Polyether polyol (referred to as polyether) is currently the largest sales of synthetic oil, which is based on ethylene oxide, propylene oxide, butylene oxide, etc., under the action of a catalyst, ring-opening homopolymerization or copolymerization. A linear polymer produced. The largest yield of polyether is glycerol (glycerol) as initiator and epoxide (usually PO and EO), by changing the feeding mode of PO and EO (mixing plus or separately adding), adding ratio, Various general-purpose polyether polyols are produced under conditions such as the order of addition.
First, the physical and chemical properties
Boiling point >200 °C (lit.)
Flash point >230 °F
Refractive index n20/D 1.466
Vapor pressure <0.3 mm Hg ( 20 °C)
Vapor density >1 (vs air)
Second, the main characteristics
The polyether polyol is an oligomer having a main chain containing an ether bond (-R-O-R-) and a terminal group or a pendant group having more than two hydroxyl groups (-OH). It is a ring-opening polymerization of a low molecular weight polyol, a polyamine or an active hydrogen-containing compound as a starting agent, and an alkylene oxide under the action of a catalyst. The oxidized olefin is mainly propylene oxide (propylene oxide), ethylene oxide (ethylene oxide), of which propylene oxide is most important. Polyol starting agents include diols such as propylene glycol and ethylene glycol, triols such as glycerol trimethylolpropane, and polyhydric alcohols such as pentaerythritol, tetraol, xylitol, sorbitol, and sucrose; and amine initiators. It is diethylamine, diethylenetriamine, and the like.
Polyethers generally use propylene glycol polyether having a molecular weight of 800 to 2000, trimethylolpropane polyether having a molecular weight of 400 to 4000, and polytetrahydrofuran having a terminal hydroxyl group. The polyether resins used as the adhesive should be removed from the basic catalyst remaining during the polymerization because they can catalyze the dimerization of the isocyanate and affect the quality of the adhesive. It is usually neutralized with an acid to make the polyether slightly weak (does not affect the reaction of the polyurethane). The polyether used in the preparation of polyurethane adhesives is more stringent. In addition to the hydroxyl value and acid value, the potassium and sodium ions should be less than 10 and the water content should be less than 0.05%. Otherwise, gelation may occur. Polyurethane adhesives formulated with polyether resins have good water resistance, impact resistance and low temperature properties.
Polyether polyols with different functionalities can be prepared according to the number of active atoms contained in the initiator. The most commonly used polyethers in the preparation of polyurethane adhesives are polyoxypropylene diols and polyoxypropylene triols, in addition to poly Tetrahydrofuran diol.
Third, the main purpose
1, detergent or defoamer
L61, L64, F68 are used to prepare low foaming, high detergency synthetic detergent;
L61, L81 are used as defoamers in the papermaking or fermentation industry;
F68 is used as an antifoaming agent in the blood circulation of artificial heart-lung machines to prevent air from entering.
2. Excipients and emulsifiers
Polyethers are very toxic and are often used as pharmaceutical excipients and emulsifiers; they are often used in oral, nasal sprays, eye, ear drops and shampoos.
3, wetting agent
Polyether is an effective wetting agent for use in dyed, photographic development and electroplating acidic baths. F68 is used in sugar mills and more sugar is available due to increased water permeability.
4, antistatic agent
Polyether is a useful antistatic agent and L44 provides long-lasting electrostatic protection for synthetic fibers.
5, dispersant
The polyether acts as a dispersant in the emulsion coating. F68 is used as an emulsifier in the emulsion polymerization of vinyl acetate. L62 and L64 can be used as pesticide emulsifiers and used as coolant and lubricant in metal cutting and grinding. Used as a lubricant when vulcanizing rubber.
6, demulsifier
Polyether can be used as a crude oil demulsifier, L64, F68 can effectively prevent the formation of hard scale in the oil pipeline, and for the recovery of secondary oil.
7, paper additives
Polyether can be used as a papermaking aid, F68 can effectively improve the quality of coated paper; also used as a rinse aid.
8, preparation application
Polyether polyol series products are mainly used in the preparation of rigid polyurethane foam, widely used in refrigerators, freezers, refrigerated trucks, insulation panels, pipe insulation and other fields. The obtained product has low thermal conductivity and good dimensional stability, and is also an important raw material for preparing a combined polyether.
Polyether polyols are produced in the polyurethane industry and are mainly used in polyurethane foams. The main varieties are polyoxypropylene polyols and polytetrahydrofuran ether polyols.
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