1、The bubble nucleus formation stage of foam: Synthetic resin is added with chemical blowing agent or gas, when the temperature or pressure is lowered, gas will be generated and foam will be formed, when the gas in the melt or solution exceeds its saturation limit and forms a supersaturated solution, the gas will escape from the melt and bubbles will be formed. At a certain temperature and pressure, the decrease of solubility coefficient will cause the concentration of dissolved gas to decrease and the excess gas released to form bubbles.
2、Bubble nucleation growth of foam: In the process of foaming, the growth rate of bubble pore is determined by the growth rate of pressure inside the bubble pore and the deformation ability of the bubble pore rate. After the formation of bubbles, because the pressure of the gas inside the bubble is inversely proportional to the radius, the higher the pressure inside the bubble, and increase the number of bubbles through nucleation, coupled with the expansion of the bubble to expand the growth of the foam. The factors that promote the growth of foam are mainly the increase of dissolved gas, the increase of temperature, the expansion of gas and bubble and.
3、Stable curing of foam: Of course, if the bubble growth process is not interrupted at a certain stage, some bubbles can grow to a very large size, so that the material forming the wall of the bubble reaches the limit of rupture, and finally all the bubbles will collude with each other to make the whole foam structure deflate, or there will be a slow diffusion of all the gas from the bubble to the atmosphere, the pressure of the gas in the foam gradually decays, then the bubble The pressure of the gas in the foam gradually decreases, then the bubble hole will gradually become smaller and disappear.