Natrosol™ B hydroxyethylcellulose
Natrosol B hydroxyethylcellulose (HEC) delivers all the benefits of standard Natrosol HEC, but in addition, offers enzyme resistance (biostability). This best-in-class, bio-resistant HEC will maintain stability even in the presence of cellulose enzyme produced by microbial activity. Natrosol B HEC grades for paints and coatings applications are typically glyoxylated (R-treated) for ease of incorporation. In latex architectural paints, Natrosol B HEC is know for superior color performance, stability, shear-thinning, application properties and sag resistance.
Product Literature(publicly available)
Additional Product Literature
Safety Data Sheets
Biostability and Enzyme Resistance
Biostability of waterborne paints and coatings is a complex and multi-faceted subject, but is often broken down into three general areas:
• Viscosity loss due to cellulase enzyme attack on cellulosic thickeners
• Resistance of the finished paint to growth of microorganisms (including bacteria and mold)
• Resistance of the dried paint film to surface growth of mold and mildew
The first two items above are generally mitigated through the use of biocides in the paint formulation.
Enzyme production is a byproduct of bacterial activity. Enzymes can be found in process water and finished paint, even after bacterial activity has been killed
through the use of biocides. In particular, cellulase enzymes can be introduced in to the paint making operation through untreated water and raw materials. Over time, the presence of cellulase enzymes will break the bonds between adjacent unsubstituted anhydroglucose units in the cellulose backbone. This reduces the molecular weight leading to significant viscosity loss in paint.
Ashland offers superior biostable cellulosic thickeners in our Natrosol B-series HEC and Natrosol Plus modified HEC thickeners. These high performance workhorse thickeners for latex are manufactured in a way so as to protect the backbone from enzyme attack. The end result is 95 percent viscosity retention over time, even when paint is intentionally dosed with cellulose enzyme (at 1.0 ppm).