CA2143972A1

CA2143972A1 - High functionality polyether polyols containing hydroxyl groups and a process for the production thereof

Info

Publication number: CA2143972A1
Application number: CA002143972A
Authority: CA
Inventors: Pramod Gupta; Herbert Gebauer; Hans-Joachim Sandhagen
Original assignee: Individual
Current assignee: Bayer AG
Priority date: 1994-03-09
Filing date: 1995-03-06
Publication date: 1995-09-10
Also published as: BR9501005A; ES2125501T3; DE59504657D1; DK0671424T3; EP0671424A1; DE4407904A1; ATE175218T1; JPH07286039A; EP0671424B1

Abstract

Relatively high functionality, modified polyether polyols containing hydroxyl groups and having a very low double bond content with a total functionality of (nx-my) are produced by reacting n mol of a starting polyether polyol having a functionality x, optionally in the presence of a catalyst, with m mol of a compound containing at least one group reactive with hydroxyl functions, which compound has a functionality y at a temperature of from about 40 to about 200°C. The compound containing at least one group which is reactive with hydroxyl groups is selected from (a) diisocyanates and polyisocyanates and (b) polycarboxylic acids and their anhydrides.

Description

` - 21~3972 Bg/m-637PE
~IIGE~ FUNCTIONALITY POLY~; l H~;K
POLYOLS CONTAIN~NG ~YDROXYL GROUPS
AND A PROCESS FOR TE~E PRODUCTION TEIEREOF

BACKGROUND OF T~E ~VENTION

This invention relates to high functionality, modif~led polyether polyols containing hydroyl groups and having a very low content of double bonds and to a process for the production thereof.
Polyether polyols may be obtained by polyaddition of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide onto 5 compounds with active hydrogen atoms (starter compounds) such as alcohols, amines, acid amides, and phenols. Such polyether polyols are useful for the production of polyurethane plastics, surfactants and lubricants.
Polyaddition of epoxides onto starter compounds is generally carried out using an alkali catalyst. The most commonly used alkali catalysts are alkali hydroxides. However, polyether polyols produced with alkali catalysts are contaminated with monofunctional polyethers having 25 tèrminal double bonds. These monofunctional polyethers are formed by rearrangement of epoxides (e.g., propylene oxide) to form allyl or propenyl alcohols which may then act as starters for further alkali- --catalyzed polyaddition. In an analogous reaction, ethylene oxide produces monofunctional ethers with a terminal vinyl ether structure.
The proportion of monofunctional polyethers increases only as the - resultant polyethers increase in chain length or decrease in OH value.
For this reason, it is virtually impossible to produce polyethers in which the individual polyether chains achieve molecular weights of from about 2,000 to about 2,500 which are free of monofunctional polyethers having terminal doublë- bonds from starter compounds and propylene oxide.

Le A 30 007-FC - 1-The relatively high contenl of monofunctional polyethers obtained in conventional alkali hydroxide catalyzed processes rednces the desired functionality of the polyether. Such a loss of functionality is not desirable in the production of for example polyu, etl ,a"e elaslor"ers.
s In general monofunctional materials are disadvantageous in polyurethane polyaddilion processes because they act as chai terminators.
It is known from the literature that polyether polyols produced using metal-cyanide coil,plexes as the catalyst (U.S. Patent 4 985 491) l0 have very low conlents of monofunctional polyethers with terminal double bonds. This process also allows the production of higher molecular weight polyether polyols than does the alkali-catalyzed process. One disadvantage of this known process is the use of a metal-cyanide catalyst. Ethylene oxide addition cannot be salisra.;torily performed (EP-5 A 0 406 440 page 3 lines 24-27) using a metal-cyanide catalyst.
Further removal of the metal cyanide catalyst and disposal by any of the known processes is complicated.
EP-A 0 369 487 recol"r"el,ds the use of catalyst containing barium and strontium for the production of polyether polyols having low 20 double bond cGnlel,ls. Use of these catalysts is very complicated and consequently uneconomical. Removal of these catalysts may also be problematic.

SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for 25 the production of polyether polyols with a functionality at least as high as that of starter without the use of alkali hydroxide metal cyanide barium or strontium catalysts.
It is another object of the ~ ese"l invention to provide a process for the production of high functionality polyether polyols than that 30 of starters having low double bond conlenLs in which the use of uneconomical catalysts is unnecessary.

