Chemical Bonding and Adhesive Systems

Chemical bonding via adhesive binders: Latex bonding—water-based polymer dispersion (acrylic, SBR, vinyl acetate 5-30% by dry weight) applied via spray, saturation, or print-bonding, then dried (120-180°C) forming flexible adhesive film at fiber junctions. Application methods: saturation (web immersed in binder bath, full penetration, 15-30% add-on, used for wipes), spray bonding (atomized binder sprayed onto web surface, 5-15% add-on, softer hand, hygiene products), and print bonding (engraved roller applying binder in patterns, 5-20% add-on, controlled stiffness/softness, carpet backing). Binder types: acrylics (soft, good adhesion, water sensitivity), SBR styrene-butadiene rubber (carpet backing, good stability), EVA ethylene vinyl acetate (flexibility, used in hygiene), and PVA polyvinyl alcohol (water-soluble for disposables). Properties: soft hand (low add-on) to stiff (high add-on), good drapability, strength 30-200 N/5cm depending on add-on/fiber. Limitations: wet strength loss (water-based binders unless crosslinked), migration in use, potential for skin irritation (residual chemicals) requiring testing for skin-contact applications. Post-treatments: crosslinking (improving wash resistance), softening (reducing stiffness), and functional finishes (flame retardant, water repellent, antimicrobial). Applications: wipes (low add-on for softness), interlinings (high add-on for stability), medical textiles, carpet backing (20-30% SBR latex).