Non-aqueous coating composition

Abstract

The present invention discloses a polyurea compound being the reaction product of - components (I) comprising (a1) a polyisocyanate or a condensed derivative thereof and (b1) a mono-amine, or - components (II) comprising (a2) a polyamine and a (b2) mono-isocyanate. The present invention also discloses a process for the preparation of the polyurea compound. The present invention further relates to a thixotropic coating composition comprising between 0.5 and 25% by weight of the polyurea compound.

Description

[0001] Non- Aqueous Coating Composition

[0002] Field of the Invention

[0003] The invention relates to particular polyurea rheological compounds, to thixotropic coating compositions comprising said particular polyurea compound, to a method for providing said thixotropic coating compositions to a substrate and to a coated substrate obtained by said method.

[0004] State of the Art

[0005] The use of polymer coatings to protect surfaces and enhance the aesthetic and functional properties of materials is well known. These polymer coatings are typically applied to surfaces as liquid systems using techniques such as rolling, brushing, sprinkling, casting and pneumatic or electrostatic spraying.

[0006] The rheological profile of the liquid coating systems on application is typically chosen such that the coating can be applied by the method of choice without problems and flow evenly over the substrate to which it is applied creating the best final appearance. At the same time, the liquid film should not be allowed to sag or form tears on non-horizontal substrates. Such sagging tends to be particularly pronounced for thicker films of coatings and also at any localized buildup of the film, such as at edges, holes and character lines in a substrate.

[0007] There is a need to control the fluidity of the applied coating film during its liquid stage, which includes any heating cycles following application that may be used to promote curing, such that enough leveling is obtained without detrimental sagging. This is particularly true for clear coatings that are used in automotive applications for example, where obtaining extremely well- leveled films without sagging complications is of the highest importance.

[0008] Rheology control agents are normally introduced into coating compositions to create a pseudoplastic rheology profile and / or thixotropic behaviour. In addition to the rheological performance of a coating, its optical performance is also of the utmost importance. For clear coat applications, no detectable haze or turbidity should be present after completion of the curing cycle and no color formation or yellowing should have resulted from the presence of the rheology control agents. Further, in order to limit costs and the interference with other coating properties, and also to minimize the optical effects which are proportional to the amount of rheology control agents added, efficient rheology control agents that can do their job at low concentrations would be preferred.

[0009] There has been a significant focus on the use of polyurea rheology control agents derived from the reaction of an isocyanate component with an amine component. Such polyurea based particulate materials are for example disclosed US4311622 and US4677028.

[0010] The use of different amines and / or isocyanates will yield different polyurea compounds. It is clear that a given polyurea compound will have a defined package of both advantageous and disadvantageous rheological and optical properties. Consequently, there exists a need for polyurea compounds, which can be used at low concentrations in coating compositions presenting an ideal combination of rheological and optical properties without yellowing.

[0011] Application of liquid paints on large objects such as motor vehicle body components, airplanes, trains, or garage doors is often done via electrostatic spraying using rotary atomizers, which atomize the paint to be applied using a rotating bell cup. Compared to pneumatic spraying, electrostatic spraying offers the advantage of improving the transfer efficiency by reducing the amount of overspray via charging of the paint droplets. Even with electrostatic spraying the amount of overspray can still be as high as 20-30%.

[0012] Overspray is also highly undesired in case of e.g. multi-tone cars, application of stripes or logo’s or any other case where paint needs to be applied only on well-defined locations. With spray application techniques, parts that are not intended to be coated need to be masked for this purpose. Masking is a time-consuming, labor intensive and costly process and results in considerable waste streams.

[0013] The aforementioned disadvantages of spray application of liquid paints can be strongly reduced or even eliminated by using overspray-free application techniques. In this technique the paint is deposited on the target locations using a print head applicator device providing drop-on-demand or jet stream-on-demand. The print head can be located close to the target location to be coated which ensures that the paint impinges the object only at the target location thereby practically eliminating overspray. Examples of overspray free applications are described for instance in WO2011138048, WO2014121926, EP1884365, US2015 / 0086723 and US2017182516.

[0014] Said prior art documents only relate to methods and devices for the overspray-free coating or printing but do not focus on the coating composition nor on the requirements or specific problems arising from coating compositions used in the overspray-free application process.

[0015] In overspray-free application, the distance between the print head and the substrate surface to be covered is, as opposed to spray applications, typically in the range comprised between 0.3 cm and less than 15 cm, whereas in spray painting the distance is typically more than 15 cm, typically in the range of about 15 - 25 cm. The time for the paint from leaving the print head to arriving at the substrate surface to be painted is, as opposed to spray applications, very short; typically less than 50 milliseconds which results in the important difference that in overspray-free application practically no solvent evaporation can take place before the composition arrives on the substrate surface. The composition and the viscosity of the coating composition arriving on the substrate is substantially the same as the coating composition leaving the print head. A Newtonian coating composition would have, as a result of its low viscosity required for overspray-free application, a low viscosity when applied to the substrate surface, resulting in unacceptably high sagging on non-horizontal oriented surfaces and even on practically horizontal surface parts like the roof of cars. Therefore, there are conflicting requirements in coating compositions for overspray-free application: on the one hand there is a need for low viscosity in order to be able to eject jet streams or droplet streams through the very small openings of the printing head and on the other hand the requirement of low sagging tendency of the coating composition when applied on the substrate surface.

[0016] The above described conflict of requirements in general is overcome by the use of coating compositions comprising sag control agents with increased thixotropic effect and / or increased amounts of sag control agents, yet said remedy often results in yellowing and water whitening of the resulting coating.

[0017] Aim of the Invention

[0018] The present invention aims to provide a thixotropic coating composition that does not present the limitations of the current state of the art coating systems. It is the aim of the present invention to provide a thixotropic coating composition with improved rheological and optical performances, that does not show any significant yellowing upon curing at room temperature or higher.

[0019] It is a further aim of the present invention to provide thixotropic coating compositions suitable for being used in overspray-free application techniques, the resulting coatings not being prone to yellowing.

[0020] Summary of the Invention.

[0021] The present invention discloses a polyurea compound being the reaction product of

[0022] - components (I) comprising (a1) a polyisocyanate and (b1) a mono-amine, or

[0023] - components (II) comprising (a2) a polyamine and (b2) a mono-isocyanate wherein: polyisocyanate (a1) is a diisocyanate characterized in that isocyanate functional groups are linked through an alkylene group wherein the isocyanate functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched; or a condensed derivative of a diisocyanate characterized in that the isocyanate functional group and the condensed structure are linked through an alkylene group wherein the isocyanate functional group and the condensed structure are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched; or a mixture of one or more diisocyanate(s) and one or more condensed derivative(s) of a diisocyanate; a polyamine (a2) is characterized in that amine functional groups are linked through an alkylene group wherein the amine functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched; mono-amine (b1) is a primary or secondary amine characterized in that the carbon bonded to the nitrogen atom is part of an entity independently selected from the group consisting of a (cyclo)alkyl group, an ether substituted (cyclo)alkyl group and an aryl substituted (cyclo)alkyl group; mono-isocyanate (b2) is characterized in that the carbon bonded to the nitrogen atom of the isocyanate functional group is part of an entity selected from the group consisting of a cycloalkyl group an ether substituted (cyclo)alkyl group and an aryl substituted (cyclo)alkyl group.

[0024] Preferred embodiments of the present invention disclose one or more of the following features:

[0025] • the polyurea compound is the reaction product of polyisocyanate (a1) and mono-amine (b1) wherein:

[0026] - polyisocyanate (a1) is a diisocyanate selected from the group consisting of 1 ,5- pentamethylene diisocyanate, 2-methyl-1 ,5-pentamethylene diisocyanate, 1 ,4- tetramethylene diisocyanate, and mixtures thereof; and

[0027] - mono-amine (b1) is a primary amine selected from the group consisting of hexylamine, cyclohexylamine, benzylamine, S-alpha-methylbenzylamine, R-alpha- methylbenzylamine, 2-phenethylamine, 3-methoxypropylamine and mixtures thereof; • the polyurea compound is the reaction product of polyisocyanate (a1) and mono-amine (b1) wherein:

[0028] - polyisocyanate (a1) is 1 ,5-pentamethylene diisocyanate; and

[0029] - mono-amine (b1) of components (I), is a primary amine selected from the group consisting of benzylamine, S-alpha-methylbenzylamine, R-alpha-methylbenzylamine, 3- methoxypropylamine and mixtures thereof

[0030] • the polyurea compound is the reaction product of polyamine (a2) and mono-isocyanate (b2) wherein: polyamine (a2) is a diamine selected from the group consisting of 1 ,5-pentamethylene diamine, 2-methyl-1 ,5-pentamethylene diamine, 3-methyl-1 ,5-pentamethylene diamine 1 ,4-tetramethylene diamine, 2-methyl-1 ,4-tetramethylene diamine and mixtures thereof; and

[0031] - the mono-isocyanate (b2) is selected from the group consisting of a cyclohexyl isocyanate, benzyl isocyanate, S-alpha-methylbenzyl isocyanate, R-alpha- methylbenzyl isocyanate, 2-phenylethyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof;

[0032] • the polyurea compound is the reaction product of polyamine (a2) and mono-isocyanate (b2) wherein:

[0033] - the polyamine (a2) is 1 ,5-pentamethylene diamine; and

[0034] - the mono-isocyanate (b2) is selected from the group consisting of benzyl isocyanate, S-alpha-methylbenzyl isocyanate, R-alpha-methylbenzyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof;

[0035] • the average number of urea bonds in the polyurea compound is at least 1 .7 .

[0036] The present invention also discloses a process for the preparation of the polyurea compound, wherein the polyurea is obtained by reacting polyisocyanate (a1) and mono-amine (b1) or polyamine (a2) and mono-isocyanate (b2) in the presence of a liquid medium.

[0037] Preferred embodiments of the process of the present invention disclose one or more of the following features:

[0038] • the equivalent ratio of amine / isocyanate ranges from 0.7 / 1 to 1 .3 / 1 , preferably from 0.8 / 1 to 1.2, more preferably from 0.9 / 1 to 1.1 / 1 ;

[0039] • the liquid reaction medium comprises film forming resin(s) (FFR) and organic solvent(s); wherein:

[0040] - the film forming resin(s) (FFR) is (are) present in an amount between 2 and 95 weight percentage, preferably between 4 and 85% by weight, more preferably between 6 and 80% by weight, most preferably between 8 and 75% by weight, relative to the total weight of film forming resin(s) (FFR) and solvent;

[0041] - the film forming resin(s) (FFR) is(are) selected from the group consisting of polyester resins, (meth)acrylic resins, polycarbonate resins, polyether resins, polyurethane resins, amino resins, and mixtures and hybrids thereof;

[0042] - the film forming resin(s) (FFR), comprise(s) hydroxy, primary amine, secondary amine, mercaptane, activated unsaturated C=C moieties, carboxylic acid, epoxide, isocyanate, an activated methylene, methine species such as acetyl acetone, acetoacetate or malonate or derivatives thereof, and mixtures thereof; The present invention further discloses:

[0043] • a sagging control agent comprising between 50 and 100% by weight of at least one polyurea compound of the present invention and from 0 to 50% by weight of one or more rheology additives selected from the group consisting of clays, silicas, microgels, amide waxes or polyurea products, different from the polyurea compounds of the present invention, based on the total of polyurea compound according to the present invention and the one or more other rheology additive(s), being 100% by weight.

[0044] • a composition comprising between 5 and 30% by weight, preferably between 6 and 25% by weight, more preferably between 7 and 20% by weight, most preferably between 8 and 15% by weight of the polyurea of the present invention, between 3 and 30% by weight, preferably between 4 and 25% by weight, more preferably between 5 and 20% by weight, most preferably between 6 and 15% by weight of film forming resin (FFR) and between 40 and 92% by weight, preferably between 50 and 90% by weight, more preferably between 60 and 88% by weight, most preferably between 70 and 86% by weight of organic solvent, based on the total of polyurea, film forming resin (FFR) and organic solvent being 100% by weight;

[0045] • a composition comprising between 0.5 and 10% by weight, preferably between 1 and 9% by weight, more preferably between 2 and 8% by weight, most preferably between 3 and 7% by weight of the polyurea of the present invention, between 35 and 99% by weight, preferably between 40 and 90% by weight, more preferably between 45 and 75% by weight, most preferably between 45 and 65% by weight of film forming resin (FFR) and between 0 and 64.5% by weight, preferably between 1 and 59% by weight, more preferably between 17 and 53% by weight, most preferably between 28 and 52% by weight of organic solvent, based on the total of polyurea, film forming resin (FFR) and organic solvent being 100% by weight;

[0046] The present invention further discloses a thixotropic coating composition comprising one or more film forming resin(s) (FFR) and between 0.1 and 25% by weight of sagging control agent, based on the total weight of film forming resin(s) (FFR) and sagging control agent(s), said sagging control agent comprising between 50 and 100% by weight (based on the total weight of sagging control agent(s)) of at least one polyurea compound of the present invention.

