Alkyd resin compositions comprising an aromatic compound

Abstract

The invention relates to an alkyd resin composition comprising (A) at least one oil or unsaturated fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with structure (I); with R1 = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC.

Description

[0001] ALKYD RESIN COMPOSITIONS COMPRISING AN AROMATIC

[0002] COMPOUND

[0003] Field of the invention

[0004] The present invention relates to an alkyd resin composition comprising an aromatic compound. The present invention furthermore relates to the process for making this alkyd resin composition. The present invention also relates to the use of these alkyd resin compositions.

[0005] Background of the invention

[0006] Alkyd resins have long been established as one of the most widely used resins in the coatings industry due to their versatile properties, which include good adhesion, gloss, durability, and flexibility.

[0007] They are synthesized by the polycondensation of polyhydric alcohols (such as glycerol or pentaerythritol), polybasic acids (such as phthalic anhydride), and fatty acids derived from natural oils, providing them with both thermoplastic and thermosetting characteristics. Fatty acids can be added as such or alternatively as natural oils, as triglycerides.

[0008] Alkyd resins can be classified based on their oil length, which significantly influences their final properties. Oil length is defined as the weight percentage of fatty acid building blocks (calculated as their triglycerides):

[0009] - Short-oil alkyd resins (with <40% oil content) tend to dry faster and form harder films, making them suitable for industrial baking enamels and lacquers.

[0010] - Medium-oil alkyd resins (with 40-60% oil content) balance durability and flexibility and are commonly used in general industrial coatings, stoving enamels, flow coatings and architectural coatings

[0011] - Long-oil alkyd resins (with >60% oil content) are softer and more flexible, often used in air-drying systems such as decorative paints. In general, long oil lengths (55 % or higher) result in improved oxidative drying, good substrate adhesion, excellent flow properties, good solubility in aliphatic solvents, and low viscosity, even with low solvent content. However, these alkyds show strong yellowing.

[0012] Despite their widespread use, traditional alkyd resins are not without limitations. One of the primary challenges in the use of alkyd resins formulations in coatings is curing, particularly in air-drying systems where the resin relies on oxidative cross-linking to form a solid film. This process is complex therefore is often slow leading to long drying times and potential issues such as surface tackiness or incomplete through-drying.

[0013] When an alkyd-based paint is applied onto a surface, the fatty acid moieties of the alkyd resin react with oxygen from the atmosphere to form hydroperoxides which subsequently decompose to form free radicals. Reaction of these free radicals with the unsaturated carbon-carbon bonds of the fatty acid moieties causes covalent bonds to be formed between the unsaturated fatty acids chains, thus forming cross-links between polymer chains. In this way, a liquid coating composition that comprises alkyd resin hardens to form a solid cured coating. This process is also referred to as auto-oxidation or drying.

[0014] Autoxidation and crosslinking of the unsaturated oil / fatty acid component can proceed unaided, but the time for drying is generally found to be unacceptably long for many practical purposes. The reactions are significantly accelerated by the presence of a metal-based drying catalyst, commonly referred to as a "drier". Whereas an alkyd coating may takes months to dry in the absence of a drying catalyst, in the presence of such a catalyst, drying can be accomplished within a few hours.

[0015] US-B2-1 1643501 describes an oxidising, ionic, short-oil alkyd resin composition (OSAR) comprising conjugated and diallylic ethylenic functional groups, unsaturated fatty acids, a polyol, and a mono- and / or poly carboxylic acid component, like phthalic anhydride, and ionic constituents (IOC). In the disclosed embodiment, the inclusion of ionic components within the OSAR composition is reported to confer enhanced gloss and increased hardness.

[0016] In WO2016102464 a coating composition is described, comprising an alkyd-comprising resin and a drier comprising a dinuclear ligand-manganese complex comprising manganese and a 1 ,4,7-trisubstituted-1 ,4,7- triazacyclononane ligand, wherein the alkyd comprising resin is an alkyd- stabilized non-aqueous dispersion of particles of addition polymer in a nonaqueous liquid phase comprising alkyd. of the invention

[0017] It is an objective of the present invention to address one or more of the disadvantages faced in the prior art. It is another objective of the invention to provide novel alkyd resin formulations that introduce alternative functionalized aromatic compounds as innovative building blocks for alkyd resins formulations. Further objectives include the use of biobased aromatic compounds as innovative building blocks for alkyd resins formulations. A particular objective is to provide an efficient and low-cost process for the production of biobased 3-methyl phthalic anhydride (3-MPA) based alkyd coatings. A further objective is to provide a new type of cross-linking capability.

[0018] Accordingly, the present invention relates to an alkyd resin composition comprising (A) at least one unsaturated oil or fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the following structure: with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC.

[0019] Furthermore, the present invention relates to a process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the following structure: with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC are added to a reactor to form a reaction medium and the reaction medium is stirred and heated to at least 100°C. The present invention also relates to a process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated oil, and (B) at least one polyol are added to a reactor, stirred and heated to at least 100°C, forming a mono-di-tri-glyceride mixture and to this mono-di-tri-glyceride mixture (C) at least a catalyst and (D) at least one aromatic compound with the following structure: with R1 = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC is added to form a reaction medium and the reaction medium is stirred and heated to at least 100°C.

[0020] The present invention also relates to the use of at least one aromatic compound with the following structure: with R1 =CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC; into an alkyd resin composition comprising furthermore (A) at least one unsaturated oil or fatty acid, (B) at least one polyol, (C) at least a catalyst. The present invention is distinguished from the prior art by the incorporation of at least one methyl substituent within the aromatic compound employed as a building block. In the present invention it is considered that the observed increase in hardness is attributable to the use of the aromatic compound and its reactivity imparted by said methyl group during the oxidative drying.

[0021] Furthermore, the present invention introduces an advancement in the sustainability profile of alkyd resin compositions by utilising an aromatic compound synthetized from biobased origins, thereby reducing dependence on exclusively fossil-derived feedstocks.

[0022] Detailed description of the invention

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0024] Applications are more and more tested with sample amounts of biobased 3-MPA and / or 3,6-DMPA and / or 4,6 DMPA or 4-MPA. The innovative alkyd resin composition of the present invention relates to a final resin composition comprising at least one aromatic compound with the following structure: with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC. These molecules are relatively new and up till now available in small amounts only. For application in alkyd resin compositions, it is needed that larger quantities can be produced, otherwise application will remain possible on small scale only. On the other hand, the aromatic compound such as for example 3- methylphthalic anhydride (3-MPA), showed surprisingly outstanding oxidative cross-linking capabilities, specially in respect to its non-substituted counterpart like phthalic anhydride (PA). This leads to faster drying times, better film formation, improved film properties and reduced environmental impact, even when added in low quantities as specialty chemical.

