JP2002506897A - Method for producing polyether polyol and polyol produced therefrom - Google Patents

Abstract

  (57) [Summary] The method using an imidazole catalyst produces a polyether polyol suitable for use in the production of rigid polyurethane foam. The imidazole catalyst does not lose its reactivity even at a high temperature and can be used for the production of a polyol at a high temperature, shortening the residence time in the polyol production process and reducing energy consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for producing a polyether polyol. The present invention particularly relates to a method for producing a polyether polyol which is effective for producing a rigid polyurethane foam.

[0002] Polyether polyols are effective in producing polyurethane products. It is known to use polyether polyols in processes for making polyurethane products such as flexible foams, rigid foams, elastomers and sealants. Of these, rigid polyurethane foams are important products having both thermal and structural applications.

[0003] US Pat. No. 4,332,936 to Nodelman discloses the production of polyether polyols which are described as being particularly suitable for the production of rigid polyurethane foams. Here, it is disclosed that a polyfunctional hydroxy initiator, such as sucrose, is mixed or dissolved with dimethylformamide before reacting the initiator with the alkylene oxide in the presence of an amine catalyst.

US Pat. Nos. 5,030,758 and 5,141,968 to Dietrich et al. Disclose the production of polyether polyols using amine catalysts. These documents relate to aromatic amine-initiated polyols.

In the field of producing polyether polyols that are effective in producing rigid polyurethane foams, it is desirable to produce polyols using methods that can be used at elevated temperatures. It is also desirable in this field to produce polyols using methods involving the use of highly reactive catalysts. Furthermore, in this field, it is desirable to produce the polyol using a method in which the catalyst is highly reactive at high temperatures. It is also desirable to produce the polyether polyol in the final polyether polyol diluent under conditions of imidazole catalysis, characterized by the reaction of the initiator and the reaction of the diluent with the alkylene oxide.

In one aspect, the invention comprises mixing an initiator with an alkylene oxide in the presence of an imidazole catalyst at high temperature alkoxylation conditions sufficient to produce a polyether polyol, provided that the aromatic amine initiator When using an agent,
A process for producing a polyether polyol, wherein the alkoxylation is carried out at a temperature higher than 125 ° C.

[0007] In another aspect, the invention comprises mixing an initiator with an alkylene oxide in the presence of an imidazole catalyst at high temperature alkoxylation conditions sufficient to produce a polyether polyol, provided that the aromatic amine If an initiator is used, it is a polyether polyol produced by the process, wherein the alkoxylation is carried out at a temperature above 125 ° C.

[0008] In one embodiment, the invention is a method of making a rigid polyether polyol in the presence of an imidazole catalyst. In the present invention, the imidazole catalyst is any compound having the formula:

[0009]

Embedded image (Where X, Y, Z, and Z ′ are hydrogen, a methyl group, an ethyl group, or a phenyl group, and include imidazole, N-methylimidazole, 2-methylimidazole,
4-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, N-phenylimidazole, 2-phenylimidazole, and 4
-Combined to include phenylimidazole). Combinations of these compounds may also be used, hereinafter referred to as imidazole catalysts.

[0010] In the process of the present invention, the polyol is prepared by mixing the initiator with the alkylene oxide in the presence of an imidazole catalyst. The initiator is at least 2
It is an effective starting material for the production of polyols, characterized in that it contains one active hydrogen-containing group. In the present invention, an active hydrogen-containing group is a group having a hydrogen capable of reacting with an alkylene oxide in the presence of an imidazole catalyst. Preferably, the active hydrogen containing group is an amino or hydroxy group. The active hydrogen-containing group may be an aliphatic molecule or an aromatic molecule. For example, initiators useful in the present invention are aliphatic alcohols or amines having at least two active hydrogen containing groups. In addition, an effective initiator in the present invention is an aromatic diamine or polyamine.

The initiators useful in the present invention include water, organic dicarboxylic acids such as succinic, adipic, phthalic and terephthalic acids, aliphatic and aromatic, having from 1 to 4 carbon atoms in the alkyl moiety. Unsaturated or N-mono, N, N- and N, N'-dialkyl-substituted diamines, such as unsubstituted or mono- or dialkyl-substituted ethylenediamine, diethylenetriamine, triethylenetetraamine, 1,3-propylenediamine, 1,3- and 1,4-butylenediamine, 1,2-, 1,3-, 1
, 4-, 1,5- and 1,6-hexamethylenediamine, phenylenediamine,
2,3-, 2,4- and 2,6-tolylenediamine, and 4,4'-, 2,4 '
-And 2,2'-diaminodiphenylmethane. Other suitable initiator molecules useful in the present invention are alkanolamines such as ethanolamine, N-methyl- and N-ethylethanolamine, dialkanolamines such as diethanolamine, N-methyl- and N-ethyl-diethanolamine, And trialkanolamines, such as triethanolamine, and ammonia.

