Hollow glass products can be sealed with lids or plugs and can hold various materials quantitatively. Widely used as packaging containers for beverages, alcohol, chemicals, medicines, stationery, and cosmetics. Glass bottles and jars are transparent, easy to clean, have good chemical stability, do not contaminate the contents, have high air tightness, excellent storage performance, rich shapes, and decorations, can be recycled many times, and have rich sources of raw materials. However, glass bottles and jars are easily broken and have a large weight-to-volume ratio. These shortcomings are gradually being improved with the development of process technology.
The production of glass products is the highest in the production of glass bottles and jars. In 1980, the world output of glass products was 68Mt, of which the output of glass bottles and jars was 40.8Mt.
From 2000 BC to 500 BC, humans could make hollow glassware. After the blowpipe began to be used in 200 BC, the oil production and brewing industries used insulating glass as containers. During the Roman Empire, the demand for glass containers increased, and most of the products were round-bottomed and had to be supported by iron or wooden frames. Later, due to the development of molds for blowing glass, flat-bottom bottles without brackets were produced. From the 5th to the 15th century, the technology of pressing, drawing, and blowing was greatly developed, which laid the foundation for the mechanization of glass manufacturing. In 1867, the German Siemens brothers applied the regenerator continuous melting pool kiln to the glass industry, which made the mass production of glass bottles and jars possible. From 1880 to 1890, the molding technology of pressing-blowing method to manufacture wide-mouth bottles and blow-blowing method to manufacture small-mouth bottles (see glass manufacturing) was invented. The first bottle-making machine driven by an electric motor appeared in 1900. From 1904 to 1905, M.J. Owens of the United States created a fully automatic vacuum suction bottle making machine. Since 1910, gob feeders have been developed. In 1914, the semi-automatic blow-blowing process was mature. In 1925, the American Hardford-Emper Company successfully developed a determinant bottle making machine, which was produced by the blow-blowing method, and later developed to also be produced by the pressure-blowing method. This determinant bottle making machine is still the main model used today, and it is gradually developing in the direction of multi-unit and multi-drop material.
In the Tang and Song dynasties, China has used blowpipes to blow hollow glass containers. The modern glass industry was formed from 1904 to 1908. Shanghai Jinghua Glass Factory, established in 1931, is the first factory in China to continuously manufacture glass bottles and cans using horizontal flame and horseshoe flame regenerator kilns and automatic bottle making machines. After the 1950s, a number of large-scale modern bottle-making factories were built. In the 1980s, the biggest improvement in the production of glass bottles and jars was the lightweight of glass bottles, which could save raw materials, fuel, increase production speed and reduce transportation costs.
There are many types of glass bottles and jars, and there are many classification methods.
① According to the shape, there are general bottles, bottles with handles, and tubes, etc., with a capacity of 1ml to 25l.
② According to the shape of the bottom, there are round, oval, square, rectangular, flat and other bottles and cans, most of which are round.
③ According to the size of the bottle mouth, there are bottles and cans such as wide mouth, small mouth and spray mouth. Bottles with an inner diameter of more than 30mm and no shoulders or less shoulders are called wide-mouth bottles, which are often used to hold semi-fluid and powdered or block solid objects; those with an inner diameter of less than 30mm are called small-mouth bottles, which are often used to hold various fluid items.
④ According to the form of the bottle mouth and the bottle cap, there are continuous thread bottle mouth, cork bottle mouth, pouring bottle mouth, crown cap bottle mouth, rolling cap bottle mouth, plastic cap bottle mouth, spray bottle mouth , Press up – unscrew the bottle mouth, side seal – pry open bottle mouth, glass stopper frosted bottle mouth, handle bottle mouth and tube bottle mouth and other bottles and cans. The dimensions and tolerances of the bottle mouth are standardized.
⑤ According to the use requirements of bottles and cans, there are one-time use bottles and cans and recycled bottles and cans. One-time bottles and cans are discarded after being used once; recycled bottles and cans can be recycled multiple times and used for turnover.
