Properties of Tyvek Īccording to DuPont's Web site, the fibers are 0.5–10 μm (compared to 75 μm for a human hair). According to the American Chemistry Council, these plastic film drop-off locations accept Tyvek.
Recently, plastic bag recycling has become more prevalent. DuPont runs a program in the United States where disposable clothing, coveralls, lab coats, medical packaging and other non-hazardous Tyvek disposable garments can be recycled, as well as providing a mail-in recycling program for envelopes. Some Tyvek products are marked with the #2 resin-code for HDPE, and can be collected with plastic bottles as part of some municipal curbside recycling programs. Though Tyvek superficially resembles paper (for example, it can be written and printed on), it is plastic, and it cannot be recycled with paper. Dielectric bonding can be effective in some circumstances, as is ultrasonic welding. Heat sealing can be used to melt Tyvek and cause it to bond to itself, but this form of bonding tends to create puckers in the otherwise flat material.
Once pinned onto a shirt these numbers go wherever their runners do. This number is printed on a flexible yet durable paper specifically designed to hold up against any elements participants may endure during their races such as rain, mud, or wind. Each individual runner is assigned a bib number when they register for a race or pick up their event packet. Bib numbers are a timer’s and race director’s most important tool.