چكيده به لاتين
Hot melt adhesives (HMA) have been commercially available for a long time and are used in a wide variety of applications. For hot melt adhesives, wax is actually a critical component. The purpose of this research is to determine the effect of the type of wax on the adhesive properties of the ethylene-vinyl acetate heat melt copolymer adhesive mixture. Therefore, in this research, by using 8 types of polyethylene waxes, including synthetic Fischer-Tropsch waxes, purified waxes, extracted waxes and waxes obtained from the thermal fracture process along with one type of polypropylene wax, Two types of ethylene vinyl acetate (EVA) copolymer with different percentage of vinyl acetate (VA) and one type of resin, hot melt adhesive mixture were prepared and investigated. The difference in the structure and properties of waxes and polymers used in the adhesive mixture, such as crystallinity, viscosity, softening point, etc., caused a change in the properties, performance, and as a result, the application of the final adhesive mixture. In this research, using fast infrared transformation (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) along with tests to determine the physical properties and adhesion were used to determine the differences in the materials used and their effect on the properties and performance of the adhesive. The results of this research showed that increasing the value of VA decreased the degree of crystallinity and increased the flexibility of the chains of the components of the adhesive mixture. The results of FTIR spectroscopy showed that all waxes have an aliphatic structure. According to the results of DSC calorimetry, the highest degree of crystallinity was specific to synthetic wax by Fischer-Tropsch (SX) method at the rate of 84.1%. According to the results of XRD spectroscopy, the highest degree of crystallinity was obtained in the sample containing propylene wax (HMA-930-PP) at the rate of 14.20%. The existing differences caused the sample containing synthetic wax by the Fischer-Tropsch method (HMA-930-SX) to have the highest overlapping shear adhesion strength of 71.9 MPa. And another synthetic wax with this method (HMA-930-352) obtained the highest peeling strength of 4.46 KPa at 28°C. On the other hand, the highest adhesion strength at 5°C for the purified polyethylene wax sample (HMA-930-366) was 3.12 KPa. At the temperature of 0°C, the sample containing the same type of purified polyethylene wax with EVA with higher VA content (HMA-910-366) showed the highest adhesion strength of 3.61 KPa.
