Research On Cushioning Properties Of Molded Pulp Products

Because of its outstanding environmental-friendly property, molded pulp products have been used as one of package cushioning for many years, and it's generally taken as a kind of perfect substitute for those package cushioning materials with serious pollution such as EPS, EPE, etc. However, owing to its cushioning mechanism is quite different from that of conventional package cushioning materials, so at present people has little knowledge for cushioning properties of molded pulp products. Moreover, the lack of necessary experimental data and effective principle and method of design for molded pulp products, so the method of try and trail is customarily adopted. The method has some disadvantages such as long design cycle, high cost, especially inaccurate and lack of reliability, and has been hampering the development of molded pulp packaging industry.On the basis of comprehensive analysis on the domestic and oversea research results, a hypothesis of equivalent area is firstly put forward in the paper. Then the Finite Element Method is utilized to analyze the mechanical properties of molded pulp products, and theory of equivalent area is obtained in the procedure of analysis and calculation. Next the stress and strain (σ-ε) curve, cushioning coefficient and maximum stress (C-σm) curve, and maximum acceleration and static stress (Gm-σst) curves are gained by static compression testing and dynamic compression testing for molded pulp products. Finally a method of package cushioning design for molded pulp products are put forward on the basis of the new theory and curves, it plays an important role in instructing the design of package cushioning for molded pulp products.The main achievements are as follows:(1) The equivalent area theory is presented, and it makes the calculation on the cushioning characteristics curves of molded pulp products possible, and unifies the performance evaluation of molded pulp products with that of conventional package cushioning materials.(2) The compression characteristics and cushioning properties of molded pulp products aretested and analyzed, the stress and strain (σ-ε) curves, cushioning coefficient and maximum stress (C-σm) curve, and maximum acceleration and static stress (Gm-σst) curves are obtained.(3) A method of package cushioning design for molded pulp products are put forward on the basis of the Equivalent Area Theory.In summary, the Equivalent Area Theory, the method of package cushioning design give some new idea and new method for the application of molded pulp products in the field of shipping package. It will shorten the design cycle and decrease design cost and impulse the rapid development of molded pulp packaging industry.