PREPARATION OF SPECIFIC METHOD POLYESTERS biobased

The invention relates to a process for preparing a linear polyester resin or branched structure and free of unsaturated fatty acids, which is hydroxylated or carboxylated based on renewable raw materials, in particular at least based on a specific bio-based polyol .

The functionalized oil-polyester resins are well known for pourfeuilles metal coating applications known by the term "coils".

Polyester polyols based resins called renewable components also "biobased" for use in the metal foils coatings are already described in WO 2012/042153 and in particular resins without oil. These polyester resins are rosin-based. However, as such, they need improvement in terms of durability and resistance to yellowing.

BA Noordover et al discloses in J. Biomacromolecules 2006, 7, 3406-3416 co- and terpolyesters based on isosorbide and succinic acid and other renewable monomers such as 2,3-butanediol or 1 , 3 propanediol or citric acid.

No presence of longer chain polyacids at least Cs is mentioned or suggested in these documents.

The present invention seeks to develop by a specific process, the new resins hydroxylated or carboxylated polyesters, oil-free and free of any unsaturated fatty acid residue having a durability and resistance to yellowing and a compromise hardness / improved flexibility while having good chemical resistance, particularly to organic solvents and water, on the resulting coating, in particular for application on metal sheets.

The object of the present invention relates to a method for preparing a linear or branched polyester resin that is hydroxylated and / or carboxylated based on a specific composition with renewable raw materials and in particular based on a bio-based polyol specific. More specifically, the object of the invention relates to a process for preparing a polyester resin hydroxylated or carboxylated, optionally hydroxylated and carboxylated linear or branched, free unsaturated fatty acid, said process comprising the reaction between an acid component ) and an alcohol component b), with said acid component a) comprising:

a1) at least one polybasic acid or carboxylic anhydride, C 4 to C 6, preferably of functionality f has i ranging from 2 to 4 and more preferably equal to 2,

a2) at least one polyacid or carboxylic anhydride in the Cs to C 4 , preferably of functionality f has 2 ranging from 2 to 4 and more preferably equal to 2 and

a3) optionally, at least one monobasic saturated C2 to C22 may optionally bear a hydroxyl group, and

with said alcohol component b) comprising:

b1) at least one biobased polyol fbi functionality of at least 2, preferably 2, bearing a pattern 1, 4: 3.6 dianhydrohexitol,

and at least one of the two polyols b2) and b3) as follows:

b2) at least one polyol different from b1) of fb2 functionality of at least 2, preferably

2, especially C3-C36

b3) at least one polyol different from b1) and b2) fb3 functionality of at least 3, preferably 3,

with said reaction taking place according to the following successive steps:

i) reaction of the whole acid component) with said component b1) of the alcohol component b) and up to a conversion of at least 85%, preferably

100% of said component b1), followed by

ii) reacting the product of step i) with the rest of said alcohol component b) comprising at least one of said polyols b2) or b3),

reactions of said steps i) and ii) takes place in solution in at least one organic solvent capable of forming an azeotrope with water.

According to a particular option, the two polyols b2) and b3) as defined above are present in said component b).

Said solvent according to this method allows both the effect of the azeotrope and removal of water of reaction, in particular in said step i) and also the solubilization of the reactive components, in particular step i) .

Said organic solvent may in particular be selected from: ketones, in particular methyl amyl ketone, methyl isobutyl ketone, 2-heptanone, 2-octanone and more particularly methyl amyl ketone, methyl isobutyl ketone or 2-heptanone, aromatic solvents, especially xylene or toluene, cycloaliphatic solvents, in particular cyclohexane or alkanes at least C7 and preferably ketones, in particular methyl amyl ketone, methyl isobutyl ketone.

More particularly, said step i) may be performed in the presence of a catalyst selected from:

tin derivatives, in particular tin oxalate or butyl stannoic acid or tin (II) oxide

titanium compounds, in particular alkyl titanates such as ethyl titanate, isopropyl titanate, butyl titanate or 2-ethyl hexyl and more particularly isopropyl titanate or butyl titanate.

