HFC-245fa型环保聚氨酯组合聚醚的开发

HFC-245fa型环保聚氨酯组合聚醚的开发 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 HFC-245fa 1211芮敬功 胡锋 孔新平 蔡达红 (1．南京红宝丽股份有限公司 江苏高淳211300) (2．广东科龙电器股份有限有限公司 广东顺德) ：HFC-245fa具有ODP＝0、GWP值低等优点，是一种被誉为下一代中最有希望的新型环保 聚氨酯发泡剂。通过合成新型聚醚多元醇及对配方的优化试验，解决了HFC-245fa聚氨酯硬质泡沫塑料导热系数高、表面发酥等难题，研制开发的H-Y61系列组合聚醚各项性能均达到或接近CFC-11型同类产品水平。 ：聚氨酯；硬质泡沫塑料；发泡剂；CFC替代 1 聚氨酯硬质泡沫塑料（以下简称聚氨酯硬泡）是一种性能优越的高分子合成材料，具有密度小、强 度高、导热系数低、粘接强度大等特点，是目前公认的最佳绝热保温材料，已广泛应用于冰箱、冰柜、 冷藏集装箱及建筑、交通运输、石油化工管道、军用航空等诸方面。于上世纪二十年代末发展起来的CFC化合物在许多方面有着显著特性，如不可燃、无毒、有适宜的沸点、较低的气体导热系数及非常稳定的 化学性质，被广泛用做喷雾推进剂、发泡剂、制冷剂及清洗剂等，其中CFC-11长期以来一直被视为聚氨酯硬泡的最佳发泡剂。但不幸的是，正是由于CFC化合物这一极其重要的稳定性，使其能够在大气中长 期存在，透过大气对流层，到达大气臭氧层。并且由于CFC化合物中的氯元素能与臭氧发生反应，大量 CFC化合物的生产和使用，将导致大气臭氧层的减少，破坏地球生态环境。CFC分解破坏臭氧层的过程是： CFCl Cl＋CFCl 32 Cl＋O ClO＋O 32 ClO＋O Cl＋2O 32 自从1992年哥本哈根第四次保护臭氧层议定书缔约国大会决议以来，世界各国都开展了CFC替代技术的研究。发达国家已经禁用CFC物质，发展中国家也即将禁用CFC物质；聚氨酯硬质泡沫塑料是CFC-11的主要消耗领域，因此在聚氨酯硬质泡沫塑料的生产过程中，进行无氟替代工作就显得尤为重要。 理想的替代发泡剂应具备以下的特性： （1）不易燃易爆，便于生产、贮运及使用； （2）低毒性、不致癌，对人无伤害； （3）化学稳定性好，便于加工操作； （4）气相导热系数低； （5）对环境无影响，是绿色环保产品。 在工业生产中，CFC-11的替代主要有以下四种方案，（1）50%CFC-11替代方案。（2）以HCFC-141b替代CFC-11方案；（3）环戊烷（包括环/异戊烷）替代CFC-11方案。（4）以CO（即全水发泡）替代2CFC-11方案。第一种方案随着CFC-11的全面禁用即将被废止；第二种方案因HCFC-141b臭氧消耗潜值不为零（ODP＝0.11）等因素，决定了它只能作为CFC-11的过渡性替代物；第三种环戊烷替代方案，因 其对大气臭氧层无破坏作用(ODP＝0)等原因，而受到一些经济发达国家的青睐，但其易燃、易爆等因素 限制了它的推广应用。第四种方案是一种较为经济和环保的替代方案，近二年的发展极其迅速，但由于 其导热系数较高，从而限制了其应用范围，一般只用于管道保温等领域。 HFC-245fa（1,1,1,3,3-五氟丙烷）具有ODP＝0、GWP值低、不燃、无毒等特点，且不需对现有发泡 设备进行较大改动即可使用，被视为最有前途的新一代环保型聚氨酯发泡剂，目前该产品已处于半工业 化生产。各类应用试验已取得重要突破。 318 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 2 HFC-245fa 2.1 HFC-245fa HFC-245fa是液体碳氢氟化物，它无色透明，比重大于水，具有较低的沸点和较高的蒸气压，蒸气 导热系数高于CFC-11。HFC-245fa分子量与CFC-11分子量相近，在组合聚醚中的用量与CFC-11相当， HFC-245fa在聚醚多元醇中的溶解性总体来说是不错的。现将HFC-245fa与CFC-11的有关物理特性列于表1。 1 HFC-245faCFC-11 HFC-245fa CFC-11 物理特性 CF分子式 CHCHF CFCl 3223 134.0 137.4 分子量 15.3 23.8 沸点/? -1密度(20?)/ g?mL1.32 1.49 122.8 88.3 蒸气压(20?)/ kPa －1气体热导率/ mW?(m?K)11.6 7.7 HFC-245fa没有着火点和闪点，没有燃烧极限，在空气中不能形成燃烧和爆炸。目前大多数聚氨酯 硬泡发泡设备都可以处理不燃和中等可燃性液体发泡剂，因此现有发泡设备只需稍加改动即可安全使用。 HFC-245fa对冰箱内衬材料ABS板和HIPS板均无腐蚀作用，因此在使用HFC-245fa作发泡剂时，无需对冰箱内胆材料进行改性。 2.2 HFC-245fa HFC-245fa是一种零臭氧消耗物质（ODP＝0），对大气臭氧层无破坏作用；它的温室效应值仅为 CFC-11的20%（GWP＝0.2）。通过对发泡剂产生的直接温室效应、致冷剂所产生的直接温室效应、能源 消耗产生的间接温室效应的综合考查，可以发现在冰箱保温材料中使用的HFC-245fa所产生的地球综合变暖值（TEWI）与环戊烷相当。HFC-245fa属于非挥发性有机化合物；挥发气体在大气层中的存在年限 远低于CFC-11。毒性研究表明，HFC-245fa实际毒性与HCFC-141b相当，甚至更低，其主要表现为快速致毒性低、不影响发育、无诱发因素等方面。现将HFC-245fa与CFC-11的环保特性列于表2 2 HFC-245faCFC-11 HFC-245fa CFC-11 环保特性 ODP 0 1.0 GWP 0.2 1.0 可挥发性低层污染 无 无 8.4 50 大气层中寿命（年） 3 3.1 聚醚多元醇HBL06 羟值420?20mgKOH/g，自制； 聚酯多元醇HBL16 平均分子量为1000，自制； 六氢化三嗪 试剂级，美国气体产品公司； 二甲基环已胺 工业级，美国气体产品公司； 泡沫稳定剂CXW03 工业级，自制； 发泡剂HFC-245fa 纯度?99.5%，美国Honeywell (原AlliedSignal)公司； 异氰酸酯PAPI 工业级，美国亨斯迈公司。 3.2 电动搅拌桨 JJ-1型，常州国华有限公司； 天平 常熟衡器厂； 温度计 常州市新区苏南仪表厂； 319 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 高压发泡机 A System 100型，意大利Cannon公司； 万能试验机 SPL-10KN型，日本岛津公司； 环境试验箱 Hygros 250型，意大利ACS公司。 