Tyvek () is a brand of synthetic flashspun high-density polyethylene fibers. The name "Tyvek" is a registered trademark of the American multinational chemical company DuPont, which discovered and commercialized Tyvek in the late 1950s and early 1960s. Tyvek's properties—such as being difficult to tear but easily cut, and waterproof against liquids while allowing water vapor to penetrate—have led to it being used in a variety of applications. Tyvek is often used as housewrap, a synthetic material used to protect buildings during construction, or as personal protective equipment (PPE). History Tyvek is a nonwoven product consisting of spun bond olefin fiber. It was first discovered in 1955 by a researcher for the DuPont textile company working in an experimental lab, who noticed a type of white fluff coming out of a pipe. That fluff was a form of polyethylene, which DuPont requested a patent for within a year of the discovery. After technologies improved during the next few years, in 1959 DuPont discovered that when the fluff was spun at high speeds it produced a durable fabric that could be cut with a blade. While the product Tyvek was used since 1959, DuPont did not trademark the actual brand until 1965, making it available for commercial purposes in April 1967. As of 1970, Tyvek had reached the mainstream construction industry on both a national and global scale, and is often used for the construction of houses due to its ability to keep out liquid, while allowing vapor through. In 1972, DuPont released Tyvek packaging for sterile instruments that were to be used by surgeons and doctors in the medical field. 21st century In 2017, the DuPont company merged with another chemical company, The Dow Chemical Company to form DowDuPont. DowDuPont currently manufactures Tyvek at the Spruance plant in Richmond, Virginia, and in Sandweiler-Contern, Luxembourg. In 2018, DowDuPont announced plans to expand the Tyvek production capacity of the Sandweiler-Contern factory. Scientific characteristics and properties Adhesion and bonding To bond Tyvek to both itself and a variety of substrates, DuPont recommends starch, dextrin, casein, and animal-based adhesives over most synthetic-based adhesives, emphasizing the effectiveness of water-based and quick-drying glues. DuPont also claims that the following adhesives are highly effective: Ethylene/vinyl acetate Acrylic pressure-sensitive tape Solvent-based single-component polyurethane Hot glue Heat sealing can be used to melt Tyvek and cause it to bond to itself, but this form of bonding tends to create puckers