The weight ratio of said catalyst based on the weight of total reactants of step i) (a) + b1)) can vary in particular from 0.01 to 0.5% and preferably from 0.01 to 0.25%.

Step i) of said process may be carried out at a temperature ranging from 150 to 220 ° C and preferably from 175 to 220 ° C.

On said step ii), it may be carried out at a temperature ranging from 180 to 250 ° C and preferably from 190 to 220 ° C.

A resin or a biobased product means it comprises a first non-fossil material which is renewable and vegetable or animal origin.

The characteristic of "biobased" of a product or resin or a raw material used as a component of said product, such as a polybasic acid, a polyol or a fatty acid can be determined by determining the amount of carbon 14 C, which attests renewable carbon source said component as such or incorporated into a final product after reaction (which does not change the rate). Indeed, a biobased component is one in which the carbon originates from carbon dioxide (CO2) fixed by photosynthesis from the atmosphere. The specific fixed carbon content of 14 C is the signing of a bio-based component that differs from that corresponding to a fossil component. This content can be determined according to ASTM D 6866 (ASTM D 6866-06) or ASTM D 7026 (ASTM D 7026-04), in particular by mass spectrometry according to ASTM D6866-06.

Regarding the resin prepared by said process, a weight fraction of at least 50%, preferably at least 75% of said polyol b) is biosourced.

More particularly, said component b1) is selected from biobased: 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).

According to a more particular option, at least 50%, preferably at least 75% by weight relative to the total weight of said components a) + b) is biobased.

Still more particularly, the components a) and b) are 100% bio-based.

According to another particular option, said polyol b2) is biobased and selected from 1, 3 propylene diol or the 1, 2 propylene diol, 1, 4 butane diol or diols based (meaning derivatives) saturated fatty acids. Such diols can have a chain C12 to C36.

Still more particularly, said polyol b3) is biobased and selected from glycerol and ether polyols derivatives, such as polyglycerols which are oligomers derived from glycerol.

Said polyacid a1) includes within its coverage acids such as aconitic derived from sugar cane C6 acid functionality f and a i = 3. The polyacid a1) can also bear a hydroxyl group among such as citric acid with f a i = 3 and carrier in addition to a hydroxyl function or with malic f has i = 2 and bearing a hydroxyl or glutamic acid with f a i = 2 and bearing an amino group.

On said polyacid a1) according to a particular choice, it is an aliphatic diacid biobased selected from: succinic acid, tartaric acid, citric acid, malic acid, itaconic acid, glutaric acid, glutamic acid, fumaric acid, dicarboxylic furan acid, tetrahydrofuran acid 2 5 dicarboxylic acid or tetrahydrofuran 3,5 dicarboxylic acid, preferably succinic acid, itaconic acid, glutamic acid, fumaric acid, furan dicarboxylic acid or dicarboxylic acid tetrahydrofuran or 2,5 dicarboxylic acid tetrahydrofuran 3.5.

In the case where the functionality of one of said components is greater than 2, preferably the number average functionality of the mixture of components a) + b) does not exceed 2. Said polyester is linear or branched structure and by definition it may not contain crosslinked structure which is thus excluded by definition. The skilled person in particular knows how to choose the proportions and features of reactive components and the reactive functional conversion rate to avoid chemical crosslinking or gelling of the reagent system. This issue may arise when one of the reactive components (a) and (b) is of average functionality of greater than 2 to obtain a branched structure. It is possible to control the structure without any possible crosslinking by adjusting the proportions of components a) and b) so that the number average functionality (per mole of reactant component) on all of the reactive components (a + b) does not exceed 2 or is above 2 to limit the degree of conversion before the gel point (gellation) predictable either by experiment or by calculation according to the Macosko-Miller relationship and / or by gradual addition of the component less functionalized on the most efficient stirring functionalized component (maintained in excess of reactive functions by the gradual addition of the second reagent component). The Macosko-Miller relationship mentioned above is as defined in Macromolecules, vol. 9, pages 199-21 1 (1976) and is considered well known to those skilled in the art. For clarity, we remind below this relationship which links the r critical report c reactive functions for two reactive components A and B to gel, r c = function A function B, with the average functionality of A IA is, and that of B is IB with the critical rate of conversion to gel point x g following:

r c * x g 2 = 1 / [(f B -1) * (f A -1)]