3.3 3.3.1 实验方法：将合成的聚醚多元醇、泡沫稳定剂、催化剂、发泡剂等按确定比例混合均匀制成H-Y61，控制好H-Y61与异氰酸酯的料温及模具温度，按配方称取H-Y61与异氰酸酯，混合后在电搅拌器上搅拌 10秒，随后倒入模具中，使其发泡。待泡沫熟化彻底后测定其性能。 3.3.2 泡沫性能按国家 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 方法测试，力学性能采用SPL-10KN型万能试验机测试、尺寸稳定性采用 HYGROS250型环境试验箱来测定。 4 4.1 导热系数是衡量聚氨酯硬泡绝热保温性能的重要指标，它直接影响着冰箱、板材等制成品的保温效 果和能耗。聚氨酯硬泡热量的传递有三种途径，第一种是由气体进行的，约占总量的50%，第二种是由聚氨酯基体进行的，约占总量的20%；第三种是由辐射传递的，约占总量的30%。与CFC-11蒸汽导热系数7.7 mW/(m?K)相比，HFC-245fa具有较高的蒸气导热系数，从而导致泡沫塑料总体导热系数变大。 由辐射传递的那部分热量，可通过降低泡沫塑料辐射因子的方式加以减少，从而达到降低泡沫塑料 总体导热系数的目的。辐射因子对泡沫泡孔有很强的依赖性，如果制成极细而均匀的泡孔，这一因子可 降低至最小。因此，可以通过选择含有特定基团的起始剂合成聚醚多元醇，在聚醚多元醇分子中引入特 定的基团及配方的优化使泡沫结构得到改善。达到泡孔均匀细微化的效果，从而降低其导热系数。我们 在实验中发现胺类起始剂合成的聚醚多元醇，发泡制品泡孔结构优于脂肪族类起始剂合成聚醚多元醇发 泡制品。因此我们选择芳香族多胺等为起始剂，在聚醚多元醇分子结构中引入胺基结构，合成了具有适 宜的官能度（f＝4~5）和羟值（420?20mgKOH/g）的聚醚多元醇HBL06。以其为主体聚醚，通过配方的优化，尤其是泡沫稳定剂的优化选择试验，制得的泡沫导热系数已大为改善，已接近CFC-11型同类产品水平。 4.2 在冰箱、复合板材等产品发泡过程中，泡沫与基材应具有良好的粘接性能，否则会造成脱胶现象， 严重影响产品质量。在实验中我们发现，由于HFC-245fa沸点较低,在发泡反应初期就大量气化,将大量的反应热带走,导致反应初期泡沫中自由异氰酸酯基团含量过高，从而导致泡沫表面发酥发脆,影响了泡沫基材的粘接性能。当合成聚醚多元醇的起始剂和羟值一定时，改善泡沫表面酥脆性及粘接性能的方法通常 是调节聚醚中水的含量。在HFC-245fa发泡体系中，HFC-245fa与水虽都能提供发泡气源，但它们的发 泡原理是不相同的。HFC-245fa是物理发泡剂，发泡过程中吸收反应热气化形成气源。而H O是化学发2 泡剂，它与异氰酸酯反应产生CO，以CO作为发泡气源。实验中我们发现，在泡沫自由发泡芯密度保22 持不变的情况下，无论是水的用量过高还是过低，泡沫的表面都会发酥发脆。这是由于水的用量过高时， 泡沫中水与异氰酸酯反应生成的脲基甲酸酯结构含量就增高，而脲基甲酸酯结构的大量形成将导致泡沫 表面酥脆。而水的含量过低时，HFC-245fa的用量则将大大增加，反应中随着HFC-245fa的气化，大量的反应热将会被带走，导致泡沫中自由异氰酸酯含量增大，影响了泡沫的粘接性能。经过多次的反复试 验，我们将水的含量控制在一个适宜的水平，泡沫表面酥脆性明显改善，粘接性能大为提高。在这个水 平，水与异氰酸酯反应产生的脲基甲酸酯量被控制在一定的范围内，而反应产生的热量又部分弥补了因 HFC-245fa气化而造成的热量不足的问题。 4.3 由于HFC-245fa沸点较低，发泡过程中，发泡料在出发泡机枪头时就已发泡，从而导致发泡料粘度 过大，影响了泡沫在冰箱或板材内的流动。我们在实验中采用复配催化剂，由有机金属盐与六氢化三嗪 320 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 及二甲基环已胺按比例复配而成。在反应的初期，它能有效抑制物理发泡反应的进行，避免因HFC-245fa汽化过快而造成的并泡；在反应中期，它能保持发泡反应与凝胶反应的平衡，从而减缓反应料粘度增加 速度，确保泡沫具有良好的流动性；在反应的后期能有效地促进聚醚多元醇与异氰酸酯的反应及异氰酸 酯自身的三聚化反应，从而达到促进泡沫后固化反应，减少自由异氰酸酯组分含量的目的。 同时，我们对异氰酸酯等原材料也进行了试验筛选。通过以上对原材料的筛选试验，我们研制开发 的H-Y61系列组合聚醚及其发泡制品的各项性能，经中国家用电器研究所检测，均达到了CFC-11型同类产品水平。NAH-Y21是CFC-11型对照产品。 3 H-Y61 NAH-Y21 检测指标 泡沫密度/kg?m－334.6 32.7 -120.2 19.9 导热系数/mW?(m?K) 92 93 闭孔率/% 168.7 169.2 压缩强度/kPa 184.6 188.5 拉伸强度/kPa 204.7 208.5 粘接强度/kPa 3 3 吸水率(V/V)/% 0.75 0.65 高温(100?,48h)尺寸稳定性/% 0.12 0.18 低温(－40?,24h)尺寸稳定性/% 5 通过对聚醚多元醇、催化剂、泡沫稳定剂等多种原材料的筛选试验及配方的优化，研制开发的H-Y61系列组合聚醚的各项参数及其发泡制品的泡沫性能均已达到或接近CFC-11型同类产品水平。通过小规模的应用试验证明，H-Y61系列产品能满足实际生产需要,可以在我国的聚氨酯行业中推广使用。 1 Alliedsignal公司. HFC-245fa产品说明书.1997年 2 Doerge H P. New Developments in HFC-245fa Appliance foam. In: Polyurethanes World Congress’97. 1997. Bayer Corporatinon 3 Tsukida N, Sato H, Aoyagi M, et al. New Polyols and Formulations for Energy-Saving Insulation Using Hfc-245fa As Blowing Agent. In: Polyurethanes World Congress'97.1997. Asahi Glass Co. Ltd 4 于文杰. HCFC-141b冰箱用聚醚的应用研究.见：中国聚氨酯工业协会第八次年会论文集. 北京.1996.86 5 刘贤明,王彤. HFC-245fa发泡剂. 聚氨酯工业,1998,(2):5 6 李绍雄,朱吕民. 聚氨酯树脂. 南京:江苏科学技术出版社,1993.199 7 宋建国,张庆伟,孔新平. 氟里昂(CFC)发泡剂替代技术的最新进展. 化工新型材料,2002,(8):20 8 凯文?F?曼斯菲尔德,刘益基. 