⑥ According to the molding method, there are molded bottles and tube bottles. The molded bottle is made by directly molding the glass liquid in the mold; the tube bottle is first drawn from the glass liquid into a glass tube, and then processed and formed.
⑦ According to the color of the bottle, there are colorless, colored and opalescent bottles. Glass jars are mostly clear and colorless, allowing the contents to maintain a normal appearance. Followed by green and brown. Green ones usually hold beverages; brown ones are used for medicine or beer. They absorb UV light and help protect the contents. The United States stipulates that the average wall thickness of this colored glass bottle should make the transmittance of light waves with a wavelength of 290 to 450 nm less than 10%. A small number of cosmetics, vanishing cream and ointments are packed in opalescent glass bottles.
Raw materials and chemical composition Bottle and jar glass batches are generally composed of 7 to 12 kinds of raw materials. There are mainly quartz sand, soda ash, limestone, dolomite, feldspar, borax, lead and barium compounds. In addition, there are auxiliary materials such as clarifying agents, coloring agents, decolorizing agents, and opacifying agents (see glass manufacturing). Coarse-grained quartz is difficult to melt completely; if the particles are too fine, scum and dust are easily generated during the melting process, which affects melting and easily blocks the furnace regenerator. The suitable particle size is 0.25-0.5mm. In order to use waste glass, broken glass is generally added, and the dosage is usually 20-60%, and the maximum can reach 90%.
Quality requirements Glass bottles and jars should have certain performance and meet certain quality standards.
①Quality of glass: pure and uniform, no defects such as sand, streaks, bubbles, etc. The transparency of colorless glass is high; the color of colored glass is uniform and stable, and it can absorb light energy of a certain wavelength.
②Physical and chemical properties: It has certain chemical stability and does not interact with the contents. It has certain shock resistance and mechanical strength, can withstand heating and cooling processes such as washing and sterilization, as well as withstand filling, storage and transportation, and can remain intact when encountering general internal and external stress, vibration, and impact.
③Moulding quality: maintain a certain capacity, weight and shape, with uniform wall thickness and smooth and flat mouth to ensure convenient filling and good sealing. There are no defects such as distortion, uneven surface, unevenness and cracks.
Manufacturing process Glass bottle and can manufacturing mainly includes batch material preparation, melting, forming, annealing, surface treatment and processing, inspection and packaging and other processes.
①Material preparation: including raw material storage, weighing, mixing and delivery of batches. It is required that the ingredients are mixed evenly and the chemical composition is stable.
② Melting: The melting of bottle and jar glass is mostly carried out in a continuous operation flame pool kiln (see glass melting furnace). The daily output of the horizontal flame pool kiln is generally more than 200t, and the large one is 400-500t. The daily output of the horseshoe-shaped flame pool kiln is mostly below 200t. The maximum glass melting temperature is 1580-1600 °C. The energy consumption of melting accounts for about 70% of the total energy consumption in production. Energy can be effectively saved through measures such as overall thermal insulation of the pool kiln, increasing the capacity of the regenerator checker bricks, improving the distribution of the stockpile, improving the combustion efficiency, and controlling the convection of the glass liquid. Bubbling in the melting tank can improve the convection of glass liquid, strengthen the process of clarification and homogenization, and increase the output. The use of electric heating in the flame kiln can increase the output and improve the quality without enlarging the furnace.
③Molding: The molding method is mainly used, and the small-mouth bottle is formed by the blow-blow method, and the wide-mouth bottle is formed by the pressure-blow method (see glass manufacturing). Control laws are used less frequently. The production of modern glass bottles and jars widely adopts high-speed molding of automatic bottle making machines. This kind of bottle making machine has certain requirements on the weight, shape and uniformity of the gob, so the temperature in the feeding tank should be strictly controlled. There are many types of automatic bottle making machines, among which the determinant bottle making machine is the most commonly used. This kind of bottle making machine gob obeys the bottle making machine, not the bottle making machine obeys the gob, so there is no rotating part, the operation is safe, and any branch can be stopped for maintenance alone without affecting the operation of other branches (Figure 1). ). The determinant bottle making machine has a wide range of bottles and cans, and has great flexibility. It has been developed into 12 groups, double-drop or three-drop molding and microcomputer control.
