文档介绍：相对温度指数(relative temperature index, RTI):
UL对材料所做的一种长期(6000-20000小时)操作温度测试。
RTI不同于热变型温度(HDT),热变型温度乃是一种短期间于一定压力下的待测体变形的温度。了解塑料的长期使用温度,一般情况下都是看UL黄卡中的RTI值(相对温度指数),也有用CUT值(半生命周期连续使用温度)表示,或者用ARO值(热老化实际工作值)来表示。
RTI, Elec
RTI, Mech w/impact
RTI, Mech, w/o impact
Elec--Electrical表示对于电气特性的;Imp--Impact表示有冲击负荷时的;str表示静态下的;Mech--Mechanical-机械条件下;w/impact-有冲击条件下;W/o Imp--Without Impact-无冲击条件下
UL94测试的第二部分是确定材料的相对温度指数(RTI)。RTI是一个特定温度,材料置于该温度中60,000小时后其特性的原始值降至二分之一。如果未经测试,则该材料采用普通级RTI。RTI 值越高,通常代表该材料等级越高。
Coefficient of Linear Thermal Expansion(CLTE)的定义: Jh]=e+<  
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Like metals, thermoplastic materials expand when heated and contract when cooled. Generally, for a given change in temperature, plastic materials change dimensionally much more than metals. The coefficient of linear thermal expansion, CLTE, is the ratio of the change of a linear dimension to the original dimension of the material for a unit change of temperature. YH6A+~'^  
NO zG2 A  
It is generally given in units of in./in./°F or cm/cm/°C. Table 1 presents typical values for mon materials. This is a very important consideration if dissimilar materials are to be assembled. It should be noted that many thermoplastics, especially those with glass reinforcement or liquid L=2 ^Xq  
crystalline resins, may have different coefficients for the mold flow, cross-flow, and thickness directions. jg,z|