因LDPE、HDPE的流動（dòng）性好（hǎo），加工（gōng）溫度低，粘度大小適中，分（fèn）解溫度低，在惰性氣體中高溫度300℃不分解，所以是一（yī）種加工性能很（hěn）好的（de）塑料。但LLDPE的粘度稍高，需（xū）要增（zēng）加電機功率20%～30%；易發生熔體破裂，需增（zēng）加口模間隙和（hé）加入加工助劑；加（jiā）工（gōng）溫（wēn）度稍高，可達200～215℃。聚乙烯的吸水率低，加工前不需要幹燥處理。

聚乙（yǐ）烯熔體屬於非（fēi）牛頓流體，粘度隨溫度的變化波動較小，而剪切速率的增加下降快，並呈（chéng）線性關係，其中以LLDPE的下降最慢。

聚乙烯製品在冷卻（què）過程中容易結晶，因此，在加工過程中應注意模溫。以控製製品的結晶度（dù），使（shǐ）之具有不（bú）同的性能。聚（jù）乙烯的（de）成型收縮率大，在設計（jì）模具時一定（dìng）要考慮。

Due to the good fluidity of LDPE and HDPE, low processing temperature, moderate viscosity, low decomposition temperature, and high temperature of 300 °C in inert gas do not decompose, it is a plastic with good processing performance.However, the viscosity of LLDPE is slightly higher, and the motor power needs to be increased by 20%~30%; It is easy to melt rupture, and it is necessary to increase the gap between the mouth die and add processing aids,Its processing temperature is slightly higher, up to 200~215 °C.Polyethylene has low water absorption and does not need to be dried before processing.

Polyethylene melt belongs to a non-Newtonian fluid, the viscosity fluctuates less with the change of temperature, while the increase of shear rate decreases quickly and linearly, among which LLDPE decreases the slowest.

Polyethylene products are easy to crystallize during the cooling process, so pay attention to the mold temperature during processing. In order to control the crystallinity of the product, so that it has different properties.The molding shrinkage rate of polyethylene is large, which must be considered when designing the mold.

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