[0012] Preferably, the initiator used in the present invention is a polyhydric alcohol, especially a dihydric and / or
Or Mannich-based polyols obtained from trihydric alcohols such as ethanediol, nonylphenol, bisphenol A, bisphenol F, novolak phenolic resins, formaldehyde and phenol or alkylphenol reacted with diethanol or dipropanolamine (Mannich base),
Propylene glycol, dipropylene glycol, 1,4-butanediol, 1
, 6-hexanediol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, alpha methylglucoside and sucrose.
In the present invention, since the reaction product of water and the alkoxide is a dihydric alcohol,
Water is a dihydric alcohol. More preferably, the initiator used in the present invention is glycerin, water, sucrose and mixtures thereof.

The initiator useful in the present invention may be an alkoxylated product of the above initiator molecules. For example, in a preferred embodiment, an effective initiator for the present invention is propoxylated or ethoxylated ethylene glycol. Another example of a similarly effective initiator is propoxylated or ethoxylated glycerin. Yet another example of a similarly effective initiator is propoxylated or ethoxylated propylene glycol.

In the present invention, a mixture of initiators may be used, and is preferred. Examples of mixed initiators include sucrose and water, glycerin and sorbitol, propylene glycol and sucrose, and mixtures of ethylene glycol and sucrose. More preferably, the initiator used in the present invention is a propoxylated mixed initiator. Most preferably, the initiator used in the present invention is a propoxylated mixture of sucrose and glycerin.

In the process of the present invention, the polyol is prepared by mixing the initiator with the alkylene oxide in the presence of an imidazole catalyst. Alkylene oxides that can be used in the present invention include those that are effective in producing polyether polyols. Preferably, the alkylene oxide has 2 to 8 carbons. More preferably, the alkylene oxide has 2 to 4 carbons. Most preferably, the alkylene oxide is ethylene oxide, propylene oxide,
Butylene oxide and mixtures thereof.

The polyol produced by the method of the present invention can be used for applications in which similar conventional polyols can be used, but is particularly effective in producing a rigid polyurethane foam. Polyols useful for making rigid polyurethane foams typically have an OH functionality of 2-8, an OH number of 200-2000, and a molecular weight of 62-2000. These ranges represent the reaction products resulting from the alkoxylation of an initiator such as water with a low OH functionality of 2 and an initiator such as sucrose with a high OH functionality of 8. The invention also encompasses the alkoxylation of initiators with intermediate functionality as well as mixtures of initiators.

Preferably, the polyols of the present invention have an average functionality of 2 to 8 and an OH of 200 to 800.
And a molecular weight of 150-2400. More preferably, the polyols of the present invention have an average functionality of 3-8, an OH number of 200-600, and a molecular weight of 300-2400. Most preferably, the polyols of the present invention have an average functionality of 4-8, an OH number of 300-600, and a molecular weight of 350-1600.

In the method of the present invention, the reaction between the initiator and the alkylene oxide is performed in the presence of an imidazole catalyst. Preferably, 0.0001 to 0.01 parts of the imidazole catalyst is used. Most preferably, 0.001 part of the imidazole catalyst is used. The amount of catalyst is calculated by dividing the mass of the imidazole catalyst by the total mass of product produced and diluent present in the reactor.

In the process of the present invention, the reaction between the initiator and the alkylene oxide is carried out at a high temperature alkoxylation condition sufficient to produce a polyether polyol. The production of conventional polyether polyols by conventional methods is well known to those skilled in the art of producing polyols. The high-temperature alkoxylation conditions of the present invention are substantially the same except that the temperature at which the alkoxylation is carried out is not lower than 100 ° C. and not higher than the decomposition or discoloration temperature of the polyol. These conditions range from 10 psig (69 kPa) to 100 psig (
690 kPa) and a temperature between 100 ° C and 150 ° C. More preferably, the high temperature alkoxylation conditions are at a pressure of 30 psig (206 kPa) to 80 psig (551 kPa). Even more preferably, the temperature for these high temperature alkoxylation conditions is from 120C to 150C. Most preferably, the temperature for the high temperature alkoxylation conditions is between 130C and 145C. When the process of the present invention is used to make a polyol from a composition containing an aromatic amine initiator, the alkoxylation is performed at a temperature greater than 125 ° C.

