Preparation And Application Of Filling Foam For Air-leakage Blocking In Coal Mine

Coal spontaneous combustion is one of the main disasters in the process of coalmining. Controlling air-leakage is the key to prevention of coal spontaneouscombustion. Building insulation foams are widely used to filling and air-leakageblocking in mine at home and abroad due to its rapid construction and good sealing.However, there are different defects in the existing organic curing foams, such as highcost, flammable and releasing toxic gases of polyurethane foam, brittleness and highcontent free formaldehyde of blocking foam. Accord to lack of of existing organiccuring foam in mine, a new type of air-leakage blocking composite foam is developedin this paper, which has the advantages of low free formaldehyde content, goodtightness, high compressive strength, good flame resistance, and low density.In this paper, a new phenolic resin foamable at room temperature was madewithout dehydration process for the raw materials of paraformaldehyde and phenol.And foam Orthogonalthe test was designed to study the influence of differentormaldehyde/phenol molar ratios, catalysts, reaction temperature and time on thecontents of remnant monomers free formaldehyde and free phenol in foamablephenolic resol resin. Base on the results, Single factor experiment was designed tostudy the influence of various significantly a factor on the resin properties, and theoptimal reaction conditions was obtained. Then, some new explore ways was tried tolower the content of free formaldehyde, it was found that urea and composite catalystwas helpful to free formaldehyde. And the best reaction conditions are, F/P1.6,reaction temperature75℃, reaction time180minutes, the composite catalyst0.05mol, urea added3g.In order to optimize the phenolic resin curing system, the effect of differentcuring agents, surfactants, foaming agents on curing behavior, mechanical propertiesand exothermic characteristics of foam are studied, and the optimal amount of curingagent, surfactant and foaming agent are obtained. The mechanism of a curing agentand a surface active agent for foam is disclosed, and the principal of foaming andcuring for phenolic resin was to explored.In order to solve poor toughness of phenol foam, the effect of different molecularweight glycol on foaming behavior, impact strength, combustion properties of phenolfoam is studied. The toughening mechanism and optimal added amount of glycol wereobtained. Glycol can significantly improve toughness and compression strength of closed foam, and reduces shrinkage ratio. When6%glycol is added,.the foamproperties is best.In order to improve flame retardant foam and anti-burning capacity, differenttypes of flame retardant are added to prepared composite foam. The effect of differentkinds and content of flame retardant on oxygen index was investigated. The resultshows that: the Expandable Graphite (EG) works well than Triphosphate (TCPP) andZinc borate (FB) with the same adding; TCPP and EG have a good synergistic effect;the performance of curing foam is optimal when1%EG and1%of TCPP are mixedand added, of which the oxygen index of the composite foam is35.4, flaming time is0s, flameless combustion time is3s, flame propagation length is10mm.Finally, the developed filling foam was applied for industrial Test. Engineeringpractice in coal mine shows that composite foam has an excellent sealing performanceand safety performance, being good for fast filling of many locations, like high-riskarea, gob, up and down the corner etc. At the same time, the material meets the newestindustry standards, so it will havea broad application prospects.