When we talk about co-extrude film what we are refer to? How does the film we use is produced?
Food packaging film is made by two processes: Co-extrude and Lamination. Today we mainly talk about co-extruded film. There are three different process for co-extrusion: blow molding, water cooling and cast.
So, what are the production methods of food packaging film?
1. Blow method
Through the air cooling to make film surface cooling, so it can be quickly cooled, soft, spherical stretching, its transparency is slightly inferior to the water cooling and cast, but flatness and films are better for making pouches, while the spherical stretching of the production of high-barrier food stretch film ductility has a go impact.
2. Water Cooling
Through the direct contact of water and film surface cooling, so it can be quickly cooled, spherical stretching, its flatness is slightly inferior to the flow method, but better transparency, while the spherical stretching of the production of high-barrier food stretch film ductility has a go impact.
3. Cast method
Through the cooling roller cooling, the foodstuffs high barrier stretch film made longitudinally has specific stretching, transversely has no stretching, the overall flatness is good, the transparency is second to the blowing method, but the stretching ductility is better.
Eleven-layer flow co-extruded film using the flow delay process, eleven-layer film structure 1 time co-extrusion molding, molding like a waterfall after the flow delay process flow down, after the cold water rollers become cold forming into plastic film, because the food packaging film itself has not been stretched, good ductility performance, is the ideal stretch machine forming stretch film, applied to batch food packaging, than the traditional type of vacuum machine, save manpower, high efficiency.
As the very main object of use of food packaging film, a wide variety of different requirements, the contents being packaged from raw to cooked, from low to high temperature, from easy to corrupt fresh fruit to hard nuts, from vacuum packaging bags to inflatable packaging bags, basically covers the range of composite packaging bags.
1. Isolation requirements: most of the food category is rich in fats and oils, fats and oils are prone to oxidation and deterioration, so the strict requirements for oxygen barrier, the food packaging film within the moisture increase or decrease requirements are also very high.
2. Moisture activity: food all contain specific moisture, when the packaging material is selected, in the case of food processing conditions, the formula remains unchanged, the moisture content of food changes very little. When the conditions change, it will directly affect the original moisture activity value of the food, and moisture is one of the important factors causing food deterioration, as long as there is a specific moisture content, microorganisms can grow. For different moisture content foods, different materials and methods should be used.
a. Moisture low activity food. Bacteria are not able to survive in the moisture activity of less than 0.65 food, for moisture activity of less than 0.60 dry food, as long as it can be kept dry for a long time can be free of food spoilage caused by bacteria.
b. Food with medium moisture activity. For moisture activity in the 0.60-0.90 intermediate moisture food, to maintain food quality methods are, vacuum packaging, nitrogen packaging, deoxidizer packaging, etc., placed in the food fatty oxidative deterioration, food discoloration, etc.
c. Moisture higher activity food. For moisture activity in the 0.9-1.0 multi-moisture system food, quality maintenance methods: 100 ℃ or more heating sterilization, the use of hydrogen peroxide, radiation and other sterilization of aseptic packaging.
3. Food packaging film inflatable packaging role: The role of inflatable packaging is to extend the shelf life, the type of inflatable packaging bags with different requirements.
4. Cereal packaging bag requirements: Grain has a respiratory effect, different grains on the oxygen adsorption capacity varies greatly, in each grain packaging bags, can be used in the excellent isolation of food packaging film filled with oxygen to the better preservation of food inflatable packaging bags.
5. Vacuum requirements: Evacuated packaging isolated oxygen, moisture-proof, both to protect the quality of materials and make the appearance of goods look good, generous.
Post time: Aug-20-2021