Non-aqueous crosslinkable composition

Abstract

The present invention relates to a polyol component (A) comprising at least one polyacrylate polyol (A1), a crosslinkable composition comprising the polyol component (A), and its use in coatings. More specifically, the polyol component (A) comprises at least one polyacrylate polyol (A1) obtained from monomers of a hydroxyalkyl (meth)acrylate monomer (a1) and a (substituted) alicyclic (meth)acrylate monomer (a4), the Mn of the polyacrylate polyol (A1) being 500 - 2000 daltons and the Mw being 800 - 4000 daltons. The crosslinkable composition comprises the polyol component (A) and a crosslinking agent (C) having functional groups reactive with the polyacrylate polyol (A1). The crosslinkable composition is particularly suitable for varnish and topcoat applications.

Description

Field of the Invention

[0001] The present invention relates to a polyol component comprising a polyacrylate polyol, a crosslinkable composition comprising said polyol component, and its use in coatings. Background Art

[0002] Currently, the regulatory requirements for the content of volatile organic components (VOCs) in the coatings market are becoming increasingly stringent, especially in, for example, general industry, marine and protective coatings, and automotive applications. This is particularly challenging for one-component paints that contain amino resins as crosslinking agent components. Therefore, there is a need to increase the solids content of modern paints. It is known that increasing the solids content (and thus formulating high-solids paint compositions) can be achieved by reducing the molecular weight of the binder present in the coating formulation (or coating composition). However, a lower molecular weight will result in a lower glass transition temperature Tg of the binder. Therefore, reducing the molecular weight of the binder in the paint formulation will seriously affect the properties of the resulting paint or coating (Epple, U. and Vogel, K-H, European Coatings Journal, 07-08 (2005), page 49), for example resulting in lower hardness and reduced resistance of the coating to important chemicals.

[0003] Generally, in HS crosslinkable compositions described in the art that comprise a polyol and an amino resin or a polyisocyanate hardener, polyacrylate polyols are used, which comprise esters of acrylic acid and alcohols having a large alicyclic moiety (such as isobornyl methacrylate (IBOMA)) as monomers.

[0004] In the present specification, a high-solids (HS) crosslinkable coating composition refers to a composition having a volatile organic compound (VOC) content of less than 460 g / l, preferably an uncolored crosslinkable coating composition having a VOC of less than 460 g / l, preferably less than 420 g / l, and more preferably less than 400 g / l.

[0005] Resins containing isobornyl (meth)acrylate monomers are described, for example, in EP0676423. This document demonstrates the trend that the solids content of paint formulations containing such resins with IBOMA monomers increases as the number average molecular weight of the polyol (or film-forming polymer) decreases. Unfortunately, this is also accompanied by a decrease in the hardness of the resulting paint.

[0006] US4605719 describes other examples of resins containing isobornyl methacrylate and their use in paint formulations that also contain melamine-formaldehyde resins. However, these paint formulations also only produce a maximum solids content of 54.5% in varnish formulations. In pigmented formulations, the solids content (including pigments) can be increased to 63.5%, but this is accompanied by a low Persoz hardness of only 235 for the resulting coating.

[0007] In addition, since IBOMA is usually derived from natural resources, the quality and purity of IBOMA are not always sufficiently reproducible in current production and purification processes to guarantee high-quality polyacrylate resins. This can lead to, for example, deviations in the color or odor of the polyacrylate resin and make the use of such a large monomer in polyacrylate polyols less attractive economically for certain applications that require high-quality polyacrylate resins. Furthermore, since IBOMA is a bio-based substance, its availability decreases over time.

[0008] Several alternative monomers for IBOMA are known in the art, as described, for example, in CN106752879. However, according to the teachings of this document, those skilled in the art obtained resins with a number average molecular weight Mn greater than 10,000 daltons, which makes these resins very unsuitable for high-solids paint systems.

[0009] Therefore, there is still a need for a (super) high-solids (unpigmented) crosslinkable coating composition having a measured VOC below 460 g / l, even more preferably below 420 g / l, and most preferably below 400 g / l, which provides good hardness, good or preferably improved appearance, excellent sag resistance, and excellent chemical resistance for the resulting coating. Summary of the Invention

[0011] Accordingly, in one aspect of the present invention, there is provided a polyol component (A) comprising at least one polyacrylate polyol (A1).

[0012] In another aspect of the present invention, there is provided a crosslinkable composition comprising the polyol component (A).

[0013] In other aspects of the present invention, there are also provided a binder module comprising at least one polyacrylate polyol (A1) and a method for providing a coating.

[0014] Advantageous aspects of the present invention are further discussed in the following description.

