Polyether manufacturing method

Abstract

To provide a method for producing polyethers that do not generate high molecular weight polyethylene glycol as a by-product, and a method for producing polyethers that impart good moldability to resins modified with polyethers, and that impart good physical properties such as strength, elongation, and water resistance to molded articles obtained from such resins. [Solution] A method for producing a polyether to which propylene oxide and ethylene oxide are added, comprising the steps of: reacting a compound having a hydroxyl group with propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct; dehydrating the reaction mixture in the presence of an alkali metal hydroxide; and reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol.

Description

Technical Field

[0001] The present invention relates to a method for producing polyethers.

Background Art

[0002] Conventionally, generally, polyethers obtained by adding propylene oxide and ethylene oxide are produced by subjecting an initiator such as a polyhydric alcohol to ring-opening addition of an alkylene oxide such as propylene oxide in the presence of a sodium-based catalyst such as sodium hydroxide or a potassium-based catalyst such as potassium hydroxide. However, in such a conventional production method, when propylene oxide is subjected to ring-opening addition as the alkylene oxide, most of the terminal hydroxyl groups of the obtained polyether become secondary hydroxyl groups, and there is a problem that the reactivity of the polyether is low. As a method for producing a polyether having a high primary hydroxyl group conversion rate of terminal hydroxyl groups, in the first step, propylene oxide is subjected to ring-opening addition to an initiator in the presence of a double metal cyanide catalyst, and then in the second step, ethylene oxide and propylene oxide are randomly subjected to ring-opening addition, and finally in the third step, ethylene oxide is subjected to ring-opening addition in the presence of an alkali metal catalyst (see, for example, Patent Documents 1 and 2). However, in the methods described in Patent Documents 1 and 2, high molecular weight polyethylene glycol is generated, and there is a problem that the physical properties of the resin molded product from which this high molecular weight polyethylene glycol is obtained are significantly deteriorated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to provide a method for producing a polyether that does not generate high molecular weight polyethylene glycol as a by-product, and a method for producing a polyether that gives good moldability to a resin modified using the polyether, and gives good physical properties such as strength, elongation, and water resistance to a molded article obtained from such resin. [Means for solving the problem]

[0005] The inventors of this invention arrived at this present invention after diligent research. The present invention relates to a method for producing a polyether to which propylene oxide and ethylene oxide have been added, comprising the steps of: reacting a compound having a hydroxyl group with propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct; dehydrating the reaction mixture in the presence of an alkali metal hydroxide; and reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a method for producing a polyether that does not generate high molecular weight polyethylene glycol as a by-product, and a method for producing a polyether that gives good moldability to a resin modified using the polyether, and gives good physical properties such as strength, elongation, and water resistance to a molded article obtained from such resin. [Modes for carrying out the invention]

[0007] The present invention relates to a method for producing a polyether to which propylene oxide and ethylene oxide have been added, comprising the steps of: reacting a compound having a hydroxyl group with propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct; dehydrating the reaction mixture in the presence of an alkali metal hydroxide; and reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol.

[0008] <A step of reacting a compound having a hydroxyl group with propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct (hereinafter sometimes referred to as the first polymerization step)> The present invention provides a method for producing a compound having a hydroxyl group and propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct.

[0009] In the manufacturing method of the present invention, examples of composite metal cyanide catalysts (Double Metal Cyanide Complex catalysts, sometimes referred to as DMC catalysts) used as catalysts include Zn3[Fe(CN)6]2, Zn3[Co(CN)6]2, Fe[Fe(CN)6], and Fe[Co(CN)6].

[0010] As a complex metal cyanide catalyst, a catalyst having a structure in which organic ligands are coordinated to a catalytic skeleton of Zn3[Co(CN)6]2 (i.e., a zinc hexacyanocobaltate complex) is more preferred.

