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Polyether polyol (polyether for short) is a kind of organic polymer, which is prepared by the addition reaction of initiator (compound containing active hydrogen group) and ethylene oxide (EO), propylene oxide (PO), and ethylene oxide (BO) in the presence of catalyst. The largest production of polyether is to use glycerol (glycerol) as the starting agent and epoxide (usually used together with PO and EO) to produce various general polyether polyols by changing the feeding mode (mixed or separate), dosing ratio, feeding order and other conditions of PO and EO.
Boiling point>200 ℃ (lit.)
Flash point>230 ° F
Refractive index n20/D 1.466
Vapor pressure
Vapor density>1 (vs air)
Polyether polyols are oligomers with ether bonds (- R - O - R -) in the main chain and more than 2 hydroxyl groups (- OH) in the end group or side group. It is formed by ring-opening polymerization of low molecular weight polyols, polyamines or compounds containing active hydrogen with olefin oxide under the action of catalyst. Olefins are mainly propylene oxide (propylene oxide) and ethylene oxide (ethylene oxide), of which propylene oxide is the most important. The starting agents of polyols include binary alcohols such as propylene glycol and ethylene glycol, ternary alcohols such as glycerol trimethylolpropane, and polyols such as pentaeryl, tetranol, xylitol, sorbitol, and sucrose; The amine initiators are diethylamine, diethylenetriamine, etc.
Polyethers generally use propylene glycol polyether with molecular weight of 800-2000, trimethylolpropane polyether with molecular weight of 400-4000 and hydroxy-terminated polytetrahydrofuran. For polyether resins used as adhesives, the residual alkaline catalysts during polymerization should be removed, because they can catalyze the dimerization of isocyanates and affect the quality of adhesives. Generally, acid is used to neutralize the polyether to make it slightly acidic (without affecting the reaction of polyurethane). Polyether used to prepare polyurethane adhesive has strict requirements. In addition to hydroxyl value and acid value, the content of potassium and sodium ions should be less than 10, and the water 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 resistance.
Polyether polyols with different functions 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 propylene oxide glycol and propylene oxide triol, as well as polytetrahydrofuran glycol.
1. Polyether polynonalcohol can be used to produce aromatic and aliphatic versions of hard foam. In addition, they also have aromatic versions of mixed fats, usually made from recycled raw materials, usually polyethylene terephthalate (PET), which are widely used in refrigerators, refrigerators, refrigerated vehicles, insulation boards, pipe insulation and other fields
2. Polyether polyol is mainly used to produce polyurethane soft foam, polyurethane hard foam, coating, adhesive, sealant, elastomer (CASE) products
3. Polyether polynonalcohol produces foam stabilizer, paper industry defoamer, crude oil demulsifier, high-efficiency low foam detergent, lubricant, quenching agent, latex foaming agent, rubber lubricant and surfactant.
1. Pretreatment of raw materials: in the ring-opening polymerization reaction, in order to ensure the reaction speed, molecular weight control and product color and color of polyether polyol synthesis. Unsaturation, etc., First of all, purify the polymerization monomer and remove the catalyst. Water, aldehyde, oxygen, hydroxysugar and other trace impurities in the initiator and reaction system.
2. Ring-opening polymerization reaction: the ring-opening polymerization reaction using epoxide as raw material belongs to exothermic reaction, so the reaction heat should be removed with condensate in time during the reaction process. In addition, oxygen will produce oxidation and polymerization inhibition in the polymerization reaction. Therefore, before the reaction, vacuum pump must be used to pump as much air as possible in the reactor to ensure that the reaction is carried out under oxygen-free conditions. At the same time, in the reaction process, it is necessary to continuously vacuum to produce high-quality polyether polyols.
3. Post-treatment process: polyether polyols produced by polymerization must undergo post-treatment. Post-treatment mainly includes neutralization, adsorption, dehydration, filtration, distillation, etc. After a series of post-treatment, polyether polyols not only neutralized the residual impurities in the catalyst. Filter them out and use adsorbent. Dehydration. During distillation, other harmful impurities are removed to obtain polyether products with low water content, light color, no odor and good performance.
