Painting Knowledge: Construction Requirements For Polyurethane Rigid Foam Spraying
HC surface treatment network: 1, ambient temperature requirements
The suitable temperature for spraying foam is 15 ~ 35 ° C, the temperature is too low, the foam is easy to fall off the surface of the object, and the density of the foam is obviously increased, and the consumption is obviously increased. When the ambient temperature is high, the foaming agent is lost. Too big.
Isocyanates readily react with water to form brittle urea-containing materials. The surface to be sprayed should not have dew or frost. When the humidity of the air is too high, dehumidification should be carried out, otherwise the adhesion of the foam to the object will be affected and it will fall off easily.
3, the wind
When spraying outdoors, when the wind speed is 5m/s, the heat loss is too large, it is difficult to obtain high-quality foam, and the loss of raw materials is large, and at the same time, the environment is obviously polluted.
4, spraying surface
The surface to be sprayed shall be free from rust, dust, oil and moisture, and shall be treated to meet construction requirements when necessary.