Synthesis And Property Study On Polyurethane Reinforcing Agent Used For Coal Mine Safety Materials

Coal is our courties's main resource type, it accounts for approximately 70% of the share in the energy structure, so the production of coal affect the pace of China's economic development directly. The coal resources has a large of reserve volume, but the wide distribution and very complex coal geography condition brought great difficulty to the coal mining, plus the weak consciousness of coal mining safety managers and lack of relevant national laws and regulations lead to a vey serious of safety situation in China's coal mining. In recent years, people and the government has more and more higher strictly requirements on coal safety with the rapid development of economy and the enhanced safety consciousness by people, it's also because of relevant national laws and regulations become perfect and the social's more attention, so the coal safety products emerged in recent years under this background, and it has a good momentum of development.Chemical grouting material is one of materials which used in coal mine safety control currently. It mainly contains epoxy, polyurethane, acrylate, phenolic resin, urine aldehyde resin and sodium silicate, etc, it applicates in all aspect of coal safety management. Such as it can used as Reinforcing agent, Plugging agent, filling materials, Sealing material, Preventing fire material, Extinguishing material and Coating material and so on, and polyurethane is used most widely between these materials.We can get A components by using polyether polyols, catalysts, flame retardant and foam stabilizer, and then we can get PU Reinforcing agent by the reaction of A component with B component(polyaryl polymethylene isocyanate). We studied effect of various factors on the reaction and product performance, the influence of catalyst were examined first, we found that when the amount of catalyst I is more than 0.15, its curing speed accelerate gently, thus the optimum content of catalyst I is 0.15. Moreover the synergy of two kinds of catalyst was studied in this paper, when the amount of catalyst two added is 0.06 percent, there is a appropriate speed of the reaction, and the material synthesized has a very good mechanical performance, thus the best content of catalyst two is 0.06; The best hydroxyl value was established through the study on effect of polyether polyols hydroxyl value on material, when hydroxyl value of polyether polyols is 370mgKOH/g, the material has good strength and proper elongation; the effect of Isocyanate index on the material properties was also studied in this paper, when the value of isocyanate index is 1.05, material has a good comprehensive performance; affluence of composite flame retardants on properties of material has been researched in this studY, which has been found thaT excessive amount of flame retardants had a bad influence on gel time and mechanical properties, and the best amount is 15%～20%; material temperature was proved that it has a great influence on viscosity and gel time of material; stirring speed has a great effect on material density which has been determined in experiment, so the mechanical properties of materials was affected seriously, suitable mixing speed was 200-300rpm; through the application of this material on coal mine which roof collapse accidents was happened in, it proved that the material can solve such safety problem effectively.Modern instruments such as Infrared Spectroscopy (IR), Scanning Electron Microscopy (SEM), Thermo Gravimetric Analysis (TG) etc. were used for tracing synthetic process and characterizing structures and properties of products. Infrared spectroscopy showed that -NCO and -OH groups were involved in the reaction to form the urethane groups; the analysis about thermo gravimetric analysis showed that the increase of hydroxyl value and the improvement of isocyanate index are conducive to rise of glass transition temperature the increase scanning electron microscopy used in characterizing film's break surface and results showed that section with low cross-linking and isocyanate index is smooth, conversely the section is very rough.