I. Water proportioning
Water: amine: silicone oil = 100: 7: 35
Amine is A-33 or A38 imports of domestic can be.
Silicone oil can be imported L-580, or domestic L-568 or Dow Corning SZ580 or DC5180, but the stability of imported best. L-568 in the summer with water when there is serious delamination.
This ratio is suitable for foaming index 8.3-3.3 that is, the original density between 12-30 density. Solid ammonia: water ratio: water: amine: silicone oil = 100:1.91:35 or 100:1.91:0.45
Where the amine is a solid triethylene diamine.
Second, the selection principle of TDI index
Foaming index * 9.667 + 8.68 * (1.05-1.35) If the MC is included in the TDI index is not less than 105.
Third, the clearance in the mixing head of the foaming machine parts
There should be 2 wires between the column and the bearing in the mixing head of the foaming machine, and 2 wires between the bearing and the clamping base, and there should be 2 mm gap between the wall of the mixing chamber and the stirring bar, in order not to produce friction as the best.
Fourth, the correct installation of the pot
Diameter 1.27 plastic film 4 m small pot inside diameter 38 mm plus 10-15 mm or 42 mm is better 10-15 mm large pot lower diameter is usually smaller than the small pot 20 mm (the distance between the two pots during installation to less than 15 mm is better.
V. The specific recipe changes due to the change of the ring temperature and material temperature
Usually the ring temperature (such as summer) high material temperature high density of sponge issued than the normal situation of a lower density, here mainly in the ring temperature. If in winter, the density is usually a density higher. So according to the seasonal changes in the formula should also be appropriate changes (to pay attention to the speed of the conveyor belt, has reduced the emergence of pressure tendons and foam decline)
Sixth, the foam after a period of decline, a significant increase in the amount of tin does not respond
Mainly in the low density, in the case of low ring temperature (such as ring temperature below 20 degrees), can send more, and to the case of high ring temperature ( such as summer ) is sent less prone to decline in the case. Skin no bond, you can properly increase the density, reduce the speed of the conveyor belt, may also be caused by silicone oil. Such as 18 density plus powder 60 recipe, the original L-568 can only be sent to 50-65 when the plastic sheeting loose slippage and replaced by SZ-580 is much better can be sent to more than 85-90. At the same time in the case of the ring temperature of 24 degrees. Material temperature at 22-27 degrees did not change. May also be due to the foaming process in the tray heat generation caused by the rapid start of the first reason. If there are conditions, you can reduce the flow of amine.
Seven, 18D recipe plus powder 60 parts of the formula
Winter can send more than 150 no problem. But in summer, when L-568 is used, the plastic film becomes loose when it is more than 50-60. The outer skin cured into powder, no tension. I also tested lowering the material temperature (polyether 23, TDI 20 degrees), but also the same. Feel the late curing slow and changed to SZ580 can be sent to 90 of the above symptoms. And switch to L-618 can be sent to more than 100 but the plastic film becomes loose when the transfer speed appropriate down to increase the density of 0.5-1 density. It can be concluded.
It has something to do with silicone oil.
There is a relationship with the ambient temperature.
It is possible to increase the density by decreasing the speed of the conveyor belt and it is proved to be effective.
The amount of amine can be reduced appropriately.
Eight, the foam appears serious net crush tendons
Cause: Mainly the amount of catalyst is not enough. Solution: Increase the amount of tin and amine.
If the mixture can not increase the amount of amine to increase the amount of tin at least 15% increase in the best synchronization. Sponge bubble edge: there is a diameter of about 20 centimeters of pressure tendons or several.
Solution: This is mainly generated by the extrusion of the chain plate. Can be appropriate to increase the speed of the conveyor belt. Sometimes the sponge foam disappears on its own for a period of time. You can also increase the amount of ammonia and tin can also be solved. Hair original density below 15 is more likely to have this problem. It is important to choose the right ammonia. Through the foam practice AM-90 ammonia hair effect is very good.
On horizontal foaming: 1.
1. nozzle foam when the middle of the sponge split . In the center of the top of the sponge body from the top to the bottom of the vertical crack of about 10 cm. It is mainly due to the slow start of low ammonia and too steep fall plate. Increase the amount of ammonia or adjust the fall plate. Lateral cracking of the sponge body: usually caused by too high ammonia and fast start. Side lifting film pulling crack. Properly reduce the amount of ammonia can be.
Lift the film to be 0.8-1 m away from the highest point of the bubble body
Foaming liquid does not start or start very slowly, sponge forming bubble hole rough: mainly is not injected on the gas or the amount of gas injection is too low. The solution is mainly to increase the amount of gas injection.
The foam is slow to start, forming a submerged flow. The formulation of the hair type 2 No. black. It is mainly caused by low ammonia or low gas injection. Solution if the ammonia in a certain amount of gas injection volume is low to increase the gas injection. If the amount of gas injection is high preslow increase the amount of ammonia. Submerged flow back. In the first two methods can not be solved in the case of appropriate to increase the speed of the conveyor belt.
Sponge late curing slow soft sticky: hair FR-25 yellow formula. Mainly toluene is too high caused by. Nozzle foam formation of submerged flow performance: starting hair line without curvature. Into the cross at the start of the hair sponge body in the middle of cracking. Tianjin Li Zhongcheng: 1. TDI flow can be controlled 56-79 kg transmission 4 meters or so.
High resilience silicone oil control at about 0.5 parts. Diethanolamine control at about 1.5 parts, and water preparation for a component. The more common formulas for high resilience are 30 density and 45 density. At the beginning of foaming, the main attention to the tin should be slightly high micro-closed pores. Normal after reducing the amount of tin. But the amount of fallback should not be too large, usually fallback 1-2 cm. The amount of air injection when foaming has a great impact on the height of the sponge. The high volume of air injection sponge is high. The air injection amount is usually lower than the ordinary bubble air injection amount.
The ammonia of low density: Model A340 gas flow meter usually has: 0.05, 0.1, 0.2 or marked 100 150 200 250
Mixing head speed is usually 3600-4200 rpm or 3700-5100 rpm
The outlet of the nozzle can be 70×2 wrapped with 20-purpose soft gauze or 80×2 or 90×2 or 100×2
Ammonia model CH-90 is mainly suitable for adding 200-300 portions of barite powder. The dosage is 0.2-0.22 parts.
Slow rebound foam
1. Slow rebound horizontal foam usually sends 45 densities. 33 density without adding powder vertical bubble silicone oil dosage of 0.4 parts to enhance to pay attention to the lower side of the slow point to fat some.
2. Slow rebound TDI recipe algorithm: (water × 9.667 + 0.155 × hydroxyl value) × TDI index 85-90
3. Slow rebound soft without tension is due to the low amount of TDI. TDI index should be increased appropriately.
4. Do super hard slow rebound. In addition to increasing the amount of white polyether, it is more important to increase the TDI index can be added to the index 130