[0025] The following molecules are preferably represented above in the structure of the aromatic compound: 3-methylphthalic anhydride (3-MPA) (CAS 4792-30- 7), 3-methylphthalic acid (3-MPA) (CAS 37102-74-2), 4-methylphthalic anhydride (4-MPA) (CAS 19438-61 -0), 4-methylphthalic acid (4-MPA) (CAS 4316-23-8), 3,6-dimethylphthalic acid (DMPA) (CAS 944-38-7), 3,6-dimethylphthalic anhydride (DMPA) (CAS 5463-50-3), 4,6-dimethylphthalic acid (DMPA) and 4,6 dimethylphthalic anhydride (DMPA). Of these, 3-MPA and 3,6-DMPA are biobased, while the others are fossil based molecules. Also the term “bio-based MPA and / or DMPA” or “bio-MPA” or “bio MPA” is sometimes used, and includes 3-methylphthalic anhydride (3-MPA), 3-methylphthalic acid (3-MPA), 3,6- dimethylphthalic acid (DMPA), 3,6-dimethylphthalic anhydride (DMPA).

[0026] The present invention was aimed to replace phthalic anhydride (PA), or functionally equivalent molecules, either fully or at least partially with substituted aromatic compounds, such as bio-based methyl phthalic anhydride (3-MPA), without requiring further changes to the formulation. However, we observed that the polyesterification of aromatic compounds with the structure as described above, including 3-MPA, during alkyd resin composition production occurs at a much slower rate compared to PA, under the same process conditions. To solve this issue, we now found that a catalyst is needed to accelerate the reaction rate in for example 3-MPA-based and DMPA-based alkyd resin synthesis. Surprisingly, we found that the catalysed reaction speed of for example 3-MPA matches the reaction speed of the traditional PA-based formulation by using the catalyst concentrations and same reaction conditions outlined in this invention.

[0027] Besides replacement of phthalic anhydride, also molecules like for example fumaric acid, maleic anhydride, levopimaric acid, itaconic acid, isophtalic acid, terephthalic acid, succinic acid, furan dicarboxylic acid may be fully or at least partially replaced with the substituted aromatic compounds, such as bio-based methyl phthalic anhydride (3-MPA), without requiring further changes to the formulation. The term “acid value (AV)” in the context of alkyd resin composition synthesis is a measure of the amount of free acid present in the resin and is used to quantify the degree of polymerization of the components. It is a titration technique. It is defined as the amount of potassium hydroxide (KOH) in milligrams required to neutralize one gram of the resin sample. This value helps to determine the degree of polymerization and the extent of the reaction during the synthesis of alkyd resin compositions. It is calculated using the following empirical equation 1 : equation 1

[0028] The acid value (AV) obtained from Equation 1 is then used to calculate the degree of polymerization (or conversion) as a percentage (%), using equation 2: [equation 2] with AVO being the acid value before reaction and AVt being the acid value at time t of the reaction. Generally, the reaction is considered completed when a plateau of the curve is reached and preferably when an acid value is measured corresponding to a conversion greater than 95%. Preferably, the process is stopped when a calculated conversion reaches a plateau and / or values equal to or above 90%, preferably 95%, more preferably 97% are reached. Acid value measurements are used to monitor reaction of both alkyds that have mainly carboxyl functional end groups and alkyds that have mainly hydroxyl functional end groups.

[0029] Together with the acid value, another important parameter to measure is viscosity. Viscosity is correlated with the molecular weight of the polymers obtained in the alkyd synthesis reaction by the Mark-Houwink relationship defined as:

[0030] [r|] = K*Ma[equation 3] with [q] being the intrinsic viscosity of the polymer solution, M the molecular weight of the polymer chains in the solution and and a being the Mark-Houwink parameter for a specific polymer solution. It might occur that for an obtained acid value that is within specifications, the viscosity value is too low. This is an indication that the stoichiometry of the reaction has resulted in chain lengths that are small in mass and therefore the global molecular weight of the obtained resin is too low.

[0031] The innovative alkyd resin composition of the invention relates to a resin composition comprising (A) at least one unsaturated oil and / or fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the structure as described above.

[0032] The polymerization of alkyd resins primarily involves an esterification reaction, where hydroxyl groups from the polyols react with carboxyl groups from the polybasic acids or fatty acids. The general mechanism is exemplified as follows, with the components and overall reactions involved in the synthesis of an alkyd resin composition. The presence of both polyols (in the below example glycerol and pentaerythritol) is not strictly required - synthesis can proceed with only one polyol: alkyd

[0033] The backbone of this alkyd resin example is based on (methyl)phthalic anhydride, glycerol and pentaerythritol. The reaction of the anhydride with the alcohol functional groups of glycerol and pentaerythritol starts first (number 1 in above scheme), these react together to form ester bonds. Alkyd resin synthesis occurs in a step-growth manner. In this mechanism, small oligomers are formed in the early stages of the reaction, which subsequently react with other oligomers or monomers to form larger chains. Because glycerol is trifunctional and the two most reactive functional groups are the two outer groups and these will react first and because pentaerythritol is four functional and two groups will react first, these alcohols have, after they have been formed into oligomers, free OH-groups left that can be used to attach the fatty acid side chain to the polymeric backbone, thereby providing the resin with some flexibility but also the necessary double bonds for the final oxidative crosslinking in the applied coating. It is possible to only use glycerol, but in this case pentaerythritol is used to replace some of the glycerol and thereby resulting in a branched polymer with fatty acid side chains instead of a pure linear polymer. The purpose of this is to create branched alkyd resin molecules with more unsaturated side chains and thus more crosslinking in the final coating, while keeping a relatively low viscosity which improves the solid contents of the paint as well as its applicability with a brush, roller or spray gun.

[0034] Worth mentioning is that the second acid group of the anhydride might behave differently for phthalic anhydride and methyl phthalic anhydride, as the methyl group of the latter could cause some steric hindrance around the carboxylic group and thereby a slower reaction rate of that acid group.

[0035] It was found that by replacing phthalic anhydride with the aromatic compound with the structure as described above the reaction was taking place at a very slow rate. Catalysts are generally used to speed up the synthesis and to achieve desired performance characteristics in the alkyd synthesis process. To solve the problem a suitable catalyst was searched for, as the more commonly used catalyst for phthalic anhydride was not performing optimally. Various materials may be used to catalyse the reaction between anhydrides and polyols. The catalyst (C) of the present invention is preferably one out of the group of metal salts and / or inorganic acids and / or bases, organic acids and / or bases, and / or organometallic acids and / or bases.

[0036] Examples of catalysts in alkyd resin formulations to facilitate the esterification process are acid catalysts, such as p-toluene-sulfonic acid (pTSA) or sulfonic acids, hydrochloric acid, or phosphoric acid, preferably used in a concentration in the range of from 0.5 up to 3.0 wt.% of the total solid matter in the formulation. Other examples of catalysts in alkyd resin formulations are metallic catalysts, like lithium, bismuth, tin and titanium compounds, like titanium alkoxides and / or titanium chelates, preferably used in very low concentrations, more preferably in the range of from 0.01 up to 1 wt.% based on the solid content of the resin.

