A paper cups with lids is basically a disposable cup made of paper and is coated with plastic or was, to avoid any kind of liquid from leaking out. It is made of re cycled paper and it is widely used all around the world. Paper cups were invented in imperial China, in 2nd century BC. Paper cups were constructed in different shapes, sizes and colours and were known as Chih pei. Paper cups were used to serve tea in past centuries. Later, the modern paper cup was developed in the 20th century. Paper cups are also used in hospitals for health reasons.
The base of paler coffee cup is called cup board. It is made on a special paper machines. They are made water proof. As the paper needs a higher amount of stiffness.. The paper coffee cups forming process requires good extending properties of the board and also the plastic coating. A properly formed mouth roll gives stiffness to the cup. It is also easy in handling. The basic weight of a normal cupboards are around 170-350 g/m. The paper coffee cups are mostly made from non recycled materials. The paper cup has an extra layer to prevent heat when it is held in hands. For example, when a coffee is poured in the paper cup, but due to the extra layer of heat retention, heat will not be able to reach the hand. It is called as a corrugated layer. Paper cups basically for hot drinks are glued up together, and a small amount of clay is dropped in the bottom of the cup. When the clay is dropped it starts to spin really very fast so that it easily reaches the walls of the cup. By this method the paper becomes water resistant. But one disadvantage of this method is that cup board can be smelled and tasted in the cup when any of the beverage is poured in. Water proofing is mostly done fir hot drinks. Whereas cups for cold drink are not treated like that. Those cups which are used for cold drinks etc are actually sprayed on the both sides, either it is outside or inside with wax. But this technique is old now. As a new techniques has been introduced. The new technique which is invented is of using polyethylene. Polyethylene is a method in which it covers the surface of the board with a thin layer of polythene making the cup water proof and also welds the seams together. Later paper cups are printed after they are water proofed.
Printing of paper cups is known as flexography. But now another development is introduced known as direct-printing, it allows printing on a very small quantities.