[0011] Examples of organic ligands include tert-butyl alcohol (hereinafter sometimes referred to as "TBA"), n-butyl alcohol, iso-butyl alcohol, tert-pentyl alcohol, iso-pentyl alcohol, N,N-dimethylacetamide, ethylene glycol mono-tert-butyl ether, ethylene glycol dimethyl ether (also called glyme), diethylene glycol dimethyl ether (also called diglyme), triethylene glycol dimethyl ether (also called triglyme), iso-propyl alcohol, and dioxane. Dioxane may be 1,4-dioxane or 1,3-dioxane, but 1,4-dioxane is preferred. One organic ligand may be used, or two or more may be used in combination. Among these, catalysts having TBA as an organic ligand are preferred because they yield polyether polyols with a narrower molecular weight distribution and lower viscosity, and the reaction proceeds more rapidly. The amount of complex metal cyanide catalyst used is preferably 0.03 to 1.00% by weight, more preferably 0.04 to 0.50% by weight, and particularly preferably 0.05 to 0.20% by weight, based on the compound having a hydroxyl group. If the amount is 0.03% by weight or more, the reaction time will not be prolonged, and if it is 1.00% by weight or less, the reaction can be easily controlled.

[0012] In the manufacturing method of the present invention, the compound having a hydroxyl group is not particularly limited as long as it is a compound having a hydroxyl group in its molecule, and two or more types may be used in combination. The number of hydroxyl groups may be one or two or more, and two to eight is preferred. The hydroxyl value (according to JIS K-1557) of compounds having hydroxyl groups is preferably 80 to 400 mg KOH / g, more preferably 120 to 340 mg KOH / g, and particularly preferably 160 to 300 mg KOH / g, from the viewpoint of quality and productivity.

[0013] Specific examples of compounds having a hydroxyl group include monohydric alcohols having 1 to 20 carbon atoms (e.g., methanol, butanol, lauryl alcohol, stearyl alcohol, and allyl alcohol), monohydric phenols having 6 to 18 carbon atoms (e.g., alkylphenols such as ethylphenol), and compounds in which alkylene oxide (hereinafter sometimes abbreviated as AO) is added and polymerized to these compounds having a hydroxyl group, as well as compounds in which AO is added and polymerized to monocarboxylic acids having 2 to 18 carbon atoms (e.g., propionic acid, acrylic acid, stearic acid, and benzoic acid) or secondary amines having 2 to 20 carbon atoms (e.g., dibutylamine), and two or more of these may be used in combination.

[0014] Specific examples of compounds having two or more hydroxyl groups include polyhydric alcohols, compounds in which AO is added and polymerized to these hydroxyl-containing compounds, and compounds in which AO is added and polymerized to polyhydric phenols, amines, and polycarboxylic acids, and two or more of these may be used in combination.

[0015] The above polyhydric alcohols include dihydric alcohols with 2 to 20 carbon atoms (aliphatic diols, e.g., alkylene glycols such as ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, neopentyl glycol; polyalkylene glycols such as diethylene glycol; and alicyclic diols, e.g., cyclohexanediol, cyclohexanedimethanol, and other cycloalkylene glycols), trihydric alcohols with 3 to 20 carbon atoms (aliphatic triols, e.g., glycerin, trimethylolpropane, trimethylol Examples include alkanetriols such as ethanolethane and hexanetriol, polyhydric alcohols with 5 to 20 carbon atoms (aliphatic polyols, such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, dipentaerythritol, and other alkanepolyols and their intramolecular or intermolecular dehydrated products; as well as sugars such as sucrose, glucose, mannose, fructose, methyl glucoside and their derivatives), natural oil-based polyols such as castor oil, and combinations of two or more of these.

[0016] Examples of polyvalent (2-8 or more valent) phenols include monocyclic polyvalent phenols such as pyrogallol, hydroquinone, and phloroglucin; bisphenols such as bisphenol A, bisphenol F, and bisphenol sulfone; condensates of phenol and formaldehyde (novolac); polyphenols as described in US Patent No. 3265641, for example; and combinations of two or more of these.

