Who can tell me the difference between a plastic lunch box and an injection lunch box?

Different processing technologies: plastic absorption and injection molding are two different processing technologies.

The equipment used is different: I have never seen the equipment for plastic absorption, and I know a little about injection molding machines.

Different materials are used: plastic absorption generally uses plates to change their shapes through vacuum adsorption, and injection molding is to melt plastic particles and then pump them into a mold to cool them.