用新发泡剂生产硬质聚氨酯泡沫塑料时所用的新型添加剂.见：第二届 聚氨酯中国'98国际会议论文集. 北京.1998.130 The Development of HFC-245fa Polyurethane Foam System 1211Rui Jinggong Hu Feng Kong Xinping Cai Dahong (1．Nanjing Hongbaoli Co.Ltd, Jiangsu Gaochun211300) (2．Guangdong Kelon Electrical Holding Co. Ltd, Guangdong Shunde 528303) Abstract: features with zero ODP and lower GWP etc, which is deemed as the most prospective & environmental-friendly polyurethane blowing agent among those of the next generation. Through conduct of optimizing test of new polyether polyol & its starting formulations, the problems of higher thermal conductivity, surface brittleness of the rigid polyurethane foam are consequently resolved. All properties of new designed H-Y61 series blended polyols obtain or approach that of the similar products blown by CFC-11. 321 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 Keywords: polyurethane; rigid foam; blowing agent; CFC substitution ： 男，1944年10月生，中共党员，东南大学系统工程专业企业管理方向研究 生班、澳门科技大学工商管理研究生班毕业，双硕士学位，高级经济师。现任红宝丽 集团总裁，南京红宝丽股份有限公司董事长兼总经理。 322 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 Development on Environmental PU Polyether Blend Using HFC-245fa as the Blowing Agent [1][2][1][1]Ring Jinggong Hu Feng kong Xinping Cai Dahong (1. Nanjing Hongbaoli Co., Ltd., 211300) (2. Guangdong Kelong Co., Ltd.) ABSTRACT HFC-245fa is honored as the most promising new type environmental blowing agent for its zero ODP and low GWP. By synthesizing new type polyether polyols and optimizing formulations, we have solved the problems such as thermal conductivity too high, foam surface too crisp and so on. Properties of polyether blend H-Y61 have reached (or approached) the same level comparing with CFC-11 foams. Keywords: polyurethane; rigid foam; blowing agent; CFC replacement 1. INTRODUCTION Polyurethane rigid foam (PURF) is a type of organic synthetical material with predominant performances, including low density, high intensity, low thermal conductivity, high adhesive performance and so on. It is accepted as the optimal thermal insulation material and has been widely used in refrigerator, refrigerated cabinet, construction, traffic, petrochemical pipes and martial voyage etc. CFCs, developed in the end of 20th, have many marked properties, such as non-flammability, non-toxicity, suitable boiling point, low thermal conductivity and super steady chemical properties, resulting being widely used as spray accelerant, blowing agent, refrigeration and scour etc. Especially, CFC-11 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 Earth's ozone layer and destroy the global entironment. The decomposition and destruction mechanism of CFCs is as follows: CFCl Cl＋CFCl 32 Cl＋O ClO＋O 32 ClO＋O Cl＋2O 32 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, CFC-11 will be prohibited in PURF as a blowing agent. PURF is the primary consumption of CFC-11, so it is