Method for the production of esters of polyalcohols

• US 20050176910A1
• Filed: 06/06/2003
• Published: 08/11/2005
• Est. Priority Date: 06/11/2002
• Status: Active Grant

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Koniger, Rainer, Hartmann, Gabriele, Schwalm, Reinhold, Daniel, Thomas, Jaworek, Thomas, Wolf, Lothar, Wickel, Stefan
• Granted Patent: US 7,250,481 B2
• Time in Patent Office: Days
• US Class Current: 526/321
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C07C 67/08 by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
• CPC Class Codes: C07C 69/54 Acrylic acid esters; Methacrylic acid esters
• CPC Class Codes: C08G 65/3322 acyclic

Abstract

Unsaturated acids are esterified with polyalcohols. The resulting reaction mixtures have utility.

Claims

1. A process for preparing a crosslinked hydrogel, which comprises

a) reacting a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B in the presence of at least one esterification catalyst C and of at least one polymerization inhibitor D and also optionally of a water-azeotroping solvent E to form an ester F,

b) optionally removing some or all of the water formed in a) from the reaction mixture during and/or after a),

f) optionally neutralizing the reaction mixture,

h) optionally removing any solvent E by distillation and/or

i) stripping with a reaction-inert gas,

k) polymerizing the reaction mixture from one of a) to i), if conducted, with optionally additional monoethylenically unsaturated compounds N and also optionally at least one further copolymerizable hydrophilic monomer M in the presence of at least one radical initiator K and of optionally at least one grafting base L,

l) optionally postcrosslinking the reaction mixture obtained from k),

m) drying the reaction mixture obtained from k) or l), and

n) optionally grinding and/or sieving the reaction mixture obtained from k), l) or m).

2. The process as claimed in claim 1 wherein

said polyalcohol A has at least two hydroxyl functions,

the molar excess of said ethylenically unsaturated carboxylic acid B to said polyalcohol A per hydroxyl group to be esterified in A is at least 1.05:

1, and

the optionally neutralized carboxylic acid B in the reaction mixture obtained after the last step substantially remains in said reaction mixture.

3. The process as claimed in claim 1, wherein not more than 75% by weight of said carboxylic acid B is removed from said reaction mixture obtained after the last of steps a) to i), said reaction mixture comprising said ester F.

4. The process as claimed in any preceding claim claim 1, wherein said reaction mixture obtained after the last of steps a) to i) which comprises said ester F, has a DIN EN 3682 acid number of at least 25 mg of KOH/g.

5. The process as claimed in claim 1, wherein said reaction mixture obtained after the last of steps a) to i), which comprises said ester F, comprises at least 0.5% by weight of said carboxylic acid B.

6. The process as claimed in claim 1, wherein said polyalcohol A is a polyol which comprises an additional functionality, said additional functionality being at least one ether, carboxyl or C₁-C₄-alkyloxycarbonyl function.

7. The process as claimed in claim 1, wherein said polyalcohol A is a polyol selected from the group consisting of ditrimethylolpropane, dipentaerythritol, dimethylolpropionic acid, dimethylolbutyric acid, and mixtures thereof.

8. The process as claimed in claim 1, wherein at least one polyalcohol A is selected from the group consisting of polyols, functionalized polyols, alkoxylated polyols, sugar alcohols, partially alkoxylated sugar alcohols, polyetherols, polyesterols, partially or fully alkoxylated polyesterols, partially or fully hydrolyzed alkoxylated polyesterols, and mixtures thereof.

9. The process as claimed in claim 1, wherein said polyalcohol A is a polyol which has been quadruply ethoxylated per hydroxyl group.

10. The process as claimed in claim 9, wherein said polyol is trimethylolpropane or pentaerythritol.

11. The process as claimed in claim 1, wherein said polyalcohol A is a from 3- to 4-tuply ethoxylated glycerol.

12. The process as claimed in claim 1, wherein said ester F in reaction step k) has a degree of esterification (based on the n-hydric polyalcohol A) of at least 2 and less than n.

13. The process as claimed in claim 1, wherein said polyalcohol has the formula VIIa

R⁸—

(O(CH(R¹⁰)CH(R¹⁰)O)_y—

H)_x 

 

(VIIa),

where

R⁸ is a polyvalent straight-chain or branched C₂-C₁₀-alkyl radical,

x is independently in each occurrence a positive integer of 2 or greater, and

y is independently in each occurrence a number from 3 to 8 for x=2 and a number from 2 to 7 for x=3 or greater.

14. The process as claimed in claim 13, wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer from 1 to 6 for each x.

15. The process as claimed in claim 13, wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer from 1 to 4 for each x.

16. The process as claimed in claim 13, wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer of more than 8 for x=2 and

y is independently in each occurrence a positive integer of more than 7 for x=3 or greater.

17. The process as claimed in claim 13, wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer of 15 or more for each x.

18. The process as claimed in claim 1, wherein the molar ratio of said at least one ethylenically unsaturated carboxylic acid B to said polyalcohol A in said reaction a) is at least 5:

1, based on the hydroxyl groups of said polyalcohol A.