1. Polyoxypropylene glycol
Polypropylene glycol, also known as polypropylene glycol (PPG), is prepared in a glass-lined or stainless steel reactor. Add the mixture of initiator (1,2-propanediol or dipropylene glycol) and catalyst (potassium hydroxide) into the reactor for preparing the catalyst, heat it to 80~100 ℃, and remove the solvent in the catalyst under vacuum to promote the formation of alcohols. Then the catalyst is transferred into the reactor, heated to 90~120 ℃, and epoxy propane is added into the reactor at this temperature to maintain the pressure in the reactor at 0.07~0.35MPa. At this temperature and pressure, propylene oxide is continuously polymerized until it reaches a certain molecular weight. Under negative pressure, after the residual propylene oxide monomer is evaporated, the polyether mixture is transferred to the neutralization kettle, neutralized with acidic substances, and then filtered, refined, and added with stabilizer to obtain the product.
2. Polytetrahydrofuran glycol
Polytetrahydrofuran glycol (PTHF) or polyoxytetramethylene glycol (PIG, PTMEG, PTMG, PTMO) is prepared by ring-opening polymerization of tetrahydrofuran in the presence of cationic catalyst. Production process: add tetrahydrofuran in the reaction kettle, and the temperature is reduced to below - 5 ℃. Under strong stirring, drop the fuming sulfuric acid catalyst, keep the reaction material low temperature, add a certain amount of water under stirring, and heat it up to 70~90 ℃. Steam out the unreacted tetrahydrofuran monomer, and after static layering, neutralization, filtration, vacuum extraction and other processes, prepare polytetrahydrofuran glycol.
Polytetrahydrofuran glycol has a high price and is generally used to prepare high-performance polyurethane materials. Its products have excellent performance of low temperature resistance, water resistance, oil resistance, wear resistance and mold resistance.
3. Tetrahydrofuran - propylene oxide copolymer glycol
The tetrahydrofuran-propylene oxide copolymer glycol is prepared by the ring-opening polymerization of tetrahydrofuran and propylene oxide under the catalysis of lewis acid through neutralization, water washing, dehydration and filtration. The structural formula is as follows:
See Table 3-28 for product specifications of tetrahydrofuran-propylene oxide copolymer glycol. The cost of the copolyether is lower than that of pure polytetrahydrofuran glycol, and its product performance is similar to that of PTMG, which is especially suitable for manufacturing low-temperature resistant polyurethane materials (cold resistance can reach - 200 ℃).
4. Special polyether polyol
4.1 Active polyether polyol
Using primary hydroxyl group or using amino group to replace secondary hydroxyl group of common polyether end group, new varieties such as cold curing process, reaction injection molding, self skinning foam and high resilience were introduced.
4.2 Flame retardant polyether polyol
The flame retardant molecules will enter the polymer molecular chain through chemical reaction to make the flame retardant performance lasting. There are usually three methods
① Use compounds containing flame retardant elements as initiators, such as phosphorus oxychloride, antimony pentoxide, tetrahydroxymethyl phosphorus chloride and many low molecular weight phosphate esters, to react with ordinary low molecular weight polyols, and then conduct ring-opening polymerization with propylene oxide and ethylene oxide.
② Halogen-containing epoxy monomer is used as raw material for ring-opening polymerization.
③ At the same time, halogen-containing epoxy monomer and compounds containing phosphorus, antimony and other compounds are used for ring-opening polymerization with the initiator mixture to produce a composite polyether polyol.
4.3 Grafted polyether polyol
Basically, ordinary or highly active polyether polyols are used as the parent, or polyether polyols containing unsaturated bonds are used as the parent, and vinyl monomer compounds are produced by one-step copolymerization or two-step copolymerization, and then transferred to the refined container to remove the unreacted monomers, and the product is added with stabilizer.
4.4 Polytetrahydrofuran polyol
It is used to prepare high-performance polyurethane fiber, thermal plastic, synthetic leather and other products.
4.5 Heterocyclic modified polyether polyol
Aromatic rings or heterocycles are introduced into the polymer system.
| Nature of inquiries | Department | Location | Telephone | |
|---|---|---|---|---|
| Sales/distribution | Chinese polyether sales manufacturer | China | +86-19117288062 | service@skychemwin.com |
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