Spray foam molding control factors
DATE：2022/1/19 8:46:47 / READ： / SOURCE：This station
Spray foam molding control factors
① Milky time. That is, after the reaction solution is sprayed onto the target object, the time for the color to turn white is generally controlled between 3 and 7:0. If the time is too short, it is easy to block the spray gun. If the time is too long, it is easy to cause material loss or dripping.curing time. Usually expressed in terms of the time the foam does not stick to the hand. Too long curing time is not conducive to continuous spraying, and the previous layer of foam is easily blown by the next layer of spraying.
③ Atomization wind pressure. For air spraying, the atomizing air pressure varies according to the formula, flow rate and material viscosity, and is generally controlled at about 0.5 to 0.6 MPa. Because the chemical is too low, the material is not mixed evenly, which affects the final quality of the foam.
④Spraying speed. The spraying speed can control the spraying flow at about 1kg/min, the corresponding spray gun moving speed is 0.5-0.8m/s, and the thickness of the obtained single-layer foam is about 15mm. It should be noted that when the moving speed is too slow, the surface is not easy to be sprayed flat.
⑤ Surface temperature. If the temperature of the surface to be sprayed is lower than 10°C, the milking time will be longer, the bulk density of the bottom layer after foaming is too large, and the bonding is not strong, which can be remedied by the following measures:
a. Adjust the formula, increase the amount of amine and organotin catalysts, and shorten the milking time;
b. The two-component material is heated, and the output material belt is kept warm to ensure that the temperature of the material entering the spray gun is about 20 °C;
c. The spray compressed air is heated, and the temperature entering the spray gun is controlled to be about 40-80 °C. The temperature of the hot air varies according to the different ambient temperatures and needs.
Author：admin