[0037] More preferably, catalyst (C) of the present invention is lithium hydroxide, butyl-stannoic acid, mono-butyl-tin oxide, di-butyl-tin oxide, hydrochloric acid, and / or p-toluene sulphonic acid, tri(isopropyl)orthotitanate (TIPOT), tetra- - isopropyl titanate and / or bismuth carboxylate. It was found that lithium hydroxide, butyl-stannoic acid, mono-butyl-tin oxide, di-butyl-tin oxide, hydrochloric acid, bismuth carboxylate, and / or p-toluene sulphonic acid had the best performance for the alkyd resin composition of the invention.

[0038] Advantageously, the amount of catalyst is in the range of from 0.001 up to 0.8 wt%, more preferably in the range of 0.003 up to 0.6 wt%, even more preferably in the range of 0.004 to 0.5 wt%, even more preferably in the range of 0.005 to 0.4 wt%, most preferably in the range of 0.005 to 0.3 wt%.

[0039] Alkyd resins are commonly used as binders in paint formulations due to their excellent film-forming properties, adhesion, and durability. However, the composition and optimization of the coating formulation require other components such as pigments and additives. When applied onto a surface the fatty acids moieties react with the oxygen from the atmosphere to form hydroperoxides which subsequentially decompose to form free radicals. Reaction of these free radicals with the unsaturated carbon-carbon bonds of the fatty acid moieties causes covalent bonds to be formed between the alkyd polymer chains, thus forming cross-links between polymer chains. In this way, a liquid coating composition that comprises alkyd resin hardens to form a solid cured coating. This process is also referred as auto oxidation or simply drying.

[0040] Until now, the time employed for such a composition to dry, relied only on the concentration and type of oil and / or fatty acids used to prepare the resin. Autoxidation and cross linking of the unsaturated oil / fatty acid may proceed unaided, but the time for drying is generally found to be problematic in environments requiring fast turnaround times or multiple coats, where long drying intervals can lead to inefficiencies. The reactions may be significantly accelerated by adding drying catalysts, usually transition metal-based, commonly referred as driers. By switching from a lower valence state to a higher valence state these metals within the dryer catalyses auto-oxidation, forming a complex with both atmospheric oxygen and the double bonds of the unsaturated fatty acids groups within the composition.

[0041] In WO2016102464 a coating composition is described comprising an alkyd comprising resin and a catalyst comprising a dinuclear ligand-manganese complex comprising manganese and a 1 ,4,7-trisubstituted-1 ,4,7- triazacyclononane ligand.

[0042] The following molecules are preferred as the aromatic compound in the composition of the invention: biobased 3-methylphthalic anhydride (3-MPA), biobased 3-methylphthalic acid (3-MPA), biobased 3,6-dimethylphthalic acid (DMPA), biobased 3,6-dimethylphthalic anhydride (DMPA), fossil based 4- methylphthalic anhydride (4-MPA), fossil based 4-methylphthalic acid (4-MPA), 4,6-dimethylphthalic anhydride (DMPA) and 4,6-dimethylphthalic acid. More preferably, the aromatic compound is bio-based 3-MPA and / or DMPA, even more preferably bio-based 3-MPA.

[0043] As it is the idea that the aromatic compound replaces at least partly phthalic anhydride, or similar molecules with similar functionality, in conventional resins, the aromatic compound is preferably present in the range of from 5 up to 60 wt%, more preferably in the range of from 5 up to 50 wt% relative to the total amount of solid matter of the resin, even more preferably in the range of from 10 up to 40 wt%, even more preferably in the range of 10 up to 30% wt. For a medium oil alkyd, the aromatic compound is preferably present in the range of from 5 up to 60 wt%, more preferably in the range of from 20 up to 50 wt% relative to the total amount of solid matter of the resin, even more preferably in the range of from 30 up to 40 wt%. For a short oil alkyd, the aromatic compound is preferably present in the range of from 30 up to 60 wt%, more preferably in the range of from 35 up to 55 wt%, more preferably in the range of from 40 up to 50 wt%.

[0044] We also surprisingly found that the aromatic compound comprises extra cross-linking functionalities. Thus, besides replacing molecules with similar functionalities like phthalic anhydride, the aromatic compound might be added as specialty chemical for the crosslinking effect. In this case the aromatic compound is preferably present in the range of from 0.1 up to 5 wt% relative to the total amount of solid matter of the resin, more preferably in the range of from 0.5 up to 3 wt%. Preferably, the alkyd resin composition furthermore comprises phthalic anhydride (PA). More preferably, the molar ratio between (i) the total amount of aromatic compound and (ii) PA is in the range of from 100:1 up to 1 :100, preferably in the range of from 10:1 up to 1 :10, more preferably in the range of 5:1 up to 1 :5.

[0045] Advantageously, the polyol (B) is a trivalent alcohol and / or a quadrivalent alcohol, more preferably trimethylolpropane, glycerol, and / or pentaerythritol. Also (di)pentaerythritol, a hexavalent alcohol is a preferred option. The polyol (B) suitably is glycerol, that can be part of a natural oil, where three fatty acid molecules are attached to.

[0046] It is furthermore included that the fatty acid (A) and the polyol (B) are one molecule in the form of a triglyceride of the natural oil. Examples that are suitable for the present invention are tung oil, soybean oil, safflower oil, rapeseed oil, linseed oil, camelina oil, (dehydrated) castor oil, tall oil, calendula oil, cotton seed oil, corn oil, hemp oil, palm oil and sunflower oil.

[0047] Examples of suitable fatty acids are unsaturated ones that include unsaturated conjugated or non-conjugated double bonds and aliphatic chain lengths of a number of carbon atoms between C10 - C24. Fatty acids can be different combinations of fatty acids derived from natural oils such as soybean oil, linseed oil, sunflower oil, rapeseed oil, camelina oil, safflower oil, cotton seed oil, tall oil, palm oil or even less common oil types such as tung oil, calendula oil, wood oil, tallow oil, corn oil, hemp oil, (dehydrated) castor oil, fish oil, coconut oil, palm kernel oil, and combinations thereof.

[0048] Advantageously, the fatty acid (A) comprises fatty acids derived from natural oils, more preferably derived from soybean oil, linseed oil, sunflower oil, rapeseed oil, camelina oil, tall oil, cotton seed oil, safflower oil, palm oil and / or combinations thereof, even more preferably derived from soybean oil, rapeseed oil, linseed oil, camelina oil, tall oil, cottonseed oil and sunflower oil.

[0049] Even more preferable fatty acids derived from sunflower oil, tall oil and / or soybean oil are used, as these contain a relatively high % of desired conjugated double bonds. Also the whole oil might be used, in the form of a triglyceride instead of a fatty acid.

[0050] In a further alternative embodiment, the whole oil is used, next to a separately added polyol (B) and / or a separately added fatty acid (A). In such a situation there is the possibility to set every ratio between (A) and (B) instead of the fixed ratio that a natural oil provides.