[0047] Preferred embodiments of the thixotropic coating composition of the present invention disclose one or more of the following features:

[0048] • the thixotropic coating composition comprises at least 40% by weight of non-volatile compounds and at most 60% by weight of water-free volatile organic solvents, the sum of the weight percentages of the non-volatile compounds and the water-free volatile organic solvents not exceeding 100% by weight; the non-volatile compounds comprising from 20 to 98% by weight of a one or more film forming resin(s) (FFR), one or more sagging control agent(s) and optionally one or more crosslinker(s) (C), catalyst(s), reactive diluents and binder resins, and from 2 to 80% by weight of one or more additives and auxiliaries, the sum not exceeding 100% by weight of non-volatile compounds;

[0049] • the thixotropic coating composition comprises: at least one film forming resin (FFR); at least one crosslinker (C), reactable with the at least one film forming resin (FFR);

[0050] • the thixotropic coating composition comprises one or more film forming resins (FFR) selected from the group consisting of polyester polyols and (meth)acrylic polyols, polyacrylate polyester polyol hybrids and mixtures thereof; • the thixotropic coating composition comprises one or more crosslinkers (C) selected from the group consisting of amino crosslinker resins, polyisocyanates, and mixtures thereof;

[0051] • the thixotropic coating composition comprises:

[0052] - from 10 to 89, preferably from 20 to 80, more preferably from 30 to 70% by weight of at least one film forming resin (FFR);

[0053] - from 10 to 89, preferably from 20 to 80% by weight of at least one crosslinker (C); based on the total amount of film forming resin (FFR) and crosslinker (C) being 100% by weight;

[0054] • the thixotropic coating composition comprises one or more additives and auxiliaries are selected from the group consisting of pigments, dyes, surfactants, pigment dispersion aids, complexing agents, levelling agents, wetting agents, anti-cratering agents, antifoaming agents, matting agents, heat stabilizers, light stabilizers, UV absorbers, antioxidants, radical inhibitors, and fillers, and mixtures thereof.

[0055] The present invention also discloses a method of providing a coating layer comprising the steps of applying the thixotropic coating composition, preferably a clear-coat composition to at least a part of an object, preferably the (exterior) surface of a transportation vehicle, and curing or drying the applied coating layer, preferably in a temperature range of 5 to 180 °C, wherein the coating layer may be applied using an overspray-free application process on at least part of a non-horizontal surface of the object.

[0056] The present invention further relates to a coated substrate obtained by the method of the present invention.

[0057] Detailed Description of the Invention.

[0058] In the present invention, it has been found that a thixotropic coating composition comprising a specific polyurea compound (SCA), results in a coating having improved rheological and optical properties and above all a reduced or no yellowing, compared to coatings obtained from coating compositions comprising the state in the art polyurea compounds.

[0059] In a particular embodiment the thixotropic coating composition is a non-aqueous thixotropic coating composition selected from the group consisting of volatile-organic-compound (VOC)- comprising coating compositions and VOC-free coating compositions, wherein water may be present in one or more of the constituents of said compositions in such an amount that its overall weight percentage is less than 2, preferably less than 1 .5, more preferably less than 1 , most preferably less than 0.5 and even less than 0.1 , based on the total of all the constituents of said thixotropic coating composition including volatile organic compounds and water, if present, the total being 100% by weight.

[0060] In another particular embodiment the thixotropic coating composition is a crosslinkable thixotropic coating composition more preferably selected from the group consisting of VOC comprising crosslinkable coating compositions and VOC-free crosslinkable coating compositions.

[0061] The specific polyurea compound (SCA) is the reaction product of components (I) comprising (a1) a polyisocyanate and (b1) a mono-amine or components (II) comprising (a2) a polyamine and (b2) a mono-isocyanate wherein:

[0062] - polyisocyanate (a1) is - a diisocyanate characterized in that the isocyanate functional groups are linked through an alkylene group wherein the isocyanate functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, preferably linear; or

[0063] - a condensed derivative of a diisocyanate, such as an uretdione, a biuret, an isocyanurate (trimers), or an asymmetrical trimer, characterized in that the isocyanate functional group and the condensed structure are linked through an alkylene group wherein the isocyanate group and the condensed structure are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, preferably linear; or mixtures thereof; and

[0064] - polyamine (a2) is characterized in that the amine functional groups are linked through an alkylene group wherein the amine functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, preferably linear;

[0065] - mono-amine (b1) is a primary or secondary amine characterized in that the carbon atom bonded to the nitrogen atom is part of an entity independently selected from the group consisting of an (cyclo)alkyl group, an ether substituted (cyclo)alkyl group, a phenyl substituted (cyclo)alkyl group and mixtures thereof; preferably a phenyl substituted (cyclo)alkyl group, more preferably a phenyl substituted C1-C2 alkyl group,

[0066] - mono-isocyanate (b2) is characterized in that the carbon atom bonded to the nitrogen atom of the isocyanate functional group is part of an entity selected from the group consisting of an (cyclo)alkyl group, an ether substituted (cyclo)alkyl group and a phenyl substituted (cyclo)alkyl group, preferably a phenyl substituted (cyclo)alkyl group, more preferably a phenyl substituted C1-C2 alkyl group.

[0067] By polyisocyanate (a1), in the present invention is meant a diisocyanate and / or its condensed derivatives.

[0068] Preferably, the specific polyurea compound (SCA) is the reaction product of components (I) comprising (a1) a polyisocyanate and (b1) a mono-amine wherein:

[0069] - polyisocyanate (a1) is

[0070] - a diisocyanate characterized in that the isocyanate functional groups are linked through an alkylene group wherein the isocyanate functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, preferably linear; or

[0071] - a condensed derivative of a diisocyanate, such as an uretdione, a biuret, an isocyanurate (trimers), or an asymmetrical trimer, characterized in that the isocyanate functional group and the condensed structure are linked through an alkylene group wherein the isocyanate group and the condensed structure are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, preferably linear; or mixtures thereof; and - mono-amine (b1) is a primary or secondary amine characterized in that the carbon atom bonded to the nitrogen atom is part of an entity independently selected from the group consisting of an (cyclo)alkyl group, an ether substituted (cyclo)alkyl group, a phenyl substituted (cyclo)alkyl group and mixtures thereof, preferably a phenyl substituted (cyclo)alkyl group, more preferably a phenyl substituted C1-C2 alkyl group.

[0072] Preferably polyisocyanate (a1) is a diisocyanate wherein the isocyanate groups are situated in positions 1 and 5 of the linking alkylene group, said diisocyanate most preferably being selected from the group consisting of 1 ,5-pentamethylene diisocyanate, 2-methyl-1 ,5- pentamethylene diisocyanate, 1 ,5-diisocyanato-2,2-dimethylpentane and mixtures thereof, even most preferably polyisocyanate (a1) is 1 ,5-pentamethylene diisocyanate.

[0073] Alternatively polyisocyanate (a1) is a diisocyanate wherein the isocyanate groups are situated in position 1 and 4 of the linking alkylene group, such as 1 ,4-tetramethylene diisocyanate or wherein the isocyanate groups are situated in position 1 and 3 of the linking alkylene group, such as 1 ,3-trimethylene diisocyanate.

[0074] Preferably polyisocyanate a1) is a condensed derivative of a diisocyanate. By condensed derivative, in the present invention is meant , a polyisocyanate comprising more than one isocyanate functional group and a condensed structural element to which the isocyanate functional groups are attached. By condensed structural element in the present invention is meant an uretdione, a biuret or an isocyanurate structure.

[0075] Preferably the condensed derivatives are selected from the group consisting of uretdione dimers of diisocyanates, biuret dimers of diisocyanates, biuret trimers of diisocyanates and mixtures thereof, wherein the diisocyanate is selected from the group consisting of 1 ,5- pentamethylene diisocyanate, 2-methyl-1 ,5-pentamethylene diisocyanate, 1 ,5-diisocyanato-

[0076] 2.2-dimethylpentane and mixtures thereof., preferably the diisocyanate is 1 ,5-pentamethylene diisocyanate.

[0077] Alternatively the condensed derivatives are selected from the group consisting of uretdione dimers of diisocyanates, biuret dimers of diisocyanates, biuret trimers of diisocyanates and mixtures thereof, wherein the diisocyanate is selected from the group consisting of 1 ,4-- tetramethylene diisocyanate and 1 ,3-trimethylene diisocyanate.

[0078] Preferably polyisocyanate (a1) is a diisocyanate selected from the group consisting of 1 ,5- pentamethylene diisocyanate, 1 ,4-tetramethylene diisocyanate and mixtures thereof.

[0079] Most preferably polyisocyanate (a1) is 1 ,5-pentamethylene diisocyanate .

[0080] Preferably polyamine (a2) is a diamine wherein the amino groups are situated in positions 1 and 5 of the linking alkylene group, said diamine more preferably being selected from the group consisting of 1 ,5-pentamethylene diamine, 2-methyl-1 ,5-pentamethylene diamine, 3-methyl- 1 ,5-pentamethylene diamine and 2,2-dimethyl-1 ,5-pentanediamine and mixtures thereof.

[0081] Alternatively polyamine (a2) is a diamine wherein the amino groups are situated in position 1 and 4 of the linking alkylene group, such as for example 1 ,4-tetramethylene diamine, 2-methyl- 1 ,4-tetramethylene diamine and 2,3-dimethyl-1 ,4-butanediamine, or (a2) is a diamine wherein the amino groups are situated in position 1 and 3 of the linking alkylene group, such as for example 1 ,3-propanediamine, 2-methyl-1 ,3-propanediamine, 3-methylbutane-1 ,3-diamine,

[0082] 2.2-dimethyl-1 ,3-propanediamine and 2,2-diethyl-1 ,3-propanediamine. More preferably polyamine (a2) is a diamine selected from the group consisting of 1 ,5- pentamethylene diamine, 1 ,4-tetramethylene diamine and mixtures thereof.

[0083] Most preferably polyamine (a2) is 1 ,5-pentamethylene diamine .

[0084] Preferably mono-amine (b1) is a primary amine selected from the group consisting of n- alkylamine, cycloalkylamine, benzylamine, alpha-alkylbenzylamine (preferably S-alpha- methylbenzylamine, R-alpha-methylbenzylamine and alpha-ethylbenzylamine), 2- phenethylamine, 3-methoxypropylamine and mixtures thereof.

[0085] More preferably mono-amine (b1) is a primary amine selected from the group consisting of C2-C4 alkylamine, cycloalkylamine, benzylamine, S-alpha-methylbenzylamine, R-alpha- methylbenzylamine, 2-phenethylamine, 3-methoxypropylamine and mixtures thereof. Even more preferably mono-amine (b1) is selected from the group consisting of benzylamine, S- alpha-methylbenzylamine, 3-methoxypropylamine and mixtures thereof. Most preferably mono-amine (b1) is benzylamine or S-alpha-methylbenzylamine, even most preferably benzylamine.

[0086] Preferably the mono-isocyanate (b2) is selected from the group consisting of n-hexyl isocyanate, cyclohexyl isocyanate, benzyl isocyanate, S-alpha-methylbenzyl isocyanate, 2- phenylethyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof.

[0087] More preferably the mono-isocyanate (b2) of components (II) is selected from the group consisting of benzyl isocyanate, S-alpha-methylbenzyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof. Most preferably mono-isocyanate (b2) is benzyl isocyanate or S-alpha-methylbenzylisocyanate.

[0088] In view of environmental interests it is preferred to use in the composition of the polyurea compound (SCA) an as high as possible percentage of constituents originating from recycled or renewable feedstock. In this context, “renewable feedstock” refers to natural resources which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes (in a finite amount of time in a human time scale). Substances or mixtures of substances obtained from such renewable feedstock should have in total a recycled or bio-based carbon content of more than 20% by weight of total carbon content of the substance or mixture, the bio-based carbon content being determined using the ASTM D6866-20 standard. Therefore, the polyisocyanate (a1) (i.e. 1 ,5-pentamethylene diisocyanate) or mono-isocyanate (b2) as well as the polyamine (a2) or the mono-amine (b1) in the polyurea compound (SCA) of the present invention may each be fully or partly obtained from renewable feedstock. Amines from renewable biobased resources are well known in the art (e.g. amino acids).

