This polymer resin represents the optimal expansion to the product portfolio offered by WACKER, because it is an even better additive than the other polymer resins that are already available for UV-curing printing ink systems
VINNOL plastic label. (Credit: Wacker Chemie AG)
At the 2023 European Coatings Show, WACKER will be unveiling a new product from its VINNOL® family of solid resins: VINNOL L-6868 binder is suitable for solvent-borne coatings, printing inks, high-solids, and UV-curing systems. It can also be used to formulate wood, paper, and film coatings. The new polymer resin has the lowest viscosity within the VINNOL family. In addition, VINNOL L 6868 is compatible with a wide range of UV monomers and reactive diluents. The product’s most notable characteristic is its very good solubility in all kinds of solvents. The European Coatings Show will be held in Nuremberg, Germany, from March 28 to 30, 2023.
The binder is the film-forming component of any printing ink or coating. It encloses the pigment particles, bonds them together and to the substrate. Through its VINNOL portfolio of products, WACKER already offers an extensive range of polymer resins that perform this very task in many application areas.
As innovative technologies and new processes emerge, the requirements of the printing inks and coatings industry keep changing. For this reason, the company works continuously on developing its VINNOL resins. Its latest development: VINNOL L 6868. This polymer resin represents the optimal expansion to the product portfolio offered by WACKER, because it is an even better additive than the other polymer resins that are already available for UV-curing printing ink systems.
Development of the product started with VINNOL H 40/43, an existing polymer resin grade. This is a copolymer of vinyl chloride and vinyl acetate that has no functional groups and is suitable for a wide range of solvents and UV monomers. Overall, it has the best solubility and, up to now, offered the lowest viscosity. However, several potential customers expressed a wish that its properties be improved even further.
To achieve this, WACKER experts modified its molecular composition. They minimized the copolymerized vinyl chloride content to 44 percent and maximized the vinyl acetate content to 56 percent. The outcome is a decisive improvement in solubility that renders VINNOL L-6868 highly soluble in ketones as well as in esters, acrylic monomers, UV monomers and glycol esters. At the same time, the lowering of the vinyl chloride content, which provides toughness and hardness in the polymer as well as chemical resistance of the coating, improves the processing properties of formulations.
The combination of modified polymer composition and very low molecular weight has the effect of substantially lowering the viscosity of the polymer resin. In a 20-% methyl ethyl ketone solution at 20 °C, the viscosity of VINNOL L-6868 is just 7 mPas. By comparison, the corresponding value for VINNOL H 40/43 is 25 mPas. Even so, the new binder can be used to formulate high-solids systems, i.e. those with high pigment and binder contents. VINNOL L-6868 is also suitable for reactive curing systems.
Due to its very low molecular weight, VINNOL L-6868 represents the optimal solution for formulators addressing challenges relating to flow, 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 can also be used to formulate coatings for food-contact packaging.
Source: Company Press Release