It is a further object of the present invention to provide high functionality polyether polyols having low double bond conte"ls than those generated by alkali catalysed process.
These and other objects which will be appare"l to those skilled 5 in the art are accomplished by reacting n mols of a starting polyether polyol having a functionality of x with m mols of a compound having a functionality of y which compound has groups that are reactive with hydroxyl groups. If more than one starting polyether polyol is used, the value of x for each polyether polyol may be the same or it may be 10 different. The polyether polyol(s) produced by this reaction is(are) highly functional, modified polyether polyol(s) having a total functionality of (nx-my).

DETAILED DESCRIPTION OF THE INVENTION
In the practice of the present invention, n mols of at least one 15 hydroxy-functional starting polyether having a functionality x (where more than one hydroxy-functional sla, li"g polyether is used, x may represent the same or a dirrerenl value for each polyether polyol) are reacted with m mol of a compound having a functionality y and groups which are reactive with hydroxyl groups to produce one or more highly functional 20 modified polyethers conlaining hydroxyl groups and having a total functionality of (nx-my).
For example, a modified polyether polyol having a calculated functionality of 4 may be obtained by reacting two mols of a trifunctional polyether polyol with one mol of a difunctional compound having groups 2 5 reactive with hydroxyl functions. Two mols of a hexafunctional polyol produce a modified polyether polyol having a calculated functionality of 10 when that hexafunctional polyol is reacted with 1 mol of a hydroxyl-reactive compound having a functionality of 2.
Polyethers with functionalities such as 10 are not obtainable by 3 o conventional polyether production processes.
The presenl invention provides relatively highly functional, modified polyether polyols containing hydroxyl groups and having a very low double bond contenl with a total functionality of (nx-my) which could be two or higher. These modified polyether polyols are produced by reacting n mol of a starting polyether polyol of a functionality x, optionally in the presence of a catalyst, with m mol of a cGr"pound containing at 5 least one group reactive with hydroxyl functions, which compound has a functionality y and is selected from (a) polyisocyanates and (b) poly-carboxylic acids at 40 to 200C.
It is prererr~d that the compound cG"laining at least one group reactive with hydroxyl functions be selected from (a) di- or triisocyanates 0 and (b) di- or tricarboxylic acids. It is also prerer,ed that the starting polyether polyol(s) have a functionality of from about 2 to about 8 and an OH value of from about 28 to about 400.
In prerer,ed embodiments of the process of the present invention, the reaction of the starting polyether polyol with the compound 5 containing groups reactive with hydroxyl functions is pe, rormed either (a) at 40 to 1 50C, most prererably at 60 to 1 20C when a polyisocyanate is used as the hydroxyl-reactive compound or (b) at 120 to 220C, most prereral)ly at 130 to 1 80C when a polycarboxylic acid is used as the hydroxyl-reactive compound.
Reaction of the starting polyether polyol(s) with a polyisocyanate may be performed either discontinuously in a reaction vessel or continuously in a tubular rea~or. The starting polyether polyol and the polyisocyanate may be fed separately into the tubular reactor, upstream from which a static mixer is arranged.
2 5 Relatively highly functional, modified polyether polyols conlaining hydroxyl groups and having a very low double bond content and a total functionality of (nx-my) obtainable by reacting n mol of starting polyether polyols of variable functionality x and chain length with m mol of a polyisocyanate or polyca, I oxylic acid in accordance with the process of the present invention are particularly prerer,ed.
Starting polyethers useful in the process of the present invention include the alkoxylation products of starter compounds having molecular weights of up to 400 and having from 2 to 8 hydroxyl, thiol ~14~972 and/or amino groups. Specific examples of starter co, ~ ounds from which suitable starter polyether polyols may be made include: ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,4-butanediol, hexamethylene glycol, bisphenol A, tl imetllylGlpropa"e, glycerol, 5 pentaerythritol, sorbitol, sugar (sucrose), degraded starch, water, methylamine, ethylamine, propylamine, butylamine, aniline, benzylamine, o- and p-toluidine, a"~-naphlllylamine, ammonia, ethylenediamine, propylenediamine, 1,4-butylenediamine, 1,2-, 1,3-, 1,4-, 1,5- and 1,6-hexamethylenediamine, o-, m- and p-phenylenediamine, 2,4-, 2,6-0 tolylenediamine, 2,2'-, 2,4- and 4,4'-diaminodiphenylmethane and diethylenediamine, or mixtures of these compounds. Ethylene oxide, propylene oxide, butylene oxide and mixtures thereof may be used as the epoxides.
Synthesis of the polyether chains by alkoxylation may be 5 carried out with only a monomeric epoxide or it may also proceed rando",ly or in blocks with two or more dirrere"t monomeric epoxides.
Further details with respect to the production of such starter polyethers may be found in Ullmanns, EncycloPadie der industriellen Chemie.
English edition, 1992, Volume A21, pages 670-671. The sta, ling 2 o polyethers used in the process of the present invention preferably have a functionality of from about 2 to about 8 and an OH value of from about 28 to about 400.
Diisocyanates and polyisocyanates which are useful as the cor"pound having groups which are reactive with hydroxyl groups 25 include: aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates. Such isocyanates are described, for example, by 21~97~ -W. Siefken in Justus I iebigs Annalen der Chemie, 562, pages 75 to 136.
Examples of suitable isocyanates are those represented by the formula Q(NCO)n in which 5 n represents 2 or3, and Q represents an aliphatic hydrocarbon residue having from 2 to 18 (preferably 6 to 10) carbon atoms, a cycloaliphatic hydrocarbon residue having from 4 to 15 (preferably 5 to 10) carbon atoms, an aromatic hydrocarbon residue having from 6 to 15 (preferably 6 to 13) carbon atoms or an araliphatic hydrocarbon residue ha~ing from 8 to 15 (preferably:8 to 13) carbon atoms.
Specific examples of suitable-isocyanates include: hexamethylene diisocyanate (HDI); -1,4-cyclohexyl diisocyanate and the isomers thereof;
isophorone diisocyanate (IPDI); dimeryl diisocyanate (Ullmanns 15 Encyclopadie der Industriellen Chemie, English edition, 1992, Volume A21, bottom of page 668); 4,4'-diisocyanato-dicyclohexylmethane and the isomers thereof; 2,4-tolylene diisocyanate and the isomers thereof (TDI);