[0017] Examples of amines include those with 2 to 8 or more active hydrogen atoms, such as ammonia; aliphatic amines include alkanolamines with 2 to 20 carbon atoms (e.g., monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, and aminoethylethanolamine), alkylamines with 1 to 20 carbon atoms (e.g., n-butylamine and octylamine), alkylenediamines with 2 to 6 carbon atoms (e.g., ethylenediamine, propylenediamine, and hexamethylenediamine), and polyalkylene polyamines with 4 to 20 carbon atoms (dialkylentriamines to hexaalkyleneheptamines with 2 to 6 carbon atoms in the alkylene group, e.g., diethylenetriamine, triethylenetetramine, and tetraethylenepentamine). Other examples include aromatic mono- or polyamines having 6 to 20 carbon atoms (e.g., aniline, phenylenediamine, tolylenediamine, xylylenediamine, diethyltoluenediamine, methylenedianiline, and diphenyl etherdiamine); alicyclic amines having 4 to 20 carbon atoms (e.g., isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine); heterocyclic amines having 4 to 20 carbon atoms (e.g., piperazine, aminoethylpiperazine, and those described in Japanese Patent Publication No. 55-21044); and combinations of two or more of these.

[0018] Examples of polycarboxylic acids include aliphatic polycarboxylic acids having 4 to 18 carbon atoms (such as succinic acid, adipic acid, sebacic acid, glutaric acid, and azelaic acid), aromatic polycarboxylic acids having 8 to 18 carbon atoms (such as phthalic acid, terephthalic acid, isophthalic acid, and trimellitic acid), and mixtures of two or more of these.

[0019] When using a compound having a hydroxyl group, specifically a compound with a structure in which AO is added polymerized, it is preferably a compound with a structure in which AO is added polymerized to a polyhydric alcohol, and more preferably a compound with a structure in which AO is added polymerized to at least one polyhydric alcohol selected from diethylene glycol, glycerin, trimethylolpropane, and pentaerythritol. As the AO in the compound having an AO addition superposition structure, those having 2 to 8 carbon atoms are preferable, such as propylene oxide (hereinafter may be abbreviated as PO), ethylene oxide (hereinafter may be abbreviated as EO), 1,2-, 1,3-, 1,4-, or 2,3-butylene oxide, styrene oxide, and the combined use of two or more of these (in the case of combined use, any of random addition, block addition, and combinations thereof may be used). Preferably, it is PO and / or EO, particularly PO. The conditions for adding AO are not particularly limited, and examples include compounds obtained by adding AO at 70 to 150°C in the presence of a known alkali catalyst (such as an alkali metal hydroxide described later). Also, a commercially available AO adduct may be used.

[0020] In the production method of the present invention, the reaction mixture containing the propylene oxide adduct obtained in the first polymerization step can be obtained by reacting the compound having a hydroxyl group and propylene oxide (addition reaction) in the presence of the above-mentioned double metal cyanide catalyst. The amount of propylene oxide used in the first polymerization step is preferably 300 to 3500 parts, more preferably 500 to 2500 parts, and particularly preferably 700 to 1600 parts, relative to 100 parts of the compound having a hydroxyl group.

[0021] The first polymerization step of reacting the compound having a hydroxyl group and propylene oxide in the presence of the above-mentioned double metal cyanide catalyst can be carried out by dropping propylene oxide into a pressure-resistant reaction vessel capable of stirring and temperature adjustment, which contains the double metal cyanide catalyst and the compound having a hydroxyl group, while heating the vessel.

[0022] In the production method of the present invention, the temperature during the reaction in the first polymerization step is preferably 90 to 180°C. The lower limit of the reaction temperature is more preferably 100°C, further preferably 120°C, and the upper limit is more preferably 160°C. If the reaction temperature is lower than 90°C, the reaction time will be prolonged. If it exceeds 180°C, it will lead to the coloring of the polyol.

[0023] <A step of dehydrating the reaction mixture in the presence of an alkali metal hydroxide (hereinafter also referred to as the second polymerization step 1)> The manufacturing method of the present invention comprises a step of dehydrating the reaction mixture in the presence of an alkali metal hydroxide. In the manufacturing method of the present invention, the alkali metal hydroxide is used in the step of dehydrating the reaction mixture containing the propylene oxide adduct.