[0015] Brief Description of the Drawings

[0016] The various aspects of the present invention will now be described in more detail. In the examples, reference is made to the accompanying drawings, namely Figure 1Shows the relationship between the paint viscosity and the calculated solids content from Example 5 (triangles) and Comparative Example 6 (circles). DETAILED DESCRIPTION OF THE INVENTION

[0018] The Applicant has found crosslinkable compositions that overcome the drawbacks encountered by the compositions described in the art to date and provide the combination of properties as described above. Thus, according to one aspect of the present invention, there is provided a polyol component (A) comprising at least one polyacrylate polyol (or (meth)acrylate polyol) (A1), wherein the polyacrylate polyol (A1) is derived from:

[0019] - 10 - 60 wt% of a (meth)acrylic acid hydroxyalkyl ester monomer (a1), preferably 10 - 55 wt%, more preferably 15 - 50 wt%, most preferably 20 - 40 wt%, wherein the hydroxylated alkyl group contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms;

[0020] - Optionally, 0 - 70 wt% of a linear or branched alkyl (meth)acrylate monomer (a2), preferably 10 - 60 wt%, more preferably 15 - 50 wt%, most preferably 15 - 40 wt%, wherein the alkyl group contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms;

[0021] - Optionally, 0 - 60 wt%, preferably 5 - 60 wt%, more preferably 10 - 50 wt%, even more preferably 10 - 40 wt% of a vinyl monomer (a3), preferably (substituted) styrene;

[0022] - 5 - 50 wt% of a (substituted) alicyclic (meth)acrylate monomer (a4), preferably 10 - 45 wt%, more preferably 10 - 40 wt%, most preferably 15 - 35 wt%; preferably the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) contains 5 - 16 carbon atoms, more preferably 6 - 12 carbon atoms, more preferably the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) comprises a (substituted) cycloalkyl moiety, a (substituted) bicyclo[x.y.z]alkyl moiety or a (substituted) tricyclo[x.y.z1.z2]alkyl moiety (the sum of x + y + z + 2, or x + y + z1 + z2 + 2 is equal to the total number of carbon atoms in the alicyclic moiety); and

[0023] - Optionally, 0 - 5 wt% of (meth)acrylic acid (a5), preferably 0 - 3 wt% of (meth)acrylic acid, more preferably 0 - 1 wt% of (meth)acrylic acid, even more preferably 0 - 0.5 wt% of (meth)acrylic acid, most preferably the polyacrylate polyol (A1) is substantially free of (meth)acrylic acid;

[0024] Based on the sum of (a1), (a4) and optionally present (a2), (a3) and (a5);

[0025] The polyacrylate polyol (A1) has:

[0026] - A number average molecular weight Mn of 500 - 2000 daltons, preferably 550 - 1600 daltons, more preferably 600 - 1400 daltons, and most preferably 700 - 1300 daltons;

[0027] - A weight average molecular weight Mw of 800 - 4000 daltons, preferably 900 - 3500 daltons, more preferably 1000 - 2900 daltons, even more preferably 1000 - 2500 daltons, even more preferably 1000 - 2200 daltons, and most preferably 1000 - 2000 daltons.

[0028] In the context of this specification, a (substituted) alicyclic (meth)acrylate monomer refers to a (substituted) cycloalkyl (meth)acrylate monomer, or a (substituted) bicyclo[x.y.z]alkyl (meth)acrylate monomer or a (substituted) tricyclo[x.y.z1.z2]alkyl (meth)acrylate monomer, where the sum of x + y + zn + 2 (i.e., x + y + z + 2, or x + y + z1 + z2 + 2) is equal to the total number of carbon atoms in the alicyclic moiety. The (substituted) alicyclic (meth)acrylate monomer is a macromonomer.

[0029] In the context of this specification, the term “(substituted) alicyclic (meth)acrylate monomer” includes both substituted and unsubstituted alicyclic (meth)acrylate monomers. A substituted alicyclic (meth)acrylate monomer refers to an alicyclic (meth)acrylate monomer having one or more substituents (substituents different from a hydrogen atom) on its alicyclic ring, and an unsubstituted alicyclic (meth)acrylate monomer refers to an alicyclic (meth)acrylate monomer having no such substituents on its alicyclic ring.

[0030] In the context of this specification, a crosslinkable coating composition is also referred to as a crosslinkable composition or a coating composition or a composition.

[0031] When naming compounds in this specification, the prefix “(meth)acryloyl” includes “acryloyl” and “methacryloyl” and refers to a compound containing at least one CH2═CHCOO− group or CH2═CCH3COO− group and mixtures thereof, and mixtures of such compounds.

[0032] According to another aspect of the present invention, there is provided a crosslinkable composition comprising:

[0033] a) The polyol component (A) of the present invention (as described above);

[0034] b) Optionally, at least one polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups;

[0035] c) At least one crosslinking agent (C) containing functional groups capable of reacting with the polyacrylate polyol (A1), the optional polyol (B) and / or the optional reactive diluent (F); and

[0036] d) Optionally, at least one catalyst (D) for catalyzing the reaction between the hydroxyl groups in the polyacrylate polyol (A1), the optional polyol (B), the optional reactive diluent (F) and the functional groups in the crosslinking agent (C), the amount of the catalyst (D) being 0-10 wt%, preferably 0-3 wt%, of the total amount of the polyacrylate polyol (A1), the optional polyol (B), the crosslinking agent (C), the optional catalyst (D) and the optional pot life extender (E), the reactive diluent (F) and / or the anti-sagging agent (G).