[0089] Preferably the polyurea compound (SCA) according to the present invention is characterized in that the average number of urea bonds in the polyurea compound ranges from 1.7 to 4, preferably from 1 .7 to 3.5, more preferably from 1 .7 to 3 per molecule, most preferably from 1 .8 to 2.8, or even from 1 .9 to 2.5, or even from 2 to 2.3.

[0090] Specifically preferred polyurea compounds (SCA) are:

[0091] - the reaction product of a diisocyanate (a1) characterized in that the isocyanate functional groups are linked through an alkylene group wherein the isocyanate functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear, and a mono-amine (b1) selected from the group consisting of n-alkylamine, cycloalkylamine, benzylamine, S-alpha- methylbenzylamine, R-alpha-methylbenzylamine, 2-phenethylamine, 3- methoxypropylamine and mixtures thereof; even more preferably the reaction product of 1 ,5-pentamethylene diisocyanate and benzylamine; 1 ,5-pentamethylene diisocyanate and S-alpha-methylbenzylamine; and 1 ,5- pentamethylene diisocyanate and 3- methoxypropylamine; and

[0092] - the reaction product of a polyamine (a2) characterized in that the amine functional groups are linked through an alkylene group wherein the amine functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear, and a mono-isocyanate (b2) selected from the group consisting of benzyl isocyanate, S-alpha-methylbenzyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof; even more preferably the reaction product of 1 ,5- pentamethylene diamine and benzylisocyanate; 1 ,5-pentamethylene diamine and S-alpha- methylbenzylisocyanate; and 1 ,5- pentamethylene diamine and 3- m et h oxy p ro py I i socya n ate ; wherein the average number of urea bonds in the polyurea compound ranges from 2 to 2.3.

[0093] Most preferred polyurea compounds (SCA) are the reaction product of 1 ,5-pentamethylene diisocyanate and benzylamine and the reaction product of 1 ,5-pentamethylene diamine and benzylisocyanate.

[0094] Even most preferred polyurea compounds (SCA) are the reaction product of 1 ,5- pentamethylene diisocyanate and benzylamine.

[0095] Further preferably, the polyurea compounds (SCA) are not the reaction product of 1 ,5- pentamethylene diisocyanate and alpha-ethylbenzylamine.

[0096] The specific polyurea compound of the present invention is used as sagging control agent optionally in combination with other rheology additives chosen from clays (clay sag control agents), silicas (silica-based sag control agents), microgels (microgel sag control agents), amide waxes (amide based sag control agents) or polyurea products (sag control agents based on polyurea products), different from the polyurea compounds of the present invention, such as those disclosed in for example EP0192304, US4311622, US4677028, US4839406, US2004186261, US2008132639 and US2012226075 among others.

[0097] A rheology additive, in the context of the present invention, is a compound with the capability to modify the rheological profile of a coating composition. There are different types of rheology additives, the type of rheology additive is preferably selected from the group consisting of polyurea products, clays, silicas, microgels and amide waxes.

[0098] A sagging control agent, in the context of the present invention, comprises at least one rheology additive. The sagging control agent can comprise of one type of rheology additive or it can be a mixture of different types of rheology additives.

[0099] The polyurea compound according to the present invention may be used in a sagging control agent in combination with one or more rheology additive(s) selected from the group consisting of clays (clay sag control agents), silicas (silica-based sag control agents), microgels (microgel sag control agents), amide waxes (amide based sag control agents) or polyurea products (sag control agents based on polyurea products), different from the polyurea compounds of the present invention. In this particular embodiment, the polyurea compound of the present invention is used in an amount of from 50 to 100 % by weight, based on the total of polyurea compound of the present invention and the one or more other rheology additive(s), being 100% by weight.

[0100] For conventional coating application techniques, the sagging control agent may comprise 100% by weight of the polyurea compound of the present invention.

[0101] In particular when overspray-free application techniques are concerned the sagging control agent preferably comprises a mixture of the specific polyurea compound of the present invention and a second rheology additive different from the specific polyurea compound of the present invention, wherein:

[0102] - the specific polyurea compound of the present invention is characterized by a melting temperature Tm1 ;

[0103] - the second rheology additive, is characterized by a melting temperature Tm2 and is preferably selected from the group consisting of silica, polymeric microgels, clays and polyurea based products different from the particulate polyurea compound of the present invention;

[0104] - Tm2 > (Tm1 + 10°C);

[0105] - Tm1 + 10°C < Thrd <Tm2, Thrd being the curing or drying temperature of the coating composition.

[0106] Further preferably, the sagging control agent comprises a mixture of rheology additives each being the specific polyurea compound of the present invention, wherein:

[0107] - the first specific polyurea compound of the present invention is characterized by a melting temperature Tm1 ;

[0108] - the second specific polyurea compound of the present invention is characterized by a melting temperature Tm2 and is preferably combined with a rheology additive selected from the group consisting of silica, polymeric microgels and clays;

[0109] - Tm2 > (Tm1 + 10°C);

[0110] Tm1 + 10°C < Thrd <Tm2, Thrd being the curing or drying temperature of the coating composition.

[0111] More preferably, the sagging control agent comprises a mixture of a rheology additive different from the specific polyurea compound of the present invention and a second rheology additive being the specific polyurea compound of the present invention, wherein:

[0112] - the rheology additive different from the specific polyurea compound of the present invention is characterized by a melting temperature Tm1 ;

[0113] - the second rheology additive is the specific polyurea compound of the present invention, is characterized by a melting temperature Tm2 and is preferably combined with a rheology additive selected from the group consisting of silica, polymeric microgels and clays;

[0114] - Tm2 > (Tm1 + 10°C);

[0115] - Tm1 + 10°C < Thrd <Tm2, Thrd being the curing or drying temperature of the coating composition.

[0116] Polyurea compounds obtained from reaction of a diisocyanate and a monoamine wherein the isocyanate functional groups of the diisocyanate are situated on carbon position 1 and 5 or on carbon position 1 and less than 5 of the linking alkylene group already are mentioned in prior art documents. The same applies for polyurea compounds obtained from reaction of a diamine and a monoisocyanate wherein the amine functional groups of the diamine are situated in carbon position 1 and 5 or in carbon position 1 and less than 5 of the linking alkylene group.

[0117] US7632882 discloses polyurea obtained from reaction of a diisocyanate wherein the isocyanate groups are in the position 1 and 5 or in the position 1 and 4 of the linking alkylene group and an alkanolamine (examples XI, XIII and XIV) . 1 ,5-diisocyanato-2-methylpentane and 1 ,4-diisocyanatobutane are listed in a series of experiments along with 1 ,6-hexamethylene diisocyanate, 1 ,8-diisocyanatooctane and 1 ,12-diisocyanatododecane. The polyurea of the example XXVI to XXIX are obtained from 2-methyl-1 ,5 pentanediamine, and pentyl isocyanate, hexyl isocyanate, octyl isocyanate and dodecyl isocyanate as monoisocyanate. Data showed that a reduction of the number of carbon atoms between the isocyanate groups resulted in longer gel time.

[0118] In WO02064684 an extensive list of aliphatic diisocyanates is disclosed in paragraph 42, among which 1 ,3-trimethylene diisocyanate, 1 ,4-tetramethylene diisocyanate and 1 ,5- pentamethylene diisocyanate. 1 ,6-hexamethylene diisocyanate is disclosed as the preferred one. A list of monoamines is disclosed in paragraph 40 of which benzyl amine and hexyl amine are preferred, hexyl amine being the most preferred.

[0119] In W02005061632 an extensive list of aliphatic diisocyanates is disclosed in paragraph 24, among which 1 ,3-trimethylene diisocyanate, 1 ,4-tetramethylene diisocyanate and 1 ,5- pentamethylene diisocyanate. 1 ,6-hexamethylene diisocyanate is disclosed as the preferred one. A list of monoamines is disclosed in paragraph 23, of which benzyl amine and hexyl amine are preferred, hexyl amine being the most preferred. Example 1 illustrates the preparation of a polyurea compound obtained from 1 ,6-hexamethylene diisocyanate and hexyl amine.

[0120] US2012214894 discloses 1 ,5-pentamethylene diisocyanate in a list of diisocyanates of which isophorone diisocyanate and 1 ,6-hexamethylene diisocyanate are preferred (paragraph 51 and 52). In paragraph 109 a list of (substituted) benzyl amines is disclosed of which aniline and benzylamine are most preferred.

[0121] WO2022229209 discloses 1 ,4-tetramethylene diisocyanate and 1 ,5-pentamethylene diisocyanate in an extensive list of polyisocyanates (paragraph 54). Most preferably, 1 ,6- hexamethylene diisocyanate or its isocyanurate are selected. In paragraph 44 a list of monoamines is disclosed. Good results were obtained when the polyurea particles comprise a reaction product of benzyl amine and hexamethylene diisocyanate, of 3-methoxypropylamine and the isocyanurate derivative of 1 ,6-hexamethylene diisocyanate and most preferred of S- alpha-methylbenzylamine and 1 ,6-hexamethylene diisocyanate.

[0122] EP0192304 a polyurea compound being the reaction product of an isocyanurate-trimer from a diisocyanate containing 3-20 carbon atoms and of an amine containing one or more primary amino groups. Mono-amines, having alkyl-, ether substituted alkyl- and phenyl substituted alkyl groups are disclosed among many others (col. 2, 1. 61 to col. 3, 1. 14).

[0123] None of the above references discloses possible beneficial rheology and / or optical properties which could be attributed to the length of the linking alkylene group between the isocyanate groups of the diisocyanate or between the amine groups of the diamine.

[0124] The thixotropic coating composition according to the present invention comprises:

[0125] • one or more film forming resin(s) (FFR), a sagging control agent comprising the particulate polyurea compound (SCA) of the invention.

[0126] According to the invention, with film forming resin (FFR) is understood a compound, preferably a polymeric compound, that is able to form a coating (also called film), preferably able to form an organic coating film.

[0127] There are no limitations to the compositions of the backbone of the film forming resins (FFR). Preferably the film forming resins (FFR) are selected from the group consisting of polyester resins, (meth)acrylic resins, polycarbonate resins, polyether resins, polyurethane resins, amino resins, and mixtures and hybrids thereof. Such polymers are generally known to the skilled person and are commercially available.

[0128] The film forming resins (FFR) may comprise functional groups. Preferred functional groups are hydroxy, primary amine, secondary amine, mercaptane, activated unsaturated C=C moieties, carboxylic acid, epoxide, isocyanate, an activated methylene, or methine species such as (derivatives of) acetyl acetone, acetoacetate or malonate. Functional groups can also be blocked by a chemical reaction, such as for example a ketimine as a blocked version of a primary amine blocked by a ketone. A person skilled in the art is well aware of such chemical blockers. In a preferred embodiment the one or more film-forming resin(s) comprise(s) hydroxyl, thiol, carboxyl and / or epoxy functional groups. More preferably, one or more filmforming resin(s) comprise(s) hydroxyl and / or carboxyl functional groups.

[0129] In another preferred embodiment the one or more film-forming resin(s) comprise(s) ethylenically unsaturated functional groups, activated methylene and / or methine groups.

[0130] The one or more film forming resins (FFR) may comprise more than one type of functional groups. These different types of functional groups may be present in the same or in different film forming resins. The functional groups of one or more film forming resin(s) can be reactable with other functional groups of one or more film forming resin(s)). It is also possible that the functional groups of one or more film forming resin(s) can be reactable with crosslinker (C), if present.

[0131] Accordingly, a first film forming resin can be reactable with a second film forming resin which can be the same or different from the first film forming resin; and / or the first film forming resin can be reactable with crosslinker (C) if present, and / or the second film forming resin can be reactable with crosslinker (C), if present.

[0132] Of the wide variety of potentially suitable film forming resins, preferred are the polyester resins, polyurethane resins, (meth)acrylic resins, amino resins, and mixtures or hybrids thereof, wherein by mixtures a physical blend of two or more resins of similar or different type is meant, whereas hybrids comprise the chemical reaction product of two or more polymer segments of different type linked through covalent bonds.

[0133] More preferred film forming resins are the polyester resins and (meth)acrylic resins and mixtures and hybrids thereof.