[0051] Preferably the one or more alkyd resin compositions comprise at least 20 wt%, more preferably at least 30 wt%, even more at least 40 wt%, even more at least 50 wt% of unsaturated fatty acid (A) based on the total weight of the alkyd. Preferably, the one or more alkyd resins comprise at most 90 wt%, more preferably at most 85 wt%, even more preferably at most 75 wt% unsaturated fatty acid (A), even more preferably at most 60 wt% unsaturated fatty acid. A specific example of a suitable alkyd resin is the condensation product of soya bean fatty acid, bio-based 3-MPA, Fascat 4100 as catalyst, and pentaerythritol. For high solids alkyds with high oil lengths, dipentaerythritol is preferably used.

[0052] Optionally, the one or more alkyds may comprise other building blocks, which might be derived from monocarboxylic acids such as pivalic acid, 2- ethylhexanoic acid, lauric acid, palmitic acid, stearic acid, 4-tert. butyl-benzoic acid, cyclopentane carboxylic acid, naphthenic acid, cyclohexane carboxylic acid, 2,4-dimethyl benzoic acid, 2-methyl benzoic acid, benzoic acid, 2,2-dimethylol propionic acid, tetrahydrobenzoic acid, and hydrogenated or non-hydrogenated abietic acid or its isomer. If so desired, the monocarboxylic acids in question may be used wholly or in part as triglyceride, e.g. as vegetable oil, in the preparation of the alkyd resin. If so desired, mixtures of two or more of such monocarboxylic acids or triglycerides may be employed.

[0053] Advantageously, (A), (B), (C), and (D) are reacted and the reacted finished alkyd resin is mixed with a solvent comprising at least white spirit, de-aromatized white spirit, de-aromatized solvents like D40, D60, furanic based solvents, alkanes and / or aromatic solvents. More preferably, the amount of solvent is in the range of from 0.1 wt% up to 60 wt%, even more preferably in the range of from 2 wt% up to 40 wt%, even more preferably in the range of from 2 wt% up to 30 wt%, most preferably in the range of from 3 wt% up to 30 wt%. Unlike for example catalysts and curing agents, solvent concentrations are often calculated as a percentage of the total formulation, not just the solid content. This is because solvents are volatile components and are designed to evaporate after application, so their role is to adjust the application properties (viscosity, flow, drying time) rather than participate in the final film formation. White spirit also called mineral spirits also known as mineral turpentine, turpentine substitute, and petroleum spirits, depending on the region in the world, is a petroleum-derived clear liquid used as a common organic solvent in painting. White spirit is generally used as a paint thinner, or as a component thereof, though paint thinner is a broader category of solvent. Odourless mineral spirits have been refined to remove the more toxic aromatic compounds.

[0054] Optionally, the alkyds may comprise other ingredients with the aim to emulsify the alkyd in water to produce waterborne alkyd emulsions. Preferably, a compound comprising hydrophilic groups and / or a compound comprising carboxyl groups and / or di isocyanate is added to the alkyd resin composition. The compound is generally a surfactant, to ensure stabilization of the emulsion particles in water. These surfactants can be either build-in or external and either anionic or nonionic. Cationic is also possible but hardly used in the coatings industry. A combination of nonionic and anionic is preferably used. Examples of build-in surfactants are nonionic polyethylene glycol (PEG) and anionic dimethylolpropionic acid. Neutralized carboxyl groups of the polymer can act as anionic surfactant. As examples, amines like triethylamine, dimethylethanolamine and / or ammonia and alkali metal hydroxides like LiOH and / or KOH are used to neutralize these carboxyl groups. External surfactants may be anionic, like sulfates, sulfonates and carboxylates or nonionic, like alkylphenolethoxylates, block copolymers and polyethers. More preferably, water is added to the composition with or without a surfactant, even more preferably demineralized water.

[0055] Also other ingredients are normally present in waterborne alkyd emulsions like biocides, and additives like defoamers and wetting agents.

[0056] Advantageously, for self-emulsifiable polyurethane alkyd emulsions (PUD), di-isocyanates can be used in combination with the above mentioned nonionic and anionic surfactants. An example of di-isocyanates is isophoronediisocyanate (IPDI) and of a hydrophilic surfactant is dimethylolpropionic acid.

[0057] A specific example of a suitable water borne alkyd emulsion is the condensation product of soya bean fatty acid, biobased 3-MPA, Fascat 4100, poly ethylene glycol and pentaerythritol. The formed alkyd is then thinned with Isopar H, emulsified in demineralised water using a surfactant like Maxemul 7101 and neutralised with LiOH to form an alkyd emulsion. To the finished alkyd emulsion a biocide like Acticide MV, a defoamer like Byk 028 and a wetting agent like Byk 349 is added.

[0058] The present invention is furthermore directed to the process for the preparation of an alkyd resin composition. If (A) is an unsaturated fatty acid, the process is performed in one step. If (A) is a natural oil, an intermediate step is required, to convert the oil into a mono-, di-, tri-glyceride mixture, which comprises the mono-, di- and tri-glycerides that are present in the natural oil. The glycerol backbone of the natural oil is also present in the mixture, probably still bound to at least one of the glycerides.

[0059] The present invention is furthermore directed to the process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the following structure: with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC are added to a reactor to form a reaction medium and the reaction medium is stirred and heated to at least 100°C.

[0060] The present invention is also directed to the process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated oil, (B) at least one polyol are added to a reactor, stirred and heated to at least 100°C, forming a mono-di-tri-glyceride mixture and to this mono-di-tri-glyceride mixture (C) at least a catalyst and (D) at least one aromatic compound with the following structure: with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC is added to form a reaction medium and the reaction medium is stirred and heated to at least 100°C.

[0061] The mono-di-tri-glyceride mixture is formed via a transesterification reaction, comprising the various glycerides and the other polyols of which some of the OH-groups have exchanged position with unsaturated fatty acids from the oil. Preferably, this transesterification reaction is carried out in the presence of a catalyst. This transesterification catalyst might be the same catalyst as catalyst (C), but it might also be a different catalyst. An example would be Fascat 4350, which is then used for the transesterification reaction.

[0062] At temperatures above 100°C the esterification reaction with the aromatic compound as described above occurs. The esterification reaction with the natural oil as starting material occurs in the second step, where the mono-di-tri-glyceride mixture is converted into an alkyd. Water that is formed during the esterification reaction should be removed from the reaction medium, to move the equilibrium to the formation of ester bonds, and to complete the formation of the alkyd resin.

[0063] Preferably, to remove water from the reaction medium, a solvent, more preferably xylene, is used as azeotrope. In case xylene is used, it carries water, and it is evaporated from the reaction medium, followed by condensation. Water is then separated and removed, while xylene is fed back into the reaction medium. Preferably, xylene is used to regulate the reaction temperature.

[0064] Advantageously, the reaction medium is heated to a temperature in the range of from 200° up to 280°C, more preferably up to 260°C, even more preferably up to 250°C, more preferably in the range of from 225°C up to 245°C.