[0037] e) Optionally, at least one pot life extender (E);

[0038] f) Optionally, at least one reactive diluent (F) having a number average molecular weight of 62-4000 daltons, preferably 62-2000 daltons, more preferably 62-1000 daltons, a polydispersity Mw / Mn of 1-3, preferably 1-1.5, more preferably 1-1.3, even more preferably 1-1.25, and an average hydroxyl functionality of 1-6, preferably 1.5-4, more preferably 1.8-3.5;

[0039] g) Optionally, at least one anti-sagging agent (G).

[0040] In the context of this specification, the term "polyol (B) different from the polyacrylate polyol (A1)" means a polyol (B) having a different monomer composition and / or different Mn and / or different Mw and / or different glass transition temperature Tg compared to the polyacrylate polyol (A1).

[0041] The Applicant has found that coatings with good hardness, good or preferably improved appearance, excellent sag resistance and excellent chemical resistance can be obtained using this polyol component (A) and the crosslinkable composition, in combination with low VOC (obtained by the low viscosity of at least one polyacrylate polyol (A1) comprised in the polyol component (A) of less than 400 mPa·s at 70% solids content). More specifically, the (uncoloured) composition is very suitable for formulation in the case of very low volatile organic compound content (i.e. VOC content below 460 g / l, even more preferably below 420 g / l, most preferably below 400 g / l) and without highly toxic substances. In addition, the resulting crosslinked material provides good resistance to sunlight, durability and good mechanical properties. Particularly surprisingly, compared with the crosslinkable compositions described in the art, the use of the polyacrylate polyol (A1) of the present invention provides a better balance between VOC and hardness. More specifically, the inclusion of (substituted) alicyclic (meth)acrylate monomers (a4) in the polyacrylate polyol (A1), together with its low weight average molecular weight Mw and high Tg, results in formulations with low VOC and high solids content, thus avoiding the need for further dilution with solvents for spraying and thus avoiding an increase in the VOC content of the composition. In addition, using such formulations, coatings with good chemical resistance can be obtained.

[0042] The compositions of the present invention are also particularly suitable for formulating low VOC, high solids content solventborne clearcoat and topcoat compositions for, for example, vehicle refinish paints, automotive OEM, transport vehicles, general industrial applications and floor applications.

[0043] The crosslinkable composition of the present invention is preferably a so-called non-aqueous composition, which means a composition comprising less than 10% water, preferably less than 5% water, more preferably less than 1% water or even substantially anhydrous (i.e. water-free).

[0044] The polyol component (A) of the present invention preferably comprises less than 10% water, more preferably less than 5% water, most preferably less than 1% water, or even substantially anhydrous (i.e. water-free).

[0045] In the context of the present specification, polyacrylate polyol (A1) means (meth)acrylate polyol (A1).

[0046] The polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is preferably a (co)polymer, more preferably a random (co)polymer, and on average comprises at least 2 free hydroxyl (-OH) groups.

[0047] The polyacrylate polyol (A1) (or (meth)acrylic acid polyol (A1)) is preferably obtained by (co)polymerization of the following monomers and their amounts in the presence of a radical initiator (or the polyacrylate polyol (A1) contains residues formed by (co)polymerization of the following monomers and their amounts):

[0048] - 10 - 60 wt% of a hydroxyalkyl (meth)acrylate monomer (a1), preferably 10 - 55 wt%, more preferably 15 - 50 wt%, most preferably 20 - 40 wt%, wherein the hydroxylated alkyl contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, an adduct of a hydroxyalkyl (meth)acrylate and caprolactone, or a mixture thereof;

[0049] - Optionally, 0 - 70 wt% of a linear or branched alkyl (meth)acrylate monomer (a2), preferably 10 - 60 wt%, more preferably 15 - 50 wt%, most preferably 15 - 40 wt%, wherein the alkyl contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms, such as methyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, an ester of (meth)acrylic acid and an alcohol (e.g., obtained under the trade name obtained), or a mixture thereof;

[0050] - Optionally, 0 - 60 wt%, preferably 5 - 60 wt%, more preferably 10 - 50 wt%, even more preferably 10 - 40 wt% of a vinyl monomer (a3), such as styrene or vinyltoluene, preferably styrene;

[0051] - 5 - 50 wt% of a (substituted) alicyclic (meth)acrylate monomer (a4), preferably 10 - 45 wt%, more preferably 10 - 40 wt%, most preferably 15 - 35 wt%; preferably the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) contains 5 - 16 carbon atoms, more preferably 6 - 12 carbon atoms, more preferably the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) includes a (substituted) cycloalkyl moiety, a (substituted) bicyclo[x.y.z]alkyl moiety or a (substituted) tricyclo[x.y.z1.z2]alkyl moiety (the sum of x + y + z + 2, or x + y + z1 + z2 + 2 is equal to the total number of carbon atoms in the alicyclic moiety); and

[0052] - Optionally, 0 - 5 wt% of (meth)acrylic acid (a5), preferably 0 - 3 wt% of (meth)acrylic acid, more preferably 0 - 1 wt% of (meth)acrylic acid, even more preferably 0 - 0.5 wt% of (meth)acrylic acid, and most preferably the polyacrylate polyol (A1) is substantially free of (meth)acrylic acid;

[0053] Based on the sum of (a1), (a4), and optionally present (a2), (a3), and (a5).

