used for grinding and grinding. Advanced cosmetics and perfume bottles are used to grind and polish, remove mold spots and add luster. The bottle or art deco bottle is corroded by hydrofluoric acid, resulting in surface light diffusing and sensitive. For printing on the glass surface trademarks and adornment, can be used to spray color, screen printing, decals and processing method of glass glaze on the surface of the bottles, under 600 ℃, bake, glaze and glass melting, forming permanent decorative pattern. If use organic pigment enamel, simply by 200 ~ 300 ℃ melting drying.

Check: check out defective products to ensure the quality of products. The defect of glass bottle can be divided into two main categories: defects of glass and bottle. The former includes bubbles, stones, stripes and colors; The latter is crack, thickness uneven, deformation, cold spot, wrinkle, etc. In addition, it is necessary to check the weight of the bottle, the capacity, the size tolerance of the bottle and the bottle, the tolerance of internal stress, the degree of heat resistance and the degree of stress relief. Beer, beverage and food sector due to the production of high speed, large batch, by visual inspection has already can not adapt to, now has automatic inspection equipment, such as filters (check the shape of the container and size tolerance), bottle checker, crack indicator, wall thickness inspection device, extrusion tester, voltage tester, etc.

Packaging: corrugated cardboard box packing, plastic case packing and pallet assembly packaging. Automation has been achieved. Corrugated cardboard boxes are packed from empty bottles and packed and sold in the same carton. Plastic cases for plastic containers can be recycled and reused. The tray assembly type packaging is to arrange the qualified bottles into rectangular bottles, move them to the tray and pile them on the floor, and then carry them to the specified number of layers. It is also covered with a plastic wrap, which is heated to make it shrink, tightly wrapped in a solid body, and then bundled, which is also known as thermoplastic packaging.