SPECIFIC METHOD FOR PREPARING BIOBASED POLYESTERS

Abstract

The present invention relates to a method for preparing a linear or branched hydroxylated and/or carboxylated polyester resin that is free of unsaturated fatty acids, comprising reacting an acid component with an alcohol component, said acid component comprising at least one C4 to C6 polycarboxylic acid or anhydride, and at least one C8 to C54 polycarboxylic acid or anhydride, and said alcohol component comprising at least one biobased polyol having a functionality of at least 2 bearing a 1,4:3,6-dianhydrohexitol unit, and at least one of two polyols b2) and b3).

Claims

1. A process for preparing a hydroxylated or carboxylated, optionally hydroxylated and carboxylated, linear or branched polyester resin free of unsaturated fatty acid, wherein said process comprises reaction between an acid component a) and an alcohol component b), with said acid component a) comprising: a1) at least one C.sub.4 to C.sub.6 polycarboxylic acid or anhydride, a2) at least one C.sub.5 to C.sub.54 polycarboxylic acid or anhydride, and a3) optionally, at least one C.sub.2 to C.sub.22 saturated monoacid, and with said alcohol component b) comprising: b1) at least one biobased polyol having a functionality f.sub.b1 of at least 2, bearing a 1,4:3,6-dianhydrohexitol unit, and at least one of the-fallow two polyols b2) or b3): b2) at least one polyol different than b1) having a functionality f.sub.b2 of at least 2 b3) at least one polyol different than b1) and b2) having a functionality f.sub.b3 of at least 3, with said reaction being carried out according to the following successive steps: i) reaction of all of the acid component a) with said component b1) of said alcohol component b) until a conversion of at least 85%, of said component b1) is obtained, followed by ii) reaction of the product resulting from step i) with the rest of said alcohol component b), comprising at least one of said polyols b2) or b3), the reactions of said steps i) and ii) taking place in solution in at least one organic solvent which can form an azeotrope with water.

2. The process as claimed in claim 1, wherein said step i) is carried out in the presence of a catalyst chosen from: tin derivatives from tin oxalate, butylstannoic acid or tin(II) oxide, titanium derivatives from alkyl titanates.

3. The process as claimed in claim 2, wherein the amount by weight of said catalyst relative to the weight of all of the reactants of step i) (a)+b1)) ranges from 0.01% to 0.5%.

4. The process as claimed in claim 1 wherein said step i) is carried out at a temperature ranging from 150 to 220° C.

5. The process as claimed in claim 1 wherein said step ii) is carried out at a temperature ranging from 180 to 250° C.

6. The process as claimed in claim 1 wherein said organic solvent is selected from the group consisting of ketones, aromatic solvents, cycloaliphatic solvents, and alkanes which are at least C.sub.7 alkanes.

7. The process as claimed in claim 1 wherein a fraction by weight of at least 50% of said polyol b) is biobased.

8. The process as claimed in claim 1 wherein said component b1) is chosen from the group consisting of isosorbide (1,4:3,6-dianhydro-D-sorbitol), isomannide (1,4:3,6-dianhydro-D-mannitol) and isoidide (1,4:3,6-dianhydro-L-iditol).

9. The process as claimed in claim 1 wherein at least 50%, by weight relative to the overall weight of said components a)+b) is biobased.

10. The process as claimed in claim 1 wherein the components a) and b) are 100% biobased.

11. The process as claimed in claim 1 wherein said polyol b2) is biobased and chosen from the prowsonsistinq of, 1,3-propylenediol, 1,2-propylenediol, 1,4-butanediol, and diols based on saturated fatty acids.

12. The process as claimed in that claim 1 wherein said polyol b3) is biobased and chosen from the group consisting glycerol and ether-polyol derivatives thereof.

13. The process as claimed in claim 1 wherein said polyacid a1) is a biobased aliphatic diacid chosen from the group consisting of succinic acid, tartaric acid, citric acid, malic acid, itaconic acid, glutaric acid, glutamic acid, fumaric acid, furandicarboxylic acid, tetrahydrofuran-2,5-dicarboxylic acid and tetrahydrafuran-3,5-dicarboxylic acid.

14. The process as claimed in claim 1 wherein said polyacid a2) is biobased and chosen from the group consisting of azelaic acid (C.sub.9), sebacic acid (C.sub.10), undecanedioic acid, dodecanedioic acid OF and respectively C.sub.36 and C.sub.54 fatty acid dimers and trimers.

15. The process as claimed in claim 1 wherein said monoacid a3) is selected from the group consisting of acetic acid, pyruvic acid, lactic acid, rosin (which meansa abietic acid and C.sub.20 isomers) and a C.sub.12 to C.sub.22 saturated fatty acid.