[0024] Examples of alkali metal hydroxides include lithium, sodium, potassium, rubidium, and cesium hydroxides. Preferably, sodium hydroxide, potassium hydroxide, and cesium hydroxide are used, and more preferably, from the viewpoint of reaction rate, potassium hydroxide, cesium hydroxide, and combinations thereof.

[0025] Furthermore, the sodium content in the alkali metal hydroxide is preferably 1% by weight or less, more preferably 0.2% by weight or less, and particularly preferably 0.04% by weight or less. The analytical method for sodium content may be a known method such as ion chromatography, atomic absorption spectrometry, or IPC method.

[0026] The amount of alkali metal hydroxide used is preferably 0.05 to 0.5% by weight, more preferably 0.1 to 0.4% by weight, and particularly preferably 0.1 to 0.3% by weight, based on the propylene oxide adduct obtained in the first polymerization step. If the amount is 0.05% by weight or more, the reactivity is good, and if it is 0.5% by weight or less, the alkali metal hydroxide can be easily removed.

[0027] The second polymerization step 1, which is a step of dehydrating the reaction mixture in the presence of an alkali metal hydroxide, can be carried out by mixing the alkali metal hydroxide with the reaction mixture obtained in the first polymerization step in a pressure-resistant reaction vessel that allows for stirring and temperature control, and then dehydrating the inside of the reaction vessel under reduced pressure while stirring under heating.

[0028] In the manufacturing method of the present invention, the temperature during dehydration in the second polymerization step 1 is preferably 100 to 180°C. The lower limit of the reaction temperature is more preferably 105°C, even more preferably 110°C, and the upper limit is more preferably 150°C. If the reaction temperature is lower than 100°C, the dehydration step will take a long time. If it exceeds 180°C, it will lead to discoloration of the polyol.

[0029] In the manufacturing method of the present invention, the pressure (absolute pressure) during dehydration in the second polymerization step 1 is preferably 0.00 to 0.05 MPa. The upper limit is more preferably 0.02 MPa. If it exceeds 0.05 MPa, the dehydration step will take a long time.

[0030] In the manufacturing method of the present invention, the water content after dehydration in the second polymerization step 1 is preferably 0.1% or less, more preferably 0.005 to 0.08%, and particularly preferably 0.01 to 0.03%. In this invention, the moisture content is measured by the Karl Fischer method in accordance with JIS K 0068.

[0031] <A step of reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol (hereinafter also referred to as the second polymerization step 2)> The present invention's manufacturing method includes a step of reacting a propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol.

[0032] In the production method of the present invention, the molecular structure of the tertiary alcohol is not particularly limited as long as the carbon atom to which the hydroxyl group is bonded is tertiary; it may or may not have a branched chain, and may also have a cyclic structure.

[0033] In the manufacturing method of the present invention, the amount of tertiary alcohol used is preferably 10 to 80% by weight, more preferably 13 to 60% by weight, and particularly preferably 18 to 45% by weight, based on the propylene oxide adduct obtained in the first polymerization step.

[0034] In the production method of the present invention, the tertiary alcohol preferably has 4 to 18 total carbon atoms, more preferably 4 to 12, and even more preferably 4 to 8, from the viewpoint of solvent removal. Furthermore, the tertiary alcohol may have substituents within a range that does not impair the effects of the present invention. The substituents are not particularly limited as long as they are not hydroxyl groups, and examples include alkoxy groups.

[0035] In the manufacturing method of the present invention, the tertiary alcohol is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 60 to 90°C, from the viewpoint of solvent removal.

[0036] In the manufacturing method of the present invention, the polyether obtained in the second polymerization step 2 can be obtained by reacting (addition reaction) the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of the tertiary alcohol. The amount of ethylene oxide used in the second polymerization step 2 is preferably 4 to 45% by weight, more preferably 6 to 35% by weight, and particularly preferably 8 to 25% by weight, based on the propylene oxide adduct contained in the reaction mixture. If the amount is 4% by weight or more, the rate of primary conversion of terminal hydroxyl groups increases, and if it is 45% by weight or less, the foam properties are good.