especially important to develop no-fluorine replacement research in the production of PURF. The perfect replacements of CFCs should have the following characteristics: (1) noninflammable, non-explosive; (2) low- toxic, non-cancerogenic, non-harmful; (3) good chemical stability, processable; (4) low vapor thermal conductivity; (5) green and environmental. In industry production, there are four projects in CFC-11 replacement as follows: (1) 50% CFC-11 replacement; (2) HCFC-141b replacement; (3) Cyclopentane (or cyclopentane/ isopentane) replacement; (4) CO replacement (all-water-blown). 2 Project 1 will be abolished with fully prohibition of CFC-11; Project 2 can only be a transitional project for its nonzero ODP (=0.11); Project 3 has got favour in some developed countries for its zero ODP, but flammability and explosivity of CP 323 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 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 COlimits its application area and it is only widely used in thermal 2 insulation pipes. HFC-245fa（1,1,1,3,3-pentaflurine propane）is honored as the most promising new type environmental blowing agent for its marked properties, such as zero ODP, low GWP, non-flammability, non-toxicity, no significant change to equipments, etc. Now HFC-245fa has been semi-industrialization and the application experiments have gained significant breakthrough. 2. CHARACTERISTICS 2.1 Physical and Chemical Characteristics of HFC-245fa HFC-245fa 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 CFC-11). As the molecular weight of HFC-245fa is adjacent to CFC-11’s, the dosage in polyether is also adjacent, and solubility of HFC-245fa in polyether polyols is preferable in sum. Physical characteristics of HFC-245fa and CFC-11 are listed in Table 1: Table 1. Contrast on Physical Characteristics between HFC-245fa and CFC-11 Physical Characteristics HFC-245fa CFC-11 Molecular Formula CFCHCHF CFCl 3223 Molecular Weight 134.0 137.4 15.3 23.8 Boiling Point / ? -1Density（20?）/g?mL1.32 1.49 122.8 88.3 Vapor Pressure（20?）/ kPa -1Vapor Thermal Conductivity/ m W?(m?K) 11.6 7.7 HFC-245fa 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 non-flammable or middle-flammable liquid blowing agent, so existing foaming equipments require little modification. HFC-245fa has no corruption to refrigerator inner materials (ABS Board and HIPS Board), therefore, the inner materials also need no modification. 2.2 Environmental Characteristics of HFC-245fa HFC-245 is a matter with ODP=0 and GWP=0.2 (CFC-11: GWP=1.0). 