Preparation of 3-alkoxy-2-hydroxypropyl ester of 2-ethylhexanoic acid and its application in polymer latexes and coatings

Abstract

In recent years, most of the coalescing aids commonly used in the market contain volatile organic compounds (VOCs) with low boiling point. Herein, we designed and prepared a novel environmentally friendly coalescing aid, 2-ethylhexanoic acid-3-alkoxy-2-hydroxypropyl ester. Under the action of a catalyst, 2-ethylhexanoic acid and alkyl glycidyl ether were used as raw materials for ring-opening esterification reaction, and 2-ethylhexanoic acid-3-alkoxy-2-hydroxypropyl ester was finally generated. We conducted a single-factor experiment and orthogonal experiment L₉(3⁴) to explore the optimal reaction conditions. The structure of the product was characterized by ¹HNMR and FTIR. The boiling point of the product was determined to be 270–283°C, which was in line with the requirements of the national environmental protection regulations for VOCs. Compared with traditional coalescing aids, the product has low volatility, is not classified as a VOC and is safe and environmentally friendly. The properties of the product were characterized, and the applications of the product in polymer latex and coating were determined. We measured the minimum film-forming temperature (MFFT), atomic force microscopy (AFM), water absorption, scrub resistance, adhesion, color difference, and other properties of the film. The results show that the performance of the new coalescing aid is superior to Texanol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate), which is commonly used in the market, and it has obvious advantages.