Polyether polyol (polyether for short) is a kind of synthetic oil with large sales volume at present. It is a linear polymer prepared from ethylene oxide, propylene oxide and butane oxide by ring opening homopolymerization or copolymerization under the action of catalyst. With glycerol (glycerin) as initiator and epoxide (generally used together with PO and EO), a large amount of polyether can be produced by changing the feeding mode (mixing or separating), dosing ratio, feeding sequence and other conditions of PO and EO.
1 Physical and chemical properties
Boiling point>200 ℃ (ignition)
Flash point>230 ° F
Refractive index n20/D 1.466
Vapor pressure<0.3 mm Hg (20 ℃)
Vapor density>1 (vs air)
2 Main features
Polyether polyols are oligomers with ether bonds (- R-O-R -) on the main chain and more than two hydroxyl groups (- OH) on the end or side groups. With low molecular weight polyols, polyamines or compounds containing active hydrogen as initiators, - polymerizes with oxidized olefins in the presence of catalysts. Oxidized olefins are mainly propylene oxide (propylene oxide) and ethylene oxide (ethylene oxide), of which propylene oxide is the most important. Polyol initiators include binary alcohols, such as propylene glycol and ethylene glycol, ternary alcohols, such as glycerol trimethylpropane, and polyols, such as pentanol, tetraol, xylitol, sorbitol, and sucrose; Amine initiators include diethylamine, diethylenetriamine, etc.
Polyether is generally used for propylene glycol polyether with molecular weight of 800~2000, trimethylpropane polyether with molecular weight of 400~4000 and hydroxyl terminated polytetrahydrofuran. Polyether resin used as adhesive shall remove the alkaline catalyst left during polymerization, because they will catalyze the dimerization of isocyanate and affect the quality of adhesive. It is usually neutralized with acid to make the polyether slightly acidic (without affecting the reaction of polyurethane). Polyether has strict requirements for preparing polyurethane adhesive. In addition to hydroxyl value and acid value, the content of potassium ion and sodium ion should be less than 10, and the moisture content should be less than 0.05%, otherwise gel may be generated. The polyurethane adhesive prepared with polyether resin has good water resistance, impact resistance and low temperature performance.
Polyether polyols with different functions can be prepared according to the number of active atoms in the initiator. The common polyethers used in the preparation of polyurethane adhesive are epoxy glycol, propylene trioxide, and polytetrahydrofuran glycol.
3 Main purpose
Detergent or defoamer
L61, L64 and F68 are used to prepare synthetic detergent with low foam and high detergency;
L61 and L81 defoamers used in papermaking or fermentation industry;
F68 is used as an anti foaming agent to prevent air from entering the artificial heart lung machine during blood circulation.
Excipients and emulsifiers
Polyether has low toxicity and is often used as pharmaceutical excipient and emulsifier; It is commonly used in oral and nasal sprays, eye drops, ear drops, shampoo, etc.
Wetting agent
Polyether is an effective wetting agent, which can be used in acid baths for fabric dyeing, photographic development and electroplating. When F68 is used in sugar factory, more sugar can be obtained due to the increase of water permeability.
Antistatic agent
Polyether is a useful antistatic agent, L44 can provide lasting electrostatic protection for synthetic fibers.
dispersant
Polyether is used as dispersant in latex paint. F68 was used as emulsifier in vinyl acetate lotion polymerization. L62 and L64 can be used as pesticide emulsifiers, coolants and lubricants in metal cutting and grinding. It is used as a lubricant when vulcanizing rubber.
Demulsifier
Polyether can be used as demulsifier for crude oil. L64 and F68 can effectively prevent the oil pipeline from scaling and can be used for the recovery of secondary oil.
Papermaking additive
Polyether can be used as papermaking additive, and F68 can effectively improve the quality of coated paper; It is also used as a bleach.
Preparation and application
Polyether polyol series products are mainly used to prepare rigid polyurethane foam plastics, which are widely used in refrigerators, freezers, refrigerated vehicles, heat insulation panels, pipe insulation and other fields. The product has low thermal conductivity and good dimensional stability, and is also an important raw material for preparing composite polyether.
The production of polyether polyols is mainly used for polyurethane foam in the polyurethane industry. Main varieties include epoxy polypropylene polyol, polytetrahydrofuran ether polyol, etc
