Study On The Physical Foaming Technology Of Water-based Polyurethane And The Performance Of Film Formation

Water-based polyurethane is a binary colloidal system with water as a dispersive medium and polyurethane as a dispersion.With the soundness of environmental laws and regulations and the rapid improvement of public awareness of environmental protection,the research and development of water-based polyurethane has attracted much industry attention.At present,in the process of water-based polyurethane synthesis,in order to improve the dispersion of polyurethane,it is often necessary to add a small amount of organic solvents,which in turn caused the actual preparation and use of water-based polyurethane in the actual process of solvent volatilization,adverse environmental protection problems.Secondly,the application of water-based polyurethane in leather is relatively single,the current use is mainly concentrated in the surface decoration of leather,limiting the application of environmental protection materials in leather.In this paper,first of all,without adding organic solvents,the use of toluene-2,4-disocyatatin(TDI)and polytetrahydrofuran ether glycol(PTMEG)as the main raw materials,the use of nilate,sulfonate composite hydro-expansion chain,control pre-polymer polymerization and dispersion,to obtain pure water-based polymer materials.The effects of the compound hydrophilic-based ratio on the dispersion performance of water-based polyurethane pre-polymer,emulsion performance,emulsion foam performance and emulsion film formation were studied.Using laser particle size analyzer,infrared spectroscopy,pull test,thermal reanalysis,atomic force microscope and other means to comprehensively carry out a systematic and in-depth representation of the resulting water-based polyurethane emulsion and water-based polyurethane film.Water-based polyurethane emulsion X-3 to meet leather performance requirements.Secondly,the use of home-made whole water-based water-based polyurethane emulsion X-3,the use of special foaming technology for the emulsion formulation,physical foaming process and coating drying stereotypes for screening test results: when foaming agent and stable foam ingester dosage in 3%-5%,water-based polyurethane emulsion has better foaming power and foam stability When using acrylic-binding thickeners,the emulsion viscosity varies less with temperature,and the leveling performance of the thickening system is good;The effect of the foaming multiple of the experimental emulsion on the mechanical and hygienic properties of the foam coating in the physical foaming process,through the detection of scanning electric mirror,pull test,breathable and permeable vapor of the foam coating,found that the mechanical properties and sanitary properties are a pair of contradictions,according to the specific requirements of the product foaming ratio can be selected betw?Finally,the clean production technology is realized,the whole water-based polymer material and the organic compound of leather,water-based polyurethane instead of the traditional solvent-based polyurethane coating,the production process only the evaporation of water vapor,eliminating DMF,toluene and other solvent emissions of environmental pollution.The consumption of energy is very low with the traditional drying technology instead of the complex solvent-type solidification-wash-drying process.The process route,process points,product formulation,production equipment requirements and transformation of leather physical foaming are discussed,and the feasibility of the process is verified by engineering practice.The performance of physical foam coating dermis and traditional process deracity,peeling strength,embossing performance and so on is detected.The resulting foam-coated leather has a peel strength of 35.1N/2.5 cm,481.3 ml/(cm2.h)breathability,and is higher in yellowing grade than conventional processes.