[0054] Preferably, the (meth)acrylic acid polyol (A1) is obtained by (co)polymerization of the following monomers and their amounts:

[0055] - 10 - 60 wt% of a hydroxyalkyl acrylate monomer (a1') or a hydroxyalkyl methacrylate monomer (a1"), preferably 10 - 55 wt%, more preferably 15 - 50 wt%, and most preferably 20 - 40 wt%, where the hydroxylated alkyl contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, an adduct of a hydroxyalkyl (meth)acrylate and caprolactone, or a mixture thereof;

[0056] - Optionally, 0 - 70 wt% of a linear or branched alkyl acrylate monomer (a2') or a linear or branched alkyl methacrylate monomer (a2"), preferably 10 - 60 wt%, more preferably 15 - 50 wt%, most preferably 15 - 40 wt% or even less than 20 wt%, where the alkyl contains 1 - 20 carbon atoms, preferably 1 - 12 carbon atoms, such as methyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, an ester of (meth)acrylic acid and an alcohol (e.g., obtained under the trade name ), or a mixture thereof;

[0057] - Optionally, 0 - 60 wt%, preferably 5 - 60 wt%, more preferably 10 - 50 wt%, even more preferably 10 - 40 wt% of a vinyl monomer (a3), such as styrene or vinyltoluene, preferably styrene;

[0058] - 5 - 50 wt% of a (substituted) alicyclic acrylate monomer (a4') or (substituted) alicyclic methacrylate monomer (a4"), preferably 10 - 45 wt%, more preferably 10 - 40 wt%, most preferably 15 - 35 wt%; preferably, the alicyclic group of the (substituted) alicyclic acrylate (a4') or (substituted) alicyclic methacrylate (a4") contains 5 - 16 carbon atoms, more preferably 6 - 12 carbon atoms; more preferably, the alicyclic group of the (substituted) alicyclic acrylate (a4') or (substituted) alicyclic methacrylate (a4") includes a (substituted) cycloalkyl moiety, a (substituted) bicyclo[x.y.z]alkyl moiety or a (substituted) tricyclo[x.y.z1.z2]alkyl moiety (the sum of x + y + z + 2, or x + y + z1 + z2 + 2 is equal to the total number of carbon atoms in the alicyclic moiety); the alkyl moiety contains 5 - 16 carbon atoms, preferably 6 - 12 carbon atoms, more preferably 6 - 9 carbon atoms, or most preferably the alkyl moiety contains 10 carbon atoms; and

[0059] - Optionally, 0 - 5 wt% of (meth)acrylic acid (a5), preferably 0 - 3 wt% of (meth)acrylic acid, more preferably 0 - 1 wt% of (meth)acrylic acid, even more preferably 0 - 0.5 wt% of (meth)acrylic acid, most preferably the polyacrylate polyol (A1) is substantially free of (meth)acrylic acid;

[0060] Based on the sum of (a1'), (a1"), (a4'), (a4") and optionally present (a2'), (a2"), (a3) and (a5). Preferably, in the monomers used, the ratio of (acrylate monomers (a1')+(a2')+(a4')) / (methacrylate monomers (a1")+(a2")+(a4")) is 0 - 1, more preferably 0.1 - 1, even more preferably 0.2 - 0.95.

[0061] In the context of the present specification, a random (co)polymer means a (co)polymer in which the monomer residues are randomly located in the (co)polymer molecule. Suitable methods for preparing random (co)polymers will be apparent to those skilled in the art. Preferably, when the polyacrylate polyol (A1) is a random (co)polymer, the method for preparing the random (co)polymer (A1) does not control the end group portion of the random (co)polymer (A1). More preferably, when the polyacrylate polyol (A1) is a random (co)polymer, the random (co)polymer (A1) has a random distribution of OH functional groups on its polymer chain (in addition to the monomer residues being randomly located in the (co)polymer molecule, see above), the random (co)polymer (A1) does not contain monomers containing C═C unsaturated bonds other than (a1) to (a5) (more particularly, the random (co)polymer (A1) contains 0 wt% of polybutadiene), and / or the random (co)polymer (A1) does not contain epoxy functional groups (residues) in its side chain (more particularly, the random (co)polymer (A1) contains 0 wt% of epoxy functional groups (residues) in its side chain), for example, residues of reaction products of glycidyl (meth)acrylate with long-chain (linear or branched) carboxylic acids).

