BIOBASED HYDROXYL OR CARBOXYL POLYESTER RESINS

Abstract

The present invention relates to a linear or branched structured hydroxylated or carboxylated polyester resin that is free of unsaturated fatty acids, that is made from an acid component and an alcohol component, said acid component comprising at least one C4 to C6 carboxylic polyacid or anhydride, and at least one C5 to C54 carboxylic polyacid or anhydride, and with 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 polyester resin having a linear or branched structure and free of unsaturated fatty acids, which is hydroxylated or carboxylated, optionally hydroxylated and carboxylated, which is derived from: a) an acid component a) comprising: a1) at least one C.sub.4 to C6 polycarboxylic acid or anhydride, a2) at least one C.sub.8 to C54 polycarboxylic acid or anhydride, a3) optionally, at least one C.sub.2 to C.sub.22 saturated monoacid, which can optionally bear a hydroxyl group, b) an 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 following two polyols b2) and b3): b2) at least one polyol different than b1) and having a functionality f.sub.b2 of at least 2, b3) at least one polyol different than b1) and than b2) having a functionality f.sub.b3 of at least 3.

2. The resin of claim 1, wherein said unit of polyol b1) is isosorbide (1,4:3,6-dianhydro-D-sorbitol), isomannide (1,4:3,6-dianhydro-D-mannitol) or isoidide (1,4:3,6-dianhydro-L-iditol).

3. The resin of claim 1 wherein a fraction of at least 50%, by weight of said resin is biobased.

4. The resin of claim 1 wherein said component b) comprises b2) and b3) and that at least 50% by weight, of said component b) is biobased.

5. The resin of claim 1 wherein the components a) and b) are 100% biobased.

6. The resin of claim 1 wherein said polyol b2) is biobased and is chosen from the group consisting of 1,3-propylenediol, 1,2-propylenediol, 1,4-butanediol, and diols derived from saturated fatty acids.

7. The resin of claim 1 wherein said polyol b3) is biobased and chosen from glycerol and ether-polyol derivatives thereof.

8. The resin of 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 tetrahydrofuran-3,5-dicarboxylic acid.

9. The resin of 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, and respectively C.sub.36 and C.sub.54 fatty acid dimers and trimers.

10. The resin of claim 1 wherein said monoacid a3) is present in the composition of said resin and selected from the group consisting of acetic acid, pyruvic acid, lactic acid or rosin (meaning abietic acid and C.sub.20 isomers), and a C.sub.12 to C.sub.22 saturated fatty acid.

11. The resin of claim 1 wherein said polyol b1) represents at least 30% by weight of said resin.

12. The resin of claim 1 having an OH and/or carboxylic acid functionality corresponding to an OH and/or acid number ranging from 10 to 200 mg KOH/g.

13. The resin of claim 1 having a carboxyl functionality corresponding to an acid number of less than 20 mg KOH/g and an OH functionality corresponding to an OH number ranging from 10 to 200 mg KOH/g.

14. The resin of claim 1 having a number-average molecular weight Mn ranging from 500 to 20 000.

15. The resin of claim 1 having a Tg ranging from −10° C. to 100° C.

16. A solution of resin in an organic solvent, comprising at least one resin of claim 1.

17. The solution of claim 16 wherein said solvent is selected from the group consisting of methyl esters and ethyl esters of C.sub.2 to C.sub.4 monocarboxylic acids, esters of said monocarboxylic acids with methoxy or ethoxy monoethers of C.sub.2 to C.sub.4 diols, methyl and ethyl diesters of C.sub.4 to C.sub.6 dicarboxylic acids, terpenes, polyhydroxyalkanoates, methyl and ethyl esters of fatty acid oils, and esters of lactic acid with C.sub.1 to C.sub.8 alcohols.

18. A coating composition comprising at least one resin of claim 1.

19. The coating composition of claim 18 which is a crosslinkable composition comprising, in addition to said resin, at least one crosslinking agent, bearing groups which are reactive with the hydroxyl and/or carboxyl groups borne by said resin.

20. The coating composition of claim 18 wherein said crosslinking agent is selected from the group consisting of melamine, polyisocyanate, polyanhydride, and polysilane, when said resin is hydroxylated, or said crosslinking agent is selected from the group consisting of polyepoxides and polyols when said resin is carboxylated.

21. The composition of claim 17 which is a coating composition in an organic solvent medium which is a paint or varnish composition.

