Preparation and Determining Factors in Adhesion Properties of Acrylic Pressure-Sensitive Adhesive

n acrylic pressure-sensitive adhesive was prepared by free radical polymerization of 2-ethyl hexyl acrylate in ethyl acetate and in the presence of an oil soluble initiator such as AIBN. In order to adjust the appropriate properties for the synthesized acrylic pressure-sensitive adhesive, two comonomers; vinyl acetate and hydroxyl ethyl acrylate were introduced into the structure of the acrylic adhesive. The prepared acrylic pressure-sensitive adhesive was characterized by analytical instruments such as FTIR (Fourier transform infrared), NMR (nuclear magnetic resonance), GPC (gel permeation chromatography) and HPLC (high performance liquid chromatography). Reaction conditions such as comonomer type and concentration, reaction time and initiator could affect the final properties of the synthesized acrylic pressure-sensitive adhesive. Therefore, the effect of parameters, especially time of the reaction, initiator concentration and that of each comonomer and degree of cross-linking was studied with respect to the final properties of the acrylic pressure-sensitive adhesive such as tack, peel strength and shear strength.Shear strength of the adhesive was increased by increases in the amount of HEA and VAc and reducing the amount of the initiator. Tack of the polymer was improved by the higher amounts of initiator and VAc monomer. Moreover, the peel strength of polymer was decreased by increasing the amount of VAc and raised by increasing the amount of HEA. It was found that cross-linking significantly raised shear strength of the adhesive. The optimum time of reaction was obtained by 10 h and the optimum amounts of initiator, vinyl acetate and hydroxyl ethyl acrylate were 0.5, 22 and 6 wt%, respectively.