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 comparative between HFC-245fa and CP. HFC-245fa is a non-volatility organic compound and the existing time of its volatile gas is much shorter than CFC-11’s. Toxicity research indicates that toxicity of HFC-245fa is equivalent to (or even lower than) HFC-141b’s, which mainly showed in low rapid toxicity, no-influence on growth and no premium etc. Environmental characteristics of HFC-245fa and CFC-11 are listed in Table 2: Table 2. Contrast on Environmental Characteristics between HFC-245fa and CFC-11 Environmental Characteristics HFC-245fa CFC-11 ODP 0 1.0 GWP 0.2 1.0 Volatility Bottom Pollution 无 无 Longevity in the aerosphere (y) 8.4 50 3. EXPERIMENTAL 324 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 3.1 Materials Polyether polyol HBL06, Hydroxyl Value=420?20mgKOH/g, homemade; Polyether polyol HBL06, Average Molecular Weight=1000, homemade; Hexanhydrogentriazine, Reagent Grade, Gas, U.S.A; Dimethylcyclohexanamine, Industrial Grade, Gas, U.S.A; Foam Stability CXW03, Industrial Grade, homemade; Blowing Agent HFC-245fa, Purity?99.5%,Alliedsignal, U.S.A; PAPI, Industrial Grade, ICI, U.S.A 3.2 Apparatus Electric Stirrer, JJ-1, Changzhou Guohua Co., Ltd.; Scale, Changshu Weighting Apparatus Company; Thermometer, Changzhou Sunan Instrument Company; High Pressure Foaming Machine, A SYSTEM 100, Cannon Co., Ltd., Italy; Omnipotent Testing Machine, SPL-10KN, Daojing Co., Ltd., Japan; Environmental Testing Chamber, HYGROS 250, ACS Co., Ltd., Italy 3.3 Experiments 3.3.1 Preparation for PURF Prepare H-Y61 by mixing polyether polyol, stabilizer, catalyst and blowing agent, etc at a certain ratio. Control material temperature of H-Y61/ PAPI and mould temperature. Weight H-Y61 and PAPI according to the formulation, and mix 10 s with an electric stirrer. Then pour the mixture into mould to blow. Measure foam performances after curing completely. 3.3.2 PURF Performance Testing Test foam performances according to the National Standard. Use Omnipotent Testing Machine SPL-10KN to measure mechanic performance. Use Environmental Testing Chamber GROS250 to measure dimension stability. 4. RESULTS AND DISCUSSION 4.1 Improving in Thermal Conductivity Thermal Conductivity is a key index to evaluate thermal insulation performance of PURF, and have direct influence to thermal insulation effect and energy consumption of refrigerator. There are three approaches to transfer heat: (1) transferring by gas, occupying about 50%; (2) transferring by polyurethane, occupying 20%; (3) transferring by radiation, occupying about 30%. Comparing with vapor thermal conductivity of CFC-11 ( 7.17 mW/(m?K) ), vapor thermal conductivity of HFC-245fa is relatively higher, resulting in total thermal conductivity of HFC-245fa increased. Radiant transfer heat can be reduced by decreasing radiation factor, which results in total thermal conductivity decreased. Radiation factor is depended on foam-cells, so it can be decreased to the lowest if even and small foam-cells are developed. Therefore, by choosing initiator containing special groups to synthesize polyether polyol, importing special groups into polyether polyol molecular structure, and