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. The resin of claim 1, wherein said at least one C.sub.4 to C.sub.6 polycarboxylic acid or anhydride has a functionality f.sub.a1 ranging from 2 to 4 and the at least one C.sub.8 to C.sub.54 polycarboxylic acid or anhydride has a functionality f.sub.a2 ranging from 2 to 4.

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

30. The resin of claim 1, wherein f.sub.a1=2, fa.sub.2=2, f.sub.b1=2, and f.sub.b2=2 and f.sub.b3=3.

Description

EXPERIMENTAL SECTION

1) Raw Materials Used

[0065]

TABLE-US-00001 TABLE 1 raw materials used Component Nature of type Trade Chemical Technical function and according to name name Supplier function functionality invention Polysorb ® Isosorbide Roquette Diol* OH/2 b1) P Oleris ® Sebacic Arkema Diacid* Carboxy/2 a2) Sebacic acid acid Bio SA Succinic Bio Diacid* Carboxy/2 a1) acid Amber 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 Dibasic Mixture of Invista Resin Resin Ester esters** solvent solvent (DBE) *biobased **mixture of methyl esters of adipic, glutaric and succinic acid
2) Preparation of the Resin (Procedure Example 1 according to the Invention)

[0066] An electrically heated 3-liter reactor, equipped: [0067] with a distillation column of the Vigreux type surmounted by a Dean-Stark separator, with a [0068] dip tube for introducing nitrogen, [0069] with a temperature probe, is charged with: [0070] 582 g of isosorbide, [0071] 246.8 g of sebacic acid, [0072] 380.9 g of succinic acid, [0073] 0.13 g of Fascat® 4100 (butylstannoic acid).

[0074] 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 to 220° C. while at the same time removing the reaction water in the form of a heteroazeotrope with the MIBK until a constant acid number of 165 mg KOH/g is obtained, corresponding to a degree of conversion of the isosorbide of 99.5%. The duration of this first step is 8 h. Cooling to 180° C. is carried out 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.

[0075] The final characteristics of the product are: [0076] Coloration: 3 Gardner (ISO method 4630) [0077] Dry extract: 60% (ISO method 3251) [0078] Brookfield viscosity at 25° C. (ISO method 3219): 4350 mPa.Math.s [0079] Acid number: 8 mg KOH/g (ISO method 2114) [0080] OH number (essential functionality) (mg KOH/g): 70 (ISO method 2554). [0081] 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%.

Comparative Example 2

[0082] Example 1 is reproduced, but this time without sebacic acid.

[0083] During this test, the final polyester obtained is insoluble in PMA and it is necessary to add dibasic ester supplied by Invista, which is a mixture of methyl esters derived from adipic acid, from succinic acid and from glutaric acid, having a respective composition by weight (weight percentage): [0084] dimethyl ester of adipic acid: 0.1-22%, [0085] dimethyl ester of succinic acid: 0.1-98% [0086] dimethyl ester of glutaric acid: 0.3-99%.

[0087] The final characteristics of the product are:

Coloration: 3 Gardner (ISO method 4630)
Dry extract: 48% (ISO method 3251) for an MPA/DBE ratio of 67/33
Brookfield viscosity at 25° C. (ISO method 3219): 800 mPa.Math.s
Acid number: 8 mg KOH/g (ISO method 2114)
OH number (essential functionality) (mg KOH/g): 70. isosorbide measured by carbon 13 NMR analysis: 0.09% in the solvented resin, which corresponds to a final degree of conversion of the isosorbide of 99.5%.

3) Application of the Resins in Satin Paints for Metal Sheet

3.1) Satin Paint Formulation

[0088]

TABLE-US-00002 TABLE 2 Compositions and raw materials used Parts by weight out of Component Chemical Component 1000 ref. Function name Supplier Resin example 1 209 (1) Binder Hydroxylated — (part 1) resin according to the invention PMA (part 1) 25.5 (2) Solvent Methoxypropyl BASF acetate Disperbyk ®-161 5.5 (3) Dispersant Block copolymer BYK TiO.sub.2-Kronos 243 (4) Pigment Titanium oxide Kronos 2360 Silice Aerosil ® 2.5 (5) Rheological Silica Evonik R972 additive Resin example 1 220 (1) Binder Hydroxylated — (part 2) resin according to invention PPA (part 2) 31 (2) Solvent Methoxypropyl BASF acetate Silice Syloid ® ED 30 (6) Matting Silica Grace 40 agent Cymel ® 303 LF 46 (7) Crosslinking Methylated Allnex agent melamine PTSA catalyst 7.5 (8) Catalyst p-Toluenesulfonic Aldrich acid (12.5% in butanol) PMA (part 3) 154 (2) Solvent Methoxypropyl BASF acetate Solvarex ® 9 24 (9) Solvent Aromatic Total hydrocarbon Crayvallac ® 2 (10)  Spreading Polyester Arkema Flow 200 agent Total 1000

