脱模剂的隔离性取决于其表面性质, 而表面不湿润性物质的物性值是根据其临界表面张力( rc ) 的概念得出的。rc 的测定方法是在被测物质的表面上滴上表面张力不同的几种物质的液滴,测出它们的接触角θ。用被测物质的表面张力与其接触角θ的余弦值cosθ作图得一直线, 延长这条直线和纵坐标相交, 其交点对应的横坐标值就是被测物质的表面张力值, 也叫该物质的临界表面张力r c。这个值有表示: 当物质表面上液体表面张力r L 大于物质的临界表面张力r c 时, 液体不湿润物质的表面; 当r L< r c时, 液体就会湿润物质的表面。因此, 临界表面张力小的物质作脱模剂, 是隔离性最好的脱模剂。
The isolation of release agent depends on its surface properties, and the physical properties of surface non-wetting substances are derived from the concept of critical surface tension (rc). RC is determined by droplets of several substances with different surface tensions on the surface of the substance under test, and their contact angle is measured. The surface tension of the substance under test and cosine value of its contact angle theta are used to plot a straight line, which is intersected with the longitudinal coordinates. The abscissa value corresponding to the intersection point is the surface tension value of the substance under test, also known as the critical surface tension R C of the substance. This value indicates that when the surface tension R L of the liquid on the material surface is greater than the critical surface tension R C of the material, the liquid does not wet the surface of the material; when R L < R c, the liquid will wet the surface of the material. Therefore, the material with small critical surface tension as the release agent is the best release agent for isolation.