[0065] Preferably, the reaction takes place under an inert nitrogen atmosphere to avoid discolouration and other undesired reactions.

[0066] In case in the first step the natural oil is reacted with the polyol, for example glycerol and / or pentaerythritol, using a catalyst, the below reaction, as described in the reaction equation, occurs.

[0067] A mono-di-tri-glyceride mixture is formed via a transesterification reaction, comprising the various glycerides and the other polyols of which some of the OH- groups have exchanged position with unsaturated fatty acids from the oil.

[0068] As described earlier, one of the ways to monitor the progress of the process is to measure the acid value (AV) via a titration technique. It is defined as the amount of potassium hydroxide (KOH) in milligrams required to neutralize one gram of the resin sample. This value helps to determine the degree of polymerization and the extent of the reaction during the synthesis of alkyd resin compositions. It is calculated using the following empirical equation 1 :

[0069] [equation 1 ]

[0070] The acid value (AV) obtained from Equation 1 is then used to calculate the degree of polymerization (or conversion) as a percentage (%), using equation 2: [equation 2] with AVO being the acid value before reaction and AVt being the acid value at time t of the reaction. Generally, the reaction is considered completed when a plateau of the curve is reached and preferably a conversion greater than 95% is reached, more preferably greater than 97%.

[0071] Together with the acid value, another important parameter to measure is viscosity. Viscosity is correlated with the molecular weight of the polymers obtained in the alkyd synthesis reaction by the Mark-Houwink relationship defined as:

[0072] [r|] = K*Ma[equation 3] with [q] being the intrinsic viscosity of the polymer solution, M the molecular weight of the polymer chains in the solution and and a being the Mark-Houwink parameter for a specific polymer solution.

[0073] Another way to monitor the progress of the process is to measure the progress via Fourier Transform Infrared (FTIR) spectroscopy or for example H- NMR or another titration technique.

[0074] Alkyd resin compositions, reacted in the way described above, using the novel aromatic component of the invention, might be processed into solvent borne alkyds. Advantageously, solvent is added in an amount in the range of from 2 wt% up to 40 wt%, even more preferably in the range of from 3 wt% up to 25 wt% relative to the reacted alkyd resin. Unlike for example catalysts and curing agents, solvent concentrations are often calculated as a percentage of the total formulation, not just the solid content. This is because solvents are volatile components and are designed to evaporate after application, so their role is to adjust the application properties (viscosity, flow, drying time) rather than participate in the final film formation.

[0075] Alkyd resin compositions, reacted in the way described above, using the novel aromatic component of the invention, might also be used as such without any use of solvent in a 100% solid resin.

[0076] Advantageously, the solvent comprises at least white spirit, de-aromatized white spirit, furanic based solvents, alkanes and / or aromatic solvents. White spirit also called mineral spirits also known as mineral turpentine, turpentine substitute, and petroleum spirits, depending on the region in the world, is a petroleum derived clear liquid used as a common organic solvent in coatings. White spirit is generally used as a paint thinner, or as a component thereof, though paint thinner is a broader category of solvent. Odourless mineral spirits have been refined to remove the more toxic aromatic compounds.

[0077] Alkyd resin compositions, prepared in the way described above, using the novel aromatic compound, are suitably modified to be emulsified in water using the so-called phase inversion process with surfactants. These surfactants can be built into the alkyd resins. These can be nonionic surfactants, like polyethylene glycol (PEG). This can be combined with neutralization of carboxyl groups of the alkyd resin providing anionic stabilization. This is combined with external surfactants that can be anionic or nonionic.

[0078] These alkyd emulsions are produced using the phase inversion process. The alkyd resin is charged in a vessel in which normally a stirrer is present that is capable of mixing at high shear. The temperature is preferably raised to approximately 50-60°C to decrease the viscosity of the alkyd resin. A small amount of solvent might be added to further decrease the viscosity. Subsequently, water with surfactant is charged in the vessel and under mixing the emulsion is formed, going through a so-called butter-phase from water in oil to oil in water.

[0079] Alkyd resin compositions, cooked in the way described above, using the aromatic compound according to the invention, can be modified to be suitably used in a polyurethane alkyd via self-emulsifiable emulsions using a solvent assisted dispersion process. For this process at least two alkyd diols are prepared, that might contain poly ethylene glycol (PEG). Preferably, a compound comprising hydrophilic groups and / or a compound comprising carboxyl groups and / or di isocyanate is added to the alkyd resin composition. Because emulsification takes place in the presence of solvent, the molecular weight of the produced resin can be higher compared to alkyd emulsions produced using the phase inversion process. The at least two alkyd diols are added to a low boiling solvent like for example methyl ethyl keton (MEK) or acetone, coupled with a diisocyanate like for example isophorone diisocyanate (IPDI) and dimethylolpropionic acid to form the following chains: alkyd - IPDI - dimethylolpropionic acid - IPDI - alkyd. The coupling reaction is suitably catalysed with for instance amines like triethylamine (TEA). Amines or alkali metal hydroxides are preferably added to neutralize the carboxyl groups to form anionic stabilization. Subsequently, water is added to the composition, preferably demineralized water, as a result of which the resin emulsifies, and particles are formed automatically. The solvent is preferably removed by stripping.

[0080] Another inventiveness aspect of the obtained novel alkyd based coating formulations, comprising the aromatic compound of the invention, relates to the discovery that the measured hardness and MEK double rubs are remarkably higher compared to alkyd-based coatings that are not based on the novel formulations, but on alkyds with only aromatic anhydrides like phthalic anhydride. This can be explained as follows: during the drying process of the applied alkyd- based coating, the substituted aromatics also participate in the oxidative crosslinking process, thus leading to improved properties of the final coating and drying times. Improved properties include a remarkable increase in film strength, mechanical and chemical resistance and coating hardness.

[0081] A comparison between the two drying mechanisms of this moiety is depicted in the reaction scheme below. The extra methyl group in the MPA based alkyd, offers extra cross linking in oxidative drying mechanism improving on paint mechanical and chemical properties.

[0082] PA-based alkyd MPA- based alkyd

[0083] The substituted group is reactive given that the bond dissociation enthalpies value found was identical to that of toluene (which is a well-known number, namely 375.0 ± 8.4 kJ / mol = 89.7 ± 2.0 kcal / mol from the Handbook of Bond Dissociation Energies in Organic Compounds; Luo, Y.-R., Ed.; CRC Press: London, U.K., 2003).

[0084] It is thus expected that radical chemistry can occur that hinges on the abstraction of a hydrogen atom from that moiety as depicted in the reaction scheme below.

[0085] Additionally, the novel formulation, because of the relative lower viscosity of a MPA based alkyd coating, compared to a similar performing PA based alkyd coating, can rely on the use of less volatile organic solvents (VOCs) (e.g., mineral spirits), which will contribute to a reduction in environmental and health concerns due to their release into the atmosphere during drying.

