Spray molding process
DATE：2021/11/25 8:58:11 / READ： / SOURCE：This station
Spray molding process
Rigid polyfoam is very suitable for on-site foam molding of the appearance and quality of equipment and equipment. The construction method of this kind of foam plastic is similar. It is to spray the material with good fluidity into high pressure by air and spray it on the surface of the work for foam molding. The advantages of spray foam molding are as follows.① No mold required.
②Whether it is a horizontal plane, a vertical plane, a top, a surface with a single shape or a complex shape, it can be sprayed.
The labor productivity is high. If the coating speed is calculated at 2kg/min, the density of the foam is 30kg/m2, and 4m of foam can be sprayed in 1h. In large-area construction, the superiority of shun foam molding is more prominent.
④The rigid polyurethane foam obtained by spray foaming has no connection and good thermal insulation effect.
For this reason, the following two questions must be paid attention to when designing this foam formula. The spraying type rigid foam is not foamed in a certain shape of the mold, but directly foamed on the surface of the coated object, so that the foaming speed of the reaction material is required to be faster. Especially for the construction surface perpendicular to the top, it is required to start foaming before the material is lost (usually 3~5s). The solidification speed should also be moderate, controlled within 20-30s, otherwise it will cause excessive foam density or construction difficulties.
②The physical properties of materials. This refers to the viscosity and mutual capacity of the material. It is required that the spray foaming polyether component and the iso-ester component have low viscosity, good fluidity and strong mutual compatibility. Because the spray-type rigid foam materials are atomized and mixed outside the spray gun with the help of high pressure or air, and the contact time is short. Therefore, the atomization can be fully dispersed only when the two-component materials have low viscosity and good fluidity. mix.
Author：admin