1. Water distribution ratio
Water: amine: silicone oil = 100: 7: 35
The amine is A-33 or A38, which can be imported or domestically produced.
The silicone oil can be imported L-580, or domestic L-568 or Dow Corning SZ580 or DC5180, etc. But the imported stability is the best. L-568 experienced severe stratification during water distribution in the summer.
This ratio is suitable for foaming index 8.3-3.3, that is, the original density is between 12-30 densities. Solid ammonia: water ratio: water: amine: silicone oil = 100:1.91:35 or 100: 1.91: 0.45
The amine is solid triphexylenediamine.
2. Selection principles of TDI index
Foaming index *9.667+8.68*(1.05-1.35) If MC is included, the TDI index is not less than 105.
3. Gaps in the mixing head parts of the foaming machine
There should be 2 wires between the column and the bearing in the mixing head of the foaming machine. At the same time, the difference between the bearing and the card seat should be 2 wires. There should be a 2 mm gap between the mixing chamber wall and the stirring rod to prevent friction. optimal.
4. Install the pot correctly
Diameter 1.27 plastic film 4 meters inner diameter of small pot 38 mm plus 10-15 mm or 42 mm is better 10-15 mm lower diameter of large pot is usually 20 mm smaller than small pot (the distance between the two pots during installation It is better to be less than 15 mm.
5. The specific formula changes due to changes in ambient temperature and material temperature
Usually when the ambient temperature (such as summer) is high and the material temperature is high, the density of the sponge is one density lower than normal. This is mainly reflected in the ambient temperature. If in winter, the density is usually one density higher. Therefore, the formula should be appropriately changed according to seasonal changes (pay attention to the speed of the conveyor belt to reduce the occurrence of rib compression and foam sliding)
6. The foam dropped after a period of time, and there was no response to a large increase in the amount of tin
Mainly manifested in low density. When the ambient temperature is low (such as the ambient temperature is lower than 20 degrees), it can be released more, but when the ambient temperature is high (such as summer), it can be released less easily. There is a decline. The surface has no adhesive force, and the density can be increased appropriately to reduce the speed of the conveyor belt. It may also be caused by silicone oil. For example, with a formula of 18 density and 60 powder, the original L-568 could only deliver 50-65 pieces, but the plastic sheet would loosen and slide down. However, after switching to SZ-580, it was much better and could deliver 85-90 or more. At the same time, the ambient temperature is 24 degrees. The material temperature does not change at 22-27 degrees. It may also be due to the heat generated by the tray during the foaming process that causes the rapid rise in the early stage. If conditions permit, the amine flow rate can be appropriately reduced.
7. 18D formula plus 60 parts of powder
More than 150 can be sent in winter without any problem. In summer, when L-568 is used for more than 50-60 times, the plastic film becomes loose. The outer skin is cured into powder form and has no pulling force. It has also been tested that lowering the material temperature (polyether 23, TDI 20 degrees) is the same. I felt that the post-curing process was slow, so when I replaced it with SZ580, I could deliver 90 pieces and the above symptoms appeared. When using L-618, more than 100 pieces can be delivered, but when the plastic film becomes loose, the conveying speed is appropriately reduced and the density increases by 0.5-1 density. It can be concluded.
It has something to do with silicone oil.
It is related to the ambient temperature.
The conveyor belt speed can be appropriately reduced to increase density, which is proven to be effective.
The amount of amine can be appropriately reduced.
8. The foam has serious reticular compression
Reason: The main reason is that the amount of catalyst is not enough. Solution: Increase the dosage of tin and amine.
If the mixture cannot increase the amount of amine, increase the amount of tin by at least 15% simultaneously.Proceeding is best. Sponge foam edge: There are one or several pressure ribs with a diameter of about 20 cm.
Solution: This is mainly caused by the extrusion of the chain plate. The conveyor belt speed can be appropriately increased. Sometimes the sponge disappears after foaming for a while. It can also be solved by appropriately increasing the dosage of ammonia and tin. This problem is more likely to occur when the original density is below 15. Choosing the right ammonia is important. Ammonia hair with AM-90 works well by foaming practice.
On horizontal foaming:
1. The sponge cracked in the middle when the nozzle was foaming. There is a vertical split of about 10 cm from top to bottom in the center of the top of the cavernous body. The main reason is that ammonia rises slowly when it is low and the falling plate is too steep. Increase the amount of ammonia or adjust the drop plate. Sylvian cavernous fissure: usually caused by too high ammonia and rapid onset. Pulling of the lateral lift membrane. Just reduce the amount of ammonia appropriately.
The membrane should be lifted 0.8-1 meters away from the highest point of the bubble body
The foaming liquid does not rise or rises very slowly, and the sponge molding cells are rough: the main reason is that the air is not injected or the amount of air injected is too low. The solution is mainly to increase the gas injection volume.
The foaming liquid rises slowly and forms an undercurrent. Formula for hair type 2 black. Mainly caused by low ammonia or low gas injection volume. Solution: If the gas injection volume is low under a certain amount of ammonia, increase the gas injection. If the gas injection volume is high, slowly increase the ammonia volume in the early stage. Undercurrent returns. If the first two methods cannot solve the problem, increase the conveyor belt speed appropriately.
The sponge cures slowly and becomes soft and sticky in the later stage: FR-25 yellow formula. Mainly caused by too high toluene. The performance of undercurrent formed by foaming in the nozzle: the starting line has no curvature. The middle part of the corpus cavernosum begins to crack at the intersection. Tianjin Li Zhongcheng: 1. TDI flow can control 56-79 kg to be transmitted about 4 meters.
High resilience silicone oil is controlled at about 0.5 parts. Diethanolamine is controlled at about 1.5 parts, and is prepared as one component with water. The more commonly used formulas for high rebound are 30 density and 45 density. At the beginning of foaming, it is important to note that the tin should be slightly higher and slightly closed. After normalization, reduce the amount of tin. But the amount of fallback should not be too large, usually 1-2 cm. The amount of air injected during foaming has a great influence on the height of the sponge. The higher the air injection volume, the higher the sponge. The gas injection volume is usually lower than that of ordinary bubbles.
Producing low-density ammonia: Model A340 gas flow meters usually have: 0.05, 0.1, 0.2 or marked 100, 150, 200, 250
The mixing head speed is generally 3600-4200 rpm or 3700-5100 rpm
The outlet of the nozzle can be 70×2 wrapped with 20 mesh soft gauze or 80×2 or 90×2 or 100×2
Ammonia model CH-90 is mainly suitable for 200-300 parts of weighted crystal powder. Dosage is 0.2-0.22 servings.
Slow rebound foaming
1. Slow rebound horizontal foam usually has a density of 45. The amount of silicone oil used for vertical soaking of 33 density without adding powder is 0.4 parts. Please pay attention to the increase slowly and the bottom part should be fatter.
2. Slow rebound TDI formula algorithm: (water ×9.667+0.155× hydroxyl value) ×TDI index 85-90
3. The slow rebound, softness and no pulling force are caused by the small amount of TDI. The TDI index should be increased appropriately.
4. Make super hard and slow rebound. In addition to increasing the dosage of white polyether, it is more important to increase the TDI index to an index of 130