3.2) Procedure for Preparing the Satin Paints

[0089] The following compounds (1) (part 1), (2) (part 1), (3), (4) and (5) are introduced, in the order indicated, into a thermostated 1-liter beaker at ambient temperature. This mixture is stirred using a stirrer of Dispermat type, then dispersed for 30 minutes at 3500 rpm. The rest (part 2) of the binder (1), the rest (part 2) of the solvent (2) and the compound (6) are then added. The dispersion is continued for 15 minutes at 2500 rpm. Still with stirring at 1000 rpm, the compounds (7) and (8) are added. The viscosity of the paint is adjusted by means of the addition of (2) (part 3) and (9). Finally, the compound (10) is added, still with stirring at 1000 rpm.

[0090] The characteristics of the satin paint obtained are given in table 3 below.

TABLE-US-00003 TABLE 3 Characteristics of the satin paint Example 1 Measurement according to Comparative Characteristics method the invention example 2 Density (g/cm.sup.3) NF EN ISO 1.27 1.32 2811-1 Solid by weight ISO 3251 58.3 57.5 (%) Dry extract (DE) Solid by volume Dry volume/total 44.2 44.7 (%) volume ratio VOC (g/l)* Calculation grams 530 558 solvent per liter of paint PVC (%)** Calculation volume 22.8 22.7 pigments/volume pigments + volume binder ratio (calculated on solids) Cone/plate ISO 2884-1 520 520 viscosity at 25° C. (m .Math. Pas) *VOC: Volatile Organic Compounds **PVC: Pigment Volume Concentration
3.3) Metal Sheet used, Conditions for Applying the Satin Paint and Conditioning before Evaluation Tests

[0091] The sheet metal used for the tests is a galvanized steel sheet 0.5 millimeter in thickness, pretreated with a solution of chromate.

[0092] The paint is applied by means of an applicator of Bar Coater type. Two types of application are carried out: [0093] top coat [0094] direct-to-metal coat.

[0095] The thickness of the top coat and of the direct-to-metal coat is 20 μm.

[0096] In the case of the top coat, the paint is applied to a sheet metal already coated with a compatible primer coat 5 μm thick. The total thickness of the coating is 25 μm, including the primer coat (top coat of 20 μm).

[0097] The sheet metal thus coated is introduced into a furnace at 385° C. The crosslinking with melamine is carried out at a peak metal temperature (called PMT) of 232° C. for 35 seconds.

[0098] The paint, as direct-to-metal coat applied on a primer as top coat, is then evaluated according to various performance tests, after conditioning of the test panels (painted sheet metal) in a room air-conditioned at 23° C.±2 with the humidity controlled at 50%±5%.

4) Tests for Evaluating the Performance Levels of the Paints

[0099]

TABLE-US-00004 TABLE 4 Tests used Description or referral to Tests normative method reference Cupping test (mm) NF EN ISO 1520 Adhesion test NF EN ISO 2409 (score of 0 = good to 5 = poor) Gloss at 60° (GU) NF EN ISO 2813 T-bend test NF EN 13523-7 (score of 0.5 T up to final value with a step of 0.5 unit at each bend up to final absence of degradation of the coating: the lower the value of T, the better the result) Persoz hardness (s) NF EN ISO 1522

5) Results and Conclusion

5.1) Direct-to-Metal Coat (DTM Application)

[0100]

TABLE-US-00005 TABLE 5 Results obtained with direct-to-metal coat Example 1 according to Comparative the invention example 2 Cupping test (mm) 4.5 2.8 Adhesion test 0 between 0 and 1 Bend test 5 T >6 T Persoz hardness (s) 207 233

5.2) To Coat on Primer

[0101]

TABLE-US-00006 TABLE 6 Results obtained with top coat Example 1 according to Comparative the invention example 2 Cupping test (mm) 6.2 5.8 Adhesion test 0 0 Gloss at 60° (GU) 28 15 Bend test 3.5 T 5 T Persoz hardness (s) 220 230

[0102] The polyol polyester based on raw materials of biobased origin, which is the subject of the invention, makes it possible to prepare coatings for a metal sheet having advantageous applicative properties with in particular a good compromise between hardness and bend test.

[0103] Example 1, according to the invention, carried out with sebacic acid results in a paint that is much more flexible (result of the bend test) with a very satisfactory level of hardness for the intended application.