Polyurethane raw materials
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I’ve been learning about polyurethanes recently, but I’m a bit confused about their raw materials: MDI can be used as a raw material for polyurethanes, and TDI can also be used as one; what’s the difference between the two? Besides MDI and TDI, what other products can be used as raw materials for polyurethanes?
It is understood that propylene oxide can also be used as a raw material for polyurethanes!
To understand this, one needs to know what polyurethane is
eo,po,mdi,kOH.........
Oil-based products and such things. . . . . . . . . . . . . . . .
IPDI, HDI, HMDI, PAPI, NDI, TMXDI, biuret polyisocyanate, polyester polyol, polyether polyol. . . . . . .
These are used for producing polyester diols: 1. UB03 (molecular weight of 2000; the dicarboxylic acid is adipic acid, while the diols are 1,4-butanediol and ethylene glycol)； 2. UB03-2N (molecular weight of 3000; the diacid is adipic acid, and the diols are 1,4-butanediol and ethylene glycol) ； 3. UB03-3N (molecular weight of 3000; the diacid is adipic acid and pimelic acid, while the diol is 1,4-butanediol and ethylene glycol) ； 4. UB18 (molecular weight of 2000; the diacid is adipic acid, and the diols are neopentyl glycol and ethylene glycol) ； 5. UB38 (molecular weight 2000; the diacid is adipic acid, and the diol is 1,4-butanediol) ； 6. UB88 (molecular weight 3000; the diacid is adipic acid, and the diols are diglycol and ethylene glycol) ； 7. UB79 (molecular weight 5000; the diacid consists of adipic acid, isophthalic acid, and phthalic anhydride, while the diol consists of diglycol and ethylene glycol) ； 8. UB79-6 (molecular weight of 3000; the diacid is adipic acid, benzene-1,2-dicarboxylic acid, and phthalic anhydride; the diol is diglycol and ethylene glycol).
The basic materials for polyurethanes can be divided into several categories: Isocyanates: IPDI, HDI, HMDI, MDI, TDI, NDI…… Macromolecular alcohols: Polyether-type PPG, PTMG, PEG； Polyester-type PCL, PCDL, PHB..... ； Polyolefin-type..... Small molecular diols: DEG, BDO, HDO, HMDO, TMP........ Small molecular diamines: EDA, IPDA........ As for other modifiers such as silanes, epoxies, oils, etc., they will not be mentioned here
Reply to 8# arrjinyang: What was said above is very comprehensive! Give it a boost!
Hehe, isocyanates and diols, among others, can all be used to make polyurethane materials
There are many raw materials used in polyurethanes. The difference between MDI and TDI, as you mentioned, lies in the reinforcing monomers within their molecules: MDI contains two benzene rings while TDI has only one, which results in a significant difference in hardness after curing! There are many just in the NCO category, and in other categories there are polyureas, polyether polyols, amino resins, fatty acid esters, polyester polyols, and so on. The choice of NCO depends on the specific requirements of multiple products, and a formulation must be designed!