4,4'-methylene-diphenyl diisocyanate and the isomers thereof (MDI); 1,5-naphthalene diisocyanate; tris-(4-isocyanatotriphenyl)-methane; and 20 mixtures of these isocyanates.
Other useful polyisocyanates include: modification products of the above-listed polyisocyanates having urethane, carbodiimide, urea or uretidione structures or mixtures thereof.
Organic polycarboxylic acids having from 2 to 20 carbon atoms, 25 preferably from 2 to 15 carbon atoms, and a functionality of 2 or 3 may be used as the polycarboxylic acid to be reacted with the starter polyether polyol in accordance with the process of the present invention.
Specific examples of suitable polycarboxylic acids include: malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic Le A 30 :~07-FC - 6 -.. . . . . . . . . . . .. . .. . . . . . . .

acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, dimeric fatty acids and trimesic acid. Either a single polycarboxylic acid or a mixture of polycarboxylic acids may be used. The polycarboxylic acids may also be 5 used in the form of their anhydrides. Phthalic anhydride and maleic anhydride are examples of suitable acid anhydrides.
If a polyisocyanate is reacted with the starter polyether polyol, .suitable optional .catalysts include.the tertiary amines and/or tin compounds known to be useful for.polyurethane reactions. If a 10 polycarboxylic acid is reacted with the.starter polyether polyol, suitable optional catalysts include the known esterification catalysts.
-In order to produce the relatively highly.functional, modified polyether polyols containing hydroxyl groups of the present invention, the polyether polyol(s) is (are) reacted with a compound containing groups 15 that are reactive with hydroxyl groups, optionally in the presence of a catalyst, at 40 to 200C.
It is preferred that this reaction be carried out at from about 40 to about 1 50C, most preferably from about 60 to about 1 20C if a polyisocyanate is being reacted with the starter polyether polyol. The 20 reaction of the present invention is preferably carried out at from about 120 to about 220C, most preferably from about 130 to about 180C if the starter polyether polyol is being reacted with a polycarboxylic acid.
The modified polyether polyols produced in accordance with the present invention are colorless to slightly colored, mobile to highly 25 viscous liquids. These modified polyether polyols have OH values of from about 10 to about 80 and a calculated molecular weight of from about 2,000 to about 32,000. The double bond content of the polyether polyols is determined using ASTM Designation: D 4671-87.

Le- A 30 :007-FC - 7 -.. . .. . . , , . . .. . . . . . . .. , . , , . . , . . . , . , ... . . , . . . ~ .

