Jinan Guozhen Machinery Equipment Co., Ltd.

Supply year Yichang area high-pressure pneumatic polyurethane spraying machine rigid foam polyurethane spraying technology is difficult to master and is prone to problems such as uneven sprayed polyurethane cells. The training of spraying construction personnel should be strengthened so that they can master the spraying technology and independently solve the technical problems encountered in spraying construction. The key technical issues that need to be solved in spray construction mainly include the following aspects. Control of milky time and atomization effect The formation of polyurethane foam needs to go through two stages: foaming and maturation.
The process from the mixing of black and white materials to the stop of foam volume expansion is called foaming. During the foaming process, the system releases a large amount of reactive heat. The uniformity of the cells should be considered during the ester spraying process. The uniformity of cells is mainly affected by the following factors:
Material ratio deviation
There is a big difference in density between machine foaming and manual foaming. Usually the fixed material ratio of the machine is: However, due to the large difference in viscosity of white materials from various manufacturers, the actual material ratio does not match the fixed material ratio of the machine. When the white material is excessive, the foam density is low, the color is whitish, the foam strength is reduced, the feel is soft, and it is easy to shrink when the temperature is low; when the black material is excessive, the foam density is high, the color is deep, the foam intensity is high, the feel is hard and brittle. In these cases, the material ratio should be checked immediately to see if the filter is clogged and whether the pressure and temperature indicators are normal to ensure the accuracy of the black and white material ratio.
()Ambient temperature
Polyurethane foaming is greatly affected by temperature. Foaming relies on heat. Without heat, the foaming agent in the system cannot evaporate and foam cannot be produced. Heat comes from two aspects: chemical reaction production and environmental supply. The heat of chemical reaction is not affected by external factors. The heat provided by the environment changes with changes in ambient temperature. When the ambient temperature is high, the environment can provide heat to the reaction system, which can increase the reaction speed and shorten the reaction time. It shows that the foam is fully foamed and the density of the foam surface and core is close to each other. When the ambient temperature is low (such as below ℃), part of the reaction heat will be dissipated into the environment. On the one hand, the loss of heat causes the foam maturation period to be extended and the foam molding shrinkage to increase (the lower the temperature, the higher the molding shrinkage); on the other hand, the amount of foam material is increased. Experiments show that the foaming volume of the same foaming material at an ambient temperature of ℃ is % smaller than that at ℃, which increases the production cost of foam.