| Buildings are susceptible to mildew,cracking and other phenomena caused by the moisture in the air,which is especially common in areas with high rainfall and humid air.Once the phenomenon occurs,it not only affects the indoor air quality,but also affects the appearance of the building,increases maintenance costs,and reduces the service life,which seriously threatens the health of residents and the safety of life and property.As a modern solution to this problem,breathable waterproof membrane have a wide application market abroad,and my country’s functional membrane industry has just started.At the same time,because China has no clear regulations on the flame retardant performance of breathable waterproof membrane,and research on the flame retardancy of functional membranes is also rarely reported,causing a large number of flammable waterproof and breathable membranes to flood the market and bury serious hidden dangers.On the other hand,from 2020,the main member of the waterproof and breathable membrane family,polytetrafluoroethylene functional membrane(PTFE),will face stricter restrictions of the European Union“Registration,Evaluation,Authorization,Restriction of Chemicals”.Therefore,there is an urgent need in the market for a product with flame retardancy and sufficient performance to replace the PTFE functional film.In this paper,polyurethane(PU)as main materials,by electrospinning,a waterproof moisture-permeable membrane prepared retardant.First,the effects of PU,LiCl,and fluorine-containing hydrophobic agent(FPU)on the hydrostatic pressure,water vapor transmission(WVT)rate,and mechanical properties of the fiber membrane were studied.The best formula was determined;On this basis,a suitable flame retardant was selected,the influence of the flame retardant concentration and spinning distance on the flame retardant performance of the fiber membrane and the waterproof and moisture permeability properties were investigated,and the best spinning formula was determined;Finally,on the basis of the previous article,two commercial functional films were developed,and the feasibility of pilot production of flame-retardant,waterproof and moisture-permeable films was explored.The specific work is as follows:(1)The effects of the concentration of PU,LiCl and FPU on the performance of the fiber membrane were investigated by means of solution property analysis,morphology analysis,pore size analysis and contact angle test.Studies have shown that increasing the concentration of PU and LiCl within a certain range can increase the moisture permeability of the fiber membrane,while increasing the concentration of LiCl and FPU can increase the water pressure resistance.The mechanical properties of fiber membranes are affected by the fiber diameter and diameter distribution and present complex changes.Finally,when the solution components are PU 16wt%,FPU 2wt%,LiCl 0.006wt%,the obtained fiber membrane can take into account waterproof moisture and mechanical properties,hydrostatic pressure is 62.25kPa,WVT is 741.3608 g/(m~2·24h),the strength is 147.45cN,the elongation at break is 201.2%,and the breaking strength is 14.8MPa.(2)The combustion process of different fiber membranes was discussed by means of vertical combustion experiment,limit oxygen index test(LOI),simultaneous thermal analysis(TG).The influence of flame retardant concentration and acceptance distance on the comprehensive performance of modified fiber membrane was investigated.Studies have shown that the flame retardant has a great influence on the mechanical properties of the fiber membrane while improving the flame-retardant ability of the fiber membrane;the receiving distance mainly changes the fiber diameter and diameter distribution,and the waterproof and moisture permeability performance is more affected by it.The final formula with the best comprehensive performance is:K522 flame retardant 5wt%,receiving distance 20cm.The obtained flame-retardant breathable waterproof membrane has a hydrostatic pressure of 35.63kPa,a WVT of 1311.26g/(m~2·24h),an elongation at break of 417%,a strength of 67.6cN,a breaking strength of 7.39MPa,and a LOI of 27.8%.The shrinkage rate of heating size is less than 1%,the burning residual carbon rate is 4.6%,and the flame is extinguished when burning.(3)The flame-retardant breathable waterproof membrane and the alkali-free glass fiber net are compounded by ultrasonic hot pressing,and the obtained composite functional membrane is close to the PU functional membrane in all aspects of performance.Its mechanical properties are stronger,reaching 52MPa.The pilot production experiment shows that the production capacity of PU functional film reaches 1300m/8h while maintaining the same performance. |
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