TODAY'S ASSOCIATIVE thickeners provide exceptional performance when selected correctly, but can result in many hours of technical service work if the wrong one is used or if the right product is incorrectly used.
This situation can be resolved with the use of a matrix approach, which can help to speed the selection process and allow time for other, perhaps more important projects.
The higher cost of associative thickeners mandates that greater care should be taken in the selection process. Choice should be based on individual system performance rather than as an adjunct to a specific resin. A high-performance associative thickener should be chosen according to performance guidelines such as carrier solvent content, active solids of the additive, and application and stability properties.
Some associative thickeners were designed to provide brush drag and film build without significant thickening. Others develop excellent medium shear-rate viscosity (Brookfield and Kreb Stormer). It may be necessary to use a combination of rheological additives in one formulation and only one rheological additive in another. To make the selection process a little easier, the paint formulator should set up a matrix for each performance characteristic required in any given paint system produced by his or her company. The matrix will help determine the best candidate for a given flat, semigloss, gloss, or low-VOC system based on all of the key performance parameters desired. Additional minor formulation changes may have to be done, but major …