Methacrylate monomers for Polymeric Additives
Many aqueous systems utilize thickeners to provide a particular formulation with the desired viscosity. For example, certain aqueous thickeners are utilized in the formulation of oil field chemicals as well as polishing and cleaning compositions, and in the manufacture and/or preparation of personal care and food formulations. These types of thickeners are also used in specific pharmaceutical applications. In addition, thickeners are commonly used in latex paint formulations and in a variety of other coating compositions. There are many types of thickeners now used in paints and other coating formulations.
Acrylic thickeners are commonly produced by emulsion polymerization. One of the most important monomers for this kind of thickeners is VISIOMER® GMAA. Usually, crosslinkers like VISIOMER® AMA or EGDMA are added in the formulation in a low concentration in order to increase the molecular weight of the produced polymer.
Another type of thickener, also called associative thickener, is based on hydrophobically modified polymers that combine high thickening efficiency with a less marked shear-thinning viscosity profile. Here, viscosity/shear can be controlled by varying the length of the polymer’s hydrophobic groups and molecular weight. Evonik’s VISIOMER® C18PEG 1105 MA W was developed specifically with this purpose in mind and has become an industry reference.
Associative thickeners have a strong thickening effect and deliver the required Stormer viscosity already at low addition levels. In most cases, their thickening efficiency is in fact comparable to that achieved with non-associative thickeners with a high molecular weight. Both high-shear and low-shear viscosity can be calibrated. Compared to the type of conventional thickeners with high molecular weight, associative thickeners have a much less pronounced shear thinning profile.