Generally, all disposable containers are divided in two categories: semi-forming (PS) and thermo-forming (PP). They differ in consuming materials, production stages and price. In all disposable container production machines the raw material melt and then are formed into sheets and get different shapes via pressing and shaping processes. In semi-forming machines, all above-mentioned stages are integrated and the consuming material is polystyrene (PS). These machines generally produce fragile containers. However, these machines produce majority of disposable containers, including bowls, cups, dishes and mushroom container. The reason is the low price of semi-forming machines compared to forming-machines. Since the containers are fragile and harmful, especially in dealing with hot, these machines are not recommended for producing disposable glasses.

The foam sheet unit adopts the double machine series high foam sheet production process. Adding a blowing agent during the extrusion of polystyrene raw materials by using this equipment. After grinding head extrusion, foaming, cooling, shaping, pulling, and winding into the finished sheet. PS foam sheet is a new type of packaging material, which has good thermal insulation and cushioning properties and also has a pearl-like appearance and color. After vacuum forming, the PS foam sheet is made into various types of food containers such as lunch boxes, trays, dishes, etc.

Polypropylene (PP) is the main consuming material of forming machines. These machines are composed of two parts: sheet making and pressing (containers production). Therefore, in addition to selling the final product of these machines, the produced sheets could be used in different industries. Since propylene is flexible and is not harmful to human body, disposable glasses are currently made by thermo-forming machines.

Foam lunch box refers to tableware made of disposable expanded polystyrene plastic. The foam lunch box has the characteristics of oil resistance, water resistance, corrosion resistance, heat preservation, and heat insulation. The polystyrene plastic pellets and the blowing agent are heated together, the plastic pellets become soft, and the volume expands up to times at the same time. The expanded polystyrene plastic is cooled, reheated, and shaped using molds to become lunch boxes, plastic cups, plastic dishes, and other products. An expanded polystyrene product weighs times less than a regular polystyrene product of the same size. Therefore, the cost of using expanded polystyrene to make lunch boxes is greatly reduced.

In addition, the insertion of the PS symbol indicates that it is made of polystyrene and such a container is in contact with hot and greasy foods due to the release of styrene carcinogenic monomer; therefore, these containers should not be used for food and hot drinks And fatty acids, and are used only for soft drinks and cold-fat foods. These containers are available in three types of polystyrene foam (EPS), expanded polystyrene (HIPS) and ordinary polystyrene containers (GPPS).