Polyether polyol is mostly used to manufacture soft, hard and semi-rigid polyurethane foams. Polyether polyol is not only easy to obtain raw materials with low cost, but also hold good properties of synthetic polyurethane foam.It is the polyol raw material with the largest dosage for polyurethane foam industry.
Polyether polyol used for soft foam is generally long-chain polyether with low functionality. The functionality of polyether polyol in soft foam formula is generally 2 ~ 3, and the average molecular weight is between 2000 ~ 6500. Polyether triol is the most commonly used in soft foam. Generally, glycerin (glycerol) is used as RXH, which is obtained by ring-opening polymerization of 1, 2-propylene oxide or copolymerization of propylene oxide with a small amount of ethylene oxide. The molecular weight is generally in the range of 3000 ~ 7000. Glycerin are mainly used soft foam with high resilience, and can also be used in foam products such as semi-hard foam. This kind of polyether has good miscibility with water and isocyanate, the reaction activity is suitable, and the foam process stability is greatly improved. In addition, the foam curing time is shortened, which also reduces the production cost.
Polyether polyol with high functionality and high hydroxyl value is commonly used in hard foam formulations,only in this way can a sufficient degree of cross-linking and rigidity be produced. The hydroxyl value of hard foam polyether polyol is generally 350 ~ 650mg KOH/g, and the average functionality is above 3.
As for ordinary polyether polyol used in elastic non-foam, polyurethane polyether glycol and polyether triol with molecular weights ranging from 1000 to 3000 are most commonly used. In addition, sealant also uses the high molecular weight polyether triols and coatings also use polyether polyol with a molecular weight of several hundred.
