The history of plastic containers is not very long. Because of the characteristics of simple processing, beautiful, cheap and so on, plastic containers are developing very rapidly. Plastic containers are synthetic resin as the basic raw material, variety, mainly in the following three types.
First, Single layer plastic film bag: commonly used plastic varieties have high pressure polyethylene (ie, low density polyethylene), low pressure polyethylene (ie, high-density polyethylene), polypropylene, polyvinylidene chloride two. High pressure polyethylene film water resisting, softness and good low temperature resistance, and has the oxygen and carbon dioxide gas through the larger, which is suitable for the packaging of hygroscopic solid food, liquid food and frozen food, especially suitable for fresh vegetables, fruits and other packaging can maintain its "physiological respiration process, and keep the water caused by dry shrinkage metamorphism. Heat sterilization temperature, low pressure polyethylene can more than 100 DEG C and grease resistance, the range of applications than high pressure polyethylene. Polypropylene film has excellent gas and moisture insulation, oil resistance, high transparency, smooth surface, can heat sterilization temperature above 100 DEG C, and can be made thinner and directional packaging films have high strength but low temperature resistance is poor, so it can be used for other food in the frozen food packaging. Poly two vinyl chloride generally made of biaxially oriented films, large thermal shrinkage and excellent gas barrier properties, which has high transparency, good elasticity, high strength, oil resistance and other properties, suitable for vacuum packaging, shrink packaging and frozen food packaging.
Composite film bag: made of different kinds of plastic film or plastic film, paper, aluminum foil and so on. According to the requirements and requirements can be made into two, three or more layers of various types of composite film bag.
By single or composite materials by blow molding, vacuum, extrusion, injection molding method made of plastic bottles, cups, trays and plastic containers: to adapt to a variety of drinks, fast food and frozen food packaging. As for PET bottles, beverage bottles and PVC PP bottles, transparent appearance, light and strong features for fast food; polypropylene disc has the characteristics of heat resistance, sterilization temperature, which can contain jam, fruit and vegetable food heat sterilization; frozen food packaging is widely used in polyolefin plastic cup.