Viscoelastic Property Loss in Aqueous Coated Paperboard Converting
Moisture and thermal stress during converting plasticize aqueous latex coatings, reducing storage modulus and causing fold delamination unless web tension is optimized.
Styrene-Acrylic Dispersion
Synthetic Binder
Waterborne polymer emulsion containing copolymerized styrene and acrylate monomers forms tough protective films on paperboard packaging. Applying styrene-acrylic dispersion enhances water resistance and surface strength across converted paper substrates. Liquid coating units apply the dispersion onto paper webs before heat dryers drive off water, causing polymer particles to coalesce into a continuous film.
Formulations vary monomer ratios to adjust glass transition temperature and film flexibility.
Barrier Formation
Polymer chemistry dictates barrier effectiveness and adhesion to underlying cellulose fibers. Incorporating a styrene-acrylic dispersion into barrier coatings provides grease and moisture resistance for food packaging board. Coalesced polymer films prevent liquid penetration while maintaining flexibility along package score lines during carton folding.
Poor film formation leads to pinhole formation, reducing oil resistance and causing grease bleed through converted packaging walls. Coating viscosity and drying conditions must be controlled to prevent web sticking or picking during high-speed winding.
Recycling Compatibility
Repulpability performance depends on polymer film fragment size during hydrapulping operations. Waterborne dispersions that fragment into soft sticky particles contaminate process water and create micro-stickies in recycled paper systems. Laboratory repulpability testing verifies whether the coating separates into screenable flakes or remains emulsified.
Balancing barrier performance against recycling compatibility determines suitable coating applications.
Polymer Barrier Coatings and Pulpability Test Standards
Polymer barrier paperboard compliance requires passing 0.15mm laboratory slot screening with under 15 percent reject mass to prevent EPR fee penalties.