The disposable lunch boxes made of plastic mainly include PP polypropylene and PS polystyrene, which are non-toxic, tasteless and odorless, and PP is relatively soft. Generally, the use temperature of PP is – 6 ℃ to+120 ℃, so it is particularly suitable for holding hot food, which can be heated in the microwave oven, or even cooked in the steam cabinet. The use temperature of modified PP can be controlled between – 18 ℃ and+110 ℃. In addition to heating to 100 ℃, the lunch boxes made of PP can be used, It can also be put into the refrigerator for cold storage.
PS is hard and transparent, but it is easy to tear. PS starts to become soft when the temperature reaches 75 degrees, so it is not suitable for holding hot rice and hot dishes. However, PS has good low-temperature performance and is the best packaging material for ice cream.
In order to reduce costs, some lunch box factories use PP as the box and PS as the box cover. The advantage is that the cover is transparent, and PS is hard. It can be made of thinner sheet materials to reduce costs. However, consumers of this design must understand the difference between the two materials, and remember not to put the whole box of rice with the cover into the microwave oven for heating.
