Encapsulation of a pressure-sensitive adhesive by spray-drying: microparticles preparation and evaluation of their crushing strength

J Microencapsul. 2012;29(2):185-93. doi: 10.3109/02652048.2011.642014. Epub 2011 Dec 13.

Abstract

An industrial pressure-sensitive adhesive was microencapsulated by spray-drying using an aqueous colloidal ethylcellulose dispersion (Aquacoat® ECD) plasticised by triacetin to form the wall material. Unloaded (0:100) and adhesive-loaded (25:75) particles were produced in a Büchi B-191 mini spray-dryer with product yields of 62% and 57%, respectively. Microparticles were spherical and narrow sized with mean D₃,₂ diameters of 3.165 ± 0.001 and 5.544 ± 0.105 µm, respectively. The microparticles were found to redisperse well in water and exhibit enough stability in neutral and alkaline aqueous media to be further used in a coating slip. Crush tests on single microparticles with diameters ranging from 2 to 12 µm were performed using a nanoindenter. They revealed that the crushing force of both kinds of microparticles increased linearly with their diameter and that the adhesive loading reduced the mechanical strength of the prepared microparticles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesives*
  • Biomechanical Phenomena
  • Cellulose / analogs & derivatives*
  • Cellulose / chemistry
  • Particle Size
  • Pressure

Substances

  • Adhesives
  • ethyl cellulose
  • Cellulose