[0086] Given these technological advancements and market demands, there is a continuous need to improve the performance and the environmental footprint of alkyd resin-based coatings.

[0087] Alkyd resin compositions have long been established as one of the most widely used resins in the coatings industry due to their versatile properties, which include good adhesion, gloss, durability, and flexibility. However, recycling once it has been applied on a wall or an object, like a car or a more industrial agricultural machine or building machine as a coating is very difficult. Therefore, there is a great effort taking place to replace all ingredients of the coating by biobased ingredients, while focussing on maintaining the right properties. Some of these ingredients are easier to replace than others. One of the harder ingredients to replace up till now was phthalic anhydride, as it has some unique properties in the coating. It was now found that by using the aromatic compounds of the invention, properties of the coating were not only maintained, but some were also even improved.

[0088] Therefore, the present invention is also directed to the use of at least one aromatic compound with the following structure with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC; into an alkyd resin composition comprising furthermore (A) at least one unsaturated oil or fatty acid, (B) at least one polyol, (C) at least a catalyst.

[0089] Advantageously, the alkyd resin composition is further used to formulate an alkyd-based coating. This can be either a solvent borne or a water borne alkyd coating.

[0090] With the use of the above aromatic compound, the chemical resistance is improved. Advantageously, it is used to increase the chemical resistance, preferably water resistance and grease resistance of the resulting alkyd-based coating.

[0091] Advantageously, the use of the above aromatic compound in an alkyd resin composition and / or alkyd-based coating increases mechanical resistance, more preferably abrasion resistance of the resulting alkyd-based coating.

[0092] Advantageously, the use of the above aromatic compound in an alkyd resin composition and / or alkyd-based coating increases solvent rub resistance, more preferably MEK rub resistance of the resulting alkyd-based coating.

[0093] Advantageously, the use of the above aromatic compound in an alkyd resin composition and / or alkyd-based coating increases hardness, tensile strength and tensile e-modulus (elongation at break) of a resulting alkyd-based coating.

[0094] Advantageously, the use of the above aromatic compound in an alkyd resin composition and / or alkyd-based coating decreases the dark yellowing of a resulting alkyd-based coating.

[0095] Advantageously, the use of the above aromatic compound in an alkyd resin composition and / or alkyd-based coating decreases the drying time of fresh films of a resulting alkyd-based coating. Advantageously, the use of the above aromatic compound in an alkyd resin composition wherein the alkyd resin is blended with other resin types, preferably acrylic resins, urethane resins and / or phthalic anhydride-based alkyd resins.

[0096] The following, non-limiting examples and figures are provided to illustrate the invention.

[0097] Figure 1 illustrates the results of experiment 2. It shows the acid value versus the reaction time for the samples of the PA005 and MPA001 recipes.

[0098] Figure 2 illustrates the results of experiment 2. It shows the conversion versus the reaction time for the samples of the PA005 and MPA001 recipes.

[0099] Figure 3 illustrates the results of experiment 2. It shows GPC chromatograms of PA005, MPA001 , and commercial Setal 270.

[0100] Figure 4 illustrates the results of experiment 3. It shows the acid value versus the reaction time for MPA001 with various catalysts.

[0101] Figure 5 illustrates the results of experiment 3. It shows the conversion versus the reaction time for MPA001 with various catalysts.

[0102] Figure 6 illustrates the results of experiment 5. It shows the tensile strength in mega Pascal (MPa) versus the dry layer thickness in pm of clear paint films.

[0103] Figure 7 illustrates the results of experiment 5. It shows the E-modulus in mega Pascal (MPa) versus the dry layer thickness in pm of clear paint films.

[0104] Figure 8 illustrates the results of experiment 6. It shows the Koning hardness measurements of paint films.

[0105] Figure 9 illustrates the results of experiment 7. It shows the solvent rub measurement using MEK of paint films.

[0106] The following, non-limiting examples are provided to illustrate the invention.

[0107] In a first experiment the evaluation of the bond dissociation energy (BDE) of three components was studied. The following approach was taken: Consider for the organic compounds under interest the equations below:

[0108] The aim was to compute the appropriate C-H BDE for these three compounds by high-end quantum chemical methods. Toluene was included, as experimental values for the bond dissociation enthalpies are known (375.0 ± 8.4 kJ / mol = 89.7 ± 2.0 kcal / mol2.

[0109] As computational method wB97XD / 6-311 G(2d,2p) was used - this is a high-end density functional (DFT) method, and has a big basis set suitable for the task at hand.

[0110] The enthalpies are given in Hartree (the energy unit for quantum chemistry; 1 H = 627.51 kcal / mol) and the resulting bond dissociation energy is then given in kcal / mol at the very end. The value for toluene indicates the precision of the method used.

[0111] Table 1 : the calculated BDE (in H and in kcal / mol) for molecules I, II and III. It can be concluded that the BDE of (II) is virtually identical to that of toluene. It is thus to be expected that radical chemistry can occur that hinges on the abstraction of a hydrogen atom from that moiety.

[0112] Example 2:

[0113] The synthesis of a 3-methylphthalic acid / anhydride (MPA) based alkyd resin in comparison to the phthalic acid / anhydride-based alkyd resin was performed in an experimental set up constructed to mimic the set ups used in industry as close as possible within the lab.

[0114] All syntheses were designed to replicate the properties of a commercially available alkyd resin known as Setal 270.

[0115] The reaction was carried out in a standard 2 L four-neck flask equipped with a thermometer, a nitrogen inlet, an insulated Vigreux column, a Dean Stark water separator, and a reflux condenser. The flask was placed in an electrical heating mantle, which was used to maintain the reaction temperature at 240°C. Mechanical stirring was provided through an overhead stirrer mounted above the flask. To regulate temperature control, xylene was intermittently introduced in 2- 5 mL aliquots via the top of the condenser, specifically when the temperature exceeded 245°C. Nitrogen flow was maintained throughout the reaction to ensure an inert atmosphere.

[0116] The progress of the syntheses was monitored by measuring the acid value at various reaction intervals. Once the acid value dropped below 12, viscosity measurements were also conducted to further assess the reaction. The acid value was determined by titrating a known quantity of the reaction mixture, dissolved in 50 mL of a 2:1 toluene / ethanol solution, with approximately 0.1 M KOH in ethanol, using phenolphthalein as a visual indicator.

[0117] Equation 1 (outlined in the previous section) was employed to calculate the acid value. The conversion during the polymerization process was subsequently determined using the acid value and calculated by applying Equation 2 (also described in the previous section).

[0118] The viscosity of the resin samples was measured after dilution with white spirit to achieve a solids content of 70%, in accordance with the Setal 270 datasheet. A Thermo Scientific Haake Mars 60 rheometer, configured in a plateplate setup, was employed for the measurements. The test was conducted at a constant rotational speed of 50 RPM, with the temperature maintained at 23°C for a duration of 180 seconds. The average viscosity from the final 10 seconds of the measurement period was used for analysis.

