Meaning
Epoxy acrylic oligomer is a hybrid pre-polymer containing both epoxy and acrylic functional groups designed for rapid cross-linking under ultraviolet radiation or electron beam exposure. Formulators synthesise this prepolymer by reacting an epoxy resin with acrylic acid to graft polymerisable unsaturation onto the backbone. The material provides the reactive base for high-performance coatings, adhesives, and UV-curable inks requiring rapid cure speeds alongside chemical resistance.
Cure kinetics
Radical polymerisation initiates instantly upon photon absorption, converting the liquid resin network into a hard thermoset film within fractions of a second. Photoinitiators absorb specific ultraviolet wavelengths to generate free radicals that attack the acrylate double bonds situated at the terminal ends of the oligomer chains. Cross-link density dictates the final hardness, chemical inertness, and tensile strength of the cured network.
Excessive cure shrinkage occurs when low molecular weight reactive diluents are added in incorrect proportions to lower viscosity for processing.
Viscosity behavior
Moulders and coaters evaluate dynamic viscosity to determine pumpability and flow properties across varying thermal profiles. Elevated temperatures reduce intermolecular friction within the liquid resin, allowing smoother dispensing through automated metering equipment. Shear-thinning behavior helps prevent sagging on vertical substrates during application before the polymerisation reaction locks the geometry in place.
Temperature drift alters the fluid resistance, leading to inconsistent film thickness or void formation within enclosed mould cavities during processing.
Conversion rate
Residual unsaturation percentage measures the completeness of the cross-linking reaction after irradiation exposure. Incomplete conversion leaves unreacted double bonds trapped within the matrix, which causes embrittlement, yellowing, and premature degradation under environmental stress. Spectroscopic analysis quantifies the disappearance of acrylate absorption peaks to verify that the manufactured part achieves its specified mechanical properties before final packaging.
Complete network formation ensures the moulded component withstands sustained mechanical loads without creeping or deforming under thermal stress.
