Hygiene products—diapers, sanitary napkins, adult incontinence pads—require adhesives that bond delicate nonwovens, elastics, and poly backsheets without irritating skin or losing integrity after fluid absorption. High Quality Hot Melt Adhesive in this sector are formulated with medical-grade raw materials, low odor, and precise elastic retention. Failure leads to leaking, leg cuff rollout, or customer rash complaints.

Technical specifications for hygiene-grade hot melts:

Whiteness index: >85 (color stability after aging); yellowing indicates oxidation of tackifier or unsaturated polymer.

Odor level: Quality adhesives are practically odorless at application temperature (150°C). Low molecular weight waxes cause burnt candle smell.

Viscosity at 150°C: For fine swirl spray (0.2–0.5 g/m²), viscosity 800–2.000 cP needed. For slot coating (1–5 g/m²), 3.000–8.000 cP.

Peel adhesion on PE/PP nonwoven: ≥3 N/25 mm with elastic thread retention at 200% elongation.

Key quality checks for hygiene manufacturers:

Thermo-oxidative stability: No char formation after 48h at 160°C. Char particles block spray nozzles (0.3 mm orifice) and cause uneven coating.

Set time: <1 second for high-speed elastic attachment lines (1.000 pieces/min). Delayed setting causes spring-back of elastics.

Low surface energy bonding: Must adhere to siliconized release papers (peel ≤0.2 N/25 mm) and breathable films.

Biocompatibility: Passes cytotoxicity test (ISO 10993-5) and skin irritation patch test.

Why cheap hot melts fail in hygiene:

Use of unrefined hydrocarbon resins leads to strong odor and skin sensitivity.

High filler content (talc, CaCO₃) reduces flexibility—elastic threads cut through adhesive film.

Poor heat stability causes gel formation, leading to “adhesive balls” on nonwoven surface.

High quality hygiene hot melt adhesives cost slightly more per kilogram but reduce product reject rates (often from 0.5% to 0.02%) and prevent costly recalls. Look for low-VOC, phthalate-free, and hypoallergenic certifications.