lepidla

Lepidla, or adhesives, are substances used to bond two surfaces by forming a bond at the interface. They work by wetting surfaces, creating a cohesive network through chemical reactions, or establishing strong physical interactions that hold parts together once cured. Adhesive bonds can distribute load across a bonded area and can seal joints against air and moisture, often enabling design features not possible with mechanical fasteners.

Historically, natural adhesives such as animal glue, starch pastes, and casein were common. Modern adhesives are largely synthetic and diverse, including epoxy resins, polyurethane (PU), polyvinyl acetate (PVA) emulsions, cyanoacrylates, acrylics, and hot-melt adhesives. They are grouped by bonding mechanism (reactive versus non-reactive) and by application (woodworking, construction, packaging, automotive, electronics, textiles, medical devices).

Curing mechanisms vary: evaporating solvents or water (in many PVA and latex-based glues), moisture curing (as with some PU systems), chemical reactions between resin and hardener (epoxies, two-part variants), heat curing, or UV/light curing. Bond performance depends on substrate compatibility, surface preparation, adhesive viscosity, and environmental conditions such as temperature and humidity. Some adhesives offer gap filling or flexible bonds, while others provide rigid, high-strength joints.

Applications span woodworking, furniture assembly, construction and tiling, packaging, automotive and aerospace manufacturing, electronics, textiles, and medical devices. Selecting an adhesive involves considering bond strength, temperature and chemical resistance, flexibility, cure time, safety, and environmental impact. Proper surface preparation and compatible primers or activators may be required to achieve reliable bonding.

Safety and environmental aspects include exposure to volatile organic compounds, fumes, and potential skin or eye irritation. Ventilation, personal protective equipment, and appropriate handling are advised. Disposal follows local regulations, and there is ongoing effort to reduce VOC content and improve sustainability in adhesive formulations.