[0134] The one or more film forming resin(s) (FFR) used in the thixotropic coating composition according to the present invention preferably has a weight averaged molecular weight Mw, of less than 30,000 Dalton, more preferably less than 10,000 Dalton, most preferably less than 5,000 Dalton.

[0135] The number averaged molecular weight Mn of the one or more film forming resin(s) (FFR) is preferably at most 10,000 Dalton, more preferably at most 5,000 Dalton, most preferably at most 3,000 Dalton.

[0136] The polydispersity of the molecular weight distribution of the one or more film forming resin(s) (FFR) is preferably between 1.2 and 10, more preferably between 1.5 and 6 and most preferably between 1 .7 and 4.

[0137] The glass transition temperature Tg of the one or more film forming resin(s) (FFR) is preferably higher than -80 °C, more preferably higher than -40 °C, most preferably higher than -30 °C. The glass transition temperature of the one or more resin(s) does preferably not exceed 100 °C, more preferably 90 °C, most preferably 80 °C.

[0138] The weight averaged molecular weight Mw and number averaged molecular weight Mn are determined according to ASTM D 3593 by Gel Permeation Chromatography using polystyrene standards, more particularly using size exclusion chromatography.

[0139] The Tg is measured using Mettler DSC 822E calorimeter according to DEN EN ISO 16805 and ISO 11357.

[0140] The one or more film forming resin(s) (FFR) has (have) an equivalent weight in the range of 50 to 2500 g / equiv, preferably in the range of 80 to 400 g / equiv and more preferably in the range of 100 to 300 g / equiv.

[0141] According to a first embodiment, the one or more film forming resin(s) (FFR) is (are) (a) polyol(s). The polyols comprise on average at least 2, preferably more than 2, hydroxyl groups. Preferably polyols comprise on average at least 2.2 hydroxyl groups, more preferably on average at least 2.5 hydroxyl groups. The polyol of a first film-forming resin can be the same as the polyol of a second film forming resin, or the polyol of a first film forming resin can be different from the polyol of a second film-forming resin.

[0142] The polyols are preferably selected from the group consisting of polyester polyols, (meth)acrylic polyols, polycarbonate polyols, polyether polyols, polyurethane polyols, and mixtures and hybrids thereof. Such polymers are generally known to the skilled person and are commercially available.

[0143] More preferably, polyols, are selected from the group consisting of polyester polyols, (meth)acrylic polyols, or hybrids or mixtures thereof wherein by mixtures a physical blend of two or more polymeric polyols of similar or different type is meant, whereas hybrids comprise the chemical reaction product of two or more polymer segments of different type linked through covalent bonds.

[0144] Suitable polyester polyols can be obtained, for instance, by the polycondensation of one or more di- and / or higher functional hydroxy compounds with one or more di- and / or higher functional carboxylic acids, C1-C4 alkyl esters and / or anhydrides thereof, optionally in combination with one or more monofunctional carboxylic acids and / or C1-C4 alkylesters thereof and / or monofunctional hydroxy compounds. Non-limiting examples of monocarboxylic acids are linear or branched alkyl carboxylic acids comprising 4 to 30 carbon atoms, such as stearic acid, 2-ethylhexanoic acid and isononanoic acid. As non-limiting examples, di- and / or higher functional hydroxy compounds can be one or more alcohols selected from the group consisting of ethylene glycol, neopentyl glycol, 1 ,3-propanediol, 1 ,4-butanediol, isosorbide, spiroglycol, trimethylol propane, glycerol, trihydroxyethyl isocyanurate and pentaerythritol. As non-limiting examples, the di- and / or higher functional carboxylic acids are one or more selected from the group consisting of succinic acid, adipic acid, sebacic acid, 1 ,4-cyclohexyl dicarboxylic acid, hexahydrophthalic acid, terephthalic acid, isophthalic acid, phthalic acid and functional equivalents thereof. Polyester polyols can be prepared from di and / or higher functional hydroxy compounds and from carboxylic acids, and / or anhydrides and / or C1-C4 alkyl esters of the acids.

[0145] Typical preferred acid values of the polyols is less than 15, more preferably less than 10, most preferably less than 8 mg KOH / g , even less than 6 mg KOH / g, even less than 4 mg KOH / g. The acid value can be determined according to ISO 3682-1996.

[0146] Suitable (meth)acrylic polyols can be obtained, for instance, by the (co)polymerization of hydroxyl functional (meth)acrylic monomers with other ethylenically unsaturated comonomers in the presence of a free radical initiator. As a non-limiting example, the (meth)acrylic polyol can include residues formed from the polymerization of one or more hydroxyalkyl esters of (meth)acrylic acid, such as for example hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol esters of (meth)acrylic acid, polypropylene glycol esters of (meth)acrylic acid, and mixed polyethylene glycol and polypropylene glycol esters of (meth)acrylic acid. The (meth)acrylic polyol further preferably comprises monomers not containing hydroxyl groups such as methyl (meth)acrylate, tert-butyl (meth)acrylate, isobornyl (meth)acrylate, isobutyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, (meth)acrylic acid. The (meth)acrylic polyol optionally comprises non- (meth)acrylate monomers such as styrene, vinyl toluene or other substituted styrene derivatives, vinyl esters of (branched) monocarboxylic acids, maleic acid, fumaric acid, itaconic acid, cratonic acid and monoalkylesters of maleic acid.

[0147] The polyol may comprise a mixture of more than one polyol(s), in particular a mixture of at least one (meth)acrylic polyol and at least one polyester polyol.

[0148] The polyol can be a so-called hybrid polyacrylate polyester polyol, wherein the (meth)acrylic polyol is prepared in situ in the polyester polyol and wherein polyester and polyacrylate segments are linked through covalent bonds. The (meth)acrylic polyol and polyester polyol are preferably obtained with the same monomers as described here above for the (meth)acrylic polyol and the polyester polyol, respectively.

[0149] According to a second embodiment, the film forming resin(s) (FFR) (comprise(s) functionalities which are acidic protons (C-H) in activated methylene or methine groups. In this embodiment, it is preferred that film forming resin comprises malonate or acetoacetate functionalities or a mixture thereof, preferably dominantly a malonate. It is preferred that the film forming resin(s) is (are) polymer(s) chosen from the group of polyesters, alkyds, polyurethanes, polyacrylates, epoxy resins, polyamides and polyvinyl resins which contain a malonate and / or acetoacetate moiety in the main chain, pendant, terminal or combinations thereof. According to a third embodiment, the film forming resin(s) (FFR) comprise(s) functionalities which are activated unsaturated C=C moieties preferably acrylates, fumarates and maleates. Preferably, such a film forming resin is an unsaturated acryloyl functional component. Said components having activated unsaturated C=C moieties can be selected from a first preferred group of esters prepared from an acid or ester comprising an activated unsaturated C=C moiety and components containing 2-6 hydroxyl groups and 1-30 carbon atoms. These esters may optionally contain hydroxyl groups. Especially preferred examples include trimethylolpropane triacrylate, pentaerythritol triacrylate and di-trimethylolpropane tetraacrylate. Other suitable compounds may be selected from the group of resins such as polyesters, polyurethanes, polyethers, epoxy resins, and / or alkyd resins containing activated unsaturated groups. These include, for example, urethane acrylates obtained by reaction of a polyisocyanate with an hydroxyl group-containing acrylic ester, e.g., an hydroxyalkyl ester of acrylic acid or a component prepared by esterification of a polyhydroxyl component with less than a stoichiometric amount of acrylic acid; polyether acrylates obtained by esterification of an hydroxyl group-containing polyether with acrylic acid; polyfunctional acrylates obtained by reaction of an hydroxyalkyl acrylate with a polycarboxylic acid and / or a polyamino resin; polyacrylates obtained by reaction of acrylic acid with an epoxy resin; and polyalkylmaleates obtained by reaction of a monoalkylmaleate ester with an epoxy resin and / or an hydroxy functional oligomer or polymer. Such compounds are very well known and have been commercialized since long, and may be obtained from allnex under the tradename of EBECRYL®. Apart from acryloyl esters a class of suitable components are acrylamides. Also non-(meth)acrylate ethylenically unsaturated comonomers such as styrene, vinyl toluene or other substituted styrene derivatives, vinyl esters of (branched) monocarboxylic acids, maleic acid, fumaric acid, itaconic acid, cratonic acid and monoalkylesters of maleic acid can be used.

[0150] The one or more film forming resin(s) (FFR) is (are) optionally reactable with a crosslinker (C) or otherwise stated, film forming resin(s) (FFR) can be reactable with a crosslinker (C) if present in the crosslinkable composition.

[0151] Crosslinker (C) comprises an oligomeric or polymeric compound. There are no limitations to the type of crosslinker (C), and as the skilled person will know, the functional groups in crosslinker (C) will highly depend on the functional groups present in film forming resin(s) (FFR).

[0152] The functional groups of crosslinker (C) are preferably selected from the group consisting of isocyanate, hydroxy, primary amine, secondary amine, mercaptane, activated unsaturated C=C moieties, carboxylic acid, epoxide, an activated methylene, methine species such as (derivatives of) acetyl acetone, acetoacetate or malonate, and mixtures thereof. The functional groups can also be blocked by a chemical reaction. A person skilled in the art is well aware of such chemical blockers. There are no limitations to the compositions of the backbone of crosslinker (C). Such crosslinkers are generally known to the skilled person and are commercially available.

[0153] Preferably, the relative amounts of the functional groups present in film forming resin(s) (FFR) reactable with crosslinker (C) and the functional groups in crosslinker (C) are chosen such that the equivalent ratio of functional groups in crosslinker (C) I total functional groups in film forming resin(s) (FFR) is between 0.5 and 3 and preferably between 0.75 and 2 or 0.8 and 1 .8. With reference to the film forming resin(s) (FFR) of the first embodiment crosslinker component (C) can comprise amino crosslinker resins such as melamine-formaldehyde resins which are very well known and have been commercialized since long, and may be obtained from allnex under the tradenames of CYMEL® and SETAMINE®. These melamine-formaldehyde resins, optionally in solution in corresponding organic solvents, comprise products with various degrees of methylolation, degrees of etherification or degrees of condensation (monocyclic or polycyclic).

[0154] Crosslinker component (C) can also preferably comprise an isocyanate compound with at least two free isocyanate groups. Isocyanate crosslinkers are well known and have extensively been described in the art. The isocyanate compound is usually selected from the group consisting of aliphatic, cycloaliphatic, and / or aromatic polyisocyanates comprising at least two isocyanate groups and mixtures thereof. The crosslinker (C) is then preferably selected from the group consisting of hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, 1 ,2- cyclohexylene diisocyanate, 1 ,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylene diisocyanate methane, 3,3'-dimethyl-4,4'-dicyclohexylene diisocyanate methane, norbornane diisocyanate, m-and p-phenylene diisocyanate, 1 ,3- and 1 ,4-bis (isocyanate methyl) benzene, xylylene diisocyanate, a,a,a',a'-tetramethyl xylylene diisocyanate (TMXDI®), 1 ,5-dimethyl-2,4- bis (isocyanate methyl) benzene, 2,4- and 2,6-toluene diisocyanate, 2,4,6-toluene triisocyanate, 4,4'-diphenylene diisocyanate methane, 4,4'- diphenylene diisocyanate, naphthalene-1 ,5-diisocyanate, isophorone diisocyanate, 4-isocyanatomethyl-1 ,8- octamethylene diisocyanate, and mixtures of the aforementioned polyisocyanates. Other preferred isocyanate crosslinkers are (the condensed) derivatives of diisocyanates, such as biurets, isocyanurates, imino-oxadiazinediones, allophanates, uretdiones, and mixtures thereof. Examples of such adducts are the adduct of two molecules of hexamethylene diisocyanate or isophorone diisocyanate to a diol such as ethylene glycol, the adduct of 3 molecules of hexamethylene diisocyanate to 1 molecule of water, the adduct of 1 molecule of trimethylol propane to 3 molecules of isophorone diisocyanate, the adduct of 1 molecule of pentaerythritol to 4 molecules of toluene diisocyanate, the isocyanurate of hexamethylene diisocyanate (e.g. available under the trade names DESMODUR® (E) N3390, TOLONATE® HDT-LV, TOLONATE® HDT-90 or DESMODUR® ultra 2822), the biuret of hexamethylene diisocyanate, under the trade name DESMODUR® N 75, a mixture of the uretdione and the isocyanurate of hexamethylene diisocyanate, under the trade name DESMODUR® N3400, the allophanate of hexamethylene diisocyanate, available under the trade name DESMODUR® LS 2101 , and the isocyanurate of isophorone diisocyanate, available under the trade name VESTANAT® T1890. Furthermore, (co)polymers of isocyanate-functional monomers such as a,a'-dimethyl-m-isopropenyl benzyl isocyanate are suitable for use. If desired, it is also possible to use hydrophobically or hydrophilically modified polyisocyanates to impart specific properties to the coating.

