摩擦和润滑是事物矛盾的两个方面.在塑料的成型加工中,有两种摩擦是极为不利的,即聚合物加热熔融时聚合物分子之间的内摩擦以及聚合物熔体与加工机械表面的外摩擦.这些摩擦作用使熔体的流动性降低,不利于加工效率的提高.严重的摩擦会使制品表面粗糙.缺乏光泽或形成流纹.润滑剂可根据作用机理分为外部润滑剂和内部润滑剂两类. 外部润滑是一种界面润滑,与聚合物的相容性小,加工中容易从聚合物内部析出,由于润滑剂分子间的内聚能低,因此可以降低聚合物与设备表面的摩擦力,防止其粘附于机械表面,这种作用称为外部润滑作用.如氧化聚乙烯蜡.硬脂酸铅等.内部润滑剂与聚合物相容性好,但在高温下相容性增大,产生增塑作用,消弱内聚力,减小内摩擦,使熔体粘度降低,流动性增加,这种作用称为内部润滑作用.如聚乙烯蜡.ACR等.

Friction and lubrication are two aspects of the contradiction of things. In the molding process of plastics, two kinds of friction are extremely unfavorable, that is, internal friction between polymer molecules when the polymer is heated and melted and the external friction between the polymer melt and the machined surface. These frictions reduce the fluidity of the melt, which is not conducive to the improvement of the processing efficiency. Serious friction makes the surface of the product rough, lacking luster or forming a flow pattern. Lubricants can be divided into two types, external lubricants and internal lubricants based on the mechanism of action. External lubrication is a kind of interface lubrication, which is small in compatibility with the polymer. In the process of processing, it is easy to precipitate from the interior of the polymer. As the cohesive energy between the lubricants is low, the friction between the polymer and the surface of the equipment can be reduced to prevent it from adhering to the mechanical surface. This effect is called the external lubrication, such as oxidized polyethylene wax, lead stearate and so on. The internal lubricant has good compatibility with the polymer, but at high temperature. Increase in capacity, produce plasticizing, weaken internal cohesion, reduce internal friction, reduce melt viscosity and increase fluidity, this effect is called internal lubrication, such as polyethylene wax.ACR and so on.

外润滑和内润滑都是相对的,大多数品种兼具两种润滑作用,同一种润滑剂在不同的聚合物中或不同的加工条件下会表现出不同的润滑作用.

Both external and internal lubrication are relative, and most varieties have two kinds of lubrication, and the same lubricant will show different lubrication in different polymers or different processing conditions.

理想的润滑剂应满足以下要求:1.润滑效能高而持久2.与树脂的相容性适中,内外润滑平衡,不喷霜.不结垢.3.表面张力小,粘度小,扩展性好,易形成界面层.4.不降低聚合物的力学强度.热变形温度.耐候性.透明性和电性能,不影响塑料的二次加工性能.5.本身的耐热性和化学稳定性优良,高温下不分解.不挥发,不与树脂或其他助剂发生有害反应.6.不腐蚀设备,不污染制品,无毒性.

Ideal lubricants should meet the following requirements: 1. high lubrication efficiency and lasting 2. with resin compatibility, internal and external lubrication balance, no spray frost. No scaling.3. surface tension is small, small viscosity, good extensibility, easy to form the interface layer.4. does not reduce the mechanical strength of polymer. Thermal deformation temperature, weatherability, transparency and electrical properties, do not affect plastic The two processing performance.5. itself has good heat resistance and chemical stability. It does not decompose at high temperature. It does not volatilize and does not react with resin or other additives..6. does not corrode the equipment. It does not pollute the products and is non-toxic.