Synthesis and properties of soap-free P(2-EHA-BA) emulsion for removable pressure sensitive adhesives

Pressure sensitive adhesives (PSAs) are materials that can adhere strongly to solid surfaces under a light contact pressure for a short time. Soap-free emulsion polymerization of 2-ethylhexyl acrylate and n-butyl acrylate has been performed in the presence of a reactive emulsifier SR-10 to obtain high adhesion properties of PSAs. The particle size distribution was quite narrow with an average diameter of 137 nm. The FT-IR spectrum showed that the C=C bonds contained in the monomers disappeared during the reaction. The DSC result showed that all the monomers were well copolymerized. The 180 degrees peel strength could reach 183.2 N m(-1) when SR-10 was 2 wt% and the ratio of 2-EHA to BA was 4 to 1. The tack was 13 #. The shear holding time was more than 100 h. The removable PSA tapes produced from the resulting soap-free emulsion showed good adhesion properties and stabilities, which are suitable for practical applications.