16. The process as claimed in claim 1 wherein said polyol b1) represents at least 40 mol/mol % relative to the component b).

17. The process as claimed in claim 1 wherein during the first step i), the molar ratio of the carboxy groups of said component a) relative to the OH groups of said polyol b1) ranges from 1.1 to 2.1.

18. The process of claim 1, wherein said at least one C.sub.4 to Ce polycarboxylic acid or anhydride has a functionality f.sub.a, ranging from 2 to 4 and the at least one C.sub.9 to C.sub.54 polycarboxylic acid or anhydride has a functionality f.sub.a2 ranging from 2 to 4.

19. The process of claim 1, wherein the said polyol b2) is a polyol in C.sub.3-C.sub.36.

20. The process of claim 1, wherein f.sub.a1=2, f.sub.a2=2, f.sub.b1=2, f.sub.b2=2 and f.sub.b3=3.

21. The process of claim 1, wherein the reaction of all of the acid component a) with said component b1) of said alcohol component b) proceeds until a conversion of 100% of said component b1) is obtained.

22. The process of claim 2, wherein said alkyl titanates are selected from the group consisting of ethyl titanate, isopropyl titanate, butyl titanate, and 2-ethylhexyl titanate.

23. The process of claim 22, wherein said alkyl titanates are selected from the group consisting of isopropyl titanate and butyl titanate.

Description

EXPERIMENTAL SECTION

1) Raw Materials Used

[0054]

TABLE-US-00001 TABLE 1 raw materials used Component Nature of type Chemical Technical function and according to Trade name name Supplier function functionality the invention Polysorb ® P isosorbide Roquette Diol* OH/2 b1) Oleris ® Sebacic acid Arkema Diacid* Carboxy/2 a2) Sebacic acid BIO-SA ® Succinic acid Bio Amber Diacid* Carboxy/2 a1) Glycerine ® Glycerol Oleon Triol* OH/3 b3) 4813 Fascat ® Butylstannoic PMC Catalyst — Catalyst 4100 acid Organo Metallix MIBK Methyl Arkema Azeo Azeo isobutyl solvent solvent ketone MPA Methoxypropyl BASF Resin — Resin acetate solvent solvent *biobased

2) Preparation of the Resin (Procedure Example 1)

[0055] An electrically heated three-liter reactor, equipped: [0056] with a distillation column of the Vigreux type surmounted by a Dean Stark separator, [0057] with a dip tube for introducing nitrogen, [0058] with a temperature probe,
is charged with: [0059] 582 g of isosorbide, [0060] 246.8 g of sebacic acid, [0061] 380.9 g of succinic acid, [0062] 0.13 g of Fascato 4100 (butylstannoic acid)

[0063] Under a nitrogen flow, the mixture is heated to 150° C. and 50.62 g of methyl isobutyl ketone (MIBK) are introduced as azeotropic entrainer (solvent). Heating is then carried out, up to 220° C., while at the same time removing the reaction water in the form of a heteroazeotrope with the MI BK until a constant acid number of 165 mg KOH/g is reached, corresponding to a degree of conversion of the isosorbide of 99.5%. The duration of this first step is 8 h. Cooling is carried out at 180° C. and 55.7 g of glycerol are introduced into the reactor. The reaction medium is brought to 220° C., still under nitrogen, until an acid number <10 mg KOH/g is obtained. The reactor is cooled to 150° C. and 617.57 g of methoxypropyl acetate (MPA) are added as solvent for diluting the resin. At 90° C., the reactor is emptied and the dry extract is adjusted by adding 68.62 g of MPA.

[0064] The final characteristics of the product are:

Coloration: 3 Gardner (ISO method 4630)
Dry extract: 60% (ISO method 3251)
Brookfield viscosity at 25° C. (ISO method 3219): 4350 mPa.s
Acid number: 8 mg KOH/g (ISO method 2114)
OH number (essential functionality) (mg KOH/g): 70 (ISO method 2554)
Isosorbide measured by carbon 13 NMR analysis: 0.1% in the solvented resin, which
corresponds to a final degree of conversion of the isosorbide of 99.7%.

Example 2

[0065] Example 1 is reproduced, with the MI BK being replaced with xylene. The isosorbide content in the final product is 1%, which corresponds to a degree of conversion of the isosorbide of 96%.

Comparative Example 1

[0066] Example 1 is reproduced, while changing all the reagents in a single step.

[0067] The isosorbide content in the final product is 5%, which corresponds to a degree of conversion of the isosorbide of 82%.

[0068] The two-step process according to the invention makes it possible to virtually quantitatively convert the isosorbide to a final degree of at least 96%, preferably of at least 99%.