Biax Fiberfilm’s research and development effort have recently resulted in major technology breakthroughs. Spun-blown® technology is one of them which is a modified meltblown system capable of making stronger fabrics using low MFR polymers.
Spun-blown® Technology is a special practice of meltblowing technology developed by Biax-Fiberfilm Corporation to bridge the gap between the conventional meltblown and spunbond processes.
Spun-blown® process has a multi-row spinnerette similar to the spunbond technology but the filaments are attenuated at the nozzles tip using high speed air similar to meltblown process.
Biax’s Spun-blown® process allows for the production of materials with strength approaching that of spunbond but with fiber size similar to meltblown. Tensile strength is between SB and MB but with greater elongation than either, which would result in highly extensible products without being easily torn or ruptured, which is more desirable in wipes and filters application. The process can handle high operating pressures up to 2000 psi, which enables you to spin a wide variety of resins and operate at lower temperatures that would result in more flexibility and higher energy cost savings.
Spun-blown® fabrics tend to have wide a fiber size distribution, but controllable, due to the multi-row design of the Biax’s spinnerette, thus submicron fibers are naturally comingled with big microfibers which would result in strong and high efficiency filter media with higher dust holding capacity at low pressure drop.
Because of the high productivity and throughput of the Biax system, it is cost competitive with traditional spunmelt technologies.
Collecting spunmelt fiber, especially the meltblown or the spunbond fibers, is usually done on a flat belt conveyer that produces 2 dimensional webs and all fibers are laid-down in the horizontal direction.
Collecting Spun-Blown® or Meltblown fibers that are produced from multi polymer spinnerettes at the nip of two rotating drums helps many of the fibers to be aligned in the z-direction. The nip gap is usually between 0.025 to 4 inches and dictates the loftiness of the material and the amount of air entrapped. So far the produced structure is a high loft material with low recovery.
To increase the recovery of the produced structure we pass the produced 3-D structure into a through-air oven bonding or chemical bonding to freeze the formed structure and enhance its recovery upon compression.
Conventional meltblown fabrics are weak but have fine fibers in the range of 1-10 microns, while the spunbond fabrics are strong but the fiber size is big (15-50 microns) and it has less opacity or coverage beside the rough surface that they have.
The invention herein allows spinning thermoplastic fibers through fine capillaries and attenuates them with high speed air that it is at a temperature colder than the melt temperature by 50 to 150o F. By being able to do this, stronger fibers are made which provide properties approaching those of the spunbond technology.
Also the invention solves the problem of the fast cooling of the outer polymer nozzles by using air shields of hot air to delay the interaction between the ambient air and the hot attenuating air. Because of the strong fabricated fibers, a smaller amount of them will be enough to fabricate strong hybrid structures of thermoplastic fibers and staple/short fibers. Staple/short fibers could be man-made fibers or natural fibers such as pulp or cotton fibers.
Solution blowing is a unique process for spinning micro and nanofibers from polymer solutions using high-velocity gas flow as fiber-forming driving force. Biax-fiberfilm Corporation has granted several patents for the solution blowing process and still developing more solutions for this new technology.
Leveraging the unique Biax Multi-row features where every single hole has its own air jet and by tuning the nozzle spacing to fit the solution blowing technology, Biax multi-row spinnerette is the proven platform for the solution blowing process that is capable of producing submicron fibrous materials out of solutions.