Scalable aerosol-electrospun pvb/stearic acid barriers for silent outercovers

Overview

This solution is a scalable, film-free breathable fluid barrier nonwoven produced by hybrid electrospinning and aerosol deposition of polyvinyl butyral (PVB) and natural stearic acid in ethanol. It is designed for applications such as medical outercovers, protective apparel, hygiene products, and other uses where a silent, comfortable, and reliable fluid barrier is required.

The technology combines a sub-micron electrospun fiber web with aerosol-deposited micro-welds that anchor the barrier to a lightweight spunbond carrier. The result is a PFAS-free, breathable barrier that blocks liquid penetration while allowing moisture vapor to escape, eliminating the need for films that can cause rustling noise and reduce comfort.

Key benefits include:

• PFAS-free hydrophobicity using natural stearic acid and PVB
• High liquid holdout with sub-micron pores and high Laplace breakthrough pressure
• High moisture vapor transmission rate (WVTR) for breathability
• Mechanical durability with aerosol micro-welds that prevent delamination
• Cost-effective raw materials and fast ethanol-based processing for high-speed roll-to-roll converting

Technical specifications

The barrier is fabricated by multi-nozzle electrospinning of a PVB and stearic acid solution in ethanol. Long-chain alkyl groups from stearic acid self-orient to the fiber surface, providing hydrophobic behavior without fluorinated chemistry. Aerosol deposition of the same solution creates elastic micro-welds between the nanofiber web and the base spunbond nonwoven, improving adhesion and mechanical strength.

Key technical features:

• Sub-micron pore structure (approximately 0.3 µm) with a filling factor around 0.5
• Contact angle target greater than 105 degrees
• Fluid holdout greater than 62 mbar hydrohead
• Moisture vapor transmission rate greater than 2000 g/m²/24h
• Tensile strength greater than 2000 gf/3 in
• Softness target of cup crush less than 35 g
• Staged thermal dissolution (45–50°C) and ultrasonic degassing to prevent defects such as Taylor cone rupture and micro-beads
• Compatible with 20 gsm spunbond carrier webs

Technology readiness level

The technology is at an early-to-mid development stage. Water-barrier performance has been validated with an electrospun layer on nonwoven fabric, demonstrating that sub-micron pores block liquid while preserving high vapor transmission.

A 12-month validation program is planned in three phases:

• Months 1–3: Dope optimization and microstructure control, including SA/PVB blending ratios and solution viscosity tuning
• Months 4–8: Hybrid deposition and adhesion engineering, integrating aerosol deposition with electrospinning onto a spunbond carrier and optimizing thermal curing
• Months 9–12: Benchmarking, validation, and prototype delivery using standardized tests for fluid holdout, breathability, tensile strength, and softness

Upon completion, optimized roll-good prototypes with complete process parameters will be available for partner evaluation and scale-up.