The relatively highly functional, modified polyether polyols containing hydroxyl groups of the present invention are useful in the production of optionally cellular or solid polyurethanes, such as elastomers, foams, coatings and fiber-reinforced polyurethane plastics.
5 They may also be used as intermediates for lubricants or surfactants.
Having thus described our invention, the following Examples are given as being illustrative thereof. All parts and percentages given in these Examples are parts by weight or percentages by weight, unless otherwise indicated.

- Le A -30 0-07-FC 8 -~, , _ . . . . ... .. . . ... . . . . . .. . . ~ . . . . . . . . . . .. ..

EXAMPLFS
The following starting polyethers were used in the Examples which follow:
Polyether Starter Characterization of OH value ether chains (per OH
group of the Starter) PolyetherA Propylene glycol 42 mol propylene oxide 28 -- and 14.7 mol ethylene oxide Polyether B Ethylenediamine 15.9 mol propylene 60 oxide Polyether C Sorbitol 27.5 mol propylene 28 oxide and 7.8 mol ethylene oxide Polyether D Trimethylol- 14.5 mol propylene 55 propane oxide and 3.0 mol ethylene oxide Polyether E Trimethyl ol - 0 ;322 mol propylene 880 prop2n~ oxi de ~-The polyisocyanates used in the following examples were:
Polyisocyanate 1: 4,4'-methylenediphenyl diisocyanate Polyisocyanate 2: 4,4'-methylenediphenyl diisocyanate with approximately 50 wt.% of the 2,4'- isomer 15 Polyisocyanate 3: Hexamethylene diisocyanate Polyisocyanate 4: Isophorone diisocyanate Polyisocyanate 5: 4,4'-methylenedicyclohexyl diisocyanate The polycarboxylic acid used in the following Examples was adipic acid.

Le A 30 007 9 The catalysts used in the following Examples were:
Dibutyltin dilaurate (DBTL) and Methylsulfonic acid.
Example 1:
400.0 g of Polyether A and 0.4 9 of DBTL were introduced at 60C
under a nitrogen atmosphere into a 1 liter, four-necked flask fitted with a stirrer, thermorrieter, dropping funnel, and condenser.
8.4 9 of-Polyisocyanate 3,were then added at 60C within one - - hour while the mixture was stirred. ,~he reaction mixture was then held at 120C for 20 minutes and subsequently cooled to room temperature in a water bath.
The product had the following properties:
NCO content = 0.01%
OH value = 14 mg KOH/g Viscosity, 25C = 8081 mPa~s Double bond content = 63.0 mmoUl<g Functionality (calculated) = 2 Example 2:
The procedure of Example 1 was repeated using 400.00 9 of Polyether A, 0.04 9 of DBTL and 11.10 9 of Polyisocyanate 4. The properties of the product were as follows:
NCO content = < 0.01%
OH value = 14.3 mg KOH/g ~Iscosity, 25C = 8114 mPa-s Double bond content = 63.5 mmol/lcg Functionality (calculated) = 2 ,=

Le A 30 007-FC - 10 -, . . . . , , , ... . j .. . . . . . . .. .

Fxample 3:
Example 2 was repeated with the exception that only 0.01 9 of dibutyltin laurate was used. The properties of the product were as follows:
NCO content = < 0.01%
OH value = 14.4 mg KOH/g Viscosity, 25C = 8584 mPa-s Double bond content - = 62.0 mmoVkg Functionality (calculated) = 2 F~ample 4:
- Example 3 was repeated with the exception that 460.0 g of --Polyether B and 16.0 9 of Polyisocyanate 1 were used. -The-properties of the product were as follows:
NCO content = 0.05%
OH value = 47.6 mg KOH/g Viscosity, 25C = 4360 mPa-s Double bond content -11.0 mmollkg Functionality (calcuiated) = 6 Example 5:
Example 4 was repeated with the exception that 612.0 9 of Polyether D and 25.0 9 of Polyisocyanate 2 were used. -The properties of the product were as follows:
NCO content = 0.08%
OH value = 38.8 mg KOH/g Viscosity, 25C = 7165 mPa-s Double bond content = 26 mmol/kg Functionality (calculated) = 4 Le~ A :30 :007-FC - 11 -. .. . .. . . . ... . .. .. . .

