Study On Synthetic Process Of Epoxidised SIS (ESIS) And Controllable Adhesion

SIS (Styrene-isoprene block copolymer) was an important thermoplastic elastomer with high strength and simple process ability. SIS was usually used as the base material of adhesive and modifier of plastic. However, weak polarity made the application of SIS limited, especially in the bonding to the polar material. Therefore, to introduce polar groups on the molecular by was a focus of chemically modifying of SIS. Epoxidation of SIS was an important method for polarizing SIS. In this paper, synthesis process was studied to obtain the Epoxidised SIS (ESIS) with the desired epoxy value. It was very important and was of better applicable prospect for controlling the adhesion behavior by altering the epoxy value, the formulation, the depth and pattern of adhesive layer.ESIS with the range of epoxy value in 2.2 mol·kg-1～3.7 mol·kg-1 could be easily synthesized by the reactin of SIS (3421 and 1209) with performic acid which was formed by in-situ reaction of formic acid and H2O2. The appropriate reaction time was from 1 to 3 hours, the reaction temperature from 40℃to 50℃, the molar ratio of HCOOH/H2O2 between 0.5:1 and 1.5:1 and the amount of H2O2 was half of the double bond and the concentration of toluene solution of SIS was in 10%～15%. The addition process was improved to multistep droping in order to control the heat accumulation in the mass production. Meanwhile the usage amount of formic acid decreased by 40% and the epoxy value increased by 13.5% and the reaction was more easily controlled. This process was successful used in the productin of ESIS.The homogenous reaction process was explored by employing alcohol as compatilizer in the system of SIS 1209/ toluene/formic acid/H2O2/H2O. The epoxy value could reach to 0.37mol·kg-1 by homogenous reaction at room temperature with several minutes, but the concentration of ESIS was lower than 10%.Solvent adhesives were formulated with SIS/ESIS, tackifier and toluene. A quantity of the T peeling strength of adhesive/paper and adhesive/printing ink paper was tested, and it was simple investigated that the relation of the adhesion propertiy to surface papper and printing ink paer to formulas, thickness and pattern. The results meant that the controllable adhesion could be used to control the transfer of adhesive layer.