聚合物的基础培训（basictrainingforpolymeric）.ppt

Lesson 13 Ambient temp, uncertainty issue Introduction for FUTI, GTI,RTI, RTC,天马行空官方博客：/tmxk_docin ；QQ:1318241189；QQ群：175569632,*Explanation of thermal indices: In order of how easy it is to apply the thermal indices are: Functional-use Thermal Index (FUTI): Generic thermal index (GTI): Relative thermal index (RTI): Relative Thermal Capability (RTC):,天马行空官方博客：/tmxk_docin ；QQ:1318241189；QQ群：175569632,*Functional use: These temperature limits take into consideration the use of the appliance, meaning how long time it is likely that the appliance is run at this maximum temperature. If this time is shorter the allowed temperature is higher. The assumption made by the standards writers is that a material that can have a normal lifetime at 50 C can be allowed to be run at a higher temperature (say 80 C) if it only running short periods of time during its lifetime. Since commonly used materials all will be able to run continuously at 50 C or more it is not necessary to do investigations into the material properties.,How to understand 50 C or more and material properties? What kind of material properties you not necessary to do the investigation? .FUTI: (短期) .从50度开始。 .根据材料的使用条件(外壳或支持带电部件，长期工作，间隙工作)确定最大极限温度。 .它与所用的材料没有关系(与产品使用条件有关系)。 .材料厚度没有关系。 .如果测出的温升超过FUTI，可以用GTI，RTI，RTC再来评估，不轻易判不合格。 .间隙工作允许温度比长期工作外壳来的高，例: 间隙工作外壳最大温 度为80度，而长期产品的外壳温度是50度。,*Generic thermal index: These temperature limits are based on the chemical properties of the material and is the same approach taken by the IEC standards for temperature limits. Experience show that using these limits materials will retain enough of their properties during the normal lifetime of the appliance. Some materials have higher limits than given using the functional use temperatures this means that advantage can be taken of that their properties are better than may be assumed for unknown materials. .GTI: (短期) .根据材料组成成份(ABS, PC，PBT，PP，尼龙，胶木)来决定的。如 ABS为60度，PP为65度，胶木为150度，PC为80度。 .根据该材料在绝缘系统中和电气设备中的使用性能特点来决定。 .与材料厚度没有关系。 如果温升超过，通过FUTI，RTI，RTC再作评估，不轻易判不合格。,*Relative thermal index (RTI):-Based upon historical record The RTI is tested by measuring the property of interest on the material as new and then do an accelerated aging at elevated temperatures. After the aging the material shall retain 50% of the original property. This requires no knowledge of the appliance category. UL normally list the RTI for electrical properties and mechanical properties (with or without impact). At the temperature of the RTI it is expected that the material will lose some of its properties during the lifetime of the material but will retain enough of the property to be suitable for the application. The reasons the indices are given for different properties are that all properties are not lost at the same rate and temperature (e.g. some materials loose the impact strength faster that the other properties). Temperature rating for electrical properties, mechanical properties or specified property Life time: 20 years; The properties retain 50%.,.RTI: .与长期特性有关。 .RTI与相关特性如厚度，颜色等有关。 . 一个厚度或一个颜色相对应于一个RTI指数 。 .温度超过RTI，用FUTI或RTC用来评估，不轻易判不合格。 .长期评估材料特性，一般为20年。 .保证相对应特性的50(整个产品寿命周期内)。,*Relative Thermal Capability: This could be tested by measuring the property of interest after the aging on a sample representing the actual appliance and in the actual thickness. A sample may comply if it did not loose the property too fast OR of it had a surplus of this property to start with. The test value (dielectric strength, impact energy or other) would be reduced corresponding to 50%. Long time degradation of a specific property,RTC: (长期特性) .在最大操作温度情况下，该材料在产品使用寿命内整个过程中， 保证材料的关键特性(RTC主要是针对成品)。 .RTC表明一种能力：就是说，当温度超过RTI时，还能保证特定 的机械和电的性能，包括短期和长期的特性，不影响它的功能。 .RTI与材料特性厚度是一一对应的。例如：不同的厚度对应不同的 RTI，如果考虑该材料某关键特性和规定最小厚度，也就是说在最 小厚度情况下，保证某关键特性的RTI就可以认为RTC。 .因为通常材料做成成品，某些机械特性(如冲击)设计上是有余量，牺牲一些冲击特性，可提高使用温度，所以RTC温度可能会超过RTI温度。 .不能随意评估而且这个产品评估结果不能照搬到别的产品上。 评估时注意RTC是属于长期特性，短期特性也要满足要求。,E.g:,E.g:,4. Fire test: Parts of non-metallic material shall be resistant to ignition and spread of fire according to the test above. We do the fire test to check the material property to retard the flame. What is polymeric material? A compound formed by chemical reaction that result in large molecules whose molecular weight is a multiple of that of the original substance(monomer). Includes the thermoplastic, thermoset, elastomeric materials. Thermoplastic 热塑料 easily softened and re-softened by heating加热后易于成型 Thermosetting 热固性(Shaft in motor) Cures by chemical reaction and cannot be re-softened 固化成型时有化学反应发生，不能重新成型 Elastomer 弹性材料 Stretch 2 times at room temperature and regain shape 在室温时,能拉伸2倍多长,并能恢复成原形,Functional parts 功能部件 1)Enclosures, Barriers 外壳，挡板 2)Support of live parts 支持带电部件 *3)Support of connections 固定联接 4) Insulation(supplementary or reinforced)绝缘(附加绝缘或加强绝缘) Non Functional parts: Decorative parts like trims, knobs, other parts not likely ignited,Standard introduction and flammability rate of the polymeric: UL 94: Standard for the tests for flammability of plastic materials for parts in devices and appliance, covers flammability of polymeric materials used for parts in devices and appliances. (5V; 94V-0, 94V-1, 94V-2; HB; HBF, HF-1,HF-2. etc ) V: vertical; H: horizontal. 5V: 500W (125mm flame) vertical burning test. ( I think it is same as IEC707) V-0, V-1, V-2: 20mm vertical burning test. (Same as IEC707) HB: Horizontal burning test. (IEC 707 test method is same) HBF, HF-1, HF-2: Horizontal burning foamed material test. (Test method is same as IEC 707),UL 746A: Polymeric materials - short term property evaluations. (key words: short term, brand new sample) UL 746B: Polymeric materials - long term property evaluations. (key words: long term, ageing, 20 years or something) UL 746C: Polymeric materials - Use in specific applications in end products. ( key words: specific application, end products) For “application and end products”, you must consider both the short term and the long term.,C) HWI and HAI are often used in UL standard.(UL 746A or C) HWI and HAI are for the specimen sample and for end use products. UL yellow card of material is usually for the specimen material not for the end use products. HWI test method is for the determination of resistance to ignition of plastic materials by an electrically heated wire. PLC: Performance Level Category PLC =0 is the best and PLC= 5 is the worst. PLC =5 means that within 7 s, it will ignition the material.,HAI(High current arc i