hfc-245fa型环保聚氨酯组合聚醚的开发(编辑修改稿)

hfc-245fa型环保聚氨酯组合聚醚的开发(编辑修改稿)内容摘要：

resulting being widely used as spray accelerant, blowing agent, refrigeration and scour etc. Especially, CFC11 has been regarded as an optimal blowing agent in PURF for a long period. Unfortunately, just the extremely important stability results in CFCs can exist chronically in the air. As the chlorine element in CFCs can react with ozone, a mass of production and use of CFCs will deplete the Earth39。 s ozone layer and destroy the global entironment. The deposition and destruction mechanism of CFCs is as follows: CFCl3 Cl＋ CFCl2 Cl＋ O3 ClO＋ O2 ClO＋ O3 Cl＋ 2O2 Since the fourth meeting on protection the Earth’s ozone layer in Copenhagen in 1992, the research on CFCs replacement technology has been developed in the global. With the prohibition date of CFCs drawing near, CFC11 will be prohibited in PURF as a blowing agent. PURF is the primary consumption of CFC11, so it is especially important to develop nofluorine replacement research in the production of PURF. The perfect replacements of CFCs should have the following characteristics: (1) noninflammable, nonexplosive。 (2) low toxic, noncancerogenic, nonharmful。 (3) good chemical stability, processable。 (4) low vapor thermal conductivity。 (5) green and environmental. In industry production, there are four projects in CFC11 replacement as follows: (1) 50% CFC11 replacement。 (2) HCFC141b replacement。 (3) Cyclopentane (or cyclopentane/ isopentane) replacement。 (4) CO2 replacement (allwaterblown). Project 1 will be abolished with fully prohibition of CFC11。 Project 2 can only be a transitional project for its nonzero ODP (=)。 Project 3 has got favour in some developed countries for its zero ODP, but flammability and explosivity of CP 2020 中国聚氨酯行业整体淘汰 ODS 国际论坛论文集 324 limits its popularization。 Project 4 is a relatively economic and environmental replacement project and develops rapidly in the last two years. But the high thermal conductivity of CO2 limits its application area and it is only widely used in thermal insulation pipes. HFC245fa（ 1,1,1,3,3pentaflurine propane） is honored as the most promising new type environmental blowing agent for its marked properties, such as zero ODP, low GWP, nonflammability, nontoxicity, no significant change to equipments, etc. Now HFC245fa has been semiindustrialization and the application experiments have gained significant breakthrough. 2. CHARACTERISTICS Physical and Chemical Characteristics of HFC245fa HFC245fa is a liquid hydrocarbon fluoride with the following characteristics: colorless, clear, higher density (than water), lower boiling point, higher vapor pressure, higher vapor thermal conductivity (than CFC11). As the molecular weight of HFC245fa is adjacent to CFC11’s, the dosage in polyether is also adjacent, and solubility of HFC245fa in polyether polyols is preferable in sum. Physical characteristics of HFC245fa and CFC11 are listed in Table 1: Table 1. Contrast on Physical Characteristics between HFC245fa and CFC11 Physical Characteristics HFC245fa CFC11 Molecular Formula CF3CH2CHF2 CFCl3 Molecular Weight Boiling Point / ℃ Density（ 20℃） /gmL1 Vapor Pressure（ 20℃） / kPa Vapor Thermal Conductivity/ m W(mK)1 HFC245fa has no kindling point, no flash point, and no flame limits, indicating that it will not burn or blast in the air. Now most PURF foaming equipments can deal with nonflammable or middleflammable liquid blowing agent, so existing foaming equipments require little modification. HFC245fa has no corruption to refrigerator inner materials (ABS Board and HIPS Board), therefore, the inner materials also need no modification. Environmental Characteristics of HFC245fa HFC245 is a matter with ODP=0 and GWP= (CFC11: GWP=). Through examining synthetically the direct greenhouse effect of blowing agent/ cryogen and the indirect greenhouse effect of energy consumption, we can find the both TEWI are parative between HFC245fa and CP. HFC245fa is a nonvolatility anic pound and the existing time of its volatile gas is much shorter than CFC11’s. Toxicity research indicates that toxicity of HFC245fa is equivalent to (or even lower than) HFC141b’s, which mainly showed in lo。