[0062] Non-limiting examples of the (substituted) alicyclic (meth)acrylate monomer (a4) containing an alicyclic group having 5 to 16 carbon atoms for use in the present invention are (substituted) cyclopentyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, (substituted) cycloheptyl (meth)acrylate, isomers of limonene (meth)acrylate, isomers of carvone (meth)acrylate, isomers of pinene (meth)acrylate, isosorbide (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, esters of (meth)acrylic acid and hydroxylated (substituted) naphthanes, esters of (meth)acrylic acid and hydroxylated (substituted) bicycloalkyls, isomers of dimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of ethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of ethyldimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of diethylmethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of trimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of trimethylbicyclo[3.1.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, norbornyl (meth)acrylate, (substituted) norbornyl (meth)acrylate, isomers of bicyclo[2.2.1]hept-5-en-2-ylmethyl (meth)acrylate, (substituted) adamantyl (meth)acrylate, (substituted) dicyclopentadiene (meth)acrylate, (substituted) bicyclo[2.2.2]octyl (meth)acrylate, (substituted) bicyclo[4.2.0]octyl (meth)acrylate, (substituted) polycyclopentadiene (meth)acrylate, or mixtures thereof; preferably (substituted) cyclopentyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, (substituted) cycloheptyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (substituted) norbornyl (meth)acrylate, isomers of bicyclo[2.2.1]hept-5-en-2-ylmethyl (meth)acrylate, (substituted) adamantyl (meth)acrylate, (substituted) dicyclopentadiene (meth)acrylate, (substituted) polycyclopentadienyl (meth)acrylate, or mixtures thereof. The (substituted) alicyclic moiety in the monomer (a4) may further contain functional groups such as, but not limited to, hydroxyl, tertiary amine, ether, ester, epoxy, thiol, and / or carboxylic acid groups.

[0063] In one embodiment, the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) is a (substituted) cyclopentyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate or (substituted) cycloheptyl (meth)acrylate having 5 to 16 carbon atoms, preferably a (substituted) cyclopentyl (meth)acrylate or (substituted) cycloheptyl (meth)acrylate having 5 to 16 carbon atoms, or a (substituted) cyclohexyl (meth)acrylate having 7 to 16 carbon atoms, preferably 9 to 15 carbon atoms, more preferably 10 to 14 carbon atoms.

[0064] In a preferred embodiment, the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) is a (substituted) bicyclo[x.y.z]alkyl moiety having 6 to 9 carbon atoms.

[0065] In another more preferred embodiment, the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) is a substituted bicyclo[[x.y.z]alkyl moiety having 10 carbon atoms, preferably an a, b, c-trimethylbicyclo[x.y.z]heptyl moiety, where a, b, and c represent the positions of the methyl groups on the bicyclo[x.y.z]heptyl ring, more preferably an a,b,c-trimethylbicyclo[2.2.1]heptyl or a,b,c-trimethylbicyclo[3.1.1]heptyl moiety, even more preferably an isomer of 2,6,6-trimethylbicyclo[3.1.1]heptyl, 1,3,3-trimethylbicyclo[2.2.1]heptyl or 1,7,7-trimethylbicyclo[2.2.1]heptyl moiety, most preferably an isomer of 2,6,6-trimethylbicyclo[3.1.1]heptyl or 1,3,3-trimethylbicyclo[2.2.1]heptyl moiety, and even most preferably an isomer of the 1,3,3-trimethylbicyclo[2.2.1]heptyl moiety.

[0066] In an alternative embodiment, the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) is a bicyclo[x.y.z]alkyl moiety having 11 to 16 carbon atoms.

[0067] In another alternative embodiment, the alicyclic group of the (substituted) alicyclic (meth)acrylate (a4) is a (substituted) tricyclo[x.y.z1.z2]alkyl moiety having 5 to 16 carbon atoms, preferably 7 to 14 carbon atoms, more preferably 9 to 13 carbon atoms, and most preferably 11 or 12 carbon atoms. Preferably, the (substituted) tricyclo[x.y.z1.z2]alkyl moiety comprises a (partially) hydrogenated (substituted) indene moiety and / or at least one (substituted) norbornyl moiety, more preferably a (partially) hydrogenated (substituted) indene moiety and at least one (substituted) norbornyl moiety, and most preferably an (octahydro-4,7-methano-1H-indenyl)methyl moiety. Examples of such (substituted) alicyclic (meth)acrylates (a4) containing a (substituted) tricyclo[x.y.z1.z2]alkyl moiety are (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, octahydro-4,7-methano-1H-indenyl dimethanol and esters of isomers of (meth)acrylic acid, or mixtures thereof; preferably (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, octahydro-4,7-methano-1H-indenyl dimethanol and monoesters of isomers of (meth)acrylic acid, or mixtures thereof.

[0068] Preferably, the (substituted) alicyclic (meth)acrylate monomer (a4) for obtaining the (meth)acrylic polyol (A1) used in the polyol component (A) and the composition of the present invention is isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, or a mixture thereof; more preferably, the monomer (a4) is isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, or a mixture thereof; even more preferably, the monomer (a4) is 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, or a mixture thereof; most preferably, the monomer (a4) is 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, norbornenyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, octahydro-4,7-methano-1H-indenedimethanol and monoester of (meth)acrylic acid, or a mixture thereof.

