Lupasol® Polyethyleneimine

BASF Lupasol® polymers are multifunctional, cationic, branched polyethyleneimines (PEI). They are used as adhesion promoters, primers, compatibilizers, and flocculants for multiple applications and substrates.

Lupasol® is available in water-free and waterborne grades of various molecular weights. Lupasol® has the largest possible amino group density of all commercially available polyamines, with a nitrogen-to-carbon ratio of 1:2. It thus has a high cationic charge density that is strongly dependent on pH, being highest at pH 2–4. It is generally compatible with non-ionic and cationic systems and incompatible with anionic systems. Lupasol® is soluble in water as well as both polar and aprotic nonpolar solvents.

The high charge density of Lupasol® forms strong bonds on negatively charged surfaces, including cellulose, polyester, polyolefins, polyamides, and metals. Lupasol® may be used as an adhesion promoter for printing inks used on plastic films. For inkjet inks, it increases resolution and water fastness on paper. It may also be used as a primer to increase the surface energy of a variety of plastic films and metal foils, making them more receptive to applying adhesives to form multilayer flexible packaging. For applications where Lupasol® is used as an adhesion promoter, an appropriate grade to select is one having a similar molecular weight to the other polymers in the system.

In coating applications, Lupasol® can impart tie-layer and paint adhesion. Wet adhesion of paints may be improved by blending a small concentration of Lupasol® into the formula. Lupasol® is particularly useful as a primer in UV curing systems to improve adhesion where volume shrinkage occurs. Lower molecular weight Lupasol® grades are useful as cross-linkers for coating and adhesive formulations, where they increase cohesive strength while maintaining the same level of adhesion.

The high positive charge density mentioned also allows high molecular weight grades of Lupasol® to flocculate highly charged, anionic particles such as proteins, zeolites, and silicates. This property makes it useful in water treatment and protein immobilization applications.

Download the Lupasol brochure here.