During the foaming process of soft foam, I wonder if you will encounter such a problem. The phenomenon of semi-collapse occurs, and the degree of foam collapse is much greater than the normal drop. The normal drop is about 1 cm to 2 cm. , the half-collapsed bubbles are more than 5 cm, and there are many large bubbles on the surface. Regarding this phenomenon, I can only give some solutions based on the opinions of netizens. Whether the method is useful depends on the practical process. Everything is based on reality. All methods are only theoretical knowledge.
The following are some solutions:
First, if this situation is caused by assembly line foaming, it may be that the feeding time of TDI and polyether is not coordinated well. It may be that the polyether is coming out slowly. The slowness here is relative to TDI. TDI is faster. By adjusting the TDI speed and making it slower, it may have an effect. Adjust the speed of the two to each other, and there will always be results.
Second, the flow rate is too fast, add some A-1. Reduce the flow rate.
Third, increase traffic and ensure volume.
Fourth, regarding silicone oil, the choice of silicone oil must be appropriate, and the amount of silicone oil must be adjusted. If it still doesn’t work, you can consider changing the type of silicone oil.
Fifth, the temperature issue, whether it is material temperature or mold temperature, must be appropriate.
Sixth, it may not be the above problem, but an external problem. Check the design of the pipeline and whether the silicone oil or TDI pipeline has been replaced recently.
[Polyurethane soft foam slow rebound molding, high rebound molding, self-skinning raw material analysis and selection application, additive type identification, analysis and application, formula design, formula calculation, formula adjustment, process design, Cost calculation, under the guidance of the teacher, the students personally design the formula, calculate the formula, personally mix the ingredients, design the process, use a low-pressure foaming machine to foam on site, analyze the causes and treatment methods of common problems and difficult problems during foaming, and train: full water The formula design of MDI system with low VOC and high rebound, self-skinning, as well as the formula design of all-water MDI system with low VOC and zero temperature feeling and slow rebound, and the formula design of imitation latex headrest, students bring their own samples, the teacher designs the formula and process, and practices it on site teaching.
Highlights of training content:
Molding: all-water MDI system with low VOC and high rebound, self-skinning formula design, all-water MDI system with low VOC and zero temperature feeling and slow rebound, imitation latex headrest;
Block foam: MDI system slow rebound, coarse-pore ordinary cotton, hardened shoe material slow rebound, soft slow rebound, British standard flame retardant slow rebound, special sponge; ultra-soft high rebound block foam, resistance Burning high rebound block foam, etc.
