Soft Polyvinyl Chloride(Soft Polyvinyl Chloride)products occupy 30%of the PVC market and are widely used in packaging,medical equipment and other fields.Simple soft PVC products are formed by extrusion,injection molding,while products with complex structures need to be formed through mechanical fixing,adhensive bonding and thermal welding methods.At present,welding is more commonly used.How to evaluate the welding property of soft PVC materials?It is commonly used to observe the appearance of the products.Soft PVC material is a complex system that contains components such as plasticizers,fillers and stabilizers.The ratio and compatibility of these components will affect the welding effect of the material.The processing conditions is also an important factor that affects the welding effect.Therefore,testing the welding performance of soft PVC materials is of great significance to industrial production.This paper mainly contains the following two contents:1.Peel strength curves for different preheating temperatures and different preheating times can be obtained by using an open mill for welding and T-type peeling test,which reflect the differences in welding performance of different soft PVC materials.The welding property of soft PVC materials under different processing conditions(the preheating temperature of plasticizer,extruder current)has been tested.The results show that change in the preheating temperature of plasticizer resulted in a change in the peel strength of the soft PVC material,and increasing the preheating temperature of plasticizer will cause the peel strength to decrease.The working current of the extruder will also affect the welding performance of PVC materials.When the current is 6.5 A,the peel strength is the lowest.With increasing the current,the peel strength of PVC materials also increases,reaching the maximum value at 10 A.Using this method,difference in welding performance of PVC materials with the same formula and different processing conditions can be distinguished.The processing parameters can be adjusted.2.The viscoelastic behavior and interfacial diffusion process of soft PVC materials with different plasticizer content have been investigated by rheological measurements.The results show that the content of plasticizer significantly changes the viscoelastic behavior of soft PVC materials.The lower the content of plasticizer,the terminal zone exhibits a clear plateau,which is due to the influence of the elastic network in the PVC.The diffusion process of soft PVC materials can be divided into two stages.The first stage approximates Fick’s law,and the second stage deviates from Fick’s law significantly,which may be caused by the network structure in PVC.With the increase of the plasticizer content,the time required for the complex modulus of the soft PVC material to reach the plateau is significantly reduced.As the angular frequency decreases,the self-diffusion coefficient of the double-layer film also decreases. |