The Experimental Study On Polyurethane Rigid Foam Safety Performances For Coal Mines Hole Sealing Craft

The situation of safety production is more and more severe day by day in Chinese coal mines, which gas explosion and outburst accidents'death proportion is the highest in all of coal mine accidents. The most important measures to prevent and forecast the gas accidents are gas drainage technology,coal seam water injection technology, and gas pressure survey technology, however, the performance of hole sealing material is unable to meet the real craft requirements, which the quality of hole sealing is discrepancy and bring the hidden danger to the safety production. Due to this background, the research on safety performances of polyurethane rigid foam sealant material for coal mine is proposed.The experimental program is established by using the orthogonal design method and 27 proportioning experiments are made. The samples test index value is analyzed by variance and range methods, which results show that the catalyst is the most remarkable impact to foaming time and present the inverse proportion impact, the foaming agent is the most remarkable impact to foaming multiple and present the direct proportion impact. The polyurethane rigid foam with controlling foaming speed, 31 foaming multiple, dense face and hardness is obtained in according to the comparison of samples and the experimental data analysis.On the basis of studying the literature of polyurethane rigid foam performances research at home and abroad and some methods and thoughts of material performance study, the basic performances of polyurethane rigid foam are tested and analyzed, which results show the impact factors and the relation between factors and performances.On account of adhesion theories, the train of thought which inject solid surface energy into studying polyurethane rigid foam adhesion performances is proposed, and the experimental program is designed in terms of this thought. The relation between bonding strength and surface energy is gained by analysis and fitting of the solid surface energy and bond stress test data. The experimental verification is carried out with the coal samples from five high gas outburst coal mines, which results show the erratum is about 14.8% of theory result and test values. So the relation is true.On the strength of analysis of permeation laws, the study of polyurethane rigid foam permeability is proposed, and the experimental apparatus is shaped and the experimental plan is established by using Darcy's law. The permeability impact factors which hole sealing way and length are proposed by analysis of amount of experimental data. By theory analysis and sealing simulation experiments in the lab, press and pour sealing and 100~110cm sealing length are able to ensure the low permeability and saving sealing cost.The safety performances of polyurethane rigid foam are tested and analyzed in order to provide the safe and available polyurethane rigid foam sealing material to sealing craft in coal mines.