[0037] The second polymerization step 2, which involves reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of the tertiary alcohol, can be carried out by mixing the tertiary alcohol with the dehydrated reaction mixture in a pressure-resistant reaction vessel that allows for stirring and temperature control, and then adding ethylene oxide dropwise while heating the pressure-resistant reaction vessel containing the tertiary alcohol and the dehydrated reaction mixture.

[0038] In the manufacturing method of the present invention, the reaction temperature in the second polymerization step 2 is preferably 80 to 130°C. The lower limit of the reaction temperature is more preferably 85°C, even more preferably 90°C, and the upper limit is more preferably 110°C. If the reaction temperature is lower than 80°C, a polyether with a low degree of unsaturation can be obtained, but the reaction time will be longer. If the temperature exceeds 130°C, the degree of unsaturation will increase.

[0039] The polyether obtained by the production method of the present invention is preferably used as a raw material after the complex metal cyanide catalyst and alkali metal hydroxide have been removed by purification after the reaction is complete. Methods for purifying polyethers are all known and may be used. These include neutralization with an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, or acetic acid, followed by filtration of the resulting salt; using an alkaline adsorbent (e.g., synthetic magnesium silicate (e.g., Kyoward 600: manufactured by Kyowa Chemical Industry Co., Ltd.), synthetic aluminum silicate, etc.); dissolving in a solvent (such as methanol) and washing with water; using an ion exchange resin; or neutralization with carbon dioxide and filtration of the resulting carbonate. Any of these methods may be used. Furthermore, if purification is performed using water or an organic solvent, it is preferable to perform dehydration and / or solvent removal after purification. Dehydration and / or solvent removal should be performed under heating (e.g., 100-150°C) and / or under reduced pressure, if necessary. The moisture content after dehydration should preferably be 0.1% by weight or less.

[0040] The degree of unsaturation of the polyether obtained by the production method of the present invention (according to JIS K-1557) is preferably 0.001 to 0.01 mmol / g, and more preferably 0.001 to 0.005 mmol / g, from the viewpoint of foam properties.

[0041] The hydroxyl value (according to JIS K-1557) is preferably 42 mg KOH / g or less. More preferably, the lower limit is 20 mg KOH / g and the upper limit is 35 mg KOH / g. When it is 42 mg KOH / g or less, the resin properties are good.

[0042] The polyethers obtained by the manufacturing method of the present invention can be used for various applications, but polyether polyols are particularly suitable for use in producing foamed or non-foamed polyurethanes by reacting them with polyisocyanates, optionally in the presence of additives.

[0043] The method for producing polyurethane using the polyether obtained by the production method of the present invention may be a known method and is not particularly limited. The polyisocyanates used above are those that have been conventionally used in polyurethane production. Examples of such isocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, modified products thereof (e.g., modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocynurate groups, or oxazolidone groups), and mixtures of two or more of these.

[0044] Aromatic polyisocyanates include aromatic diisocyanates with 6 to 16 carbon atoms (excluding carbon atoms in the NCO group; the same applies to the isocyanates below), aromatic triisocyanates with 6 to 20 carbon atoms, and crude products of these isocyanates. Specific examples include 1,3- and / or 1,4-phenylenediisocyanate, 2,4- and / or 2,6-tolylenediisocyanate (TDI), crude TDI, 2,4'- and / or 4,4'-diphenylmethanediisocyanate (MDI), and polymethylene polyphenyl isocyanate (crude MDI).

[0045] Aliphatic polyisocyanates include aliphatic diisocyanates with 6 to 10 carbon atoms. Specific examples include 1,6-hexamethylene diisocyanate and lysine diisocyanate.

[0046] Examples of alicyclic polyisocyanates include alicyclic diisocyanates with 6 to 16 carbon atoms. Specific examples include isophorone diisocyanate (IPDI) and 4,4'-di. Examples include cyclohexylmethane diisocyanate and norbornane diisocyanate.