[0155] Crosslinker component (C) can also comprise blocked isocyanates when blocking agents having a sufficiently low deblocking temperature they can be used to block any of the polyisocyanate crosslinker component (C) mentioned above. In that case, crosslinker component (C) is substantially free of unblocked isocyanate group-containing compounds and the crosslinkable composition can be formulated as one-component formulation. The blocking agents which can be used to prepare a blocked isocyanate component are well-known to the skilled worker.

[0156] With reference to the film forming resin(s) (FFR) of the second embodiment, crosslinker component (C) comprises functionalities which are activated unsaturated C=C moieties with the same features as described for the film forming resins (FFR) of the third embodiment. The activated unsaturated moieties react with the functionalities of the film-forming resins (FFR) of the second embodiment, which are acidic protons (C-H) in activated methylene or methine groups, in the presence of a catalyst (F), which is a base. Such composition are known as a Real Michael Addition (RMA) crosslinkable compositions and are known in the art. WO1 1 / 124663, WO11 / 124664 and WO11 / 124665 describe RMA crosslinkable compositions with latent base catalyst comprising carbon dioxide blocked base catalyst which generates a strong base on carbon dioxide deblocking in the coating layer. WO14 / 166880 describes RMA crosslinkable compositions with a catalyst that does not rely on carbon dioxide deblocking, which is particularly suitable for layers where evaporation is hindered, for example for thicker layers. WO13 / 050622, WO13 / 050623, WO13 / 050624 and WO13 / 050574 describe RMA crosslinkable compositions with special pot-life and open time moderators. WO16 / 166361 , WO16 / 166381 , WO16 / 166382 and WO2018 / 005077 further describe RMA crosslinkable compositions. The description of the various embodiments of the RMA crosslinkable compositions in these prior art documents is herewith enclosed by reference. In particular reference is made to the above identified prior art concerning detailed description of all components in the RMA crosslinkable composition, their preparation, the amounts used in the RMA crosslinkable composition as well as for measurement methods and definitions and the description thereof is hereby incorporated by reference and applicable unless described otherwise herein.

[0157] With reference to the film forming resin(s) (FFR) of the third embodiment, crosslinker component (C) can comprise polyfunctional amine- and / or latent amine-functional compounds. These include, for example, polyfunctional species having free primary or secondary amine functional groups such as aliphatic and cycloaliphatic amines each having 2 to 10 primary or secondary amino groups and 2 to 100 carbon atoms. Preferred polyfunctional amines include 2 to 4 primary amino groups and 2 to 20 carbon atoms. Suitable polyfunctional amines include, but are not limited to, hexamethylene diamine, 2-methyl pentamethylene diamine, 1 ,3-diamino propane, 1 ,3-diamino pentane, dodecane diamine, 1 , 2-diamino cyclohexane, 1 ,4-diamino cyclohexane, para-phenylene diamine, 3-methyl piperidine, piperazine, N-amino ethylpiperazine, isophorone diamine, bis-hexamethylene triamine, diethylene triamine, ethylene diamine, dipropylene triamine, diethylamine triamine, triethylene tetramine, tris (2- aminoethyl) amine, ethylene oxide-amine, polyoxyalkylene amines having from 2 to 6 oxyalkylene units and preferably from 2 to 4 oxypropylene units, such as, JEFFAMINE D, ED and T (JEFFAMINE is a trademark) series polyoxypropylene amine, amine-functional acrylic resins, disclosed in e. g. US4120839, trimethyl hexamethylene diamine; and tetraethylene pentamine. Mixtures of these amine-functional curing agents and adducts of these amines and an epoxy group containing compound, and polyamide amines derived from aliphatic polyamine and a dimer of an unsaturated aliphatic fatty acid, can also be used. Latent amino-functional compounds can also be used, such as moisture deblockable polyfunctional primary or secondary amine species, preferably ketimine, aldimine, diimine or oxazolidine. These compounds react with water to form free amine groups. Especially preferred examples include ketimines formed through the condensation reaction of an amine with a ketone. Examples include the reaction product of adducts of ketone-blocked diethylene triamine or dipropylene triamine and an epoxy or isocyanate containing compound.

[0158] Crosslinker (C) can also comprise functionalities which are acidic protons (C-H) in activated methylene or methine groups with the same features as described for the film forming resins (FFR) of the second embodiment. The thixotropic coating composition can optionally comprise a catalyst (F) for catalyzing the reaction between the functional groups of film forming resin(s) (FFR)) and crosslinker (C) if present. The person skilled in the art will know that the type of catalyst (F) will in general depend on the type of functional groups of film forming resin(s) (FFR) and the type of crosslinker component (C), if present.

[0159] The thixotropic coating composition according to the present invention can also comprise a reactive diluent (H). Reactive diluents (H) generally are monomeric or oligomeric liquid compounds comprising at least 1 functional group. The type of functional group can be similar to the functional group present in film forming resin(s) (FFR). Reactive diluents (H) are used to reduce the viscosity of the total crosslinkable composition and can react with crosslinker (C), if present, and / or with film forming resin(s) (FFR). Preferably, reactive diluents (H) are not volatile (having a boiling point higher than 190°C at atmospheric pressure) and therefore do not contribute to the total volatile organic content of the composition.

[0160] In addition to the components described above, other compounds can be present in the thixotropic coating composition according to the present invention. Such compounds may be binder resins (I) other than film forming resin(s) (FFR), optionally comprising functionalities which may be reactable with the film forming resin(s) (FFR) and / or crosslinkers (C) if present. Examples of such other compounds are ketone resins, and latent amino-functional compounds such as oxazolidines, ketimines, aldimines, and diimines. These and other compounds are known to the skilled person and are mentioned, int. al., in US 5214086.

[0161] The thixotropic coating composition according to the present invention optionally comprises one or more other compounds (E), that are different from the film forming resin (FFR), the specific polyurea compound(SCA) and the reactive diluent(s) (H), binder resin(s) (I), catalyst (F) and crosslinker (C), if present).

[0162] The one or more other compound(s) (E) comprise(s) volatile organic compound(s) (E1) and / or additive(s) (E2).

[0163] The volatile organic compounds, preferably are water-free volatile organic compounds. In general, these are compounds with a boiling point at atmospheric pressure of 190 °C or less. Preferably, the amount of volatile organic compound (E1) relative to the total thixotropic coating composition is less than 60%, more preferably less than 50%, most preferably less than 40% or even less than 30% or even less than 20%.

[0164] By water-free volatile organic compounds (E1) in the present invention is meant volatile organic compounds containing less than 2% by weight of water, preferably less than 1 .5% by weight, more preferably less than 1% by weight, most preferably less than 0.5% by weight or even less than 0.1% by weight, based on the total volatile organic solvents and water, if present, being 100% by weight.

[0165] Examples of suitable volatile organic compounds (E1) are hydrocarbons or mixtures thereof, such as toluene, xylene, SOLVESSO™ 100, SOLVESSO™ 150, ketones, terpenes, such as dipentene or pine oil; halogenated hydrocarbons, such as dichloromethane; ethers, such as ethylene glycol dimethyl ether, dipropylene glycol methyl ether; esters, such as ethyl acetate, ethyl propionate, n-propyl acetate, n-butyl acetate, hexyl acetate; ether esters, such as methoxypropyl acetate, butyl glycol acetate and ethoxyethyl propionate; alcohols, such as n- propanol, isopropanol, n-butanol, methoxypropanol and 2-ethylhexanol. Also mixtures of these compounds can be used. The thixotropic coating composition preferably further comprises one or more additive(s) (E2). Additives also encompass auxiliaries commonly used in coating compositions. The additives (E2) are commonly used in smaller amounts to improve certain important paint properties.

[0166] Examples of such additives are surfactants, rheology additives (modifiers) other than the polyurea compound of the present invention, levelling agents, slip additives, wetting agents, anti-cratering agents, antifoaming agents, adhesion promoters, dispersing agents, reactivity moderators, delustering agents, alkoxysilanes, flow modification agents, heat stabilizers, light stabilizers, UV absorbers, radical inhibitor, fire retardant agents and antioxidants.

[0167] The amount of such additives (E2) is usually from 0 to 10 % by weight, preferably from 1 to 8 % by weight, and most preferably from 2 to 7 % by weight relative to the total weight of additives (E2), the film forming resin(s) (FFR), polyurea compound (SCA) optional other binder resin(s) (I), optional reactive diluents (H) and optional crosslinker (C).

[0168] The thixotropic coating composition may also be a pigmented composition. In that case pigments and fillers are present in the composition. A pigment normally is a solid component with low solubility in the paint medium, added to the composition to provide color. The pigmented composition may comprise one or more inorganic pigments and / or one or more organic pigments. A filler is normally also a solid component with low solubility in the paint medium, added to the composition to improve other paint parameters such as increasing the volume of the paint or providing anti-corrosion properties.

[0169] The total amount of pigments, colorants and / or fillers in the thixotropic coating composition of the invention generally does not exceed 60% by weight, preferably it does not exceed 40% by weight relative to the total weight of the thixotropic coating composition including pigments, colorants and / or fillers and volatile organic solvents (E1).

[0170] The thixotropic coating composition according to the invention preferably comprises

[0171] • from 0.05 to 23% by weight, preferably from 0.1 to 20% by weight, more preferably from 0.5 to 15% by weight of sag control agent comprising the specific polyurea compound (SCA) of the present invention;

[0172] • from 0.5 to 99% by weight, preferably from 5 to 99% by weight, more preferably from 10 to 95% by weight, even more preferably from 20 to 90% by weight of film forming resin(s) (FFR);

[0173] • from 0 to 95% by weight, preferably from 10 to 80% by weight, more preferably from 15 to 50% by weight of crosslinker (C);

[0174] • from 0 to 10% by weight, preferably from 1 to 8% by weight, more preferably from 2 to 7% by weight of additives and auxiliaries (E2);

[0175] • from 0 to 10% by weight, preferably from 0.001 to 5% by weight, more preferably from 0.005 to 2% by weight of catalyst (F);

[0176] • from 0 to 70% by weight, preferably from 0 to 50% by weight, more preferably from 0 to 20% by weight of reactive diluent (H);

[0177] • from 0 to 50% by weight, preferably from 0 to 30% by weight, more preferably from 0 to 20% by weight of another resin (I). relative to the total of film forming resin(s) (FFR), sag control agent comprising polyurea compound (SCA), other optional non-volatile compounds (E2), optional crosslinker (C), optional catalyst (F), optional reactive diluent (H) and optional other binder (I) (wherein the sum of weight percentages does not exceed 100%). Preferably, reactive diluent (H) is different from film forming resin(s) (FFR).

[0178] The thixotropic coating composition according to the present invention preferably comprises from 40 to 100% by weight, preferably 50 to 100% by weight, more preferably from 60 to 100% by weight, most preferably from 70 to 100% by weight of (FFR), (SCA), optional (F), optional (I), optional (H) optional (C) and optional (E2), and from 0 to 60% by weight, more preferably from 0 to 50% by weight, even more preferably from 0 to 40% by weight, most preferably from 0 to 30% by weight, of volatile organic compound (E1) relative to the total weight of (FFR), (SCA), optional (F), optional (I), optional (H) optional (C) optional (E2),and volatile organic compound (E1).

[0179] The specific polyurea compound (SCA) is prepared by any convenient manner, generally with the reactants being stirred or agitated.

[0180] To prepare the specific polyurea compound (SCA), amine (a2, b1) components may be added to isocyanate (a1 , b2) or isocyanate (a1 , b2) may be added to amine components (a2, b1), whichever is most convenient, wherein the equivalent ratio of amine / isocyanate ranges from 0.7 / 1 to 1.3 / 1 , preferably from 0.8 / 1 to 1.2, more preferably from 0.9 / 1 to 1.1 / 1.

[0181] The polyurea formation reaction may be carried out in the presence of an inert solvent, for example acetone, methyl isobutyl ketone, N-methyl pyrrolidone, benzene, toluene, xylene, other aromatic solvent mixtures such as solvent naphtha, butyl acetate or an aliphatic hydrocarbon such as petroleum ether and mixtures thereof, or in the presence of one or more film forming resin(s) (FFR), for the final coating composition, or any other coating formulation component. Here the term "inert" indicates that the solvent does not significantly interfere in the process of polyurea formation, which means that the amount of polyurea formed when solvent is present is at least 80% of the amount produced when no solvent, or film forming resin of other coating formulation component is present.