19. A crosslinked hydrogel comprising at least one hydrophilic monomer M in copolymerized form and crosslinked with a compound of the formula

R⁸—

(O(CH(R¹⁰)CH(R¹⁰)O)_y—

C(═

O)—

R⁹)_x 

 

(VII),

where

R⁸ is a polyvalent straight-chain or branched C₂-C₁₀-alkyl radical,

R⁹ is independently in each occurrence a straight-chain or branched C₂-C₁₀-alkenyl radical,

R¹⁰ is independently in each occurrence hydrogen or methyl,

x is independently in each occurrence a positive integer of 2 or greater, and

y is independently in each occurrence a number greater than 8 for x=2 and a number greater than 7 for x=3 or greater.

28. A hygiene article, a packaging material or a nonwoven comprising said crosslinked hydrogel as claimed in claim 19.

20. A crosslinked hydrogel comprising at least one hydrophilic monomer M in copolymerized form and crosslinked with a compound of the formula

R⁸—

(O(CH(R¹⁰)CH(R¹⁰)O)_y—

C(═

O)—

R⁹)_x 

 

(VII),

where

R⁸ is a polyvalent straight-chain or branched C₂-C₁₀-alkyl radical,

R⁹ is independently in each occurrence a straight-chain or branched C₂-C₁₀-alkenyl radical,

R¹⁰ is independently in each occurrence hydrogen or methyl,

x is independently in each occurrence a positive integer of 2 or greater, and

y is 4.

21. A crosslinked hydrogel comprising at least one hydrophilic monomer M in copolymerized form and crosslinked with an ester F of a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B, said polyalcohol A being glycerol which has been triply to quadruply ethoxylated per glycerol or being a trimethylolpropane or pentaerythritol which has been quadruply ethoxylated per hydroxyl group.

22. A crosslinked hydrogel comprising at least one hydrophilic monomer M in copolymerized form and crosslinked with an ester F of a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B, said polyalcohol A being selected from the group consisting of a polyol which comprises an additional functionality, said additional functionality being at least one ether, carboxyl or C₁-C₄-alkyloxycarbonyl function, sugar alcohols, partially alkoxylated sugar alcohols, polyesterols, partially or fully alkoxylated polyesterols and partially or fully hydrolyzed alkoxylated polyesterols.

23. A crosslinked hydrogel comprising at least one hydrophilic monomer M in copolymerized form and crosslinked with an ester F of a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B, said polyalcohol A being selected from the group consisting of ditrimethylolpropane, dipentaerythritol, dimethylolpropionic acid, dimethylolbutyric acid and mixtures thereof.

24. (canceled)

25. A reaction mixture comprising an ester F of a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B and obtained by a process which comprises

a) reacting a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B in the presence of at least one esterification catalyst C and of at least one polymerization inhibitor D and also optionally of a water-azeotroping solvent E to form an ester F,

b) optionally removing some or all of the water formed in a) from the reaction mixture during and/or after a),

f) optionally neutralizing the reaction mixture,

h) optionally removing any solvent E by distillation and/or

i) stripping with a reaction-inert gas, wherein

said polyalcohol A has at least two hydroxyl functions,

the molar excess of said ethylenically unsaturated carboxylic acid B to said polyalcohol A per hydroxyl group to be esterified in A is at least 1.05:

1, and

the optionally neutralized carboxylic acid B in the reaction mixture obtained after the last step substantially remains in said reaction mixture as a radical crosslinker of water-absorbing hydrogels.

26. A crosslinked hydrogel comprising at least one hydrophilic monomer M in interpolymerized form, crosslinked with a reaction mixture comprising an ester F of a polyalcohol A with at least one ethylenically unsaturated carboxylic acid B, said reaction mixture being obtained by reaction of a polyalcohol A with at least one

a) ethylenically unsaturated carboxylic acid B in the presence of at least one esterification catalyst C and of at least one polymerization inhibitor D and also optionally of a water-azeotroping solvent E to form an ester F,

b) optionally removing some or all of the water formed in a) from the reaction mixture during and/or after a),

f) optionally neutralizing the reaction mixture,

h) optionally removing any solvent E by distillation and/or

i) stripping with a reaction-inert gas, wherein

said polyalcohol A has at least two hydroxyl functions,

the molar excess of said ethylenically unsaturated carboxylic acid B to said polyalcohol A per hydroxyl group to be esterified in A is at least 1.05:

1, and

the optionally neutralized carboxylic acid B in the reaction mixture obtained after the last step substantially remains in said reaction mixture.

27. (canceled)

29. A method of crosslinking a water-absorbing hydrogel, said method comprising:

providing to said water-absorbing hydrogel a mixture comprising

esters F of a polyalcohol of the formula (VIIa)

R⁸—

(O(CH(R¹⁰)CH(R¹⁰)O)_y—

H)_x 

 

(VIIa),

where

R⁸ is a polyvalent straight-chain or branched C₂-C₁₀-alkyl radical,

x is independently in each occurrence a positive integer of 2 or greater, and at least one ethylenically unsaturated carboxylic acid B,

comprising

1) at least one ester F wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer from 1 to 6 for every x, and

2) at least one ester F wherein

R¹⁰ is hydrogen and

y is independently in each occurrence a positive integer of 15 or more for every x,

and crosslinking said water-absorbing hydrogel.