[0047] Examples of aromatic aliphatic polyisocyanates include aromatic aliphatic diisocyanates with 8 to 12 carbon atoms. Specific examples include xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate.

[0048] Specific examples of modified polyisocyanates include urethane-modified MDI and carbodiimide-modified MDI.

[0049] When manufacturing polyurethane foam, a foaming agent is used. As a foaming agent, water, hydrogen atom-containing halogenated hydrocarbons, low-boiling-point hydrocarbons, liquefied carbon dioxide, etc., may be used, and two or more may be used in combination. Specific examples of hydrogen atom-containing halogenated hydrocarbons include HCFC (hydrochlorofluorocarbon) types (e.g., HCFC-123 and HCFC-141b) and HFC (hydrofluorocarbon) types (e.g., HFC-245fa and HFC-365mfc). Low-boiling point hydrocarbons are preferably hydrocarbons with a boiling point of -5 to 70°C, and specific examples include butane, pentane, and cyclopentane.

[0050] Furthermore, the conditions for reacting the polyether polyol with the polyisocyanate can be any known conditions. For example, first, a predetermined amount of polyether polyol and, if necessary, additives are mixed. Next, this mixture is rapidly mixed with polyisocyanate using a polyurethane low-pressure or high-pressure injection foamer or agitator. The resulting mixture is poured into a closed or open mold (made of metal or resin), and the urethane reaction is carried out. After curing for a predetermined time, the mold is removed to obtain polyurethane. [Examples]

[0051] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, % refers to weight percent and parts refers to parts by weight.

[0052] <Example 1> (Production of polyol (A1)) (First polymerization step) In a pressure-resistant reaction vessel, 100 parts of Sannix GP-600 (manufactured by Sanyo Chemical Industries) and 0.06 parts of DMC catalyst (Zn3[Co(CN)6]2,TBA / polypropylene glycol complex, manufactured by Huaian Bud Polyurethane Science & Technology (China)) were charged. After purging with nitrogen, the contents were stirred and dehydrated under reduced pressure at 130°C until the moisture content was 0.02% or less. Subsequently, 10 parts of PO were introduced, and the internal pressure of the pressure-resistant reaction vessel initially increased, then gradually decreased, and it was confirmed that it was the same as the internal pressure of the pressure-resistant reaction vessel immediately before the introduction of PO. Thereafter, while continuing to stir the contents, 890 parts of PO were added and polymerized at a reaction temperature of 130°C. The hydroxyl value of the first intermediate polyol obtained in this process was 28 mgKOH / g. (Second polymerization step) In a pressure-resistant reaction vessel separate from the one used in the first polymerization step, 855 parts of the first intermediate polyol produced in the first polymerization step and 2.5 parts of KOH catalyst were charged. The mixture was dehydrated by reducing the pressure at 130°C until the moisture content was 0.1% or less, and the second polymerization step 1 was carried out. Subsequently, after cooling to 50°C, 317 parts of tert-butyl alcohol were charged, the temperature was raised, and the mixture was stirred at 130°C for 1 hour. After that, it was cooled to 90°C, and 143 parts of EO were added and polymerized. After that, the internal pressure stopped changing and it was confirmed that the reaction had finished, the second polymerization step 2 was completed, and a liquid crude polyether was obtained. 1000 parts of this liquid crude polyether were placed in a pressure-resistant reaction vessel, nitrogen purging was performed, 20 parts of deionized water were added, then 20 parts of magnesium silicate were added, nitrogen purging was performed again, and the mixture was stirred at 90°C for 1 hour. Next, the mixture was filtered under nitrogen to obtain polyol (A1). The obtained polyol (A1) was a simple yellow transparent, with a hydroxyl value of 28 mgKOH / g, a total unsaturation degree of 0.003 meq / g, a molecular weight distribution (Mw / Mn) of 1.13, an oxyethylene group content of 12%, and a primary conversion rate of terminal hydroxyl groups of 70%.

