| In this thesis,EVA hot melt adhesives with high and low temperature resistant performance were prepared by using resins(C5,C9,C5-C9,HC5,HC9 and HC5-C9)as tackifying agents and waxes(paraffin,microcrystalline wax,Fischer-Tropsch wax 95#,Fischer-Tropsch wax PX105,PE wax H110 and PE wax SCG)as additives.The effects of the tackifying resins and waxes on the thermal property,friction coefficient and viscosity of the hot melt adhesive were studied,and the optimum components were determined.According to the optimum components,EVA hot melt adhesives with different proportions and process parameters were prepared.The effects on thermal property,mechanical property and viscosity of EVA hot melt adhesive which were caused by different ratio of resins and waxes,different blending temperatures and times were studied.Then the optimum components and preparation parameters of EVA hot melt adhesives with high and low temperature resistant performance were determined.New types of EVA anti-slip packaging material(E-S-PE/HE-S-PE)were prepared by thermal spraying and subsequent heat treatment using purchased EVA hot melt adhesive as raw material and the anti-slip mechanism of the materials were studied.The friction coefficient,bond strength and mechanical property of the materials influenced by spraying pressure,quantitative and subsequent heat treatment were also investigated,and the optimal processes were determined.Three types of anti-slip PE packaging materials(AE-S-PE,BE-S-PE and EE-S-PE),which were based on two kinds of self-made EVA and one kind of purchased hot melt adhesive as raw materials,were prepared according to the optimal parameters.The material with the optimal comprehensive properties were picked by comparing the high and low temperature resistance performance,anti-slip property,mechanical property and bond strength of the three kinds of materials,and the stacking experiments were carried out in a practical pilot-scale test.According to the results of single factor experiments,it can be found that the best addictive of tackifying resin and wax is C5/HC9 and PX105,and the optimum ratio of EVA is hot melt adhesive the type-A(40%wt EVA,45%wt C5 and 15%wt PX105)and type-B(40%wt EVA,45%wt HC9 and 15%wt PX105).The optimum blending temperature and time are 140?and 20 min,respectively.EVA hot melt adhesive owned the best temperature resistance and peel strength under the process condition above.The moderate melting viscosity suitable for thermal spraying process and the mechanical properties within the use range indicate that the material had good comprehensive properties.As shown in friction coefficient analysis,there were three range of spraying quantity which was less than 40 g/m~2,from 40 g/m~2 to110 g/m~2and more than 110 g/m~2,respectively.The best spraying pressure that matched with each range was no less than 15 Psi,no less than 20 Psi and no less than 25 Psi,respectively.Through macro and micro morphology and friction coefficient analysis,it is known that the anti-slip mechanism of E-S-PE and HE-S-PE included two aspects of chemical and physical.The maximum friction coefficients appeared at the quantity of 40 g/m~2and 70 g/m~2,respectively.The surface friction coefficient and bond strength of HE-S-PE are both higher than those of E-S-PE,but its mechanical properties are lower than those of E-S-PE.By comparing the properties of AE-S-PE,BE-S-PE and EE-S-PE,it could be seen that the BE-S-PE with the spraying quantity of 70 g/m~2achieved the best high and low temperature resistance,friction coefficient,mechanical properties and bond strength among the three materials.The stable stack layers of the anti-slip packing bags were as high as 9 layers in practical application. |
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