Study On The Modification And The Adhesive Application Of Polyvinyl Chloride

PVC is a kind of difficult bonding materials.In the actual production of PVC-U pipe,the use of two-component adhesive through continuous dropping leads to uneven distribution or partial lack of adhesive,and reduces the durability and sealing.PVC modified hot melt adhesive is compatible with the winding pipe interface in a molecular level,and it has stress dispersion and increased durability significantly.Double layer co-extrusion hot melt adhesive can improve the sealing performance of the pipeline.In this paper,PVC as the matrix of materials was modified by using of TPU,PE and EVA,with accessories for rosin resin and NanoCaCO₃.The specific work are summarized as follows:Firstly,the relationships between the ratio of materials and the performance/compatibility were investigated in PVC with TPU,PE and EVA two component mixed system respectively.In PVC/TPU two components mixed system,product flexibility and adhesion first increased and then decreased with the increase of amount of TPU.In PVC/PE two components mixed system,elastic of products is better,but viscous products is less with the increase of amount of PE.Mixing PVC/EVA can improve elasticity and rigid of products,but reduce adhesion of products.The samples have good compatibility between PVC and three polymer materials in a certain proportion range.Secondly,when the PVC/TPU/PES three components system was compared to the PVC/TPU two components system,the elasticity and adhesion of products have decreased with the increase of PES.When the PVC/TPU/NanoCaCO₃/rosin resin four components system was compared to the two components system,the elasticity of products has decreased slightly,and adhesion of product has increased slightly.The mechanical properties and adhesion have greatly improved by the four components system comparing to the PVC/TPU/PES three components.When the four components with NanoCaCO₃/resin=1/3,the combination property of the products can get the best.The tensile strength is 17.52 MPa,the elongation is 156%,and the shear strength can reach 5.43 MPa at 110 ?.Thirdly,with the introduction of PE,the elasticity of the products is greatly decreased and the adhesion of products is not significantly improved when the PVC/PE/TPU three components system was compared to the PVC/PE two components.When the PVC/PE/TPU/rosin resin four components system was compared to PVC/PE/TPU three components system in three groups,the elasticity can be greatly improved,and the adhesion of products is also greatly improved.When the four components with the rosin/total mass is 1/10,the combination property of the products can get the best.The tensile strength is 8.82 MPa,the elongation is 52.71%,and the shear strength is 1.00 MPa at 110 ?.Fourthly,with the introduction of EVA,when the PVC/EVA/TPU/rosin resin four components system was compared to the PVC/EVA two components system,all of the properties have greatly improved because the original adhesion of rosin resin is good and the original elasticity of TPU is good.In the four components?1?,when the rosin resin is 1/5 of the total quality,the combination property of the products can get the best.The tensile strength is 7.76 MPa,the elongation is 140.39%,and the shear strength can reach 2.64 MPa at 110 ?.In the four components?2?,when the TPU is 1/10 of the total quality,the combination property of the products can get the best.The tensile strength can reach 8.45 MPa,the elongation is 20.07%,and the shear strength can reach 2.46 MPa at 110?.