P-01 STRUCTURAL CHARACTERISTICS OF RUBBER AND ADHESION PROPERTIES OF TEXTILE CORDS TO RUBBER

Polyester cord play an important role in the modern tyre industry as a reinforcing materials because of their extraordinary mechanical and physical properties. Many problems concerning to the adhesion between polyester cords an tyre rubber come from the relatively low surface energy of polyethyleneterephtalate (PET) and also its chemical inertness. The standard method for improvement of adhesion between the reinforcing polyester cords and rubber matrix is established on surface modification of cords with solution or emulsion consisting of resorcinol-formaldehyde resin and vinyl pyridine latex1,2. The aim of this work is to present some results ob-tained by the studying of the influence of temperature and time of vulcanization on adhesion of polyester high modulus low shrinkage cord yarn (HMLS − Slovkord 1440 Dtex 1x2, twists 380/380 produced by SH Senica, Slovakia) to rubber. The rubber compounds contained natural rubber, SBR and polybutadiene rubber was used for fabric coating. The static adhesion strength to rubber and adhesion strength after dynamic stress (the sample was exposed to a cyclic flexural stress with frequency = 7.5 Hz for 12 h in a chamber at 80 ± 1.5 °C) to rubber was studied by means of Henley test method according to STN 6201464. The crosslink density of rubber matrix was de-termined from the results of their swelling in xylene at laboratory temperature according by ASTM D6814-02. The study was based on two-factor five-levels experi-ment. The first factor was temperature of vulcanization (x1) and the second factor was time vulcanization (x2). The experimental results were treated by the complete regres-sion analyses, using the general regression equation in the form