In view of the fact that the mold is not full, it is not just adding water or increasing the amount of TDI that can solve the problem of dissatisfaction. If the mold temperature and material temperature are reached, the foam will also rise, but it will not rise around the mold at the end. , it is likely that:
1. To see if there are enough raw materials, two methods can be used. One is to measure the density. If the density is low, it is not enough; first, confirm the density and the volume of the mold, and calculate the theoretical weight. If the weight has been reached, it means that the foaming is not enough, you can add water or MC, but if you add more water, the hardness will increase, so it is best to use more of the two. The second is to see if the exhaust is enough.
2. It is a problem with the catalytic system. The ratio of the catalyst needs to be adjusted, and at the same time, it is necessary to check whether the raw materials, silicone oil and catalyst are before the shelf life. In the later stage of foaming, the gel speed is too fast, and it is easy to collapse the foam if you add too much water, so adjust the amount of catalyst appropriately. If the gel catalyst is reduced, add a little A-1 and triethylenediamine appropriately. If the foaming ratio is not enough, you can increase the foaming ratio. The foaming time can be about 10-15 seconds, and the gelling time can be 60-60 seconds. About 80 seconds, the debonding and demoulding time can be adjusted by yourself.
3. If the material is foamed with all water, there is no 141B. Generally, water can be added to 3~6 parts. If the injection volume can be increased, the foaming ratio is not enough, and the ratio can be increased appropriately. The key is to test it. Check the density of the free foam to see if the foam is normal and whether there is any foam collapse. If the foam collapses, it is necessary to replenish silicone oil and cross-linking agent.
4. Check if there is any problem with the formula. Generally, high-resilience soft foam uses high-activity polyether and grafted polyether as the main raw materials. Car seats are mainly made of low-density and low-hardness soft foam. Check the selected polyether. Whether it is suitable or not, the polyether activity of different manufacturers is also different, and of course the price is also different.
5. Then look for problems in the process to see if the temperature of the material can be raised appropriately, that is, the foaming speed should not be too fast, otherwise it is easy to hold your breath, and the fluidity of the material will be better when the temperature is higher.
6. It is also possible that the foam is not a normal foam, and dissatisfaction is caused by foam collapse.
7. If the injection molding coefficient is insufficient, the mixing ratio of TDI can be increased, and the foaming ratio can be increased a little without changing the injection molding weight, so as to increase the foaming ratio.
