Polyether polyols with increased functionality

Details Polyether polyols with increased functionality Polyether polyols with increased functionality

2001-12-13

2003-04-15

Cooney, Jr., John M. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Cellular products or processes of preparing a cellular...

C252S182260, C252S182270, C252S182340, C521S166000, C521S174000, C568S583000, C568S606000, C568S704000, C568S712000

Reexamination Certificate

active

06548564

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a process for the preparation of a polyether polyol having a functionality of at least about 3, a molecular weight of from about 560 to about 35,000 and an OH number of from about 10 to about 1,100. This process comprises reacting (a) a polyether polyol containing one or more ether groups, having a functionality of about 2 to about 8, a molecular weight of about 106 to about 12,000, and an OH number of about 28 to about 1,400, with (b) cyanuric chloride, optionally, in the presence of (c) one or more catalysts; wherein the functionality of the resultant polyether polyols equals three times the functionality of (a) the polyether polyol, minus three. This invention also relates to the process of reacting a polyether polyol, formed by the stated reaction with cyanuric chloride, with an alkylene oxide, optionally in the presence of a catalyst, to form a polyether polyol that has a higher molecular weight and a functionality greater than or equal to the functionality of the polyether polyol used as the starter in this process.
BACKGROUND OF THE INVENTION
High functionality polyether polyols with acceptable viscosities are used as the isocyanate-reactive component in the production of rigid polyurethane foams. Polyether polyols are conventionally prepared by the alkoxylation of a suitable starter, which contains one or more OH or NH groups in the presence of a suitable catalyst. Commonly used rigid foam polyols have OH numbers from 350 to 650, viscosities at 25° C. range from 300 mPa·s to 35,000 mPa·s. Suitable starter materials used to produce polyether polyols include glycols, glycerin, trimethylolpropane, sorbitol, sucrose, and aliphatic and aromatic amines. Propylene oxide is the most commonly used alkylene oxide. Further, in order to produce rigid polyurethane foams it is necessary to employ a polyether polyol with a functionality greater than 3. Therefore, the alcohols employed to produce polyol must have a high functionality in order to admix and react with the alkylene oxides and obtain a functionality greater than 3.
It is known to prepare sucrose polyether polyols by reacting sucrose with alkylene oxide in an aqueous solution in the presence of sodium hydroxide. See, for example, LeMaistre, et al., J. Org. Chem., 13, p. 782, (1948). U.S. Pat. Nos. 3,085,085 and 3,153,002 disclose a process based on this reaction in which sucrose is reacted at elevated temperatures with ethylene oxide or propylene oxide in a concentrated aqueous solution in the presence of potassium hydroxide catalyst.
Most processes for sucrose based polyether polyols described in the literature involve the reaction of the sucrose with alkylene oxide in volume. This reaction has the advantage that products of high functionality (i.e. 7 to 8) are obtained and that the reaction time is short. In this way the sucrose is suspended in the alkylene oxide. However, in this way polyether polyols with high viscosity normally between 40,000 and 400,000 centipoises at ambient temperature, are obtained. This is not practical since problems are caused in the handling of the high viscosity polyether polyol in normal foaming machines. Also, there is a risk represented by handling large quantities of alkylene oxide within the reactors at the reaction temperature due to the high vapor pressure, which makes this highly explosive.
U.S. Pat. No. 3,941,769 discloses a process in which sucrose is reacted with epoxide in an organic; dispersing agent such as benzene, toluene, ethylbenzene, xylene or chlorobenzene (boiling range 80°-180° C.). This process has some serious disadvantages, however. First, the dispersing agents lower the reaction capacity by 10-40%. Second, the dispersing agent must be removed at the end of the production process. The products obtained by this process have high functionalities and high viscosities (104,000-400,000 mPa·s) due to the degree of alkoxylation. These also exhibit an intense brown color.
U.S. Pat. No. 4,380,502 discloses the use of polyether polyols made by alkoxylating a mixture which is from 20 to 80 wt. % sucrose and 80 to 20 wt. % formitol. This reference discloses that the polyether polyols prepared therein exhibit a color ranging from clear to yellowish.
U.S. Pat. No. 4,230,824 discloses a method for preparing a sucrose based polyether polyol which involves the use of a polyalkylene polyamine as both co-initiator and catalyst for the alkoxylation reaction of sucrose. This reference reports that the resulting polyether polyols are very high in color content.
U.S. Pat. No. 4,996,310 discloses a polyol-polyether having a molecular weight between 400 and 900, a viscosity between 500 and 3,500 centipoises at 25° C., and a content of ethylene oxide between 40% and 75% by weight. The polyether polyol is prepared by a process which comprises the steps of: (a) forming a suspension of sucrose in a triol; (b) reacting the mixture obtained in the prior step with propylene oxide in the presence of a catalyst; (c) suspending sucrose in the mixture obtained in the prior step; (d) oxyethylizing the mixture of step (c); and (e) eliminating the volatile components of the mixture and the catalyst.
U.S. Pat. No. 5,625,045 discloses a method for preparing high functionality, low viscosity, light colored sucrose-based polyethers polyols by reacting a starter mixture containing i) sucrose, ii) a low molecular weight, relatively high valency alcohol and/or an alkoxylation product of such an alcohol and iii) an alkali metal hydroxide, with an alkylene oxide at a temperature of from about 90° to about 130° C. and at a pressure of from about 0.3 to about 4 bar excess nitrogen pressure. These sucrose based polyether polyols are suitable for use in rigid polyurethane foam applications.
U.S. Pat. No. 4,332,936 describes a method for making polyether polyols from solid initiator compounds containing from 4 to 8 hydroxyl groups. The method involves dissolving the solid initiator compound in a solvent such as dimethyl formamide prior to alkoxylation.
The method is particularly useful in making high functionality sucrose-based polyether polyols that can be readily processed at moderate temperatures and give low color products. These polyether polyols are particularly suited for the production of rigid polyurethane foams.
U.S. Pat. No. 4,820,810 discloses that urea is an effective catalyst and co-initiator for the alkoxylation of aqueous sucrose solutions and results in polyether polyol products with low color content.
U.S. Pat. No. 4,446,313 describes a process for the manufacture of a polyether polyol by reaction between an organic compound containing 2 or more active hydrogen atoms in the molecule and an alkylene oxide in the presence of a catalyst comprising a tertiary amine. Suitable tertiary amine catalysts have the formula NRR′
2
in which R is a cycloalkyl or cycloalkenyl group and each R′ may be an alkyl, cycloalkyl or cycloalkenyl group.
U.S. Pat. No. 5,596,059 discloses polyoxyalkylene polyether polyols suitable for preparation of flexible polyurethane foams. These are prepared by oxyalkylating an aqueous solution of one or more polyhydric, hydroxyl-functional solid initiators under conditions where both water as well as initiator are oxyalkylated. The polyether polyols have calculated functionalities of between about 2.2 and 4.0 and hydroxyl numbers in the range of 10 to 180. The polyether polyols may be used to prepare soft, high resiliency polyurethane flexible foams at low isocyanate indexes.
EP 491233A1 discloses low viscosity, highly functional polyetherols obtained by reaction of a compound containing 2 to 8 active hydrogens in the form of hydroxyl groups, thiol groups, primary amino groups and/or secondary amino groups with one or more epoxides in the presence of a base to form an intermediate. This intermediate is further reacted with a q-valent compound that contains at least one epoxy group and at least one chlorine or bromine atom to form the polyetherols. The chlorine containing compounds referred to are epichlorohydrin types molecules

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