The advantage of the imidazole catalyst used in the process of the present invention is that when compared to other conventional amine catalysts such as triethylamine, trimethylamine and methyldiethylamine, the imidazole catalyst has a level of reactivity at conventional alkoxylation temperatures. The high and temperatures up to the decomposition temperature of most polyols and initiators increase the reactivity of the imidazole catalyst. For example, trialkylamine catalysts begin to decrease in catalytic activity as the alkoxylation temperature increases starting at about 110 ° C, while imidazole catalysts continue to increase in catalytic activity until the reaction temperature reaches at least 150 ° C. The ability to use the process of the present invention at elevated temperatures will increase the reaction rate and reduce the residence time, as well as reduce the energy expended in producing the polyether polyol.

Another advantage of amine catalysts, especially imidazole catalysts, is that the initiator can be alkoxylated in a polyol diluent without alkoxylation of the diluent using the method using the catalyst. Suitable diluents are polyether or polyester polyols prepared such that at least two, preferably three, alkylene oxides are added to each active hydrogen of the initiator. Amine catalysts only catalyze the addition of one to three alkylene oxides per initiator active hydrogen, so polyols with more than two alkylene oxide groups added without further reaction of the polyols with the alkylene oxides Can be used as a diluent. This is particularly advantageous when alkoxylating solid initiators such as sucrose and sorbitol. This is particularly advantageous if it is desired to produce a substantially homogeneous polyol made from a solid initiator. This is because a polyol that is substantially the same as the desired product, the polyol, can be used as a solvent for the initiator.

[0022] Polyols are made by both continuous and batch processes. In a batch process, the polyol is made by adding the components of the composition in one or more steps, but essentially all of the components in one step. For example, all of the initiator for the polyol is charged to the reactor at the start of the reaction. The polyol production process is then performed on the raw material “batch” to produce one polyol “batch”. In contrast, in a continuous process, the raw materials are continuously supplied to the production unit. The imidazole catalyst of the present invention can be used for both a batch method and a continuous method.

The polyol produced by the method of the present invention can be used in the same manner as a similar conventional polyol produced by a conventional method. For example, the polyols of the present invention can be used as produced or with additives. If desired, the polyols of the present invention may be mixed with other types of polyols.

The following examples illustrate the invention. This example does not limit the scope of the invention. Unless indicated otherwise, amounts are parts by weight or percent by weight.

EXAMPLES Example 1 A mixture of 300 g of glycerin and 0.5 g of 2-ethyl-4-methylimidazole was prepared by:
Heat to 100 ° C. in a 1 liter pressure reactor equipped with a stirrer. When the vessel reached thermal equilibrium, the vessel was charged with 11.96 g of propylene oxide. The initial concentration of propylene oxide was determined by gas chromatography to be 1.8 percent. After 195 minutes, the concentration of propylene oxide was 0.04 percent.

Example 2: 10.6 pounds (4.8 kg) of VORANOL 490 (trade name of The Dow Chemical Company)
And 7.1 pounds (3.2 kg) of VORANOL 370 (trade name of The Dow Chemical Company) were added to a 20 gallon (75.7 L) pressure vessel. To this was added 0.1 pounds (45.4 g) of 2-ethyl-4-methylimidazole and 16 pounds (7.3 kg) of sucrose. The mixture was heated and stirred under nitrogen until a thermal equilibrium of 120 ° C. was reached. Next, 43 pounds (19.5 kg) of propylene oxide were added at a rate of 0.11 pounds (49.9 g) / min, and the mixture was kept at 120 ° C. for 5 hours. The final product is analyzed for physical properties and
The viscosity at F (98.8 ° C.) I was 78.7 Cs, the hydroxyl content was 10.73 percent, and the Gardner color was 13.

Example 3 An experiment was conducted in which 1-methoxy-2-propanol was reacted with propylene oxide using trimethylamine and 2-ethyl-4-methylimidazole as catalysts. The reaction was performed in a 1 liter stainless steel pressure vessel heated by an electric coil heater to control the temperature. The vessel was charged with about 300 g of 1-methoxy-2-propanol, sealed, and then purged with nitrogen to remove oxygen.
In the experiment using trimethylamine as a catalyst, 300 mL of trimethylamine catalyst was added as a gas using a 50 mL syringe. In experiments using 2-ethyl-4-methylimidazole, 0.52 g of 2-ethyl-4-methyl-4-propanol was added.
Methyl imidazole was introduced into the pressure vessel. The vessel was then agitated and heated to the indicated reaction temperature, and about 6 g of propylene oxide was transferred by pressure from another small pressurized vessel to the reaction vessel using nitrogen gas. Samples were removed using a connected dip tube and analyzed for a) amine content by titration and b) unreacted propylene oxide (PO) content by gas chromatography. The PO content was also quantified by including about 6 g of methyl t-butyl ether as an unreacted internal standard for gas chromatography.

