The slow springback sponge is perforated
Polyurethane (PU) was first developed in the 1930s by German scientists, who condensed liquid isocyanate and liquid polyether or diol polyester into a new material. The physical properties of the material were different from those of polyolefin materials at that time. With the end of the second world war, the chemical manufacturing industry in the United States flourished, and the synthesis of polyurethane soft foam plastics in the 1950s, which was an important milestone of the chemical industry at that time, and provided a solid technical foundation for the development of the future polyurethane industry.
Slow springback sponge opener