This entry is just for my personal note.

TPR is an abbreviation of 'thermo plastic rubber' that has most of the desirable properties of rubber, e.g. flexibility, while at the same time they can be injection molded like a plastic. Shown in the photo is an example of a consumer goods that utilizes TPR.

Detailed Product Description (from the manufacturer's webpage)
Children's sock shoe, very cute style and fashion design.
Upper Sock:100% cotton
Outsole: Transparent TPR Rubber

References: here, here and here.