Hot melt adhesive is a special adhesive used in hygiene products (such as diapers, sanitary napkins, and medical dressings). Its raw material composition must balance adhesive performance and safety standards. The main components include:
Base Polymer (40%-60%):
EVA (Ethylene-Vinyl Acetate Copolymer): The most commonly used, accounting for approximately 50%, providing flexibility and initial tack. The vinyl acetate (VA) content is typically 18%-28% (according to the *Adhesives Industry Handbook*).
SBS (Styrene-Butadiene Block Copolymer): Used for products requiring high elasticity, accounting for 10%-30%.
Tackifying Resin (20%-40%): Rosin glycerol esters or hydrogenated petroleum resins, improving adhesion, with a softening point controlled between 80℃-120℃ (ISO 4625 standard). Plasticizers (5%-15%): Mineral oil or phthalates (must comply with FDA 21 CFR 175.105), reducing melt viscosity and improving flowability.
Antioxidants (0.1%-1%): Hindered phenols (such as BHT), preventing oxidative degradation during high-temperature processing.
Special Requirements for Hygienic Formulas:
Low Allergenicity: Must pass skin irritation testing (ISO 10993-10), heavy metals prohibited (lead content <0.1ppm, GB/T 30779-2014).
Fast Curing: Melting temperature typically 120℃-160℃, curing time <3 seconds (industry measured data).
Environmental Certification: Mainstream brands (such as Henkel and Fuller) have obtained EU REACH and FDA certifications for their hygienic hot melt adhesives.