Research On Preparation And Properties Of Novel Automotive PVC Damping Material

PVC damping materials has the advantages of fast plasticizing,high mechanical strength,good damping performance,no solvent and no pollution.Compared with traditional gasket-type damping materials,PVC damping material is easy to transport and store,and can be mechanically sprayed on the automobile production line.Due to its comprehensive performance and cost-effective,it is widely used in the field of automotive damping.Damping materials are not limited to achieving a single damping performance requirement.The preparation of environmentally friendly and stable PVC damping materials with excellent construction performance and strong damping properties is the focus and difficulty of research at home and abroad.At present,PVC damping materials produced in China are prone to sag and slip down during construction,and there is a certain gap between the damping performance and mechanical properties of materials produced by famous foreign manufacturers.The purpose of this project is to prepare a novel automotive PVC damping material with suitable viscosity for spraying,no sag and slip,high damping factor,wide damping temperature range,high mechanical strength and good toughness.The construction performance of PVC damping material is mainly determined by the wet film before plasticization,and the performance of the material is mainly determined by the plastic film after plasticization.Therefore,the rheological mechanism of the wet film and the damping mechanism of the dry film are firstly discussed,and then the effects of each composition on the export performance were discussed.The subject of the study has divided into the following three parts:(1)The rheological properties of wet film of PVC damping material were studied,and the roof attachment model and the wall adhesion model were simulated during the construction of the material.Explore the relationship between the macroscopic construction properties of materials and the dynamic viscosity,yield stress,adhesion,and thixotropism of wet films.(2)The damping mechanism of the composite plate formed by the substrate and the dry film of PVC damping material was studied,and the relationship between the damping property of the material and the damping performance of the composite plate was investigated.(3)The effects of plasticizer and filler content on the rheological properties,mechanical properties and damping properties of the materials were studied.The optimum ratio of PVC,plasticizer and filler was determined.The effect of heat stabilizer on the material stability energy was studied,and the amount of heat stabilizer added was determined.Through the above research it was found that(1)the wet film of PVC damping material is a shear-thinning pseudoplastic fluid.It has a low viscosity at high shear rate and can be sprayed.It is stable after spraying and has a high viscosity at low shear rate.When the yield stress and adhesion of the material are greater than the gravity stress,the material will sag and slip down.(2)Dry film of PVC damping material usually forms a composite material with the substrate to exert damping effect.The damping factor of material by the DMA test and the damping factor of the composite panel by the cantilever beam damper test can be calculated by the formulation,and it can verify the effect of the automotive PVC damping material in practical applications.(3)With the increasing content of the plasticizer DINP,the viscosity,yield stress and adhesion of the wet film of the material gradually decrease,and the hardness and specific gravity of the dry film of the material were reduced,the tensile strength was decreased,the elongation at break was increased,the peel strength was slightly increased,the damping property of the material was decreased.With the increasing content of the filler Ca CO₃,the viscosity,yield stress,adhesion of the wet film material and the mechanical strength,damping properties of the dry film material increased first and then decreased.The optimal ratio of PVC resin:plasticizer DINP:filler Ca CO₃is 80:35:20,and at this time,the PVC automotive damping material prepared has the best comprehensive performance.The material has the best thermal stability when the calcium-zinc stabilizer is added at 3 phr.Finally,compared with the PVC damping material produced by a famous foreign company,the mechanical properties,damping properties of the novel automotive PVC damping material prepared by this subject almost approach the foreign standards.The comprehensive performance of the materials can meet the needs of domestic automotive OEMs.