Said polyacid a2) may also be bio-based and selected from: azelaic acid (Cg), sebacic acid (C10), undecane dioic acid, dodecane dioic acid or dimers and trimers of fatty acids C36 and C54 respectively. The presence of the dibasic acid a2) and its proportion to a1) are important factors to play on the hardness / flexibility compromise of the final coating and adjusting the relative hardness / flexibility, increasing the rate a2) improves flexibility. Conversely, coating hardness increases with the rate a1).

Preferably, the molar ratio a1) / a2) ranges from 2 to 8 and more preferably 3 to 7.

Regarding said monoacid a3), it may be selected from: acetic acid, pyruvic, lactic or rosin (abietic acid and isomers C20) or a saturated fatty acid C12 to C22.

Biobased said polyol b1) may in particular be at least 40 mol / mol% relative to component b).

In a particular and preferred of said resin, said polyol b1) is at least 30% by weight of said resin, the weight of "the said resin" here means "relative to the total weight of components a) + b) used for said resin ".

More particularly, the rate of polyol b1) in mol / mol% on the whole alcohol component b) varies from 40 to 80 and preferably from 55 to 65.

The rate corresponding to the polyol b2) may range from 0 to 50 and preferably 25 to

35.

The molar ratio of the polyol b3) can vary from 0 to 20 and preferably 5 to 15. The rate of b1), b2) and b3) as given are selected from the ranges as defined also taking into account that the sum b1) + b2) + b3) is equal to 100%.

On the other hand, it is preferred that the molar ratio between polyacids a1) and a2) is from 2 to 8 and in particular from 3 to 7.

On the OH functionality or carboxyl, and carboxy optionally OH of said resin, it may correspond to an OH number and / or acid from 10 to 200 mg KOH / g.

More specifically, said resin can have a carboxylic acid functionality (carboxy) corresponding to an acid number less than 20, preferably less than 10 and more preferably less than 5 and especially 0 mgKOH / g and an OH functionality corresponding to an OH number of from 10 to 200, preferably from 10

to 150, more preferably from 10 to 100 mg KOH / g. The OH number is determined according to ISO 2554. The acid number is determined according to ISO 21 14.

The resin according to the invention can be functionalized or carboxy OH or OH and carboxy and preferably in the latter case with a predominant OH functionality, that is to say with more than 90% of functional groups being OH.

Concerning the average molecular weight Mn of the resin, it may vary from 500 to 20,000 and preferably from 750 to 10000. The molecular weight Mn is determined by calculation from the feature index (mg KOH / g) and the average functionality f r of said resin which represents the average number of OH and / or carboxyl acid groups, calculated from the mass balance (molar ratio) and the known functionality of components a) and b) used.

During the first step i), the molar ratio of carboxy groups (-CO2H) of said component a) with respect to the OH groups of said polyol b1) can vary from 1, 1 to 2.1 and preferably 1, 2 to 2, more preferably 1, 3 to 1, 9.

This report CO2H / OH is important for the high conversion and up to total of said polyol b1), in particular isosorbide.

As regards said hydroxylated and / or carboxylated resin, it can have a functionality corresponding index (OH or carboxyl acid) ranging from 10 to 200 mg KOH / g.

The feature is set according to the kind of component (a) or b)) in overall stoichiometric excess relative to the other. When it is carboxy groups which are significantly in excess and generally all of the components a) + b), the functionality is carboxyl. Conversely, if it is the OH groups which are thus in excess, the functionality of said resin will be OH.