[0182] The invention therefore relates to a process for the preparation of the polyurea compound, wherein the polyurea is obtained by reacting polyisocyanate (a1) and mono-amine (b1) or by reacting polyamine (a2) and mono-isocyanate (b2), in the presence of a liquid medium, preferably in the presence of an inert solvent or one or more film forming resin(s) (FFR).

[0183] It will be obvious that if the film forming resin(s) (FFR) is (are) highly reactive with either the amines or the isocyanate, the film forming resin(s) (FFR) and that particular susceptible compound cannot be premixed. By the term "highly reactive" is meant here that more than 30% of the susceptible amine or isocyanate reacts with the film forming resin before the amine and the isocyanate are mixed in order to prepare the polyurea compound.

[0184] Preferably, the specific polyurea compound is prepared in a mixture of film forming resin(s) (FFR), preferably hydroxyl-functional film forming resin(s) (FFR) and volatile organic compound (E1), in varying proportions resulting in different compositions of which composition 1 and composition 2 are preferred for serving as a basis for further coating design.

[0185] As such composition 1 comprises: between 5 and 30% by weight, preferably between 6 and 25% by weight, more preferably between 7 and 20% by weight, most preferably between 8 and 18% by weight of the specific polyurea compound (SCA); between 3 and 30% by weight, preferably between 4 and 25% by weight, more preferably between 5 and 20% by weight, most preferably between 6 and 15% by weight of film forming resin(s) (FFR); and between 40 and 92% by weight, preferably between 50 and 90% by weight, more preferably between 60 and 88% by weight, most preferably between 70 and 86% by weight of volatile organic compound (E1), based on the total of polyurea compound (SCA), film forming resin(s) (FFR) and organic volatile compound (E1) being 100% by weight.

[0186] Alternatively composition 2 comprises: between 0.5 and 10% by weight, preferably between 1 and 9% by weight, more preferably between 2 and 8% by weight, most preferably between 3 and 7% by weight of the specific polyurea compound (SCA); between 35 and 99% by weight, preferably between 40 and 90% by weight, more preferably between 45 and 75% by weight, most preferably between 45 and 65% by weight of film forming resin(s) (FFR); and between 0 and 64.5% by weight, preferably between 1 and 59% by weight, more preferably between 17 and 53% by weight, most preferably between 28 and 52% by weight of organic solvent (E1); based on the total of polyurea compound (SCA), film forming resin(s) (FFR) and organic solvent (E1) being 100% by weight.

[0187] According to an especially preferred embodiment, composition 1 and composition 2 are based on film forming resin(s) (FFR), selected from the group consisting of polyester polyols, polyacrylate polyols and mixtures and hybrids thereof.

[0188] The present invention further relates to a thixotropic coating composition comprising one or more film forming resin(s) (FFR) and between 0.1 and 25% by weight of sagging control agent, based on the total weight of film forming resin(s) (FFR) and sagging control agent(s), said sagging control agent comprising between 50 and 100% by weight (based on the total weight of sagging control agent(s)) of at least one polyurea compound of the present invention.

[0189] Preferably, the thixotropic coating composition comprises at least 40% by weight of nonvolatile compounds and at most 60% by weight of water-free volatile organic solvents, the sum of the weight percentages of the non-volatile compounds and the water-free volatile organic solvents not exceeding 100% by weight; the non-volatile compounds comprising from 20 to 98% by weight of a one or more film forming resin(s) (FFR), one or more sagging control agent(s) and optionally one or more crosslinker(s) (C), catalyst(s), reactive diluents and binder resins, and from 2 to 80% by weight of one or more additives and auxiliaries, the sum not exceeding 100% by weight of non-volatile compounds.

[0190] Further preferably, the thixotropic coating composition comprises: at least one film forming resin (FFR), preferably selected from the group consisting of polyester resins, (meth)acrylic resins, polycarbonate resins, polyether resins, polyurethane resins, amino resins, and mixtures and hybrids thereof, more preferably selected from the group consisting of polyester polyols and (meth)acrylic polyols, polyacrylate polyester polyol hybrids and mixtures thereof; at least one crosslinker (C), reactable with the at least one film forming resin (FFR), preferably crosslinker (C) comprising functional groups selected from the group consisting of isocyanate, hydroxy, primary amine, secondary amine, mercaptane, activated unsaturated C=C moieties, carboxylic acid, epoxide, an activated methylene, methine species such as (derivatives of) acetyl acetone, acetoacetate or malonate, and mixtures thereof, more preferably crosslinker (C) is selected from the group consisting of amino crosslinker resins, isocyanate compounds with at least two free isocyanate groups, blocked isocyanates, crosslinkers comprising activated unsaturated C=C moieties, crosslinkers comprising polyfunctional amine- and / or latent amine-functional compounds, crosslinkers comprising acidic protons (C-H) in activated methylene or methine groups, and mixtures thereof, most preferably one or more crosslinkers selected from the group consisting of amino crosslinker resins, polyisocyanates, and mixtures thereof.

[0191] Further preferably, the thixotropic coating composition comprises:

[0192] - from 10 to 89, preferably from 20 to 80, more preferably from 30 to 70% by weight of at least one film forming resin (FFR);

[0193] - from 10 to 89, preferably from 20 to 80% by weight of at least one crosslinker (C); based on the total amount of film forming resin (FFR) and crosslinker (C) being 100% by weight.

[0194] Further preferably, the thixotropic coating composition comprises one or more additives and auxiliaries are selected from the group consisting of pigments, dyes, surfactants, pigment dispersion aids, complexing agents, levelling agents, wetting agents, anti-cratering agents, antifoaming agents, matting agents, heat stabilizers, light stabilizers, UV absorbers, antioxidants, radical inhibitors, and fillers, and mixtures thereof.

[0195] The invention also relates to a process for the preparation of the coating comprising a) providing film forming resin(s) (FFR), polyurea compound (SCA) and optionally one or more further components including but not limited to crosslinking agent (C), volatile organic compounds (E1), pigment, colorant, reactive diluent (H), binder resin(s) (I), curing catalyst (F), reactivity moderators, stabilizers and coating additives (E2) and b) mixing the components.

[0196] The thixotropic coating composition can suitably be prepared, as a one-component system, by a process comprising combining the film forming resin(s) (FFR), polyurea compound (SCA), crosslinker (C) and the catalyst (F). Alternatively, in a two component system, coating composition can be prepared by a process comprising combining the film forming resin(s) (FFR), polyurea compound (SCA) and the catalyst (F) to form a binder component system and mixing, shortly before use, said binder component system with the crosslinker (C).

[0197] As is usual, in cases where the crosslinker (C) is an isocyanate-functional crosslinker, in crosslinkable compositions comprising a hydroxy-functional film forming resin(s) (FFR), the thixotropic coating composition according to the invention has a limited pot life. Therefore, the thixotropic coating composition can be suitably provided as a multi-component system, wherein reactive components are kept in separate parts, for example as a two-component system, wherein the hydroxy-functional film forming resin(s) (FFR) on the one hand and the crosslinker (C) on the other hand are part of at least two different component systems. Therefore, the invention also relates to a kit of parts for preparing a coating composition, comprising a thixotropic resin system comprising at least one film forming resin (FFR), at least one sagging control agent comprising polyurea compound (SCA) and optionally at least one catalyst (F) and a crosslinker system comprising at least one crosslinker (C).

[0198] Alternatively, the kit of parts may comprise three component systems, comprising i) a thixotropic resin system comprising at least one film forming resin (FFR) and at least one sagging control agent comprising polyurea compound (SCA) ii) a crosslinker system comprising the crosslinker (C), and iii) a diluent system comprising a volatile organic diluent (E1), wherein the catalyst (F), can be distributed over systems i), ii) or iii), and wherein at least one of the component systems optionally comprises the catalyst (F).

[0199] The other components of the thixotropic coating composition may be distributed in different ways over the component systems as described above, as long as the component systems exhibit the required storage stability. Components of the crosslinkable composition which react with each other upon storage, are preferably not combined in one component system. If desired, the components of the thixotropic coating composition may be distributed over even more component systems, for example 4 or 5 component systems

[0200] In cases where the crosslinker (C) does not readily react at storage temperature with film forming resin(s) (FFR), for example when crosslinker (C) comprises melamine-formaldehyde resins and / or blocked isocyanate groups, all components (FFR), (C), (SCA), (F) and (E1) could be supplied in a one component system

[0201] The thixotropic coating composition of the invention can be applied to any substrate. The substrate may be, for example, metal, e.g., iron, steel, tinplate and aluminum, plastic, wood, glass, synthetic material, paper, leather, concrete or another coating layer. The other coating layer can be comprised of the thixotropic coating composition of the current invention or it can be a different coating composition such as for example a solvent borne or waterborne basecoat or a primer; this primer can be any primer, but those skilled in the art know that often epoxy based or polyurethane based primers are often used in various fields of application. The thixotropic coating compositions of the current invention show particular utility as clear coats, base coats, pigmented top coats and primers.

[0202] The thixotropic coating composition according to the invention is very suitable for use as a clear coat for vehicle refinishes or automotive OEM. A clear coat is essentially free of pigments and is transparent for visible light. However, the clear coat composition may comprise matting agents, for example silica based matting agents, to control the gloss level of the coating.

[0203] When the thixotropic coating composition of the invention is a clear coat, it is preferably applied over a color- and / or effect-imparting base coat. In that case, the clear coat forms the top layer of a multi-layer lacquer coating such as typically applied on the exterior or interior of automobiles. The base coat may be a water borne base coat or a solvent borne base coat.

[0204] The thixotropic coating composition according to the present invention was found to be particularly suitable for use in crosslinkable clear coat compositions used in coating processes using different coating layers wherein the number of bake / curing steps is reduced compared to a standard multilayer coating process. The coating processes with reduced number of bake / curing steps are more economic with regard to paint and energy consumption compared to standard ways of application, in which usually a primer layer is applied on an electrodeposition coating, followed by a first bake / curing step, and subsequent application of an aqueous basecoat layer, flash-off, application of a clear coat layer and second bake / curing. In contrast, a process with reduced number of bake / curing steps is often characterized in elimination of the primer layer as well as the first bake / curing step. Instead, in a coating process with reduced number of bake / curing steps, a first aqueous colored layer is applied on a substrate such as a metal, optionally comprising an electrodeposition layer, followed by flash- off, application of an aqueous basecoat layer, another flash-off and application of a clear coat layer followed by one bake / curing step for all layers simultaneously.

[0205] The thixotropic coating composition of the current invention is also suitable as pigmented topcoat for protective coatings to coat objects such as bridges, pipelines, industrial plants or buildings, oil and gas installations, or ships. The compositions are particularly suitable for finishing and refinishing automobiles and large transportation vehicles, such as trains, trucks, buses, and airplanes. Also, the crosslinkable composition of the current invention can be used in flooring applications. In general, the crosslinkable composition of the current invention can be applied by spraying, such as for example pneumatic spraying, electrostatic spraying, airless spraying or airmix spraying, brushing, draw-down, pouring, casting or any other method to transfer a composition to a substrate.

[0206] The thixotropic coating compositions according to the present invention are suitable for being used in overspray-free application techniques, wherein the paint is deposited on the target locations using a print head applicator device providing drop-on-demand or jet stream-on- demand.

[0207] In order to be useful in overspray-free application techniques, the thixotropic coating compositions preferably are formulated in such a way so that they are characterized by: a high-shear viscosity HSV measured at 23°C at a shear rate of 1000 ± 50 s-1 that is lower than 100 mPa.s, preferably lower than 90 mPa.s, more preferably lower than 80 mPa.s and most preferably lower than 70 mPa.s and preferably at least 30 mPa.s, more preferably at least 40 mPa.s, even more preferably at least 50 mPa.s and a creep compliance Jmax measured at 23°C after 300 seconds using a creep stress of 1.0 Pa of lower than 250 Pa-1 , preferably lower than 150 Pa-1 and even more preferably lower than 50 Pa-1.

[0208] The invention also relates to a method of providing a coating, preferably a coating for at least a part of an object, for example the surface of a transportation vehicle, wherein the method comprises the steps of applying a thixotropic coating composition according to the invention to at least a part of the object, for example the exterior surface of a transportation vehicle, and curing the applied coating composition, usually in a temperature range of 5 to 180 °C, preferably of 5 to 150 °C and more preferably from 5 to 100 °C. The curing step can advantageously be carried out at medium temperatures, for example from 60 to 80 °C or even at temperatures lower or equal to 40 °C or ambient temperature.

