PP-R is an atactic polypropylene modified by ethylene based on copolymerization PP. The molecular weight of random PP is only tens of thousands of ***, ***all cohesion, low melting point and poor mechanical properties. Only the random PP modified by ethylene has practical application value. The modification process is to vaporized propylene into a reactor by gas phase method, and use gas lock system to send material from DI reactor to second reaction kettle and add ethylene in the second reaction kettle. The high activity and high selectivity propylene catalyst, added to the upper part of the reactor, is evenly dispersed into the powder layer by mixing, and the random copolymer is formed by controlling the proportion of ethylene to propylene. The polymer changed the configuration of PP chain and made ethylene polymerize randomly and evenly on the molecular chain of PP.
与普通PP相比，PP-R材料的耐应力开裂性极大，在温度和内外压力作用下，其性能衰减非常，是目前用作生产输送冷热水管的***为的材料之一。
Compared with the ordinary PP, the stress cracking resistance of the PP-R material is greatly improved. Under the action of temperature and internal and external pressure, its performance attenuation is very slow. It is one of the ideal materials used to produce *** for the production and transportation of cold and hot water pipes.
PA66 （聚酰胺66或尼龙66），同PA6相比，PA66更广泛应用于汽车工业、仪器壳体以及其它需要有抗冲击性和度要求的产品。聚酰胺树脂，英文名称为polyamide，简称PA。俗称尼龙(Nylon)，它是大分子主链重复单元中含有酰胺基团的高聚物的总称。为五大工程塑料中产量***大、品种***多、用途***广的品种。尼龙中的主要品种是尼龙6和尼龙66，占jue对主导地位， PA66美国杜邦YTFR50 BK505PPˉ6827MZˉPPSE-16674BˉPC/PC-115PCˉML-4104ZHP PP李长荣667APA66ˉ13G25PBT TV4260SPPˉ371NDˉPC/PBT 553 PC 出光 URC9010TPUˉ1185AWMPBT LW9320PP EP300RTPE/HX-093ABPP 4142TPOM/FV-30A/ PP惠州南亚3317 FNC1PC/ABSHAC8245PC/ABS380 PA6瑞士EMS BGZ-30/2 BKEVA/2842APC/DX13320C【
PA6的化学物理特性和PA66很相似，然而，它的熔点较低，而且工艺温度范围很宽。它的抗冲击性和抗溶解性比PA66要好，但吸湿性也更强。因为塑件的许多品质特性都要受到吸湿性的影响，因此使用PA6设计产品时要充分考虑这一点。为了PA6的机械特性，经常加入各种各样的改性剂。玻璃纤维就是***常见的添加剂，有时为了抗冲击性还加入合成橡胶，如EPDM和R等。对于没有添加剂的产品，PA6的收缩1%到1.5%之间。加入玻璃纤维添加剂可以使收缩率到0.3%（但和流程相垂直的方向还要稍高一些）。成型组装的收缩率主要受材料的结晶度和吸湿性影响。实际的收缩率还和塑件设计、壁厚及其它工艺参数成函数关系。
The physical and chemical properties of PA6 are similar to those of PA66. However, its melting point is low and the temperature range of the process is very wide. Its impact resistance and solubility are better than that of PA66, but its hygroscopicity is stronger. Because many quality characteristics of plastic parts are affected by hygroscopicity, we should give full c***ideration to this when using PA6 to design products. In order to improve the mechanical properties of PA6, various modifiers are often added. Glass fiber is a common additive for ***. Sometimes synthetic rubber, such as EPDM and R, is added in order to improve its impact resistance. For products without additives, PA6 shrinks between 1% and 1.5%. Adding glass fiber additives can reduce the shrinkage rate to 0.3% (but slightly higher in the direction perpendicular to the process). The shrinkage of molding and assembly is mainly affected by the crystallinity and moisture absorption of the material. The actual shrinkage rate is also related to plastic design, wall thickness and other process