[0053] <Comparative Example 1> (Production of polyol (A'1)) (First polymerization step) The first polymerization step was carried out in the same manner as in Example 1 above to obtain an intermediate polyether polyol composition. The hydroxyl value of the first intermediate polyol obtained in this step was 28 mg KOH / g. (Second polymerization step) 857 parts of the first intermediate polyol produced in the first polymerization step were added to 143 parts of EO at a reaction temperature of 130°C. After the reaction was completed, the change in internal pressure ceased, and a liquid crude polyether was obtained. The obtained liquid crude polyether was cloudy at room temperature. This liquid crude polyether was filtered using the same procedure as in Example 1 to obtain comparative polyol (A'1). The obtained polyol (A'1) showed turbidity at room temperature.

[0054] <Comparative Example 2> (Production of polyol (A'2)) (First polymerization step) The first polymerization step was carried out in the same manner as in Example 1 above to obtain an intermediate polyether polyol composition. The hydroxyl value of the first intermediate polyol obtained in this step was 28 mg KOH / g. (Second polymerization step) In a pressure-resistant reaction vessel separate from the one used in the first polymerization step, 855 parts of the first intermediate polyol produced in the first polymerization step and 2.5 parts of KOH catalyst were charged, and the mixture was dehydrated by reducing the pressure at 130°C for 1 hour. Subsequently, 143 parts of EO were added and polymerized at a reaction temperature of 130°C. After the internal pressure stopped changing, it was confirmed that the reaction had finished, and a liquid crude polyether was obtained. The obtained liquid crude polyether was cloudy at room temperature. This liquid crude polyether was filtered using the same procedure as in Example 1 to obtain comparative polyol (A'2). The obtained polyol (A'2) showed turbidity at room temperature.

[0055] <Comparative Example 3> (Production of polyol (A'3)) (First polymerization step) The first polymerization step was carried out in the same manner as in Example 1 above to obtain an intermediate polyether polyol composition. The hydroxyl value of the first intermediate polyol obtained in this step was 28 mg KOH / g. (Second polymerization step) In a pressure-resistant reaction vessel separate from the one used in the first polymerization step, 855 parts of the first intermediate polyol produced in the first polymerization step and 2.5 parts of KOH catalyst were charged, and the mixture was dehydrated by reducing the pressure at 130°C for 1 hour. Subsequently, after cooling to 90°C, 317 parts of n-butyl alcohol were charged, the temperature was increased, and the mixture was stirred at 130°C for 1 hour. After that, the mixture was cooled to 90°C, and 143 parts of EO were added for addition polymerization. After that, the internal pressure stopped changing, and it was confirmed that the reaction had finished, yielding a liquid crude polyether. This liquid crude polyether was filtered using the same procedure as in Example 1 to obtain comparative polyol (A'3). The obtained polyol (A'3) had a hydroxyl value of 90 mgKOH / g, a total unsaturation degree of 0.003 meq / g, a molecular weight distribution (Mw / Mn) of 1.28, an oxyethylene group content of 12%, and a primary conversion rate of terminal hydroxyl groups of 60%.

[0056] [Table 1]

[0057] From the above results, it can be seen that the polyol obtained in Example 1 produced less high molecular weight ethylene oxide as a by-product compared to those obtained in Comparative Examples 1 and 2, and that Example 1 had better hydroxyl value, EO content, primary classification rate, and appearance compared to Comparative Example 3.

Claims

1. A method for producing a polyether to which propylene oxide and ethylene oxide have been added, comprising the steps of: reacting a compound having a hydroxyl group with propylene oxide in the presence of a complex metal cyanide catalyst to obtain a reaction mixture containing a propylene oxide adduct; dehydrating the reaction mixture in the presence of an alkali metal hydroxide; and reacting the propylene oxide adduct contained in the dehydrated reaction mixture with ethylene oxide in the presence of a tertiary alcohol.

2. The method for producing a polyether according to claim 1, wherein the degree of unsaturation of the polyether is 0.001 to 0.004 mmol / g.

3. The method for producing a polyether according to claim 1, wherein the boiling point of the tertiary alcohol is 100°C or lower.

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