Application of the hottest aluminum material in pa

Application of aluminum materials in packaging industry

Abstract: aluminum is a kind of white light metal with rich resources, and the output of aluminum in the world is second only to steel. Its application in packaging industry ranks first among non-ferrous metals. As a packaging material, aluminum plate, aluminum block, aluminum foil and aluminum plated film are generally used. Aluminum plate is usually used as can making material or cover making material; Aluminum blocks are used to make cans that are extruded and thinned and deep drawn; Aluminum foil is generally used for moisture-proof inner packaging or composite materials and flexible packaging

key words: aluminum material packaging industry application resources are rich non-ferrous metal packaging materials aluminum plated film extrusion forming composite light metal

aluminum is a kind of white light metal with rich resources, and the output of aluminum in the world is second only to steel. Its application in packaging industry ranks first among non-ferrous metals. As a packaging material, aluminum plate, aluminum block, aluminum foil and aluminum plated film are generally used. Aluminum plate is usually used as can making material or cover making material; Aluminum blocks are used to make cans that are extruded and thinned and deep drawn; Aluminum foil is generally used for moisture-proof inner packaging or composite materials and flexible packaging

packaging plates are all anti rust aluminum alloys. Manganese and magnesium mainly play a role in improving material strength and processing performance; Copper can also improve the strength of materials, but also reduce the inch corrosion performance and processability; When zinc is added, especially when it is added at the same time as copper and magnesium, the heat treatment effect becomes better, but the corrosion resistance and processability will decline; The addition of silicon is mainly to reduce the melting point of aluminum, improve the strength and melt fluidity, and reduce the coefficient of thermal expansion. Aluminum foil is a flexible metal sheet made of industrial pure aluminum sheet with a thickness of 0.7mm (mostly 0.5mm) after multiple cold rolling and thinning

I. characteristics of aluminum materials

compared with other packaging materials, aluminum materials have the following advantages:

(1) the density of aluminum is very small, 2.7g/cm, only 35% of that of steel. This makes the container easy to achieve lightweight. A dense aluminum oxide film can be naturally formed on the surface of aluminum, and this colorless film can prevent further oxidation

(2) aluminum is non-toxic and tasteless, which meets the hygienic standard of packaged food

(3) aluminum surface has high gloss, easy coloring and good printing effect

(4) the opening performance of the easy opening cover made of aluminum is better than that of tinplate

(5) aluminum has excellent reflective and conductive properties to light and heat, which can improve the effect of heating sterilization and low temperature treatment of food cans

(6) the mechanical properties of aluminum can remain unchanged at low temperature, especially suitable for the packaging of frozen food

(7) the composite film made of aluminum foil is completely airtight and light tight, which can effectively protect the food inside. Aluminum foil can also improve the strength of aluminum-plastic composite film

(8) waste can be recycled, which can not only save energy consumption, but also prevent public hazards caused by waste, and meet the requirements of environmental protection. However, aluminum materials also have some shortcomings, mainly including:

(1) compared with tinplate and TFs, aluminum production consumes much more energy, so the price is relatively expensive

(2) aluminum is a non-magnetic material, so the original equipment that uses magnetism to absorb raw materials must be transformed

(3) aluminum materials have poor corrosion resistance and are not suitable for containing acidic, alkaline and salt rich foods

(4) aluminum material is soft, and its strength is lower than that of tinplate. It is easy to deform and scratch the surface due to collision in manufacturing and transportation

(5) aluminum is difficult to weld, so it can only be manufactured by stamping or bonding

at present, some shortcomings of aluminum can be made up by compounding with other materials. For example, the combination of aluminum foil and paper or plastic can increase its stiffness and tensile strength; In order to overcome the disadvantage of low stiffness of thin-walled aluminum cans, a small amount of liquid nitrogen can be filled before closing the container. The internal pressure generated by the vaporization of liquid nitrogen can increase the stiffness and compressive performance of the container; The aluminum foil coated with nitrocellulose and modified polyolefin not only improves the chemical properties of the aluminum foil, maintains a good printing appearance, but also provides heat tightness

II. Application of aluminum materials in packaging

1 aluminum anti-theft bottle caps

at present, most of the packaging of Baijiu, wine, medicinal wine and beverages in China is still glass bottles, of which about 50% of the bottle caps are made of aluminum, and China's anti-theft bottle caps will grow at a rate of 10% per year. It is estimated that by 2010, the consumption of anti-theft caps will reach 15billion, and about 60000 tons of aluminum strip will be required. There are nearly 200 aluminum bottle cap manufacturers in China, with an annual design capacity of about 9billion, including 30 imported production lines, with a production capacity of more than 5 billion, which can produce nearly 100 kinds of bottle caps. Aluminum bottle caps are mostly processed on production lines with a high degree of automation, so the strength, elongation and dimensional deviation of materials are strictly required, otherwise cracks or creases will occur during deep drawing processing. In order to ensure that the bottle cap is easy to print after forming, the plate surface of the bottle cap material is required to be flat without rolling marks, scratches and stains. Generally, the alloy materials used are 8001-hi4, 3003-h16, etc. The material specification is generally 0.20~43.23mm thick, the allowable tolerance is ± 0.1%, and the width is mm. Aluminum bottle cap material can be produced by hot rolling or continuous casting and rolling, and then cold rolling. The production practice shows that the hot rolled billet is better than the cast rolled billet in the use effect of the anti-theft cover