[0069] In a more preferred embodiment of the present invention, the (substituted) alicyclic (meth)acrylate monomer (a4) is 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenemethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, or a mixture thereof, preferably 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, norbornenyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, octahydro-4,7-methano-1H-indenemethanol and monoesters of (meth)acrylic acid, or a mixture thereof, and the (meth)acrylic acid hydroxyalkyl ester monomer (a1) for obtaining the (meth)acrylic acid polyol (A1) used in the polyol component (A) and the composition of the present invention is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, or a mixture thereof.

[0070] In an alternative embodiment of the present invention, the (substituted) alicyclic (meth)acrylate monomer (a4) is isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenemethanol and isomers of (meth)acrylic acid, (substituted) cyclohexyl (meth)acrylate, or a mixture thereof, preferably isobornyl (meth)acrylate, and the (meth)acrylic acid hydroxyalkyl ester monomer (a1) for obtaining the (meth)acrylic acid polyol (A1) used in the polyol component (A) and the composition of the present invention is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, or a mixture thereof, preferably 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or a mixture thereof.

[0071] In another alternative and more preferred embodiment of the present invention, the (substituted) alicyclic (meth)acrylate monomer (a4) is isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, octahydro-4,7-methano-1H-indenyl dimethanol and esters of isomers of (meth)acrylic acid, (substituted) cyclohexyl (meth)acrylate, or a mixture thereof, preferably isobornyl (meth)acrylate, and the (meth)acrylic acid hydroxyalkyl ester monomer (a1) for obtaining the (meth)acrylic acid polyol (A1) used in the polyol component (A) and the composition of the present invention contains more than 50 wt%, preferably more than 60 wt%, more preferably more than 80 wt%, most preferably more than 90 wt% or even 100 wt% of the methacrylic acid hydroxyalkyl ester monomer (a1”), based on the total weight of the (meth)acrylic acid hydroxyalkyl ester monomer (a1). Preferably, the methacrylic acid hydroxyalkyl ester monomer (a1”) is hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, or a mixture thereof, more preferably hydroxyethyl methacrylate, hydroxypropyl methacrylate, or a mixture thereof.

[0072] (Octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate is also known as 3-tricyclo[5.2.1.0 2,6 decylmethyl (meth)acrylate.

[0073] Octahydro-4,7-methano-1H-indenyl dimethanol is also known as tricyclo[5.2.1.0 2,7 decane dimethanol.

[0074] The polymerization step may include at least one polymerization initiator and / or chain transfer agent. Any initiator and / or chain transfer agent known to those skilled in the art can be used. The polymerization reaction can further be carried out in an organic solution in the presence of a known solvent. Examples of such solvents include toluene, xylene, n-butyl acetate, ethyl acetate, ethylene glycol acetate, isopentyl acetate, hexyl acetate, methoxypropyl acetate, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone and methyl isobutyl ketone. Also suitable are mixtures of high-boiling aromatic compounds, such as solvent naphtha solvents, homologues of benzene, Solvesso solvents, Shellsol solvents; and high-boiling aliphatic and alicyclic hydrocarbons, such as petroleum solvent oil, mineral turpentine, Isopar solvents, Nappar solvents, tetrahydronaphthalene and decahydronaphthalene. Mixtures of solvents can also be used. When the polymerization is carried out in a solvent, the preferred solvents are n-butyl acetate, methoxypropyl acetate and xylene, and mixtures of these solvents.

[0075] The weight average molecular weight Mw of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is less than 4000 daltons, preferably less than 3500 daltons, more preferably less than 2500 daltons, even more preferably less than 2200 daltons, and most preferably less than 2000 daltons.

[0076] The number average molecular weight Mn of the polyacrylate polyol (A1) is at most 2000 daltons, preferably at most 1600 daltons, more preferably at most 1400 daltons, and most preferably at most 1300 daltons.

[0077] The polydispersity (defined as Mw / Mn) of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is preferably less than 4, more preferably less than 3, even more preferably less than 2.5, or most preferably less than 2.

[0078] The weight average molecular weight Mw and the number average molecular weight Mn are determined by gel permeation chromatography using polystyrene standards in accordance with ASTM D 3593, and more particularly by size exclusion chromatography.

[0079] Preferably, the glass transition temperature Tg of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is higher than -25°C, preferably higher than -15°C, more preferably higher than 0°C (i.e., the glass transition temperature is 0°C or higher), and most preferably higher than 5°C. The glass transition temperature Tg of the polyacrylate polyol (A1) is lower than 50°C, preferably lower than 35°C, more preferably lower than 30°C, and most preferably lower than 25°C.

[0080] More preferably, the glass transition temperature Tg of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is 0 - 50°C, even more preferably 0 - 35°C, and most preferably 5 - 30°C.

[0081] Tg is determined using a Mettler DSC 3+ calorimeter in accordance with DIN EN ISO 16805 and ISO 11357.

[0082] Preferably, the acid value (AV) of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is lower than 20 mg KOH / g of the polyol (A1), preferably lower than 15 mg KOH / g of the polyol (A1), more preferably lower than 10 mg KOH / g of the polyol (A1), most preferably lower than 8 mg KOH / g of the polyol (A1) or even lower than 7 mg KOH / g of the polyol (A1).

