超细纤维合成革用阻燃水性聚氨酯的制备及其性能

Preparation and characterization of waterborne flame retardant polyurethane for microfiber synthetic leather

针对超细纤维合成革用聚氨酯涂层易燃、强度低、韧性不足等问题,自制了一种含磷双元醇反应型阻燃剂(DHIMP),并将其作为扩链剂与二苯基甲烷二异氰酸酯、聚四氢呋喃醚二醇、2,2-二羟甲基丁酸共聚得到分散性、稳定性良好的阻燃水性聚氨酯(P-WPU)。将P-WPU制成涂层浆料并通过双面刮涂—交换凝固—烘干等制备工艺,最终在超细纤维合成革表面构建柔软强韧的聚氨酯涂层。通过傅里叶红外光谱和核磁共振氢谱分析了DHIMP的分子结构,对比表征了DHIMP对P-WPU乳液的粒径、力学性能以及超细纤维合成革阻燃性能的影响。结果表明:DHIMP不仅提高了P-WPU涂层的阻燃性,同时也提高了其弹性模量、断裂强度、断裂伸长率;当DHIMP质量分数为11.7%时,超细纤维合成革的综合性能最佳,其断裂强度为29.04 MPa,断裂伸长率达795.40%;当DHIMP质量分数为16.1%时,阻燃超细纤维合成革的阻燃性能最佳,极限氧指数达28.6%,熔滴数量为0~1,具有良好的阻燃效果。

Objective In order to solve the problems of non-flame retardancy,low strength and lack of toughness of polyurethane coating on microfiber synthetic leather,type of phosphate-containing bialcohols as reactive flame retardants were prepared.It was copolymerized with methylene diphenyl diisocyanate(MDI),polytetramethylene ether glycol(PTMEG)and 2,2-dimethylol butyric acid(DMBA)to prepare water borne flame retardant polyurethane(WPU)with good dispersion,stability and performance,which is used for coating microfiber synthetic leather.Method A reactive flame retardant containing phosphorus was synthesized.It was characterized by Fourier transform infrared spectrometer(FT-IR)and nuclear magnetic resonance spectroscopy(1H NMR).Then,DHIMP was copolymerized with MDI,PTMEG and DMBA to obtain waterborne flame retardant polyurethane(P-WPU).P-WPU was prepared into coating slurry,and the soft and strong polyurethane coating was constructed on the surface of microfiber synthetic leather by double-side scraping,exchange curing and drying.Results The water dispersion of P-WPU was good.The particle size of the dispersion increased with the increase of DHIMP mass fraction.With the introduction of DHIMP,the Young's modulus of P-WPU film was gradually increased.When the mass fraction of DHIMP was 13.9%,the mechanical properties of P-WPU reached the best.The LOI of microfiber leather was continuously increasing with the gradual increase of DHIMP mass fraction.The results of vertical combustion test illustrated that the microfiber leather coated by P-WPU with different DHIMP mass fractions had a certain degree of flame retardancy.When the mass fraction of DHIMP was 16.1%,the vertical damage length was 2.3 cm,the continuous burning time was 0.6 s,the smoldering time was 0.3 s,the number of droplets was reduced to 0-1,and the absorbent cotton was not ignited,demonstrating a good flame-retardant effect.Conclusion 1)DHIMP was successfully prepared from p-hydroxybenzaldehyde,3-amino-propanol and DOPO.2)By introducing DHIMP as chain extender into waterborne polyurethane macromolecules,waterborne polyurethane with flame retardancy was successfully prepared.3)The flexible and flame-retardant microfiber synthetic leather was prepared with P-WPU coating.The maximum limiting oxygen index was 28.6%,the vertical damage length was 2.3 cm,the follow-fire time was 0.6 s,and the smoldering time was 0.3 s.