Development of the hottest food packaging containe

The development of food packaging containers (I)

the more material civilization progresses, the more packaging containers are used and the more exquisite they are made. From the development of food packaging containers, we can also see how human life forms and quality have evolved

friends over the age of 50 or 60 have experienced the growth of Taiwan's economy and the changes of material life, so they often like to tell their descendants how difficult life was in those years, and they are deeply afraid that young people do not understand how they grew up from adversity. People who grow up in difficulties often have some "old" problems. When some elders see that the dustbin is full of bottles and cans and other containers, they often look down upon them and complain, "when I was young, if I could see a little bottles and cans in the dustbin, I would have rushed to pick them up and change a few cents, which would be so good life and waste as modern people." Indeed, in the era of difficult material life, although food packaging containers are relatively rough, they are also rare and precious. In ancient times, when people needed containers to hold food, they usually looked for gourds, bamboo knots, curly large leaves or large shells from nature. Later, there were containers processed from natural resources, such as hollowed wood, woven straw baskets, and even animal organs, such as horns and stomachs, or containers made of leather. About 8000 years ago, human beings began to know how to make pottery, which can be used to hold food, store food, and even cook food. Later, pottery became the mainstream of food packaging containers. Three thousand years ago, glass, developed from ceramic glazes, came out and gradually developed into containers. However, the industrialized production of glass containers may only take place in the past 200 years

with the high development of material civilization, food packaging containers have become ubiquitous and indispensable products in life. All kinds of exquisite products , the packaged foods with eye-catching appearance are displayed on the shelves of various stores, which are diverse and often dazzling. Carefully observe these packaging materials, including plastic, metal, glass, and paper. Of course, some materials are the composite of these four materials, which makes food packaging containers more diversified

Plastic packaging containers

the rise of plastic packaging materials is closely related to the changes in people's lifestyle. Due to the high growth of population and the increasing pressure of food shortage, how to use portable packaging to facilitate the storage and transportation of food and increase the shelf life of food has become very important. Plastic packaging materials can meet these needs

what are the properties of plastic packaging materials that make them so easy to use? Generally speaking, due to the low density of plastic, its weight is much lighter than that of metal or glass, and it is relatively light in processing or use. Plastic has strong toughness. It is not as easy to break as glass, it is not as easy to sag when cans are under pressure, and it is not as easy to tear as paper. Many plastic materials are easy to form. A little heating can soften it and give it a certain shape. As long as the temperature is reduced, it can be shaped. We often see that when hydropower workers connect plastic water pipes, they can soften the plastic pipes with a little heating with a gas gun and let them be manipulated into various shapes

many plastics melt easily when exposed to heat, making it easy to seal. In many stores, you can see that clerks put food in plastic bags and seal the bags with a heat sealing machine, which is very convenient. In addition, it is very important that the current technology makes plastic packaging materials have a good barrier. Neither water vapor nor oxygen is easy to pass through the plastic container, so the storage time can be extended

plastics are high molecular substances formed by the connection and polymerization of many so-called "monomers". The molecular weight is about 5000 to 100000. Some plastics are composed of more than one monomer, forming so-called copolymers, which can have special properties. There are many kinds of plastics commonly used in food packaging containers, including polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), etc., with different properties. In terms of the demand for food packaging containers, the most important properties include strength and toughness, oxygen permeability, water permeability, heat sealing, and heat resistance. In order to produce plastic packaging materials that meet special needs, sometimes different materials are combined to form the so-called laminated film, so that the overall properties of the packaging materials are more in line with the needs

metal packaging container

it is a simple and effective way to preserve food by canning it with metal. The two metals commonly used in can making are tinplate and aluminum. The main body of tinplate is tinplate. Put the iron sheet into the molten tin solution, and then apply electricity to tin plating on the iron sheet to make the so-called tinplate. In order to improve the corrosion resistance of tin sheet, it is heated to produce tin iron alloy between tin layer and iron sheet layer; Then chromium compounds are used to form chromium oxide on the tin layer, so that the tin sheet is not easy to be oxidized and deteriorated. Finally, in order to lubricate the surface of tinplate, make it easy to operate when making cans, and prevent rust, it is coated with a thin layer of oil

therefore, the seemingly simple tin plate is not so simple in structure. In order to further prevent the corrosion of the tank wall caused by the ingredients in food, tinplate is often coated with a layer of paint. According to the characteristics of food, there is one painting or two painting. Coatings are high molecular components, such as epoxy resin, acrylic resin and polyester resin. After painting, it usually needs to be baked to fix it. Aluminum is a metal with good ductility. Since aluminum is easy to form a layer of alumina film on the surface after contacting with air, it has good corrosion resistance. However, this layer of alumina film is easy to be damaged when encountering halogen ions, such as chloride ions in table salt. Therefore, in practice, it still needs to be coated with a layer of high test data, which can be called directly in the main screen; The molecular film is protected from the erosion of ingredients in food

metal cans are a kind of packaging containers with good sealing performance and can completely protect food. Food placed in metal cans can be stored for several years without spoilage after being sealed and sterilized. However, modern people's dietary concept is based on "fresh" as the mainstream demand, which makes the metal cans that are popular for a time tend to decline gradually. However, in any case, metal cans will still be a very important food packaging container in the foreseeable future

glass

glass is made from x12crmowvnbn10 ⑴ ⑴ ⑴ gas turbine turbine disk trial forgings and other additives, which are obtained by using sand and soda power to instigate light ash (sodium carbonate) and limestone with experimental materials after heat treatment after forging, and are melted at a high temperature of about 1500 ℃. Put a small lump of molten glass into the mold, blow it into the shape of a container, and then make it into a glass container through cooling, annealing and other steps for food packaging. Modern equipment can produce more than 100 glass containers per minute, making glass containers occupy a place in food packaging. Using glass to package food has many advantages: it will not corrode, water vapor, oxygen, and aroma can not be penetrated, excellent barrier, transparent, hygienic, tasteless, recyclable, microwave, high temperature sterilization, etc. However, because glass containers are not impact resistant, fragile, and heavier than containers made of other materials, its application is also limited