Surfactant-free latexes as binders in paint applications

Abstract

The leakage of surfactant from waterborne coatings is a matter of concern. Therefore, there is a strong interest in developing surfactant-free polymer dispersion as binders for waterborne coatings. This will accelerate the substitution of solventborne binders by the more environmentally friendly waterborne latexes. However, as the performance of the coating depends on the interaction of the latex with pigments and fillers and this interaction is controlled by the composition of the surface of the polymer particles, it is an open question if the surfactantfree latexes are adequate for coating applications. In this work, surfactant-free latexes synthesized under industrial-like conditions using sodium styrene sulfonate (NaSS) to provide stability to the latex were used to formulate exterior paints and their performance compared with that of a commercial latex binder. It was found that for most of the application properties, the paints based on the NaSS binders present improvements with respect to the surfactant stabilized commercial binder.

Integrated Experimental and Modeling Approach to Evaluate Surface Crystallization on Polymer Coatings

“…In addition, adjustment to the effective diffusion coefficient may hardly achieve any improvement in RTSC. However, the real coating design is a systematic problem, and the need for RTSC is likely to conflict with other requirements . Thus, trade-offs must be made to meet all demands for coatings.…”

“…The nominal thicknesses of the cement mortar cylinder and coating were 30 and 0.5 mm, respectively. The surface crystallization tests were carried out for two different coatings (C-1 and C-2) following a similar procedure described in the literature . A test tray was partially filled with 15% Na 2 SO 4 solution, and filter wool was immersed in the solution.…”

“…The surface crystallization tests were carried out for two different coatings (C-1 and C-2) following a similar procedure described in the literature. 9 A test tray was partially filled with 15% Na 2 SO 4 solution, and filter wool was immersed in the solution. Then, the specimen was placed onto the wool so that the substrate of the specimen was partially immersed.…”

“…Herein, the SCLVT is regarded as the indicator of RTSC in this study, as it is much finer than the conventional visual grading method. 6,9 It should be noted that the growth of the surface crystal layer after the critical thickness is reached is not simulated. The effect of the surface crystal layer on internal salt-mass transfer is not considered as well, since the surface crystal layer critical thickness is too thin to have an impact.…”

“…However, the real coating design is a systematic problem, and the need for RTSC is likely to conflict with other requirements. 9 Thus, trade-offs must be made to meet all demands for coatings. Furthermore, to apply the coupled model to computer-aided coating design and optimization, the relationships between macroscopic coating properties and ingredient properties must be figured out.…”