Fxample 6:
Example 5 was repeated with the exception that 384.0 9 of Polyether C and 20.0 9 of Polyisocyanate 2 were used. The properties of the product were as follows:
NCO content = 0.01%
OH value = 48.2 mg KOH/g Viscosity, 25C = 7898 mPa-s Double bond content = 12.0 mmol/kg Functionality (calculated) = 10 Example 7:
4007.0 9 of Polyether A, 73.0 9 of adipic acid and 4.1 9 of ~ methylsulfonic acid were introduced at room temperature into a 10 liter - four-necked flask fitted with a stirrer,-thermometer, dropping funnel, condenser and receiver and stirred at 130C. Water was distilled off 15 during stirring. After 13.5 hours of reaction, a sample was taken and analyzed. The ester-modified polyether had the following properties:
OH value = 13.0 mg KOH/g Acid value = 0.87 mg KOH/g pH value = 3.3 Water content = 0.01%
Viscosity, 25C = 5314 mPa-s Color = colorless Double bond content = 76.0 mmol/kg Functionality (calculated) = 2 Example 8 Example 7 was repeated with the exception that 1714.0 g of Polyether D, 40.0 g of adipic acid and 0.23 g of methylsulfonic acid were used. The reaction was carried out at 130C for 34 hours and at 150C
for 12 hours. The resultant product had the following properties:

- Le A 30 007-FC 1~ -. . . . . , . . . . . . ~ . . , _ .. . . . ~ , .. .. ..

OH value = 36.3 mg KOH/g .-Acid value = 0.8 mg KOH/g pH value = 4 4 Water content . = o.o1%
Double bond content = 33 mmoUkg Viscosity at 25C = 2452 mPa-s Functionality (calculated) = 4 Fxample 9:
~. Example 6 was repeated :with the exception that 400 9 of PolyetherA, 19.8 9 of Polyether E,0.11 g-of.DBTL and 26.2 9 of Polyisocyanate 5 were used. :. The properties-of the.product were as : -follows:
NCO content = ~ 0.01%
Viscosity = 9200 mPa~s OH value = 40.1 mg KOH/g Double bond content = 58 mmoUkg Functionality (calculated) . = 3 Although the invention has been described in detail in the .-. foregoing for the purpose.of illustration, it is to be understood that such 20 - . detail is solely for that purpose and that~variations can- be made therein.
. by those skilled in the art without:departing from the.spirit and scope of . the invention except as it may be limited by the claims.

Le A ;30 007-FC - 13 -.. . .. . . . . ..

Claims

1. A process for the production of a highly functional, modified polyether polyol containing hydroxyl groups and having a low double bond content which polyether polyol has a functionality of nx-my comprising reacting (i) n mol of a polyether polyol having a functionality of x with (ii) m mol of a compound having a functionality of y which compound is selected from polyisocyanates and polycarboxylic acids or anhydrides thereof-, at a temperature of from about 40 to about 200°C.

2. The process of Claim 1. in which a. catalyst is present during the reaction.

3. The process of Claim 1 in which compound (ii) is selected from diisocyanates, triisocyanates, dicarboxylic acids, or tricarboxylic acids.

4. The process of Claim 3 in which polyether polyol (i) has a functionality of from 2 to 8 and an OH value of from about 28 to about 200.

5. The process of. Claim 1 in which. polyether polyol (i) has a functionality of from 2 to 8 and an OH value of from about 28 to about 200.

6. The process of Claim 1 in which compound (ii) is a polyisocyanate: and the reaction temperature is from about 40 to about 150°C.

7. The process of Claim 1 in which compound (ii) is a polyisocyanate and the reaction temperature is from about 60 to about 120°C.

8. The process of Claim 1 in which compound (ii) is a polycarboxylic acid and the reaction temperature is from about 120 to about 220°C.

9. The process of Claim 1 in which compound (ii) is a polycarboxylic acid and the reaction temperature is from about 130 to about 180°C.

10. The process of Claim 1 in which the process is carried out on a discontinuous basis in a reaction vessel.

11. The process of Claim 1 in which the process is carried out on a continuous basis in a tubular reactor.

12. The process of Claim 11 in which polyether polyol (i) and compound (ii) are fed into the tubular reactor separately at a point positioned up-stream from a static mixer.

13. A modified polyether polyol produced by the process of Claim 1.

14. The modified polyether polyol of Claim 13 produced from a mixture of starting polyether polyols formed from polyether polyols having different values of x and different chain lengths.