Food packaging materials refer to paper, bamboo, wood, metal, enamel, ceramics, plastics, rubber, natural fibers, chemical fibers, glass and other products used in packaging, food or food additives, and coatings that directly contact food or food additives.
In order to maintain the quality of foods, the foods will not deteriorate in the process of preservation, circulation, and sales, prevent the contamination of microorganisms and prevent super chemical and physical changes. All kinds of foods must be packaged. In order to meet the needs of food packaging, depending on the type of food. Classification of packaging materials: metal cans, glass bottles, paper containers, plastics, etc. The plastic packaging has developed rapidly.
From the material is divided into two kinds of tinplate material and aluminum.
From the canning procedure is divided into: three pieces of cans (bottom, cover, body), two pieces of cans (bottom, body, one or more punching and forming, box).
Canned metal canned foods, suitable for a variety of food packaging, storage time is longer, easy to transport and sales, easy to eat. From food, it is divided into acidic foods and sulfur-containing foods. In order to meet the packaging requirements for acidic foods and sulfur-containing foods, the tank must have an anti-corrosion layer, usually called the can inner coating, which is before canning, in the coating The whole tinplate coating will be coated on the line and baked to form a coating iron, which will then be canned. In addition to coating iron in line with health requirements: non-toxic, odorless, odorless, the coating film must also meet the requirements of cans (impact resistance, toughness, adhesion to tinplate, etc.), the requirements of the actual tank (dense film coating , film thickness, acid or sulfur resistance, and special product requirements.
China's current coating iron used in canned food can be divided into: General acid, sulfur dual-use iron: The coating used is epoxy phenolic coating, it is suitable for general vegetables, fruits, poultry, meat and so on. In canned iron, a large proportion. Anti-high-acid coating iron: mainly coating iron for tomato sauce, the coating thickness should reach 10 g/m2. There are also enamel coatings covering iron, such as aluminum powder, white powder, iron oxide red, etc. Formulated Coatings Sulfur-Resistant Coatings Iron: In order to prevent sulphide contamination, zinc oxide or zinc carbonate that absorbs sulfides is added to the coating, or tinted with aluminum powder to provide a mask of sulfur.
Stripping coating iron: generally refers to the coating iron for luncheon meat. It must have a kind of anti-adhesion in addition to the general iron properties of tank coating, so that the content can be poured out smoothly after opening and the shape of luncheon meat can be maintained. . At present, the film-forming mechanism of the release coating from the anti-sticking layer can be divided into two types: one is on the general coating iron, and the other is coated with a release layer. The other is to synthesize the synthetic wax that can play the role of anti-sticking evenly in the coating and then coat the tinplate. During the baking and filming process, the synthetic wax oozes out of the surface to form an anti-sticking layer. In addition, for the special needs of the product, there are also some special coating irons, such as M-20 coating iron for mushrooms. Asparagus with iron coating, loaded with pork (two-piece cans) # 51 coating iron.
Glass bottles have a long history as packaging containers. Glass bottles as food packaging containers have: transparency, sealability, chemical stability and reusability. But the disadvantages are fragile and heavy. From the type of glass bottles and manufacturing methods: general glass bottles, lightweight glass bottles, plastic reinforced bottles, chemically strengthened bottles, etc. Divided into glass bottles: fine bottles and wide mouth bottles. Bottles are suitable for alcohol, beverages, condiments and more. The wide-mouth bottle is suitable for canned foods such as vegetables, fruits, jams and meats.
Plastic films have been widely used as food packaging materials. The films used are: polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), biaxially oriented polypropylene (OPP), Polystyrene (PS), Polyvinyl Chloride (PVC), Polyvinylidene Chloride (PVDC), Polyester (PET), Nylon (NY), or Compound Compounds of Several Kinds Illustrated Above. film.
As a food packaging material, in addition to the above, there are ceramic products, wood products, bamboo products.
Development of packaging materials
In recent years, in order to improve food safety and reduce environmental pollution, the use of natural polymer materials as raw materials to prepare environmentally friendly, biodegradable new packaging materials has received increasing attention. In the future, environmentally-friendly packaging materials that can be recycled and reused will become the main trend in the development of the packaging industry. Green packaging materials and nano-packaging materials will be greatly developed and developed.