Disposable snack boxes have changed from foam lunch boxes to environmental protection lunch boxes. The original foam lunch box was eliminated because it was not resistant to high temperature and the production process caused damage to the environment. Instead, plastic lunch boxes, paper lunch boxes, wooden lunch boxes, degradable lunch boxes and so on. Among them, plastic has the characteristics of low toxicity, high melting point, strong plasticity, simple production and low relative cost, so it has become the mainstream material for manufacturing disposable fast food boxes.
Polypropylene has mechanical and thermal properties and is suitable for food packaging. Lunch boxes are divided into environmental protection lunch boxes, mainly including plastic, paper, starch and rare metals.
Disposable lunch boxes made of plastic mainly include PP, PP and PS polystyrene, which are non-toxic, tasteless and odorless. PP is soft. Generally, the temperature of PP is -6 degrees to+120 degrees, so it is especially suitable for holding hot meals and dishes. It can be heated in a microwave oven and even cooked in a steam cabinet. The use temperature of modified PP can be controlled from-18 to +6520.
PS is hard and transparent, but it is easy to tear. PS begins to soften when the temperature reaches 75 degrees, and it is not suitable for hot meals and hot dishes. But PS has good low temperature performance and is the best packaging material for ice cream.
In order to reduce the cost, some lunch box factories use PP as the box body and PS as the box cover. Advantages are that the cover is transparent, PS is hard, and thinner materials can be used to reduce costs. But consumers must understand the difference between the two materials in this design, and remember not to heat the whole lunch box and lid in the microwave oven.