The reaction rate was determined by plotting the unreacted PO concentration against time. When the plot of In (natural logarithm) of PO concentration (wt%) is a straight line, it gives a first-order rate constant for comparing reaction rates. When comparing between experiments with different amine catalyst concentrations, a second order rate constant is obtained by dividing this slope by the molarity. The following table shows the kinetic data for these reactions. The kinetics of the propoxylation depends on the amine catalyst and the polyol reactant. Low equivalent weight alcohols or polyols react faster than already propoxylated materials. The rate of propoxylation decreases with reaction temperature for trimethylamine and increases for imidazole.

[0029]

[Table 1] 2MP = 1-methoxy-2-propanol EMI = 2-ethyl-4-methylimidazole NMI = N-methylimidazole Suc-glyc is a 60/40 mass ratio of sucrose / glycerin propoxylated to an OH value of 370. The base polyether polyol. The basicity is determined by titration, and the unit is milliequivalent / g. The slope is the slope of the plot of IN PO against time (minutes). The rate is the slope divided by the base concentration and the unit is g / equivalent-min. The titration analysis of the catalyst was performed by adding about 5 g of sample to 50 mL of methanol. This was titrated using a Mettler DL40 automatic titrator (Mettler DL40 is a trade name of Mettler Company). Total basicity was determined as the sum of all endpoints of the titration. Gas chromatography analysis was performed using a 10 meter long, 50 μm id glass capillary column coated with a polydimethylsiloxane stationary phase. The reaction vessel was also charged with 6 g of methyl t-butyl ether used as an internal standard. MT
By comparing the peak areas of BE and propylene oxide and their relative response factors, the concentration of unreacted propylene oxide in the liquid phase can be calculated.

Example 4: Sucrose / glycerin based polyol in a 60/40 weight ratio propoxylated to an OH number of about 150 (10.8-11.6% OH, viscosity 0.89-1.17 poise)
(0.089-0.117 Ns / m ² )) was used as the reaction solvent. 468 g of this polyol were mixed with 419 g of sucrose and 1.82 g of N-methylimidazole. This mixture is
Stir in a 4 liter pressure vessel heated to 130 ° C. and kept at 130 ° C. ± 0.5 ° C. during the reaction. Over a period of 4.1 hours using a negative pressure displacement pump, 1113 g of propylene oxide were added. During the last two hours, the amount of residual propylene oxide was determined by monitoring the reactor pressure. Rate constants were obtained by plotting the natural log of the pressure against the time until the pressure was constant. The slope of this plot is -0.07
A linear linear plot with a slope of 56 / min was given. Dividing this value by the catalyst concentration at the end of the reaction (1040 ppm or 0.0127 meq / g) gave a second order rate constant of 5.95 g / meq.-min. The resulting product had an OH number of 12.16% and a viscosity at 210 ° F. of 1.05 poise (0.105 Ns / m ² ).

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG, KP , KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW (72) Inventor Kayler, Charles M. United States, Texas 77566, Lake Jackson, South Carla Lily Court 55 F Term (Reference) 4J005 AA04 AA07 AA08 AA12 AA14 BB01 BB02 4J034 BA03 DA01 DB03 DB05 DB07 DG03 DG04 DG05 DG09 DG14 DG15 DG16 DG23 KD12 KE02 Q

Claims (10)

[Claims] 1. Includes mixing an initiator with an alkylene oxide in the presence of an imidazole catalyst at high temperature alkoxylation conditions sufficient to produce a polyether polyol, provided that an aromatic amine initiator is used. , A process for producing a polyether polyol, wherein the alkoxylation is carried out at a temperature higher than 125 ° C. 2. The method of claim 1, wherein said polyether polyol is effective in producing a rigid polyurethane foam. 3. The method according to claim 2, wherein said initiator is a mixture of aliphatic alcohols. 4. The method according to claim 3, wherein said initiator is a mixture of glycerin and sucrose. 5. The method according to claim 1, wherein the imidazole catalyst is imidazole, N-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, N-phenylimidazole,
3. The method of claim 2, wherein the method is selected from the group consisting of -phenylimidazole, 4-phenylimidazole, and mixtures thereof. 6. The method of claim 5, wherein said imidazole catalyst is 2-ethyl-4-methylimidazole. 7. The method of claim 2, wherein said alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof. 8. The method of claim 7, wherein said alkylene oxide is propylene oxide. 9. The method of claim 2, wherein said high temperature alkoxylation conditions include a temperature of from 120 ° C. to 150 ° C. 10. The method of claim 2, wherein said polyether polyol has an average functionality of 4-8.