④ Annealing: The annealing of glass bottles and jars is to reduce the permanent stress remaining in the glass to the allowable value. Annealing is usually carried out in a mesh belt continuous annealing furnace, and the maximum annealing temperature is about 550-600 °C. The mesh belt annealing furnace (Fig. 2) adopts forced air circulation heating, so that the temperature distribution of the cross section of the furnace is uniform and an air curtain is formed, which restricts the longitudinal airflow movement and ensures that the temperature of each belt in the furnace is uniform and stable.
⑤Surface treatment and processing: Generally, the surface treatment of glass bottles and jars is carried out by coating the hot and cold ends of the annealing furnace. The hot end coating is to place the bottle and can in a hot state (500-600 ° C) after forming in the environment of vaporized tin tetrachloride, titanium tetrachloride or butyl tin tetrachloride, so that these metal compounds are The surface of the hot bottle and can is decomposed and oxidized into an oxide film to fill the micro-cracks on the glass surface, while preventing the generation of surface micro-cracks and improving the mechanical strength of the glass bottle and can. The cold end coating is to use monostearate, oleic acid, polyethylene emulsion, silicone or silane, etc. to spray the surface of the bottle with a temperature of about 100-150 °C at the outlet of the annealing furnace to form a lubricating film. To improve the wear resistance, lubricity and impact strength of the bottle surface. In production, cold end coating and hot end coating are often used in combination. For large-capacity bottles above 1l, some add foam polystyrene or polyethylene film sheaths on their surfaces. The sheath is heat-shrinkable. After being heated, it tightly binds the bottle body. It is tough and elastic, shockproof and anti-friction. When the bottle is broken, no fragments will fly out, which can avoid personal injury.
For reagent bottles, sample bottles, perfume bottles, etc. with glass stoppers, use mortar or emery and water as abrasives to grind mouths and stoppers. High-grade cosmetics and perfume bottles are often ground and polished to eliminate mold marks and increase luster. High-grade wine bottles or art-decorated bottles and cans are corroded with hydrofluoric acid, resulting in surface light diffusion and delicate hand feeling. In order to print trademarks and decorations on the glass surface, spray color, screen printing, and decal processing methods can be used to apply glass glaze to the surface of the bottle and jar, bake at 600 ° C, and the glaze and glass are fused to form a permanent pattern. . If it is decorated with organic pigments, it only needs to be melted and baked at 200-300 °C.
⑥Inspection: Detect defective products and ensure product quality. The defects of glass bottles can be divided into two categories: glass defects and bottle forming defects. The former includes bubbles, stones, streaks, and color irregularities; the latter includes cracks, uneven thickness, deformation, cold spots, and wrinkles. In addition, check the can weight, capacity, finish and body dimensional tolerances, resistance to internal stress, thermal shock and stress relief. Due to the high production speed and large batches of beer bottles, beverage and food bottles, etc., they can no longer be adapted by visual inspection. Now there are automatic inspection equipment, such as preselectors (checking the shape and dimensional tolerance of bottles and cans), bottle mouth inspectors, cracks Inspector, wall thickness inspection device, extrusion tester, pressure tester, etc.
⑦Packing: There are corrugated cardboard box packaging, plastic box packaging and pallet container packaging. All have been automated. The corrugated cardboard box packaging uses the same carton from empty bottle packaging to filling and sales. http://www.zyzhan.com/news/detail/17012.htmlThe plastic boxes used in plastic box packaging can be recycled and reused. Pallet container packaging is to arrange the qualified bottles into a rectangular bottle array, move them to the pallet and stack them layer by layer, and wrap them when they reach the specified number of layers. Generally, it is also covered with a plastic film sleeve, heated to shrink it, tightly wrapped into a solid whole, and then bundled, which is also called thermoplastic packaging.
