乳剂涂层在挤压嘴和运动的支持体之间的缝隙中变薄并加快运动。当支持体上的乳剂涂层厚度达到某一临界值时,再连续涂布则发生一定的困难,表现形式为,涂在支持体上的乳剂不成连续薄层而是一些条带。挤压嘴的真空度10～40毫米水柱时,乳剂涂层出现两种弊病。一种是乳剂涂层突然沿宽度方向中断,乳剂完全没有涂上,然后又继续涂布上去,但已经成为一些条带(图1a); The emulsion coating becomes thinner and accelerates in the gap between the extrusion nozzle and the moving support. When the thickness of the emulsion coating on the support reaches a certain critical value, there is some difficulty with continuous coating, in the form of an emulsion of the coating applied to the support without a continuous thin layer but some bands. Extrusion nozzle vacuum 10 ~ 40 mm water column, the emulsion coating appears two drawbacks. One is that the emulsion coating abruptly abruptly cuts across the width, the emulsion is completely uncoated, and then continues to be coated, but becomes strips (Figure 1a);