Polyethylene transparency is not high, there is a certain air permeability, moisture barrier performance is good, there is a certain tensile strength and tear strength Caesar, good flexibility. Chemical stability, insoluble in any organic solvent plastics products at room temperature, resistant to packaging design most plastic case acids, alkalis, even in concentrated nitric acid. Has good low temperature resistance (-70 degrees) clamshell packaging Easy to open type machining, heat sealing is good, but the printing is poor, often using corona treatment or chemical surface treatment to improve its printability. It is a non-toxic packaging materials. And is often used in the plastic box sealing layer of the composite coating and moisture. Also be made of linear low density polyethylene films and film bag for packaging. Now the general food packaging are mostly inner PE or CPP, etc. It is the use of clear plastic packaging its non-toxic, good moisture resistance, good flexibility, good sealing performance advantages. Used as a food packaging material composite lining.
Now the market relatively large amount of polypropylene (PP) is a propylene plastic trays polymerization, it is a very light plastic, and its transparency, good gloss, with excellent mechanical properties and tensile strength, hardness and toughness, resistance to heat resistance, high temperature at 120 degrees continuous use, cooking in boiling water. Chemically stable in a certain temperature range, acid, alkali, salt and many solvents stability. Health security. Meet the requirements of food packaging. Superior gas barrier properties of polypropylene PE. But still poor. Poor cold tolerance, low temperature brittle fracture easily. Printed polypropylene poor performance need to go through before printing surface pretreatment. Therefore, combined use of other materials. Since this product has good physical properties and relatively low price, become the most widely used food packaging plastic film substrates. Eg: for instant noodles, biscuits, candy, nuts, potato chips and other food packaging.
Widely used by the market there are polyester (PET) commonly known as polyester. Its high transparency, good gloss. Has excellent gas barrier, blocking vac tray oil and holding incense performance. Hardness and toughness, tensile strength is 5-10 times the PE, the PA 3 times. Chemical stability, resistance to acid, alkali and common organic solvents. PET plastic package in a wide temperature range to clear plastic box maintain its excellent physical and mechanical properties, the normal temperature range of -70-120 degrees to 150 degrees in use for some time. It’s health and safety is good. So the people that it is widely used in poultry packaging. Of PET composite film to the substrate can be used for cooking food packaging. PET bottles are used extensively for beverage packaging.
Polyamide (PA) commonly known as nylon, it has a strong gas barrier properties, but poor water vapor barrier plastic packaging properties, water absorption, and with the increase of the amount of water swelling, gas barrier, moisture barrier performance degradation, the intensity dimensional stability and packaging are also affected. Its good mechanical properties, tough and wear-resistant, cold, heat resistance, normal temperature range -60-130 degrees, the maximum temperature can reach 200 degrees. Chemically stable, alkali and acid intolerant, water and alcohol. Easy processing, printing is packaging company good, but poor heat sealability. Has excellent puncture resistance. Materials, non-toxic, food packaging on health safety requirements. So it is widely used in packaging and cooking frozen food packaging. Because of its good printability and puncture resistance, and now a lot of refined rice marketed cast nylon bags.
Polyvinylidene chloride (PVDC) due to their outstanding advantages that it has a gas, vapor, oil, and has excellent odor barrier properties, so the market as a barrier to it an important component of the composite material can also be prepared into the emulsion coated on the other substrate, and to improve the barrier material….