optimizing formulation, foam-cell structure can be improved, reducing in thermal conductivity decreased. In the experiment, we find that foam products synthesized with amine initiator are better than products synthesized with aliphatic initiator in foam-cell structure. Therefore, we choose aromatic polyamine as initiator, initiating amido imported into polyether polyol molecular structure, and synthesize polyether polyol HBL06 with suitable functionality (f=4-5) and hydroxyl value (420?20mgKOH/g). By optimizing formulation, especially optimizing stabilizer, thermal conductivity of foam products with HBL06 as the major polyether has been improved significantly, and has 325 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 approached the same level comparing with CFC-11 foams. 4.2 Improving in Adhesive Performance For products such as icebox and composite board etc., excellent adhesive performance between foams and materials is required. Otherwise it would reduce in coming unglued and badly affect products quality. In the experiment, we find that HFC-245fa gasifies in the initial reaction period for its low boiling point and takes much of the released heat, reducing in free isocyanate content too high and foam surface too crisp, correspondingly, foam adhesive performance decreased. When stabilizer and hydroxyl value are fixed, the common way to improve brittleness and adhesive performance is changing water content in polyethers. In HFC-245fa blown system, the foaming theories are different between HFC-245fa and HO, although they both 2 can provide foaming gas. HFC-245fa is a physical blowing agent and provides gas through gasification, whiling HO is a chemical blowing agent and provides gas (CO) through reacting with isocyanate In the 22. experiment, we find that foam surface will become crisp whether water dosage is too high or not as the free rise density fixed. This can be explained as follows: when water dosage is too high, urethane (the reaction product of water and isocyanate) content will increase, inducing in foam surface being crisp; when water dosage is too low, HFC-245fa dosage will increase, much heat will be taken away with gasification of HFC-245, inducing in free isocyanate content increasing, which affects foam adhesive performance. Through a lot of experiments, brittleness of foam surface and adhesive performance has been greatly improved by controlling water content in a suitable level. At this level, urethane content is controlled in a certain range, and the released heat also partly makes up the heat comsumption of HFC-245fa gasification. 