[0209] The thixotropic coating composition of the invention can likewise be used in non-coating applications such as for example adhesives, composites, sealants and inks.

[0210] Examples

[0211] The following illustrative examples are merely meant to exemplify the present invention but they are not intended to limit or otherwise define the scope of the present invention.

[0212] Example 1 : Synthesis of polyurea resin from pentamethylene diisocyanate and monoamine.

[0213] Polyurea 1 :

[0214] In a 5 liter glass vessel, equipped with a temperature jacket and a stirrer Resin 1 was charged and heated to 30 °C. Two equivalents of benzyl amine were then added to the reaction vessel and the mixture was homogenized for 10 to 15 minutes and subsequently cooled with ice- water. The stirrer speed was increased to 750 rpm and 1.01 equivalents of pentamethylene diisocyanate diluted with SOLVESSO™ 100 were added. The reaction mixture was stirred for 30 minutes and further diluted with SOLVESSO™ 100 to a solid content of 60% and a polyurea content of 4.2% on total, wherein Resin 1 is a polyacrylate polyol obtained by polymerization of butyl acrylate, styrene, methyl methacrylate and hydroxyethyl methacrylate to yield a polyacrylate polyol with Mn of 2560 Dalton, Mw of 8300 Dalton, OHV of 92 mg KOH / g, AV of 17 mg KOH / g. The resin was diluted with SOLVESSO™ 100 to a solid content of 65%.

[0215] The particle size of the polyurea adduct determined using the ISO 1524 method was found to be less than 15 pm.

[0216] Polyurea 1a:

[0217] In a 5 liter glass vessel, equipped with a temperature jacket and a stirrer Resin 1 (same as for Polyurea 1) is charged and heated to 30 °C. 2.02 equivalents of benzylisocyanate are then added to the reaction vessel and the mixture is homogenized for 10 to 15 minutes and subsequently cooled with ice-water. The stirrer speed is increased to 750 rpm and 1.00 equivalent of 1 ,5-pentamethylene diamine diluted with SOLVESSO™ 100 is added. The reaction mixture is stirred for 30 minutes and further diluted with SOLVESSO™ 100 to a solid content of 60% and a polyurea content of 4.2% on total.

[0218] Polyurea 2:

[0219] The procedure of Polyurea 1 was followed. The solid content of the Polyurea 2 was 60% and the polyurea content was 1 .75% on total.

[0220] Polyurea 3:

[0221] The procedure of Polyurea 1 was followed. The solid content of the Polyurea 3 was 60% and the polyurea content was 2.63% on total.

[0222] Polyurea 4:

[0223] The procedure of Polyurea 1 was followed, and instead, Resin 2 was used, which was afterwards diluted with a mixture of SOLVESSO™ 100 and xylene. The solid content of the Polyurea resin 4 was 60% and the polyurea content was 2.8% on total, wherein Resin 2 is a polyacrylate polyol obtained by polymerization of butyl acrylate, butyl methacrylate, styrene, methyl methacrylate and hydroxyethyl methacrylate to yield a polyacrylate polyol with Mn of 2100 Dalton, Mw of 4700 Dalton, OHv of 149 mg KOH / g, AV of 15 mg KOH / g. The resin was diluted with SOLVESSO™ 100 to a solid content of 65%.

[0224] Polyurea 5:

[0225] The procedure of Polyurea 4 was followed. The solid content of the Polyurea 5 was 60% and the polyurea content was 1.06% on total.

[0226] Polyurea 6:

[0227] The procedure of Polyurea 1 was followed, and instead, 2 equivalents of n-hexyl amine were added. The solid content of the Polyurea 6 was 60% and the polyurea content was 1.4% on total.

[0228] Polyurea 7:

[0229] The procedure of Polyurea 1 was followed, and instead, 2 equivalents of methoxypropylamine were added. The solid content of the Polyurea 7 was 60% and the polyurea content was 1 .3% on total. Polyurea 8:

[0230] The procedure of Polyurea 1 was followed, and instead, Resin 3 was used, which was afterwards diluted with a mixture of SOLVESSO™ 100, xylene and methoxy propanol. The solid content of the Polyurea resin 8 was 50% and the polyurea content was 3.9% on total, wherein Resin 3 is a polyester resin obtained by polymerization of neopentyl glycol, trimethylol propane, maleic anhydride, adipic acid, phthalic anhydride and isophthalic acid to yield a polyester polyol with Mn of 3582 Dalton, Mw of 22641 Dalton, AV of 8 mg KOH / g and OHV of 83 mg KOH / g. The resin was diluted with a mixture of SOLVESSO™ 100, xylene and methoxypropanol to a solid content of 60%.

[0231] Comparative Polyurea 1 :

[0232] The procedure of Polyurea 1 was followed, and instead, 1.01 equivalents of hexamethylene diisocyanate were added. The solid content of the Comp. Polyurea resin 1 was 60% and the polyurea content was 4.2% on total.

[0233] Comparative Polyurea 2:

[0234] The procedure of Comp. Polyurea 1 was followed, and instead, Resin 2 was used, which was afterwards diluted with a mixture of SOLVESSO™ 100 and xylene. The solid content of the Comp. Polyurea 2 was 60% and the polyurea content was 2.8% on total.

[0235] Comparative Polyurea 3:

[0236] The procedure of Comp. Polyurea 1 was followed, and instead, Resin 3 was used, which was afterwards diluted with a mixture of SOLVESSO™ 100, xylene and methoxypropanol. The solid content of the Comp. Polyurea 3 was 50% and the polyurea content was 3.9% on total.

[0237] Example 2: Comparison of low shear viscosity (D1) and high shear viscosity (D1000) of the polyurea resins according to the invention (Polyurea) and prior art polyurea resins (= comp. Polyurea)

[0238] D1 and D1000 were determined, respectively, by placing 0.8 grams of material on an MCR- 300 cone plate rheometer from Anton Paar. Subsequently, the 4° cone is positioned to the prescriptive gap adjustment and the material is thermostated for 3 min. Then, pre-shear at 1000 s-1is given for 30 seconds, after which the material is rested for 30 seconds and the upward viscosity curve is measured at increasing shear rates from 0.1 to 1000 s-1. After a further shear at 1000 s-1for 15 seconds, the downward viscosity curve is determined from 1000 to 0.1 s-1. The D01 , D1 and D1000 are the measured viscosity values at respectively 0.1 , 1 and 1000 s-1taken from the downward viscosity curve. Results are listed in Table 1.

[0239] Table 1

[0240] The data in Table 1 show surprisingly that at equal level of polyurea compound, much higher low shear viscosity at similar high shear viscosity is obtained for polyurea compound according to the invention (Polyurea 1 , 4 and 8 versus Comparative Polyurea 1 , 2 and 3, respectively). Similarly, the data in Table 1 show that similar low shear viscosity at similar high shear viscosity can be obtained at much lower concentrations of Polyurea compound (compare Examples 2 and 4 with Comparative Examples 1 and 2, respectively). The data in Table 1 show that the Polyurea compound according to the invention is Theologically much more efficient.

[0241] Example 3: Comparison of low shear viscosity (D0.1), high shear viscosity (D1000) and sagging behaviour of coating compositions comprising the polyurea resins according to the invention and comparative coating compositions comprising prior art polyurea resins.

[0242] The coating compositions and comparative coating compositions are represented in Table 2, wherein SET AMINE® US 138 BB-70 (allnex) is a n-butylated high imino melamine crosslinker and SETALUX® 1757 W-70 is a thermosetting hydroxylated acrylic copolymer for combination with amino resins (allnex).

[0243] Table 2.

[0244] Coating compositions of Table 2 were prepared and subsequently diluted with xylene to a D1000 spray viscosity of approx. 85 mPa.s. The sagging behaviour of these coating compositions was determined by spraying the crosslinkable composition, at a D1000 spray viscosity of approx. 85 mPa.s, on a tinplate panel of 47 x 30 cm. Halfway over the length, the panel contained 13 holes with a diameter of 1 cm, with a distance of 2.5 cm between the holes. The crosslinkable formulation was sprayed on such a panel with an increasing layer thickness from left to right. The length of each of the tears under the holes and the layer thickness above each hole were determined after curing of the paint (10 minutes flash-off at room temperature followed by 24 minutes at 140 °C). Subsequently, the tear length was plotted versus the coating layer thickness. Here, the layer thickness is reported where the tear length was 5 mm.

[0245] Results are reported in Table 3.

[0246] Table 3.

[0247] Data in Table 3 surprisingly show that at equal concentration of SCA and similar D1000 (Coating Composition 2 and Comparative Coating Composition 2), the low shear viscosity D0.1 was significantly higher for the formulation comprising a polyurea component according to the invention. This formulation also displayed a much higher layer thickness at a tear length of 5 mm, showing increased robustness for sagging.

[0248] Surprisingly, coatings comprising the polyurea compound according to the invention showed much less yellowing after overbake, giving a much better balance between sag resistance and yellowing. Because sagging (layer thickness at 5 mm tear length) for Comparative Coat. Comp. 2 was unacceptable, yellowness after overbake was not further determined. Yellowness after overbake was determined by further curing the panels at 150 °C for 1 hour and measuring Lab color values using a BykMac colorimeter.

[0249] A formulation comprising a polyurea component according to the invention containing 0.96% SCA (Comparative Coating Composition 1) was too high viscous, and therefore, a formulation with a lower content of SCA (0.65%) was prepared as shown in Coating Composition 1 . A comparison of the data of Coating Compostion 1 with the data of Comparative Coating Composition 1 , showed that despite the lower concentration of polyurea compound, the D0.1 low shear viscosity was significantly higher and the resistance against sagging tear formation was much higher.

[0250] Example 4: Comparison low shear viscosity (D0.1) and high shear viscosity (D1000), water whitening and yellowness upon overbake of coating compositions comprising the polyurea resins according to the invention and comparative coating compositions comprising prior art polyurea resins.

[0251] The coating compositions and comparative coating compositions are represented in Table 4, wherein:

[0252] DESMODUR® N 3390 is an aliphatic isocyanate (HDI trimer) (Covestro);

[0253] VESTANAT® T 1890 E is a cycloaliphatic polyisocyanate (Evonik) and

[0254] LPMA is propylene glycol monomethyl ether acetate

[0255] The coating compositions of table 4 were diluted to 28 s DinCup 4 using a 1 :1 mixture of SOLVESSO™ 100 and DOWANOL™ PM acetate. D0.1 and D1000 were determined and subsequently the coating compositions were sprayed on a tin panel for sag resistance (layer thickness at 5 mm tear length), an inert white substrate for yellowness after overbake and a black waterborne basecoat to determine water whitening. After spraying, paints were flashed-off for 10 minutes at room temperature and then baked for 24 minutes at 140 °C

[0256] Yellowness after overbake was determined by further curing the panels at 150 °C for 1 hour and measuring Lab color values using a BykMac colorimeter. In Table 5, the b-value after overbake is reported. Water whitening was determined by expositing the dried coatings to an atmosphere of 40 °C and 100% humidity for 10 days and visually assessing the panels under a strong light (lower value is less water whitening)

[0257] Table 4. *Added as 1% solution in butyl acetate

[0258] ** Added as 2% solution in butyl acetate

[0259] Table 5.

[0260] Data in Table 5 clearly demonstrate that at similar D1000 high shear viscosity, the low shear viscosity D0.1 of Coating Composition 7 is much higher compared to the low shear viscosity

[0261] D0.1 of Comparative Coating Composition 3. Also upon decreasing the concentration of Polyurea compound according to the invention (Coating Compositions 8 and 9), the D0.1 low shear viscosity is higher compared to the D0.1 low shear viscosity of Comparative Coating Composition 3. The layer thickness at 5 mm sagging tear length is much higher for Coating Composition 7 compared to the value determined for Comparative Coating Composition 3, showing that the Polyurea compound according to the invention is much more efficient in improving sag resistance of a paint. Even when the concentration of Polyurea compound according to the invention was reduced to 0.5% and 0.33% (Coating Composition 8 and Coating Composition 9 respectively), the layer thickness at 5 mm sagging tear length was still higher compared to the value determined for Comparative Coating Composition 3 with a concentration of 1.34%. Surprisingly, the yellowness after overbake approached the value obtained for a coating composition without Polyurea compound (Comparative Coating Composition 4). For all coating compositions comprising the Polyurea compound according to the invention, the water whitening was better compared to the assessment for a paint comprising a polyurea compound not according to the invention and was equal to a coating composition without Polyurea compound (Comparative Coating Composition 4).