Among the advantages of the process of the present invention include: the almost total conversion of the polyol b1) without discoloration of the final resin and with good control of the structure and functionality of said resin.

The following examples are presented by way of illustration of the invention and its benefits and by no means limit the scope of the invention.

Experimental part

1) Raw materials used

Table 1: Raw Materials

* biosourcé

2) Preparation of the resin (procedure example 1)

In a 3 liter reactor, electrically heated, with:

- A distillation column surmounted the kind Vigreux a Dean Stark separator, a dip pipe for introducing nitrogen,

a temperature probe,

on charge :

582 g d'isosorbide,

- 246.8 g of sebacic acid,

380.9 g of succinic acid,

0,13 g de Fascat® 4100 (acide butyl stannoique)

Under nitrogen flow, is heated up to 150 ° C and introduced 50.62 g of methyl isobutyl ketone (MIBK) as (solvent) azeotrope coach. then is heated to 220 ° C while removing the water of reaction as heteroazeotrope with the

MIBK to constant acid value of 165 mg KOH / g, corresponding to a conversion rate of 99.5% isosorbide. The duration of this first step is 8 h.

Cooled to 180 ° C and introduced into the reactor 55.7 g of glycerol. The reaction mixture is heated at 220 ° C still under nitrogen, until an acid number <10 mg KOH / g. The reactor was cooled to 150 ° C and 617.57 g of methoxy propyl acetate is added (MPA) as a dilution solvent of the resin. At 90 ° C, the reactor was drained and the solids content is adjusted by adding 68.62 g MPA.

The final product features are:

Colouring: 3 Gardner (ISO 4630 method)

Solids: 60% (ISO 3251 method)

Brookfield viscosity at 25 ° C (ISO 3219 method): 4350 mPa.s

acid value: 8 mg KOH / g (ISO 21 Method 14)

OH value (premium feature) (mg KOH / g): 70 (ISO 2554 method)

Isosorbide measured by carbon 13 NMR analysis: 0.1% in the solvent-resin, which corresponds to a final conversion of 99.7% isosorbide.

example 2

Example 1 was repeated replacing the MIBK by xylene.

Isosorbide content in the final product is 1%, which corresponds to a conversion rate of 96% isosorbide.

Comparative Example 1

Example 1 was repeated by charging all reactants at once.

Isosorbide content in the final product was 5%, which corresponds to a conversion rate of 82% isosorbide.

The 2-step process according to the invention can convert almost quantitatively isosorbide to a final rate of at least 96%, preferably at least 99%.

CLAIMS

1. A process for preparing a polyester resin hydroxylated or carboxylated, optionally hydroxylated and carboxylated linear or branched, free unsaturated fatty acid, said process being characterized in that it comprises the reaction between an acid component a) and alcohol component b) with said acid component a) comprising:

a1) at least one polybasic acid or carboxylic anhydride, C 4 to C 6, preferably of functionality f has i ranging from 2 to 4 and more preferably equal to 2,

a2) at least one polyacid or carboxylic anhydride in the Cs to C 4 , preferably of functionality f has 2 ranging from 2 to 4 and more preferably equal to 2 and

a3) optionally, at least one monobasic saturated C2-C22, and

with said alcohol component b) comprising:

b1) at least one biobased polyol fbi functionality of at least 2, preferably 2, bearing a pattern 1, 4: 3.6 dianhydrohexitol,

and at least one of the two polyols b2 or b3) as follows:

b2) at least one polyol different from b1) of fb2 functionality of at least 2, preferably

2, especially C3-C36

b3) at least one polyol different from b1) and b2) fb3 functionality of at least 3, preferably 3

with said reaction taking place according to the following successive steps:

i) the entire acid component reaction) with said component b1) of the alcohol component b) until a conversion of at least 85%, preferably 100% of said component b1), followed by

ii) reaction of the product from step i) with the rest of said alcohol component b) comprising at least one of said polyols b2) or b3)

reactions of said steps i) and ii) takes place in solution in at least one organic solvent capable of forming an azeotrope with water.