4.3 Improving in Foaming Processing As boiling point of HFC-245fa is relatively low, blend compositions have blown in the mixing head, reducing in too high viscosity, which affects foam flowing in iceboxes or boards. In the experiment, we choose a co-catalyst mixed at a certain ratio with organic metal salt, hexanhydrogentriazine and dimethylcyclohexanamine. In the first reactive period, this co-catalyst can efficiently restrain physical foaming and avoid foam combining due to fast gasification of HFC-245fa; in the middle period, it can hold the balance between foaming and gelling, resulting in the increasing speed of blend viscosity decreased and enduing foam good flowability; in the last period, it can effectively promote the reaction between polyether polyol and isocyanate and the tripolymerization of isocyanate, resulting in curing reaction promoted and free isocyanate content decreased. At the same time, raw materials such as PAPI have been filtrated in the experiment. By the filtration of raw materials, we develop polyether blend H-Y61. Tested by Chinese Electricity Research Institution, parameters of polyether blend H-Y61 and performances of foam products have reached the same level comparing with CFC-11 foams. Table 3. Contrast on Examine Indexes between H-Y61and NAH-Y21 Specification H-Y61 NAH-Y21 Foam Density /kg?m －334.6 32.7 -120.2 19.9 Thermal Conductivity /mW?(m?K) Closed Cells /% 92 93 Compressive Strength/kPa 168.7 169.2 Elongation Strength/kPa 184.6 188.5 Clinging Strength/kPa 204.7 208.5 Water Absorptivity (V/V)/% 3 3 0.75 0.65 High-temperature Dimensional Stability(100?,48h) /% 0.12 0.18 Low-temperature Dimensional Stability(－40?,24h)/% 5. CONCLUSIONS Through filtration of polyether polyols, catalyst, stabilizer etc. and optimizing formulation, parameters of 326 2003中国聚氨酯行业整体淘汰ODS国际论坛论文集 polyether blend H-Y61 and performances of foam products have reached (or approached) the same levels comparing with CFC-11 foams. By the application tests in miniature, we have proved that polyether blend H-Y61 can satisfy procreative needs and can be popularized in Chinese PU industry. 6. PREFERENCES 1. Production Explanation of HFC-245fa, Alliedsignal Co., 1997. 2. Doerge H P., New Developments in HFC-245fa Appliance Foam, In: Polyurethanes World Congress'97, Bayer Co., 1997. 3. Tsukida N, Sato H, Aoyagi M, et al. New Polyols and Formulations for Energy-Saving Insulation Using HFC-245fa As Blowing Agent, In: Polyurethanes World Congress'97, Asahi Glass Co. Ltd., 1997. 4. Yu Wenjie, Application Research on HCFC-141b, In： Proceedings of the Fourth Congress of Chinese Polyurethane, Beijing, 1996.86. 5. Liu Xianming, Wang Dan, Blowing Agent?HFC-245fa, Polyurethane Industry, 1998, (2): 5. 6. Li Shaoxiaong, Zhu yuming, Polyurethane Resin, Jiangsu Technology Publishing Company, Nanjing, 1993.199. 7. Song Jianguo, Zhang Qingwei, Kong Xinping, The Latest Development in CFC Replacement Technology, Chemical New materials, 2002, (8): 20. 8. Kawen?F?Mansferid, Liu Yiji, New Additive Used in PURF with New BlowingAgent, Proceedings of the Second Congress of Chinese Polyurethane, Beijing, 1998.130. 327