In the era of saving money, the price of polyether continues to rise.
I have the honor to witness the transformation of hard foam products from huge profits to small profits, and the transformation of raw materials from Li Kui to Li Gui in more than ten years. While lamenting the astounding imitation creativity of our compatriots, we should write something to avoid being suspected of “backbiter slander.”
Disclaimer in advance: Please do not copy the following things, let alone imitate them. As we all know: I have unique eyes and see things with a double layer.
[View]: 1. The appearance of polyether should be transparent regardless of its color.
If it’s translucent or opaque, be careful, there’s probably something wrong with it. First, take samples from different locations in the raw material barrel to see if there is any stratification. It is best to check the bottom of the barrel to see if there is any particle sedimentation or the like. The occurrence of this situation can only mean: ①. The polyether production is not well controlled and the reaction does not respond; ②. The post-processing of the polyether is not done well; ③. Something that saves money is mixed in.
In August this year, the three batches of Zh. Needs to be improved.
2. The color of polyether is too dark and I think everyone will not like it. At least it means that the starter was not “vacuumed enough” during polyether production or the temperature when connecting propylene oxide (PO) was too high. Even if the polyether is dark in color, it should be brownish-red. If there is an abnormal “cyan” (more greenish) color, be careful: in my impression, only rosin polyester and aromatic diamine polyether will look like this, so don’t worry. Yes, aromatic diamine polyethers are too expensive and no one can mix them in for you.
3. If the viscosity of the polyether is obviously higher than before (you can see it by shaking or tilting the polyether packaging bottle), it’s good: you can tell that the PO price has increased without making a phone call, and this year’s sucrose Great harvest, the polyether manufacturer helped you to add less PO, and he may kindly explain it as: increasing the hardness to resist shrinkage
[Sniff]: Normal polyethers starting from sugar have a “fishy” smell of caramel.
1. If there is a strong smell of ammonia and the pH test paper turns to “10” before it reaches the mouth of the bucket, there is a high probability that it contains urea;
2. If there is a “scent” similar to turpentine, it must be a product from the Northeast. (Amine ethers such as 403 are not included in this list)
[Wash]: Most rigid polyether foam can stick to your hands and be washed clean with tap water.
Whether it is difficult to wash off depends on the range of its hydroxyl value: if it is lower than 380 mgKOH/g, you can understand it (it can still be washed, but it is not as smooth), and if it is higher than 380, you don’t need to use soap. .
If the washing powder cannot be washed in one go, it must be a green product (tar-modified polyols, terpene alcohol esters, rosin polyester, modified soybean oil, castor oil, PTA polyester, etc. are all difficult to wash) , as for phenolic polyols—the price is too high and it’s troublesome to make, so only fools would add it)
[Comparison experiment]: The most convincing one is the foaming comparison experiment. The following takes the most commonly used 4110 as an example
If you want to see the situation of polyether B, then take polyether monomer A, which is usually reliable in quality, as a reference, and first design a basic formula based on the purpose (for example: thermal insulation)
A B
Polyether 100 100
Silicone oil 1.5 1.5
Water 1.0 1.0
Cyclohexylamine 1.2 1.2
141B 27 27
(Note: The selected bottles must be of the same specification and model)
1. The weight is ×2, first compare whether the appearance is transparent (the above is suitable for 25-28℃ environmental conditions), the reason for opacity is the same as before.
2. Hold a material sample bottle with each left and right hands and align them to ensure that the liquid levels on both sides are at the same level. Place it flat at chest level, and then move the front and back together to vibrate: see who “jumps higher” on both sides, so that you can roughly judge the viscosity level. .
3. Perform foaming under the same conditions as above (black/white 1.05/1, stir for 6 seconds, foam before and after one after another)�If it exceeds 10 minutes, pour it into a plastic bag and hang it up), record the respective time (milky white, brushed, non-sticky),
And roughly judge whether the density is very different based on the height of the bubble in the plastic bag. If the foaming time period of A and B polyethers is too different (the difference in milky whiteness is more than 2 seconds, the difference in drawing is more than 5 seconds, and the difference in non-stickyness is more than 7 seconds), then “add some rings to the slower combination material according to the remaining amount. “Come with hexylamine and water, pull it up quickly and high” to re-foam, and try to adjust their foaming speed and foaming size to make no difference; in addition, the foamed foam will be sent to an air-conditioned room at 20°C after it is no longer sticky for 3 minutes. Natural “aging” for 15 minutes
4. In principle, polyether polyol (such as 4110) is a initiator connected to propylene oxide (PO), and the end cap is a “secondary hydroxyl group”, so its activity should not be high. If the polyether polyol is the object of investigation In comparison, for “very economical” catalysts, there is more than 90% certainty that it contains “active hydrogen” components.
5. Check whether there is any “bubble explosion” phenomenon during the foaming and rising process (look at the “bright” area on the surface of the bubble body against the light to see if there is an explosion point, just like exploding a landmine).