[0083] The hydroxyl value of the polyacrylate polyol (A1) used in the polyol component (A) and the composition of the present invention is 60 - 300 mg KOH / g polyol (A1), preferably 80 - 280 mg KOH / g polyol (A1), more preferably 100 - 250 mg KOH / g polyol (A1), even more preferably 110 - 195 mg KOH / g polyol (A1), and most preferably 120 - 180 mg KOH / g polyol (A1).

[0084] The hydroxyl value is determined according to the ASTM E222 - 17 standard method.

[0085] Preferably, the polyacrylate polyol (A1) used in the polyol component (A) and the crosslinkable composition of the present invention has a Mn of less than 2000 daltons, preferably less than 1600 daltons; a Mw of less than 4000 daltons, preferably less than 3500 daltons, more preferably less than 2500 daltons; a polydispersity of less than 4, preferably less than 3, more preferably less than 2.5; an acid value of 0 - 15 mg KOH / g of polyol (A1), preferably 0 - 10 mg KOH / g of polyol (A1), more preferably 0 - 8 mg KOH / g of polyol (A1); a glass transition temperature higher than -15 °C, preferably higher than 0 °C and lower than 50 °C, preferably lower than 35 °C, more preferably lower than 30 °C; and contains 5 - 50 wt% of (substituted) alicyclic (meth)acrylate monomer (a4) based on the sum of (a1), (a4) and optionally present (a2), (a3) and (a5), preferably isobornyl (meth)acrylate, 2,6,6 - trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, esters of octahydro - 4,7 - methano - 1H - indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, or mixtures thereof, more preferably 2,6,6 - trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, esters of octahydro - 4,7 - methano - 1H - indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, even more preferably 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, norbornenyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and monoesters of (meth)acrylic acid, or mixtures thereof. The (meth)acrylic acid hydroxyalkyl ester monomer (a1) used to obtain the (meth)acrylic acid polyol (A1) is preferably hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, or mixtures thereof.

[0086] Alternatively, the Mn of the polyacrylate polyol (A1) (preferably a random (co)polymer in which the OH functional groups are randomly distributed on the polymer chain and the end-group functionality is not controlled) used in the polyol component (A) and the composition of the present invention is less than 1600 daltons, preferably less than 1400 daltons, more preferably less than 1300 daltons; the Mw is less than 2900 daltons, preferably the Mw is less than 2500 daltons, more preferably less than 2200 daltons, even more preferably less than 2000 daltons; the polydispersity is less than 4, preferably less than 3, more preferably less than 2.5; the acid value is 0 - 15 mg KOH / g of the polyol (A1), preferably 0 - 10 mg KOH / g of the polyol (A1); the glass transition temperature is higher than -15 °C, preferably higher than 0 °C, and lower than 50 °C, preferably lower than 35 °C, more preferably lower than 30 °C; and it contains 5 - 50 wt%, preferably 10 - 45 wt%, more preferably 10 - 40 wt%, most preferably 15 - 35 wt% of the (substituted) alicyclic (meth)acrylate monomer (a4) based on the sum of (a1), (a4) and optionally present (a2), (a3) and (a5), preferably isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenemethanol and (meth)acrylic acid, (substituted) cyclohexyl (meth)acrylate, or a mixture thereof, more preferably isobornyl (meth)acrylate. The (meth)acrylic acid hydroxyalkyl ester monomer (a1) used to obtain the (meth)acrylic acid polyol (A1) is preferably hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, or a mixture thereof, more preferably hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl methacrylate, most preferably hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, or a mixture thereof. More preferably, the (meth)acrylic acid hydroxyalkyl ester monomer (a1) used to obtain the (meth)acrylic acid polyol (A1) contains more than 50 wt%, preferably more than 60 wt%, more preferably more than 80 wt%, most preferably more than 90 wt% or even 100 wt% of the methacrylic acid hydroxyalkyl ester monomer (a1”), based on the total weight of the (meth)acrylic acid hydroxyalkyl ester monomer (a1). Even more preferably, the methacrylic acid hydroxyalkyl ester monomer (a1”) is hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, or a mixture thereof, most preferably hydroxyethyl methacrylate, hydroxypropyl methacrylate, or a mixture thereof.

[0087] In the context of this specification, the phrase "at least one" means one, two, three or more.

[0088] In the context of this specification, the phrase "at least one polyacrylate polyol (A1)" means one, or two, three or more polyacrylate polyols. More specifically, it means one polyacrylate polyol (A1), or a mixture of two, three or more polyacrylate polyols, such as those described above with respect to polyacrylate polyol (A1), and the polyacrylate polyols in such a mixture are further designated as (A1-1), (A1-2), (A1-3), etc., and each has a monomer composition different from one another and / or a different Mn and / or a different Mw. For example, a mixture of two polyacrylate polyols contains polyacrylate polyol (A1-1) and a polyacrylate polyol (A1-2) different from polyacrylate polyol (A1-1), more particularly polyacrylate polyols (A1-1) and (A1-2) having different monomer compositions.

