Study Of Skinning Foaming Flooring Substrate Made Of PVC-based Wood-plastic Composites

PVC wood composites possess the advantages of lignocellulosic fiber and polymer material, and can be used to take the place of wood. It can release the poor forest resources and the short supply of wood in China effectively. PVC wood composites have been widely used in the past few years, especially for interior decoration. Because of the composition of wood in the material, its ductility and impact strength are reduced, its brittleness is enlarged and its density is more than twice that of traditional wood. These deficiencies limit its extensive application, especially for the floor. In order to get rid of the above drawbacks this paper tries to use the method of microcellular molding. Because of the existence of good foam structure, microcellular PVC wood composites can inactive the crack and stop the expansion of the crack. So it obviously improves the properties of impact strength and ductility, and largely reduces the products'density. The extrusion microcellular molding is the principal method, because of its lower cost, high effectiveness and short consuming time, it can be industrialized easily.Production technology and formulation was studied by SJSH30/SJ45 two-step plastic extruder, and Low Foaming wood-flour/PVC composites (WF-PVC) was prepared by wood-flour to fill in poly (vinyl chloride) (PVC) matrix and using SJSZ65/132 conical twin screw extruder, which using AC modified foaming agent through the way of crust foaming method. In this study, the formula of foaming wood-flour/PVC composites was studied and the study carries out from several aspects:Firstly, the purpose of this research is to use some physical and chemical methods to construct the interfacial compatibility between PVC and wood flour. By using the microstructure and interfacial compatibility of WF-PVC was studied. The extension part break surface of the wood plastic composites appending compatilizer or not are observed by SEM. The results showed that the interface blur of the wood fiber and plastic have been appended compatilizer composite.Secondly, the effects of wood powder on the combustion properties of PVC/wood (PW) composites were studied by cone calorimeter (CONE). Compared with PVC, PVC with zinc borate and wood, it is found that char formation of PW has an appreciable increase in the presence of wood powder, the time at which the peaks of MLR,HRR,EHC appear delay and the values of peaks are reduced. The effects of wood powder on the releasing of smoke and CO were also discussed. The results show that wood powder is quite effective in reducing smoke and CO generation.Thirdly, this paper studied the productive process of PVC/wood composites from two aspects, formulas and technology. This study modifies AC vesicant, and this would be applied to the processing of composite. Through lots of industrial practice, the study summarizes the effects of all aspects of the production process to composites foaming performance. It is found that there are many factors influence the composites foaming effect, including the disposal of wood meal, the rationality of formulas and technological conditions. In this study, the machining temperatures of the extruder were set in the range of 150～185℃, and production pressure was set above 12Mpa.This paper found the technological process and process parameters which are suitable for the production of composites flooring substrates, and summarized the common problems and solutions during the production of composites foaming flooring substrates.Fourthly, this paper tested physical property and formaldehyde releasing of skinning foaming flooring substrate, through the comparison with the standard value, it is found that all indicators of foaming flooring substrate fill the bill and they can meet the quality requirements of laminate flooring substrates. PVC-based wood-plastic composite production test was also finished,PVC-based wood-plastic composites are produced by the process engineering similar to laminate flooring and engineered wood flooring. In order to decrease warp degree of PVC-based wood-plastic composites, deep research should be done.