[0119] The most promising final products, along with selected intermediate samples, were analysed via Gel Permeation Chromatography (GPC) to determine molecular weight and molecular weight distribution. The results were compared against the reference resin Setal 270. GPC analysis was conducted using an Ecom chromatograph with tetrahydrofuran (THF) as the solvent, an ultraviolet (UV) detector from Ecom, and a refractive index (Rl) detector from Lab Alliance.

[0120] The best alkyd resins recipe containing phthalic anhydride (PA) that was comparable to the reference Setal 270 was used as reference. This is PA005. When inserting 3-methyl phthalic anhydride (MPA), the recipe was slightly modified to account for the additional methyl group present in MPA (compared to PA). The resulting formulation, designated as MPA001 , is detailed in Table 2 alongside the original PA005 recipe.

[0121] Table 2: Comparison of PA005 and MPA001 recipes.

[0122] As with the PA-based syntheses, the acid value of the MPA reaction mixture was monitored over time, and the conversion was calculated accordingly. Figures 1 and 2 present the acid value and conversion of MPA001 , compared to PA005. It can be observed from the figures that the polyesterification of MPA proceeded at a slower rate compared to that of PA that might be due to steric hindrance of the methyl group at position 3.

[0123] This was an indication that a catalyst might be required, therefore an investigation into catalytic effect will be discussed in next experiment.

[0124] Gel Permeation Chromatography (GPC) measurements were conducted on the final MPA001 sample to determine the chain length and distribution, with the resulting chromatogram shown in Figure 3 alongside overlays of PA005 and Setal 270. The chromatogram illustrates an almost perfect overlay of all three samples, particularly PA005 and MPA001 , indicating that the alkyd resins synthesized are nearly identical. This similarity allows for direct comparisons in evaluating potential differences in the properties of both the resins and the paints derived from them. Differences in molecular weight or molecular weight distribution can be considered negligible as variables. Furthermore, both lab- synthesized resins are comparable to the commercially available Setal 270, which can serve as a reliable reference.

[0125] Example 3:

[0126] The synthesis of the MPA-based alkyd resin composition with various catalyst were tested. Various catalysts are known to accelerate esterification reactions, including alkyd resin synthesis. In this study, catalysts from different chemical groups were selected for comparison. The selected catalysts and their respective amounts are listed in Table 3.

[0127] Table 3: Catalyst that were tested and the concentration

[0128] The catalysts evaluation was conducted within the complete alkyd resin synthesis reaction. The graphs depicting the acid value and conversion versus reaction time for the catalysts Fascat 4100, HCI and LiOH are presented in Figures 4 and 5, respectively.

[0129] Fascat 4100, p-toluene sulphonic acid, hydrochloric acid and lithium hydroxide outperformed Fascat 4201 and Fascat 4350 which showed moderate catalytic activity (not shown here). The data furthermore show that HCI did not perform well in the MPA001 synthesis, despite being one of the best catalysts in the PA005 reaction (not showed in this patent application), thus for PA. This was unexpected.

[0130] Polyesterification with Fascat 4100 proceeds the fastest. The rapid release of water in a short period caused condensation within the flask instead of in the condenser. When these water droplets dripped back into the 240°C reaction mixture, they immediately began to boil, resulting in eruptions, splattering, and even foaming of the mixture. This behaviour was not observed when using LiOH as a catalyst. Although LiOH exhibited slightly lower catalytic efficiency compared to Fascat 4100, the improved control over the reaction outweighed the longer reaction time required. As a result, all further MPA syntheses were performed using LiOH as the catalyst.

[0131] Additionally, the choice of LiOH is further justified by the trend within the industry to move away from tin-based catalysts due to environmental concerns. LiOH has emerged as a promising alternative that is currently under exploration.

[0132] Example 4:

[0133] Two types of paints — translucent and opaque — were prepared. For each type, three formulations were developed, utilizing the three alkyd resins from this research: Setal 270, MPA-based, and PA-based.

[0134] The formulation for the translucent paint is described in table 4.

[0135] Table 4: Formulations of clear paints, m / m % listed

[0136] The formulation for the opaque paint is reported in table 5.

[0137] Table 5: Formulations of opaque paints, m / m % listed

[0138] Example 5:

[0139] Film strength assessment of the obtained paints, of example 4, was performed. The tensile strength and tensile modulus have been determined for various layer thicknesses of the PA005 and MPA001 clear paints using a Zwick Roell Z010 tensile tester. The tensile strength is shown in figure 6 whilst the E- modulus in figure 7.

[0140] Figure 6 illustrates the relationship between the tensile strength in MPa on the y-axis and layer thickness in micrometers (pm) on the x-axis for the two coatings: PA-005 (represented by open circles and a dashed line) and MPA-001 (represented by solid dots and a solid line).

[0141] Figure 7 illustrates the relationship between the variable "E" (representing Young’s elastic modulus) in MPa on the y-axis and layer thickness in micrometers (pm) on the x-axis.

[0142] Both tensile strength and E-modulus were significantly higher for thinner layers (less than 200 pm), likely due to molecular orientation or other structural factors, such as higher crosslinking density, that have a greater impact at reduced thicknesses. Below this threshold, MPA demonstrated significantly better performance compared to PA. Notably, for layers with thicknesses between 50 and 100 pm, MPA exhibited values that were double those of PA. This range between 50 and 200 pm, as emphasised by the dashed-dotted area in the graphs is also commonly the layer thickness applied in practical coating applications.

[0143] Example 6:

[0144] The Koning hardness or Pendulum Hardness of the samples were measured. The instrument consists of a pendulum which is free to swing on two balls resting on a coated test panel. The pendulum hardness test is based on the principle that the amplitude of the pendulum's oscillation will decrease more quickly when supported on a softer surface. The hardness of any given coating is given by the number of oscillations made by the pendulum within the specified limits of amplitude determined by accurately positioned photo sensors. An electronic counter records the number of swings made by the pendulum. Standard hardness tests relate oscillation damping to surface hardness. A glass panel was coated with a 60 pm wet film, held at 23°C and 50% RH for 79 days and the hardness development was monitored with the Konig test. It measures the time taken for the amplitude to decrease from 6° to 3°. The Konig pendulum is triangular with an adjustable counterpoise and swings on two ball bearings of 5mm diameter which rest on the test surface.

[0145] The measured Konig hardness of three coatings Setal 270, PA005, and MPA001 , presented in Figure 8, exhibits that the commercial Setal displays moderate hardness at around 25 swings, comparable to the PA005 which shows the lowest hardness, slightly above 20 swings. In contrast, MPA001 has the highest hardness, reaching about 50 swings, making it significantly harder than both Setal 270 and PA005. These results suggest that MPA001 has a higher cross-linked alkyd film, which might be from the methyl moiety offering an extra cross-linking group during the oxidative drying process.

[0146] MPA therefore has superior resistance to mechanical wear or deformation, when compared to paints cured using commercial formulation with PA.