2 aluminum plastic blister packaging

at present, it is more and more common to use blister packaging for the packaging of health food and medicine tablets and capsules. Aluminum plastic blister is also known as blister packaging, referred to as PTP (pressthroughpackaging). The aluminum foil used in blister packaging is a sealing material dense on the hard piece of medical plastic polyvinyl chloride (PVC), so it is also called capping material. Almost all products requiring opaque or high barrier composite materials in modern packaging use aluminum foil as the barrier layer, because aluminum foil has a highly dense metal crystal structure, which can completely block any gas, so it is widely used. It is expected that the packaging used for drug blister materials will account for about 60% - 70% of the packaging of tablets and capsules of drugs in the future, and it is one of the drug packaging materials with the best development prospects at present

however, the quality of medicinal aluminum foil in China is far from that of imported aluminum foil. From the actual situation reflected by several domestic enterprises producing PTP pharmaceutical packaging, there are mainly the following two problems

(1) the number of needle holes of medicinal aluminum foil is far from meeting the requirements. Aluminum foil pinhole is a penetration defect, which affects the barrier performance of aluminum foil. Especially for drug packaging, it is easy to make oxygen, water vapor and light penetrate and reduce the efficacy of drugs. The national standard for medicinal aluminum foil requires that the pinhole diameter is no more than 0.3mm, and the diameter of 0.1 ~ 0.3mm cannot be more than 1/m2. At present, domestic aluminum foil can rarely meet this standard

(2) the thickness of medicinal aluminum foil is uneven and the tensile strength is low. Due to the uneven thickness of aluminum foil, it is easy to cause the adhesive coating amount to be difficult to reach the standard coating amount range in the mechanical coating process of PTP aluminum foil, thus affecting the thermal strength of aluminum foil and PVC hard sheet. Due to the uneven thickness and low tensile strength, the foil is broken after the tension is applied during the actual processing of 247 geotechnical engineering, which is not conducive to the normal production. These problems need the attention of the raw material manufacturers

3 aluminum beverage cans

currently. The development of aluminum beverage cans has three characteristics, namely, easy to pull lid, special cans, and self heating/self cooling beverage cans. For a long time, although metal packaging materials such as aluminum beverage cans have been challenged by tinplate and PET materials, due to their light weight and recyclable advantages, they are still one of the major beverage packaging forms in the construction industry, which has not only been stable development, but also continuous development and innovation

recently, coins packaging company successfully developed epol (easy to open cover). This can cover is made of polymer coated steel rings and corrosion-resistant aluminum foil. It can be used in existing filling equipment. The aluminum foil cover can be safely opened, which is more suitable for the elderly and children. Due to the competition of PET bottles, the demand for aluminum cans for beverages in the Japanese market has gradually decreased in recent years, but with the development of new aluminum bottles and cans, the demand for aluminum cans has begun to rise again. At present, enterprises such as Wunei stamping industry, Daiwa can making and Mitsubishi materials have entered the field of aluminum bottle and can production, and the aluminum bottle and can cap developed by Chaiqi manufacturing plant has also been put on the market

in order to complement each other's advantages, Daiwa canning company of Japan focuses on the advantages and disadvantages of PET bottles and aluminum cans, which are two kinds of beverage packaging containers, It is the first in the world to successfully develop a new beverage packaging container "new bottle metal can (new bottle can)" which can give metal cans new tightness 。

the new bottle and can is a brand-new packaging container developed beyond the existing two-piece can and three piece can structural framework. It not only applies the current three piece metal can composite technology, crimping and capping technology, but also applies the two-piece can deep stamping technology to make the can body, and then uses the existing can contents and the processing technology with threaded screw caps, so as to realize the use of metal aluminum, The processing has formed a new type of metal bottle packaging container with a bottle shape and a 28mm diameter drinking mouth. The new container combines the advantages of metal cans and PET bottles, and overcomes the inherent shortcomings of both. Considering the environmental problems, the new bottles and cans are made of single metal aluminum alloy. The former will be positioned in special products, and PET film materials are compounded on the surface of the material, that is, the inner and outer surfaces of the can body; The inner surface of the bottom cover is also added with composite PET film, and the outer surface is coated with pet; The bottle cap is coated with low-density pet, and the outer surface is printed and coated. In this way, the inner surface of the new bottle can avoid contact with the contents, and there is no need to use various coatings traditionally used in metal cans. After the successful trial production of new bottles and cans, they have been exhibited at the 2000 Australian can industry exhibition, and won the grand prize in the name of Japanese companies. This technology is also very attractive internationally, and the demand for aluminum pet cans is likely to further expand in the future

according to the survey of Japan aluminum can recycling association, as these four companies entered the production field of aluminum bottles and cans, the sales volume of aluminum bottles and cans alone reached 1.5 billion in 2002, 2.5 times that of the previous year, and increased by about 20% on this basis in 2003

the beverage packaging market is one of the largest markets in the metal packaging market. In order to improve the brand effect, in addition to using the silvery white characteristics of aluminum, the shape of aluminum cans is also becoming more and more important. Therefore, the manufacturers of metal forming equipment are also discussing the forming and embossing technology of aluminum cans. Because aluminum is easier to form and reach the required shape, researchers are exploring aluminum can reel expansion forming, spinning forming and rheological forming technology, which will be first used in beer cans in the near future

the use of aluminum cans for beer, soda and other beverages has increased the use of aluminum products, while other industries are also considering the use of aluminum cans. According to the information provided by Industrial Information Resources Corporation of the United States, more than a year ago, Japan's largest aluminum can manufacturer Daiwa aluminum can company began to produce aluminum cans for beer and tea companies. This company has produced 480million aluminum cans last year. Together with two other Japanese aluminum can manufacturers, it is expected that the output of Japanese aluminum cans will double in the next two to three years. Because of its light weight and easy recycling, aluminum cans are favored by the beverage industry with the characteristics of simple process, low cost, rich base materials and easy recycling. Recently, it has been popularized to other industries and has replaced glass