PP Spunbond and Meltblown Nonwoven Fibre Technology
topic
PP spunbond and meltblown processes are integrated fibre formation and web laydown technologies that produce nonwoven fabrics directly from polymer chips without separate yarn and fabric formation stages — enabling the lowest-cost nonwoven fabric production ($0.40–0.90/m²) for hygiene, medical, geotextile, and filtration applications. Spunbond process (Reicofil 5, Nordson Kreyenborg, Oerlikon Neumag): PP chips (MFI 30–35 g/10 min, 230°C/2.16 kg) fed to extruder → melt filtered → spinneret (5,000–8,000 holes/m width, 0.4–0.6 mm diameter) → quench air (20°C, 0.8–1.2 m/s) → pneumatic draw unit (attenuator, 200 m/s air velocity drawing filaments to 1.5–2.5 dtex, 300–450% draw ratio at 200–400 m/min) → random laydown on moving conveyor belt → thermal bonding (calendar rolls, 140–160°C, 2,000–4,000 N/m bonding pressure, 15–25% surface bonding area) → finished spunbond web. Basis weight range: 10–200 g/m² (diaper cover stock 15–25 g/m², geotextile 100–200 g/m²); filament diameter 15–25 µm; tensile strength 15–35 N per 5 cm width per g/m² (specific strength); MD/CD ratio 1.5–3.0 (machine direction stronger than cross-direction). Meltblown process (ExxonMobil licensed, Oerlikon Neumag): very high MFI PP (MFI 800–1,500 g/10 min, 230°C, specially degraded low-MW resin) → spinneret (0.15–0.40 mm hole diameter, closely spaced 25–35 holes/cm) → hot high-velocity air jets (320–340°C, 100–500 m/s, two converging air streams) attenuate filaments to 1–5 µm microfibre diameter → randomised web laydown; basis weight 15–100 g/m². Meltblown filter performance: 2 µm effective fibre diameter (EFD) meltblown achieves 95% filter efficiency for 0.3 µm NaCl aerosol (N95 test particle) without electrostatic charge; electrostatically charged meltblown (corona discharge or water charging — PTFE particle addition or spin-finish) achieves 99.97% (HEPA equivalent) at 0.3 µm. SMS (spunbond-meltblown-spunbond) laminate: 3-layer structure bonded by thermal calendaring — spunbond top and bottom layers provide strength and abrasion resistance, meltblown core provides barrier and filtration — surgical gown (18–30 g/m²), disposable protective coverall (40–70 g/m²), N95 respirator filtration layer (basis weight 20–40 g/m² meltblown).
Role
PP spunbond and meltblown process knowledge is essential for technical nonwoven engineering — with COVID-19 pandemic demonstrating the critical strategic importance of meltblown PP microfibre production capacity (global N95 respirator meltblown PP shortage 2020, creating $4 billion emergency capacity investment globally), understanding the fibre diameter-filtration efficiency relationship and electrostatic charge mechanism is the fundamental technical knowledge required for designing filtration, medical, and hygiene nonwovens that serve the $55 billion global hygiene and medical nonwoven market.