If there is, it means that the cells of the bubble body must not be fine enough, or at least they will “eat silicone oil”. The reason is mostly due to the high aldehyde content of propylene oxide (PO) used in polyether production. It is also possible that the polyether is contaminated by hydrocarbon oils (for example, the packaging barrel is not cleaned), or that the polyether contains Incorporated into oil polyol.
6. Check whether there are horizontal lines shrinking on the appearance of the bubble body. Low functionality polyols (such as castor oil, phthalic anhydride polyester, rosin polyester, ethylene glycol, etc.) and high hydrocarbon chain structures (modified vegetable oil polyols, etc.) will cause cross-grain shrinkage. The greater the shrinkage, the weaker the skeleton. Hard, not enough cross-linking points, not enough functionality.
7. Pinch the corners to see if there is any brittle powder. The powder mixed with glycerin is the most brittle, followed by rosin polyester, urea-based third, phthalic anhydride, phenyl polyester and some varieties of modified vegetable oils on the market are not much better, used in infusion insulation to “stick” “The knot will not be good.” In addition, if there is less PO and the hydroxyl value is too high, the foam will also become brittle and aggravated (merryole).
8. Check whether there are obvious “drawing marks” on the upper part of the foam body. Combined with the residual foam body in the foam cup and “whether the mouth of the cup is round and smooth”, you can roughly judge the polyether foam. Whether it is “liquid”. Nowadays, some polyether factories do not mix things indiscriminately. It is a pity that they do not do post-processing in order to increase the “yield”. What is even more annoying is that they throw in some glacial acetic acid to neutralize the potassium hydroxide and that’s it. In fact, it is equivalent to adding it to the polyether. With the addition of potassium acetate, the fluidity cannot be “good”.
9. The foam can be cut after curing at 20°C. Compare the appearance of the cells and measure the density. Pay special attention to whether there is a “coarse pore corridor” 1.5mm below the skin on the side. If so, remove the polyether first. Used: The money earned is not enough to pay for traveling to deal with quality accidents.
10. Compare the surface of the foam (referring to the part where the surface is in contact with the air) to see if the cells are fine and smooth. Most of them are too rough and have large cells and are not suitable for high-density imitation wood products.
[Destruction Test]
The following test temperature is best: 25-28℃
1. If the above comparison test is not clear enough, spend some time destroying it:
A B
Polyether 100 100
Silicone oil 0.8 0.8
Water 2.0 2.0
Cyclohexylamine 1.2 1.2 (add or subtract as appropriate to achieve a similar material speed)
141B 20 20
Carbon tetrachloride 5 5
Divide them into ×3 fractions. Let them bubble first and leave the bottom. The remaining ingredients will be exposed to the sun during the day and placed in a 35-40°C oven at night. In this way, within 5 days, see which color becomes darker first, and then the material speed slows down after foaming, and the destructive effect on the silicone oil. It’s not difficult to judge the pros and cons.
2. Formulate polyether into imitation spray paint
Polyether 100
Silicone oil 1.5
Water 0.7
A-33 2.5
T-12 0.3
Am-1 1.0
141B 18
Execute 60g/60g (black/white) foaming to see if there is any heartburn (yellow heart) phenomenon. Pure polyether will not cause heartburn in this system.
[Other tests and instructions]
1. 403 inspection:
403 100
Silicone oil 1.0
141B 30
Foam directly 1/1, it should be set within 35 seconds
2. Other auxiliary polyethers
Try to design a reasonable ratio for testing based on different uses.
For example, “365” from Northeast China has a low hydroxyl value and low viscosity. It can only be used as an auxiliary polyether in white materials, so it can be tested by arranging it to account for 40% of the main polyether; another example is 303 and 210
and the like also need to account for a small proportion of the test.
Polyethers such as 635, 835, and 1050 can be used as the main polyether, but the hydroxyl value is too high. Then appropriately increase the proportion of black and white materials for foaming tests. After the specific calculation, we will discuss it in detail in the basic communication column.
3. Miscibility test:
If the incoming sample itself is auxiliary, then the first step is to “miscible”:
In a 100ml beaker, pour in a total of 50 grams of the main and auxiliary polyether (ester) according to the designed proportion. Stir evenly with a small glass rod to see if it is transparent; then add silicone oil, water, catalyst and physical foaming agent in proportion. Check to see if it is still transparent. If this doesn’t work, pour the mixture into a test tube and store it for at least 24 hours (sealed) to see its storage stability. For example, Takahashi’s 330N can be added to ordinary imitation wood by at least 10% without delamination, while some manufacturers can’t even add 3% – this is the gap.
�Discuss in detail.
3. Miscibility test:
If the incoming sample itself is auxiliary, then the first step is to “miscible”:
In a 100ml beaker, pour in a total of 50 grams of the main and auxiliary polyether (ester) according to the designed proportion. Stir evenly with a small glass rod to see if it is transparent; then add silicone oil, water, catalyst and physical foaming agent in proportion. Check to see if it is still transparent. If this doesn’t work, pour the mixture into a test tube and store it for at least 24 hours (sealed) to see its storage stability. For example, Takahashi’s 330N can be added to ordinary imitation wood by at least 10% without delamination, while some manufacturers can’t even add 3% – this is the gap.
