From disposable cups to current green environmental protection plastic cups, various cups come into our lives. During this period, styles of plastic cups changed from monotonus ones to colorful and beautiful ones, representing the combination of technique and arts. Till now, apart from its basic functions, manufacturers take its health, non-toxic and appearance into consideration.

Analysis to materials
The commonly used materials for plastic cups are outer space glass and AS plastic. Outer space glass is also called PC engineering plastic, a widely used material around the world, and its main composition is makrolon. Outer space glass is light and durable, possessing excellent insulativity, plasticity, size stability, chemical resistance and high strength, heat resistance and cold tolerance. Besides, the advantages of this material are self-extinguishing, antiflaming, non-toxic and colored, and its weakness is not as hard as metal, which makes it easy to scratch.

AS plactic is the copolymers of acrylonitrile and styrene, not affected by temperature or environment, resistant to grease, detergent and low alcohol, not easy to generate internal press and split, high transparency, and it is made into pallets, cups, tablewares, toothbrushes, instrument mirrors, packing boxes and other plastic made product.

Mould Method for Plastic Cups
To disposable cups, mould method usually adopts film blow molding technique. The molding way is simple but the proper is bad; To the repeatedly used cups like PP plastic cups, molding method is extrusion-blown molding, partly injection extrusion-blown moulding. The moulding teniques include injection moulding, extrusion moulding and extrusion-blown molding. To products in pipe shape, the method is extrusion molding, mainly proper for thermoplastic plastic. The principle is to make use of cylinder rotating motion to melt the plastic, extrude the plastic under pressure, after cooling and sizing, we can get pipe shape. To shell shape products, we generally adopt injection moulding. This moulding method is also the main moulding method for thermoplastic, and its principle is to make use of the motion of screw or plunger in injection molding machine, injecting the plastic into mould under high pressure and speed, cooling the mould. Because the whole process is circulatory, it is suitable for batch production and producing products in complex apperance. Film blow molding is to extrude the melt plastic from cylinder, and blow compressed air into flim cylinder from nose hole at the same time, then blow up the fim cylinder to make it mould.

To the same material, it can be produced in many forms. Because the material property is fixed, the processing technique is changeless. But to some special materials, we need to make different product apperance by physical or chemical ways.

New style materials possess the unique properties that common plastic don’t have, so they fit the future developing trendency such as water-solubility film, black and white film, decay packing film, activity plastic packing film, antimicrobial plastic film and so on. In a word, plastic becomes the rapidest development product in packing industry for its excellent comprehensive functions, resonable price and environmental protection, and it replaces other materials gradually. The prospect is promising.