Retention State
Molecular state where liquid molecules remain trapped within a polymer network through physical or chemical attraction. Residual bound solvent persists even after primary evaporation because the molecules occupy interstitial spaces or bind to functional groups.
Structural Implication
Polymer chains experience local softening or plasticisation when they hold these trapped liquids. Within a synthetic leather coating, bound solvent alters the glass transition temperature and impacts the mechanical strength of the layer. This softening allows the chain segments to move more freely than in a completely dry state.
Removal Resistance
High energy levels are required to displace these molecules from their fixed positions within the resin. Thermal drying at elevated temperatures often fails to extract every trace of bound solvent because the diffusion path through the dense polymer matrix is remarkably slow. Vacuum extraction or extended curing times become necessary to reach deep into the material.
Quality Impact
Finished goods might release these trapped chemicals over time as the material reaches equilibrium with its environment. Migration of bound solvent to the surface can cause tackiness or interfere with the adhesion of subsequent finish layers. Some substances also weaken the bond between the coating and the base fabric.
