Study On The Synthesis And Application Of Acrylic Emulsion Pressure Sensitive Adhesive For Surface Protective Film

Acrylic emulsion pressure sensitive adhesive has widepread application due to its properties such as non-toxic, environment friendly, low-cost and good adherence. As the application ratio of acrylic emulsion pressure sensitive adhesive on the protective film becoming larger, the requirements for the good performance of acrylic emulsion pressure sensitive adhesive tend to be higher, and then leading to a more intense market competition. Therefore, only the acrylic emulsion pressure sensitive adhesive with excellent performance has competitiveness in the market.This thesis introduces a preliminary emulsion semi-continuous emulsion polymerization method to prepare the pressure sensitive adhesive emulsion with acrylic acid(AA), butyl acrylate(BA),2-Ethylhexyl acrylate(EHA), hydroxyethyl acrylate (HEA) and vinyl acetate monomer(VAM) as comonomers and initiator (ammonium presulfate, APS). The pressure sensitive adhesive emulsion are used as protective film. The influences of the BA/EHA mass ratio, emulsifier content, initiator content and reaction temperature on solid content, initial viscidity and 180°peel strength of this acrylic emulsion pressure sensitive adhesive were discussed. The effects of crosslinking agent and tackifier on initial viscidity and 180°peel strength were also discussed. In addition, the acrylic emulsion pressure sensitive adhesive obtained under the optimum conditions, wascharacterized with infrared test, DSC and TGA.The research results show that the appropriate reaction conditions of acrylic emulsion pressure sensitive adhesives as follows:the BA/EHA quality ratio is 45/45, the polymerization reaction temperature is 82℃-85℃, the dosage of initiator and emulsifier is 0.15w%-0.2w% and 0.8w%-1.0w%,respectively. The performance of product obtained under this condition are as follows:the solid content is 55.5%, the initial viscidity is 23#-24#, the 180° peel strength is 5-6N/25mm. When 0.1w%-0.3w% cross linking agent was added, the 180°peel strength and initial viscidity is 2-2.5N/25mm and 15#～16#, respectively. The as-synthesized product has good adherence and appropriate peel strength, without the happening of degumming.When the dosage of tackifier was increased to 10w%-15w%, we obtained the maximum 180°peel strength and initial viscidity, which is 6-7N/25mm and 22#～24#, respectively.The acrylic emulsion pressure sensitive adhesive synthesized under the optimum conditions was characterized with infrared spectrum, DSC and thermogravimetric analysis. The as-synthesized acrylic emulsion pressure sensitive adhesive exhibits excellent stability by analyzing the infrared spectra. The temperature resistance is good, which can be concluded from TG curve. What’s more, the glass transition temperature is higher than the designed, which indicating that the crosslinking effect during the polymerization leaded to a increased glass transition temperature.