Polymers carrying hydroxyl groups and ester groups and method for the production thereof
View Patent ↗The invention relates to polymers carrying ester/hydroxyl groups, containing repetitive structural units of formulae (I) and (II) in a block-wise, alternating or statistical sequence, wherein D represents a direct bond between the polymer backbone and the hydroxyl group, a C 1 - to C 6 -alkene group, a C 5 - to C 12 -arylene group, an oxyalkene group of formula —O—R 2 —, an ester group of formula —C(O)—O—R 2 — or an amide group of formula —C(O)—N(R 3 )R 2 —, E represents a hydrocarbon group having 1 to 50 C-atoms, R 2 represents a C 2 - to C 10 -alkene group, R 3 represents hydrogen or a C 1 - to C 10 -alkyl group, which can carry substituents, k represents a number between 1 and 1000, n represents a number from 0 to 4999, m represents a number from 1 to 5000, and n+m represents a number between 10 to 5000, under the proviso that a) the molar portion of the structural units (I); on the polymer is between 0 and 99.9 mol-%, and b) the molar portion of the structural units (II) on the polymer is between 0.1 and 100 mol-% of the repetitive units. The invention also relates to a method for the production of said polymers using microwaves.
1. A process for preparing an ester of a hydroxyl-bearing polymer containing repeat structural units of the formulae (I) and (II) in alternating or random sequence
in which
D is a direct bond between polymer backbone and hydroxyl group, a C 1 - to C 6 -alkylene group, a C 5 - to C 12 -arylene group, an oxyalkylene group of the formula —O—R 2 —, an ester group of the formula —C(O)—O—R 2 — or an amide group of the formula —C(O)—N(R 3 )R 2 —,
E is a hydrocarbyl radical having 1 to 50 carbon atoms,
R 2 is a C 2 - to C 10 -alkylene radical,
R 3 is hydrogen or a C 1 - to C 10 -alkyl radical which may bear substituents,
k is a number between 1 and 1000,
n is a number from 0 to 4999,
m is a number from 1 to 5000,
n+m is a number from 10 to 5000, with the proviso that
a) the molar proportion of the structural units (I) in the polymer is between 0 and 99.9 mol %, and
b) the molar proportion of the structural units (II) in the polymer is between 0.1 and 100 mol % of the repeat units,
by irradiating the hydroxyl-bearing polymer A) containing the repeat structural unit of the formula (I) together with a hydroxycarboxylic acid B1) of the formula (III) or hydroxycarboxylic ester B2) of the formula (IV)
HO-E-COOH (III)
HO-E-COOR 5 (IV)
in which R 5 is a C 1 -C 4 -alkyl radical with microwaves in the presence of water, wherein the reaction mixture is heated by the microwave irradiation to temperatures above 100° C.
2. The process as claimed in claim 1 , wherein the hydroxyl-bearing polymer A) further comprises, as well as the structural units of the formula (I), additional structural units derived from further ethylenically unsaturated monomers.
3. The process as claimed in claim 1 , wherein the structural units of the formula (I) derive from vinyl alcohol.
4. The process as claimed in claim 2 , wherein the hydroxyl-bearing polymer A), in addition to the structural units of the formula (I), further comprises structural units derived from vinyl acetate.
5. The process as claimed in claim 1 , in which the carboxylic acid B1) or the carboxylic ester B2) is a mixture of at least one carboxylic acid and at least one dicarboxylic acid or a mixture of at least one carboxylic ester and at least one dicarboxylic ester.
6. The process as claimed in claim 1 , in which the reaction mixture used for conversion contains 5 to 98% by weight of water.
7. The process as claimed in claim 1 , in which the reaction mixture used for conversion contains 5 to 98% by weight of a mixture of water and one or more water-miscible organic solvents.
8. The process as claimed in claim 7 , in which the proportion of the water-miscible organic solvent in the solvent mixture is between 1 and 75% by weight.
9. The process as claimed in claim 1 , in which the reaction mixture is heated by means of microwave radiation to temperatures between 110 and 280° C.
10. The process as claimed in claim 1 , in which ester-bearing comonomer units of the hydroxyl-bearing polymer A) are transesterified with hydroxycarboxylic acids B1) or hydroxycarboxylic esters B2).
11. The process as claimed in claim 1 , in which the microwave irradiation is effected in a flow tube made from microwave-transparent, high-melting material.
12. The process as claimed in claim 11 , in which the longitudinal axis of the reaction tube in the direction of propagation of the microwaves is within a monomode microwave applicator.
13. The process as claimed in claim 1 , in which the microwave applicator takes the form of a cavity resonator.