2. Method according to claim 1, characterized in that said step i) is performed in the presence of a catalyst selected from:

tin derivatives, in particular tin oxalate, butyl stannoic acid or tin (II) oxide

titanium compounds, in particular alkyl titanates, such as ethyl titanate, isopropyl titanate, butyl titanate or titanate, 2-ethylhexyl, and more particularly, isopropyl titanate or titanate butyl.

3. Method according to claim 2, characterized in that the proportion by weight of said catalyst based on the weight of total reactants of step i) (a) + b1)) is from 0.01 to 0.5 %.

4. Method according to one of claims 1 to 3, characterized in that said step i) is performed at a temperature ranging from 150 to 220 ° C.

5. Method according to one of claims 1 to 4, characterized in that said step ii) is performed at a temperature ranging from 180 to 250 ° C.

6. Method according to one of claims 1 to 5, characterized in that said organic solvent is selected from: ketones, in particular methyl amyl ketone, methyl isobutyl ketone, 2-heptanone, 2-octanone and more particularly, methyl amyl ketone , methyl isobutyl ketone or 2-heptanone, aromatic solvents, particularly xylene or toluene, cycloaliphatic solvents, in particular cyclohexane or alkanes at least C7 and preferably the ketones, particularly methyl amyl ketone, methyl isobutyl ketone.

7. Method according to one of claims 1 to 6, characterized in that a weight fraction of at least 50%, preferably at least 75% of said polyol b) is biosourced. 8. Method according to one of claims 1 to 7, characterized in that said component b1) is selected from 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).

9. Method according to one of claims 1 to 8, characterized in that at least 50%, preferably at least 75% by weight relative to the total weight of said components a) + b) is biobased.

10. Method according to one of claims 1 to 9, characterized in that components a) and b) are 100% bio-based.

1 1. A method according to one of claims 1 to 10, characterized in that said polyol b2) is biobased and selected from: 1, 3 propylene diol or the 1, 2 propylene diol or 1, 4 butane diol or diols based saturated fatty acids.

12. Method according to one of claims 1 to 1 1, characterized in that said polyol b3) is biobased and selected from glycerol and ether polyols derivatives, such as polyglycerols.

13. Method according to one of claims 1 to 3, characterized in that said polyacid a1) is an aliphatic diacid biobased selected from: succinic acid, tartaric acid, citric acid, malic acid, itaconic acid, glutaric acid, glutamic acid, fumaric acid, furan dicarboxylic acid, dicarboxylic acid or acid tetrahydrofuran 2.5 3.5 tetrahydrofuran dicarboxylic acid, preferably succinic acid, acid

itaconic acid, glutamic acid, fumaric acid, furan dicarboxylic acid or dicarboxylic acid tetrahydrofuran or 2,5 dicarboxylic acid tetrahydrofuran 3.5.

14. Method according to one of claims 1 to 13, characterized in that said polyacid a2) is biobased and selected from: azelaic acid (Cg), sebacic acid (C10), undecane dioic acid, dodecane dioic acid or dimers and trimers of fatty acids C36 and C54 respectively.

15. Method according to one of claims 1 to 14, characterized in that said monobasic acid a3) is selected from: acetic acid, pyruvic, lactic or rosin (abietic acid and isomers C20) or a saturated fatty acid C12 C22.

16. A method according to one of claims 1 to 15, characterized in that said polyol b1) is at least 40 mol / mol% relative to component b).

17. A method according to one of claims 1 to 16, characterized in that, during the first step i), the molar ratio of carboxy groups of said component a) relative to the OH groups of said polyol b1) is from 1, 1 to 2.1 and preferably 1, 2 to 2, more preferably 1, 3 to 1, 9.