Researchers in Portugal have developed a new type of "microcapsule" filled with perfume and embedded in fabric for production of scented suits, socks, undergarments and other clothing. The same technology can be used in many other applications, such as to mask unpleasant body odors when using textile products. The material is also environmentally-friendly.
Microcapsules, or submicroscopic shells, have been used for years to deliver fragrances in commercial products ranging from scratch-and-sniff stickers to the peel-apart fragrance samples found in magazine inserts. But current microcapsules are made using formaldehyde, a known cancer-causing agent that is also an environmental hazard. The researchers identified polyurethane-urea, a type of environmentally-friendly plastic that is compatible with fabrics, as a solution. They used the material to prepare microcapsules containing limonene, the familiar scent abundant in lemons and widely-used in perfumes, and applied the capsules onto wool and polyester samples. In laboratory tests, the microcapsules showed good performance in terms of prolonged fragrance production and durability.
Perfume particles comprise perfume dispersed within certain water-insoluble polymeric carrier materials and encapsulated in a protective shell by coating with a friable coating material. The coated particles allow for preservation and protection of perfumes which are susceptible to degradation or loss in storage and in harsh cleaning conditions. In use, the surface coating fractures and the underlying carrier/perfume particles efficiently deliver a large variety of perfume types to fabrics or other surfaces.
Scientists at North Carolina State University have found new ways to make protective fabrics (used in flame-retardant children’s clothing or odor-inhibiting socks and shirts) last longer and work better. Instead of treating the surface of the fabrics with protective polymer coatings that can wear thin and lose effectiveness from use or repeated washing, the researchers are imbedding the polymers that make up the fabric itself with various additives. Laboratory tests show that fabrics and films made this way provide greater protection and retain their flame-retardant or antibacterial qualities longer than materials treated with conventional surface coatings. The new process could be used on fabrics and films in a wide range of products, from children’s clothing and odor-inhibiting socks and shirts, to antibacterial medical gowns, dressings and sutures.
In the new process, the researchers first formed an inclusion compound, a high-temperature crystal that contains the desired polymer additives. This "host crystal," typically is made of cyclodextrins, cyclic starch molecules composed of interlocked glucose sugar rings. Cyclodextrin molecules have a hole in their centers, much like doughnuts, and naturally stack one on top of another to form long tubes into which the additives are imbedded. After the cyclodextrin-inclusion compound is formed, they melt-press the crystals into a polyester film. Tests have shown a significant increase in the flame retardancy of polyester films created this way. Since the crystals are part of the film or fabric, washing would have far less of an impact on its effectiveness than typical flame retardants, which lose protection with repeated washing.
Another possible application for the process is the use of antibacterial polymers. Fibers imbedded with antibacterial cyclodextrin-inclusion compound crystals could be used in socks or shirts, or any other fabric that is exposed to perspiration, to reduce the likelihood of body odors. There are medical uses as well, including medical gowns and sutures made with antibacterial polymer imbedded fibers.