ECS 2023: Polymer resin binder with improved solubility from Wacker
At the European Coatings Show 2023, Wacker will present a new product in the Vinnol solid resin series: Vinnol L-6868 is suitable as a binder for solvent-based coatings, printing inks, high-solids and UV-curing systems. It can also be used to formulate wood coatings, paper and film coatings.
The new polymer resin from Wacker has the lowest viscosity within the product family. In addition, Vinnol L-6868 is compatible with a wide range of UV monomers and reactive diluents. The product is characterized above all by very good solubility in a wide range of solvents. The binder is even more suitable as an additive than polymer resins already available for UV-curing printing ink systems. The starting point for the development was the existing polymer resin grade Vinnol H 40/43, which is a copolymer of vinyl chloride and vinyl acetate without functional groups. The product is suitable for a wide range of solvents and UV monomers. Overall, it offers the best solubility and lowest viscosity to date. Further improving its properties was the wish of several potential customers.
To achieve this, Wacker experts modified the molecular composition. They minimized the polymerized vinyl chloride content to 44 percent and maximized the vinyl acetate content to 56 percent. The latter improves solubility decisively and results in Vinnol L-6868 being very soluble in ketones, but also in esters, acrylic monomers, UV monomers and glycol esters. At the same time, the lower vinyl chloride content, which is responsible in the polymer for the strength and hardness as well as the chemical resistance of the coating, improves the processing properties of the formulation. The modification in the polymer composition combined with a very low molecular weight results in a significantly lower viscosity of the polymer resin solution. In a 20 % methyl ethyl ketone solution at 20 °C, the viscosity of Vinnol L-6868 is only 7 mPa*s. By comparison, this value is 25 mPa*s for Vinnol H 40/43. At the same time, the new binder allows the formulation of so-called high solids, i.e. formulations with a high pigment and binder content. In addition, Vinnol L-6868 is suitable for reactive curing systems. With its very low molecular weight, Vinnol L-6868 is an optimal solution for formulators dealing with challenges such as flow behavior, intercoat adhesion and flexibility in UV-curing systems. Applications for the new binder include printing inks, plastic coatings, wood coatings, paper and film coatings. Vinnol L-6868 is also suitable for coating food contact packaging. The European Coatings Show will be held in Nuremberg, Germany, March 28-30, 2023.