Experimental Analysis And Multi-scale Simulation On High-speed Calendering Of Tire Belt With Rubber Compounds

The tire belt layer is composed of rubber compounds and steel cord and produced by four-roller calender.It carries most of the force of the tire.Calendering is one of the basic forming processes of polymer material and has been studied for decades in the academic and tire industry fields.However,the rheological behavior of the calendering of tire belt with rubber compounds has not been understood totally yet.Due to the complex nonlinear viscoelastic properties of the tire belt rubber compounds,roller sticking occurs in the high-speed calendering process occasionally.In order to improve the production efficiency of the tire belt layer,this paper,combined with the technical requirements of enterprises,adopted the method combining experimental research and multi-scale numerical simulation,carried out relevant research on the process of high-speed calendering of tire belt with rubber compound.The specific research content is as follows:1.The four-roller calender was used to test the production property of different batches of tire compounds at different calendering speeds.Then,the cause of roller sticking was analyzed through a series of rheological property test,molecular structure test and roller operation performance test of tire rubber compounds.The experiment results showed that the process property of the rubber compound produced by raw rubber of different origin places and different batches were difficult to keep consistent.Mooney viscometer and RPA2000 rubber processing analyzer were used to test the rheological property of different rubber compounds,and the relationships of elastic modulus,viscosity modulus,loss factor and complex viscosity with oscillation frequency,shear strain and temperature were revealed.The tire rubber compounds showed obvious viscoelastic property under the small amplitude dynamic shear flow field,and the elastic modulus and viscosity modulus of rubber compounds which were easy to stick to the roller were higher than that could be produced normally.Under the premise of consistent plasticizing effect,the smaller the molecular weight of natural rubber,the higher the adhesion,the easier to stick to the roller,and the wider the molecular weight distribution,the higher the adhesion in the low shear rate zone,the less easy to stick to the roller.2.The interaction energy between the rubber compound and the roller is an important index of the adhesion between the two.The model of natural rubber was built with the molecular dynamic simulation software Materials Studio,and the reliability of the model was verified by the solubility parameter and glass conversion temperature.Then the polymer-metal layer model was established to calculate the surface energy of the polymer layer,the surface energy of the metal layer and the total surface energy of the two at different pressures,and then the interaction energy between the natural rubber and the roller was calculated.The results showed that the pressure would affect the interaction energy between the natural rubber and the roller.The higher the pressure value,the higher the absolute value of interaction energy,which meant a higher adhesion power.3.The numerical simulation software Polyflow was used to simulate the flow process of the rubber compounds between rollers in the tire belt calendering process.We adopted the Leonov viscoelastic model which was appropriate to the particle filled elastomer rubber compounds to the calendering of tire belt with rubber compounds simulation of the two-dimensional profile.The rubber compounds showed "the velocity distribution in advance" at the top and bottom of the steel wire cord.Rubber-roller surface and rubber-cord surface existed high shear rate,and the effect of viscous heating effect is also obvious due to the high shear rate.In this paper,the separation force of roller per unit width in the theoretical analysis of calendering was obtained through the pressure data of finite element simulation,and the influence of process parameters such as rolling speed,rubber temperature and roller temperature on the roller-sticking was analyzed.In addition.by controlling the thickness of the material at the roll release point of the geometric model,the mechanism of roller sticking in the process of calendering of tire belt with rubber compounds was analyzed and the production suggestions were put forward.