因（yīn）LDPE、HDPE的流動性好，加（jiā）工溫度低，粘度大小適中（zhōng），分解溫度低，在惰性氣體中高溫度300℃不分解，所（suǒ）以是一種加工性（xìng）能（néng）很好的塑料（liào）。但LLDPE的粘度稍（shāo）高（gāo），需要增加電機功率20%～30%；易發生熔體破裂，需增加口模間隙和加入加工助劑；加工溫度稍高，可達（dá）200～215℃。聚乙烯的吸水率低，加工前不需要幹燥處（chù）理。

聚乙烯熔體屬於非牛頓流體，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（yǐ）控（kòng）製製品的結晶度，使之具有不同的（de）性能。聚乙（yǐ）烯的成型收（shōu）縮率大，在設計（jì）模具時一定要考慮。

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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