Styrene-butadiene latex finds predominant application in paper coating, with its demand consistently rising alongside the overall demand for printing paper. In recent times, there has been a push towards high-speed coating processes to enhance coated paper production capacity. Blade coaters currently operate at speeds exceeding 1500 m/min, necessitating styrene-butadiene latex coatings to possess superior high shear fluidity, water retention, anti-sticking properties, and high concentration for accelerated drying.

To meet the evolving demands of enhancing coated paper quality and reducing production costs, the industry necessitates high-strength latex. Furthermore, for improved printing efficiency and quality, coatings must exhibit excellent anti-bubble properties, ink absorption, and water resistance. These requirements have propelled a surge in research efforts worldwide, resulting in numerous patent reports on latex synthesis and significant technological breakthroughs.

1. Enhanced Composition Design Traditional papermaking latex, primarily polymerized from butadiene and styrene with minor additions of unsaturated anhydrous acid, no longer suffices given advancements in coating and printing technologies. Recent innovations incorporate polar monomers to impart specialized properties to coatings. These include unsaturated ester monomers to enhance coating adhesion, light resistance, and printing gloss, as well as nitridyl unsaturated monomers, amide compounds, hydroxyl compounds, epoxy compounds, and amino compounds to improve adhesion, stability, and printability.
2. Innovative Particle Structure Design Conventional emulsion polymerization methods struggle to produce styrene-butadiene polymers with low film-forming temperature and high stress at room temperature. However, through meticulous particle design and the creation of latex particles with a heterogeneous structure (such as core-shell structure) via multi-stage emulsion polymerization, it's possible to balance conflicting properties. Core-shell latex, characterized by interactions between the core and shell, significantly enhances membrane properties. Controlled addition of monomers and chain transfer agents improves bonding strength, blistering resistance, printing gloss, and blocking resistance.
3. Balancing Surface Strength and Blistering Resistance The gel mass fraction of the polymer significantly influences the surface strength and blistering resistance of the coating layer. Achieving a balance between dry surface strength and anti-foaming properties proves challenging. However, copolymerization of butadiene, styrene, and unsaturated carboxylic acid monomers using a specific reactive emulsifier yields latex with small particle size, high shear viscosity, and exceptional dry and wet surface strength.
4. Enhancing Coating Fluidity Coating requirements often demand both excellent fluidity and high solid content fraction. Adjusting latex particle size serves as a common method. Utilizing small particle size latex with specific hydrophilic emulsifiers yields coatings with exceptional high-speed fluidity and high dry and wet surface strength. Composite latex, combining small and large particle sizes, achieves coatings with solid mass fractions exceeding 65%, enhancing fluidity, gloss, and water resistance while maintaining coating stability.

Continuous addition of monomers containing hydrophilic functional groups yields latex with gel mass fractions surpassing 95%, eliminating the need for additional water-soluble binders in coating formulations, thereby improving peel resistance and gloss while increasing solid content.