[0147] Example 7:

[0148] The solvent rub test is used to determine the degree of cure of a coated film by determining the paint film resistance to a specified solvent. The solvent rub test is usually performed using methyl ethyl ketone (MEK) as the solvent.

[0149] This test measures the surface of a coated film with a cloth soaked with MEK until failure or breakthrough of the film occurs. The type of cloth, the stroke distance, the stroke rate, and approximate applied pressure of the rub are specified. The numbers of rubs are counted as a double rub: one rub forward and one rub backward constitutes one rub count.

[0150] Figure 9 illustrates the MEK resistance of three coatings prepared as above for the Konig hardness tests with alkyds resins Setal 270, PA005 and MPA001. Setal and PA exhibit similar performance with around 60 double rubs each, indicating moderate resistance. In contrast, MPA001 significantly outperforms both with approximately 100 double rubs, demonstrating a higher durability compared to the other two. This suggests that MPA001 has superior resistance to abrasion or chemical wear likely due to its higher cross-linked alkyd backbone.

Claims

CLAIMS1. An alkyd resin composition comprising (A) at least one unsaturated oil and / or fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the following structure:with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC.

2. Composition according to claim 1 , wherein the catalyst (C) is one out of the group of metal salts and / or inorganic acids and / or bases, organic acids and / or bases, and / or organometallic acids and / or bases, preferably lithium hydroxide, butyl-stannoic acid, mono-butyl-tin oxide, di-butyl-tin oxide, hydrochloric acid, bismuth carboxylate, tetra-isopropyl titanate and / or p-toluene sulphonic acid.

3. Composition according to claim 1 or 2, wherein the polyol (B) is a trivalent alcohol and / or a quadrivalent alcohol, preferably trimethylolpropane, glycerol and / or pentaerythritol.

4. Composition according to any of the previous claims, wherein the oil is a natural oil or the fatty acid is derived from a natural oil, preferably the natural oil is soybean oil, linseed oil, sunflower oil, rapeseed oil, camelina oil, safflower oil, tall oil, cotton seed oil, palm oil and / or combinations thereof, more preferably soybean oil, rapeseed oil, linseed oil, camelina oil, tall oil and / or sunflower oil.

5. Composition according to any of the previous claims, wherein the aromatic compound is a biobased 3-methylphthalic anhydride (3-MPA), biobased 3- methylphthalic acid (3-MPA), biobased 3,6-dimethylphthalic acid (DMPA), biobased 3,6-dimethylphthalic anhydride (DMPA), fossil based 4-methylphthalicanhydride (4-MPA), fossil based 4-methylphthalic acid (4-MPA), preferably biobased 3-MPA and / or DMPA, more preferably bio-based 3-MPA.

6. Composition according to any of the previous claims, wherein the amount of aromatic compound is in the range of from 5 up to 50 wt% relative to the total amount of solid matter of the resin.

7. Composition according to any of the previous claims, wherein the alkyd resin composition furthermore comprises PA.

8. Composition according to claim 7, wherein the molar ratio between (i) the total amount of aromatic compound and (ii) PA is in the range of from 100:1 up to 1 OO, preferably in the range of from 10:1 up to 1 :10, more preferably in the range of 5:1 up to 1 :5.

9. Composition according to any of the previous claims, wherein the amount of catalyst is in the range of from 0.001 up to 0.8 wt%, preferably in the range of 0.005 to 0.5 wt%.

10. Composition according to any of the previous claims, wherein (A), (B), (C), and (D) are reacted and resulting alkyd resin is mixed with a solvent comprising at least white spirit, de-aromatized white spirit, furanic based solvents, alkanes and / or aromatic solvents.

11. Composition according to claim 10, wherein the amount of solvent is in the range of from 0.1 wt% up to 60 wt%, preferably in the range of from 2 wt% up to 40 wt%, more preferably in the range of from 3 wt% up to 30 wt%.

12. Composition according to any of the previous claims, wherein a compound comprising hydrophilic groups and / or a compound comprising carboxyl groups and / or di isocyanate is added to the alkyd resin composition.

13. Composition according to claim 12, wherein water is added to the composition with or without a surfactant.

14. Process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated fatty acid, (B) at least one polyol, (C) at least a catalyst, and (D) at least one aromatic compound with the following structure:with Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC are added to a reactor to form a reaction medium and the reaction medium is stirred and heated to at least 100°C.

15. Process for the preparation of an alkyd resin composition, wherein (A) at least one unsaturated oil, and (B) at least one polyol are added to a reactor, stirred and heated to at least 100°C, forming a mono-di-tri-glyceride mixture and to this mono-di-tri-glyceride mixture (C) at least a catalyst and (D) at least one aromatic compound with the following structure:with R1 = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC are added to form a reaction medium and the reaction medium is stirred and heated to at least 100°C.

16. Process according to claim 14 and 15, wherein the reaction medium is heated to a temperature in the range of from 200°C up to 250°C, preferably in the range of from 225°C up to 245°C.

17. Process according to claims 14 to 16, wherein the process is stopped when a calculated conversion reaches a plateau and / or values equal to or above 90%, preferably 95%, more preferably 97% are reached.

18. Process according to claims 14 to 17, wherein solvent is added, preferably in an amount in the range of from 0.1 wt% up to 60 wt%, more preferably in the range of from 2 wt% up to 40 wt%, even more preferably in the range of from 3 wt% up to 25 wt% relative to the reaction medium.

19. Process according to claims 14 to 18, wherein a compound comprising hydrophilic groups and / or a compound comprising carboxyl groups and / or di isocyanate is added to the alkyd resin composition.

20. Process according to claim 19, wherein water is added to the composition with or without a surfactant, preferably demineralized water.

20. Use of at least one aromatic compound with the following structurewith Ri = CH3; R2 = H or CH3; R3 = COOH or form together an anhydride bridge CO-O-OC; into an alkyd resin composition comprising furthermore (A) at least one unsaturated oil and / or fatty acid, (B) at least one polyol, (C) at least a catalyst.

21. Use according to claim 20 to formulate an alkyd-based coating.

22. Use according to claim 20 and 21 to increase the chemical resistance, preferably water resistance and grease resistance of the resulting alkyd-based coating.

23. Use according to claim 20 and 21 to increase mechanical resistance, preferably abrasion resistance of the resulting alkyd-based coating.

24. Use according to claim 20 and 21 to increase solvent rub resistance, preferably MEK rub resistance of the resulting alkyd-based coating.

25. Use according to claim 20 and 21 to increase hardness, tensile strength and tensile e-modulus (elongation at break) of a resulting alkyd-based coating.

26. Use according to claim 20 and 21 to decrease the dark yellowing of a resulting alkyd-based coating.

27. Use according to claim 20 and 21 to decrease the drying time of fresh films of a resulting alkyd-based coating.

28. Use according to claim 20, wherein the alkyd resin is blended with other resin types, preferably acrylic resins, urethane resins and / or phthalic anhydride based alkyd resins.

Images