TANDEC RESEARCH

Academia and Industry fostering new devlopments in non-wovens

 

Development of Bi-Component Meltblown Fiber Nonwovens and
Its Potential to Produce Submicron fibers

Christine (Qin) Sun, and Dong Zhang

Meltblowing is a most versatile and cost effective process commercially available world-wide to produce microfiber nonwovens in one step from thermoplastic resins. In recent few years there has been a growing interest in development of bicomponent (bico) meltblown nonwovens. Various bicomponent pairs of meltblown fiber webs were successfully produced on ReicofilÒ bicomponent (bico) meltblown line at TANDEC since its installation in March 1999,
including PP, PE, PET, PBT, PA6, PTT, etc., and their bico pairs such as PP/PE, PET/PE, PBT/PP, PA6/PP, PBT/PP, PTT/PP at bico weight ratios of 25/75, 50/50, and 75/25. Surface response methodology (SRM) was applied for the systematical experimental design.

Non-round cross-sectional and more twisted side-by-side bico fibers were observed in PP/PBT, PE/PBT, PP/PA, PP/PET, PE/PET bico paired webs by SEM. The smallest fiber diameter achieved for most mono and bico webs was in the range of 1-1.5 µm. A continuing effort was made to obtain submicron meltbown fiber nonwovens by subsequently splitting the side-by-side fibers.

Two approaches of post-treatment were applied to pursue the fiber splitting — mechanical and chemical methods. The mechanical method was intended to split each component apart in a side-by-side bico fiber using hydro-entanglement, which utilized a pressurized stream of water to split the multi-component conjugate fibers. For chemical treatment, substantial portion of the conjugate fibers was removed by a dissolving process and the un-dissolvable part remained in the fibers. Figure 1 shows the web structures by SEM after each treatment.

25PET/75PA6 (hydroentanglement,120 bars) 75PLA/25PP (chemical solution treatment)

The split fiber structure showed smaller size, enhanced barrier and softness. However, more fiber breakage occurred during the hydroentanglement. The overall web uniformity was deteriorated by the hydrodynamic force and initial inconsistency of the bi-component distribution of the bico webs across the machine direction. More fundamental research is now underway at TANDEC to study the interfacial adhesion in the bico fibers and approaches to promote the fiber splitting…