How to enhance the heat resistance of plastic trays?

Plastic trays are widely used in various industries, and I believe many people do not know the heat resistance performance of plastic trays? Do you know how to enhance the heat resistance of plastic trays? Detail the product: 

The molecular structure of thermoplastic materials is linear, which softens or melts when heated, and can be molded into a certain shape. After cooling, it becomes hard again. After being heated to a certain extent, it softens again, and then hardens again after cooling, which can be repeated multiple times. Such as polyvinyl chloride, polyethylene, polystyrene, etc. The molding process of thermoplastic is relatively simple, capable of continuous production, and has a relatively high mechanical strength, so it has developed rapidly. 

The molecular structure of thermosetting plastics is a body shape structure that also softens when heated, and can be molded into shape. Nevertheless, when heated to a certain degree or with the addition of a small amount of curing agent, it hardens and sets. Reheating will not soften or change the shape. After processing and forming, thermosetting plastics no longer soften when heated, so they cannot be recycled. Examples of such plastics include phenolic plastics, amino plastics, epoxy resins, etc. The molding process of thermosetting plastics is relatively complex, so there are some difficulties in continuous production. It nevertheless has good heat resistance, is not easily deformed, and is relatively inexpensive.