Method for the production of esters of polyalcohols
First Claim
1. A process for preparing a crosslinked hydrogel, which comprisesa) reacting at least one 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/ori) stripping with a reaction-inert gas,k) polymerizing the reaction mixture from one of a) to i), in the presence of at least one radical initiator K and of optionally at least one grafting base L, with optionally at least one additional monoethylenically unsaturated compound bearing no acid groups N and also optionally at least one further copolymerizable hydrophilic monomer M, wherein ester F acts as a crosslinker, whereby a crosslinked hydrogel is formed,l) optionally postcrosslinking the reaction mixture obtained from k),m) drying the reaction mixture obtained from k) or l), andn) optionally grinding and/or sieving the reaction mixture obtained from k), l) or m), wherein said ethylenically unsaturated carboxylic acid B is present in a molar excess to said polyalcohol A per hydroxyl group to be esterified in A of at least 2.5:
- 1, and the optionally neutralized carboxylic acid B in the reaction mixture obtained after step i) substantially remains in said reaction mixture.
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Abstract
Unsaturated acids are esterified with polyalcohols. The resulting reaction mixtures have utility.
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Citations
30 Claims
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1. A process for preparing a crosslinked hydrogel, which comprises
a) reacting at least one 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), in the presence of at least one radical initiator K and of optionally at least one grafting base L, with optionally at least one additional monoethylenically unsaturated compound bearing no acid groups N and also optionally at least one further copolymerizable hydrophilic monomer M, wherein ester F acts as a crosslinker, whereby a crosslinked hydrogel is formed, 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), wherein said ethylenically unsaturated carboxylic acid B is present in a molar excess to said polyalcohol A per hydroxyl group to be esterified in A of at least 2.5: - 1, and the optionally neutralized carboxylic acid B in the reaction mixture obtained after step i) substantially remains in said reaction mixture.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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18. A crosslinked hydrogel comprising a copolymer obtained by crosslinking at least one hydrophilic monomer M or a copolymer thereof 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.
- (O(CH(R10)CH(R10)O)y—
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19. A crosslinked hydrogel comprising a copolymer obtained by crosslinking at least one hydrophilic monomer M or a copolymer thereof 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 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.
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20. A crosslinked hydrogel comprising a copolymer obtained by crosslinking at least one hydrophilic monomer M or a copolymer thereof 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 and dimethylolbutyric acid.
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21. 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 ethylenically unsaturated carboxylic acid B is present in a molar excess to said polyalcohol A per hydroxyl group to be esterified in A of at least 2.5: - 1, and
the optionally neutralized carboxylic acid B in the reaction mixture obtained after the last step substantially remains in said reaction mixture.
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Specification