[0262] Example 5: Comparison of low shear viscosity (D0.1), at preset high shear viscosity (D1000) and sagging behaviour of coating compositions comprising the polyurea resins according to the invention and comparative coating compositions comprising prior art polyurea resins.

[0263] The coating compositions along with a comparative coating composition are represented in Table 6, wherein SETAMINE® US 138 BB-70 (allnex) is a n-butylated high imino melamine crosslinker and wherein SETALUX® 1757 W-70 (allnex) is a thermosetting hydroxylated acrylic copolymer for combination with amino resins.

[0264] The coating compositions of Table 6 were prepared and diluted with xylene to a D1000 spray viscosity of approx. 100 mPa.s. Subsequently D0.1 was determined. The coating compositions of table 6, at a D100 spray viscosity of approx.. 100 mPa.s, were sprayed on a tin panel for sag resistance (layer thickness at 5 mm tear length). Results are displayed in Table 7.

[0265] Table 6.

[0266] Table 7

[0267] Results show that coating compositions comprising the Polyurea compound according to the invention show pseudoplastic behaviour and result in improved sag resistance.

[0268] Example 6: Comparison flop of coating compositions comprising the polyurea resins according to the invention and comparative coating compositions comprising prior art polyurea resins.

[0269] The coating compositions along with a comparative coating composition are represented in Table 8, wherein Stapa Metallux 2156 is a standard a silver dollar aluminium pigment (Eckard), SETAL® 168 SS-80 is a slightly branched polyester polyol (allnex) and SETALUX® 1850 SA- 50 is a hydroxyfunctional microgel (allnex).

[0270] Coating compositions were applied on a metal substrate at equal layer thickness and after 10 minutes flash-off at room temperature overcoated with a 1 component commercially available clearcoat. After 10 minutes flash-off at room temperature, the coating system was baked at 140 °C for 24 minutes.

[0271] The flop was assessed visually and found to be much better for the thixotropic coating composition according to the present invention.

[0272] Table 8

[0273] Example 7: Preparation and rheology of concentrated polyurea composition according to the invention.

[0274] A composition was prepared according to WO2018083328 comprising 10% by weight of an adduct prepared from 1 equivalent of pentamethylene diisocyanate and 2 equivalents of benzyl amine, 8% by weight of a polyester polyol and 82% by weight of xylene. Subsequently, 1.83 grams of this composition was mixed with 16.4 grams of SETAL® 1715 VX-74 (a saturated polyester resin available from allnex) and 1.96 grams of xylene yielding a composition having D1000 of 0.42 Pa.s and D0.1 of 2 Pa.s, showing the pseudoplastic behaviour of this composition.

[0275] Example 8: Preparation and rheology of polyurea resin composition according to the invention. The procedure of Polyurea 1 of Example 1 was followed, and instead, 2 equivalents of S- alpha-methylbenzylamine were added. The resulting product was diluted with butyl acetate to a solid content 58% and the polyurea content was 1.16% on total. This polyurea resin had D1000 of 0.69 Pa.s and D1 of 1 .8 Pa.s, showing the pseudoplastic behaviour of this composition.

Claims

CLAIMS1 . Polyurea compound being the reaction product of components (I) comprising (a1) a polyisocyanate and (b1) a mono-amine, or components (II) comprising (a2) a polyamine and (b2) a mono-isocyanate wherein: polyisocyanate (a1) is a diisocyanate characterized in that isocyanate functional groups are linked through an alkylene group wherein the isocyanate functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched, or a condensed derivative of a diisocyanate characterized in that the isocyanate functional group and the condensed structure are linked through an alkylene group wherein the isocyanate functional group and the condensed structure are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched; or a mixtures of one or more diisocyanate(s) and one or more condensed derivative(s) of a diisocyanate; a polyamine (a2) is characterized in that amine functional groups are linked through an alkylene group wherein the amine functional groups are situated in carbon positions 1 and 5 or in carbon positions 1 and less than 5 of the linking alkylene group, said alkylene group being linear or branched; mono-amine (b1) is a primary or secondary amine characterized in that the carbon bonded to the nitrogen atom is part of an entity independently selected from the group consisting of a (cyclo)alkyl group, an ether substituted (cyclo)alkyl group and an aryl substituted (cyclo)alkyl group; mono-isocyanate (b2) is characterized in that the carbon bonded to the nitrogen atom of the isocyanate functional group is part of an entity selected from the group consisting of a cycloalkyl group an ether substituted (cyclo)alkyl group and an aryl substituted (cyclo)alkyl group.

2. The polyurea compound according to claim 1 , wherein: polyisocyanate (a1) of components (I) is a diisocyanate selected from the group consisting of 1 ,5-pentamethylene diisocyanate, 2-methyl-1 ,5-pentamethylene diisocyanate, 1 ,4-tetramethylene diisocyanate, and mixtures thereof; and mono-amine (b1) of components (I), is a primary amine selected from the group consisting of hexylamine, cyclohexylamine, benzylamine, S-alpha- methylbenzylamine, R-alpha-methylbenzylamine, 2-phenethylamine, 3- methoxypropylamine and mixtures thereof.

3. The polyurea compound according to claim 1 or 2, wherein the polyisocyanate (a1) is 1 ,5-pentamethylene diisocyanate and wherein the mono-amine (b1) is selected from the group consisting of benzylamine, S-alpha-methylbenzylamine, R-alpha- methylbenzylamine, 3-methoxypropylamine and mixtures thereof.

4. The polyurea compound according to claim 1 , wherein:polyamine (a2) of components (II) is a diamine selected from the group consisting of 1 ,5-pentamethylene diamine, 2-methyl-1 ,5-pentamethylene diamine, 3-methyl- 1 ,5-pentamethylene diamine 1 ,4-tetramethylene diamine, 2-methyl-1 ,4- tetramethylene diamine and mixtures thereof; and the mono-isocyanate (b2) of components (II) is selected from the group consisting of a cyclohexyl isocyanate, benzyl isocyanate, S-alpha-methylbenzyl isocyanate, R-alpha-methylbenzyl isocyanate, 2-phenylethyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof.

5. The polyurea compound according to claim 1 or 4, wherein the polyamine (a2) is 1 ,5- pentamethylene diamine and wherein the mono-isocyanate (b2) is selected from the group consisting of benzyl isocyanate, S-alpha-methylbenzyl isocyanate, R-alpha- methylbenzyl isocyanate, 3-methoxypropyl isocyanate and mixtures thereof.

6. The polyurea compound according to any of the preceding claims wherein the average number of urea bonds in the polyurea compound is at least 1 .7 .

7. Process for the preparation of the polyurea compound according to any of the preceding claims, wherein the polyurea is obtained by reacting polyisocyanate (a1) and mono-amine (b1) or polyamine (a2) and mono-isocyanate (b2) in the presence of a liquid medium.

8. The process according to claim 7, wherein the equivalent ratio of amine / isocyanate ranges from 0.7 / 1 to 1.3 / 1 , preferably from 0.8 / 1 to 1.2, more preferably from 0.9 / 1 to 1.1 / 1 .

9. The process according to claim 7 or 8, wherein the liquid reaction medium comprises film forming resin(s) (FFR) and organic solvent(s); wherein: the film forming resin(s) (FFR) is (are) present in an amount between 2 and 95 weight percentage, preferably between 4 and 85% by weight, more preferably between 6 and 80% by weight, most preferably between 8 and 75% by weight, relative to the total weight of film forming resin(s) (FFR) and solvent; the film forming resin(s) (FFR) is(are) selected from the group consisting of polyester resins, (meth)acrylic resins, polycarbonate resins, polyether resins, polyurethane resins, amino resins, and mixtures and hybrids thereof; the film forming resin(s) (FFR), comprise(s) hydroxy, primary amine, secondary amine, mercaptane, activated unsaturated C=C moieties, carboxylic acid, epoxide, isocyanate, an activated methylene, methine species such as acetyl acetone, acetoacetate or malonate or derivatives thereof, and mixtures thereof.

10. A sagging control agent comprising between 50 and 100% by weight of at least one polyurea compound according to any of claims 1 to 6, and 0 to 50% of one or more rheology additive(s) selected from the group consisting of clays, silicas, microgels, amide waxes or polyurea products, different from the polyurea compounds according to any of claims 1 to 6, based on the total of the polyurea compound according to claims 1 to 6 and the one or more other rheology additive(s), being 100% by weight11 . Composition obtained by the process according to any of claims 7 to 9, comprising between 5 and 30% by weight, preferably between 6 and 25% by weight, more preferably between 7 and 20% by weight, most preferably between 8 and 15% by weight of the polyurea according to any of claims 1 to 6, between 3 and 30% by weight, preferably between 4 and 25% by weight, more preferably between 5 and 20% by weight, most preferably between 6 and 15% by weight of film forming resin (FFR) and between 40 and 92% by weight, preferably between 50 and 90% by weight, more preferably between 60 and 88% by weight, most preferably between 70 and 86% by weight of organic solvent, based on the total of polyurea, film forming resin (FFR) and organic solvent being 100% by weight.

12. Composition obtained by the process according to any of claims 7 to 9, comprising between 0.5 and 10% by weight, preferably between 1 and 9% by weight, more preferably between 2 and 8% by weight, most preferably between 3 and 7% by weight of the polyurea compound according to claims 1 to 6, between 35 and 99% by weight, preferably between 40 and 90% by weight, more preferably between 45 and 75% by weight, most preferably between 45 and 65% by weight of film forming resin (FFR) and between 0 and 64.5% by weight, preferably between 1 and 59% by weight, more preferably between 17 and 53% by weight, most preferably between 28 and 52% by weight of organic solvent, based on the total of polyurea, film forming resin (FFR) and organic solvent being 100% by weight.

13. Thixotropic coating composition comprising one or more film forming resin(s) (FFR) and between 0.1 and 25% by weight of the sagging control agent of claim 10, based on the total weight of film forming resin(s) (FFR) and sagging control agent(s).

14. The thixotropic coating composition according to claim 13, comprising at least 40% by weight of non-volatile compounds and at most 60% by weight of water-free volatile organic solvents, the sum of the weight percentages of the non-volatile compounds and the water-free volatile organic solvents not exceeding 100% by weight; the nonvolatile compounds comprising from 20 to 98% by weight of a one or more film forming resin(s) (FFR), one or more sagging control agent(s) and optionally one or more crosslinker(s) (C), catalyst(s), reactive diluents and binder resins, and from 2 to 80% by weight of one or more additives and auxiliaries, the sum not exceeding 100% by weight of non-volatile compounds.

15. The thixotropic coating composition according to claim 13 or 14 comprising: at least one film forming resin (FFR); at least one crosslinker (C), reactable with the at least one film forming resin (FFR).

16. The thixotropic coating composition according to claim 15 comprising one or more film forming resins (FFR) selected from the group consisting of polyester polyols and (meth)acrylic polyols, polyacrylate polyester polyol hybrids and mixtures thereof.

17. The thixotropic coating composition according to claim 15 comprising one or more crosslinkers (C) selected from the group consisting of amino crosslinker resins, polyisocyanates, and mixtures thereof.

18. The thixotropic coating composition according to any of claims 15 to 17 comprising: from 10 to 89, preferably from 20 to 80, more preferably from 30 to 70% by weight of at least one film forming resin (FFR); from 10 to 89, preferably from 20 to 80% by weight of at least one crosslinker (C); based on the total amount of film forming resin (FFR) and crosslinker (C) being 100% by weight.

19. The thixotropic coating composition according to claim 14 wherein the one or more additives and auxiliaries are selected from the group consisting of pigments, dyes, surfactants, pigment dispersion aids, complexing agents, levelling agents, wetting agents, anti-cratering agents, antifoaming agents, matting agents, heat stabilizers, light stabilizers, UV absorbers, antioxidants, radical inhibitors, and fillers, and mixtures thereof.

20. A method of providing a coating layer comprising the steps of applying the thixotropic coating composition according to anyone of claims 13 to 19, preferably a clear-coat composition to at least a part of an object, preferably the (exterior) surface of a transportation vehicle, and curing or drying the applied coating layer, preferably in a temperature range of 5 to 180 °C.

21. The method according to claim 20, wherein a coating layer is applied using an overspray-free application process on at least part of a non-horizontal surface of the object.

22. A coated substrate obtainable by the method of claim 20 or 21 .

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