[0089] The polyol component (A) of the present invention may optionally contain a solvent (A2), which may be the same solvent as that used during the above polymerization reaction, or it may be a different solvent. The solvent (A2) in the polyol component (A) may also include a mixture of different (types) of solvents. Generally, the solvent (A2) has a boiling point of 200 °C or lower at atmospheric pressure.

[0090] The polyol component (A) of the present invention may optionally contain one or more additives (A3). Additives also include auxiliaries commonly used in coating compositions. These additives are generally used in relatively small amounts to improve certain important paint properties. These additives may contain a volatile portion and a non-volatile portion, wherein the volatile portion contains a solvent having a boiling point of 200 °C or lower at atmospheric pressure. Examples of such additives are surfactants, leveling agents, wetting agents, anti-cratering agents, defoaming agents, heat stabilizers, light stabilizers, UV absorbers, antioxidants. In addition, the polyol component (A) may also contain a polyol (B), a pot life extender (E), a reactive diluent (F), and / or an anti-sag agent (G), as described below.

[0091] The polyol component (A) of the present invention preferably contains:

[0092] - 35 - 100 wt%, preferably 40 - 90 wt%, most preferably 50 - 85 wt% of polyacrylate polyol (A1);

[0093] - 0 - 50 wt%, preferably 10 - 40 wt%, most preferably 15 - 30 wt% of solvent (A2);

[0094] - 0 - 10 wt%, preferably 0 - 8 wt%, most preferably 0.1 - 7 wt% of additive (A3);

[0095] - 0 - 40 wt%, preferably 0 - 30 wt%, most preferably 5 - 25 wt% of at least one polyol (B), which is different from the polyacrylate polyol (A1) and contains at least two free hydroxyl groups;

[0096] - 0 - 5 wt%, preferably 0 - 4 wt%, most preferably 0.1 - 2 wt% of a pot life extender (E);

[0097] - 0 - 20 wt%, preferably 0 - 15 wt%, most preferably 1 - 10 wt% of a reactive diluent (F); and / or

[0098] - 0 - 15 wt%, preferably 0 - 10 wt%, most preferably 1 - 8 wt% of an anti - sag agent (G);

[0099] Relative to the total weight of the polyol component (A).

[0100] In a more preferred embodiment of the present invention, the polyol component (A) comprises (or consists of):

[0101] - 35 - 100 wt%, preferably 40 - 90 wt%, most preferably 50 - 85 wt% of a polyacrylate polyol (A1), and the (substituted) alicyclic (meth)acrylate monomer (a4) used to obtain (A1) is 2,6,6 - trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and esters of isomers of (meth)acrylic acid, (meth)acrylate norbornene, or a mixture thereof, preferably 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (meth)acrylate norbornene, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and monoesters of (meth)acrylic acid, or a mixture thereof;

[0102] - 10 - 40 wt%, more preferably 15 - 30 wt% of a solvent (A2), and the solvent (A2) is n - butyl acetate; and

[0103] - 5 - 35 wt%, preferably 5 - 25 wt% of at least one polyol (B), and the polyol (B) is a polyester polyol and contains at least two free hydroxyl groups;

[0104] Relative to the total weight of the polyol component (A).

[0105] In another preferred embodiment of the present invention, the polyol component (A) comprises (or consists of):

[0106] -35 - 100 wt%, preferably 40 - 90 wt%, most preferably 50 - 85 wt% of polyacrylate polyol (A1), the (substituted) alicyclic (meth)acrylate monomer (a4) used to obtain (A1) is 2,6,6 - trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and esters of isomers of (meth)acrylic acid, (meth)acrylate norbornene, or a mixture thereof, preferably 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (meth)acrylate norbornene, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and monoesters of (meth)acrylic acid, or a mixture thereof;

[0107] - 10 - 40 wt%, more preferably 15 - 30 wt% of solvent (A2), the solvent (A2) being n - butyl acetate; and

[0108] - 0 - 40 wt%, preferably 0 - 30 wt%, most preferably 5 - 25 wt% of at least one polyol (B), which is different from polyacrylate polyol (A1) and contains at least two free hydroxyl groups;

[0109] - 0 - 20 wt%, preferably 0 - 15 wt%, most preferably 1 - 10 wt% of reactive diluent (F);

[0110] Relative to the total weight of the polyol component (A).

[0111] Based on the total weight of the polyol component, preferably the residual monomer content in the polyol component (A) is less than 15000 ppm, more preferably less than 10000 ppm, even more preferably less than 8000 ppm, and most preferably less than 5000 ppm. The residual monomer content can be determined by the method published by S. Kossen, LC GC Europe, November 2001, page 2.

[0112] The flash point of the polyol component (A) is preferably higher than 20 °C, more preferably higher than 22 °C, further preferably higher than 25 °C, and most preferably 27 °C or higher. The flash point can be determined according to ISO 1523.

[0113] The content of polyacrylate polyol (A1) in the crosslinkable composition is preferably 10 - 90 wt%, more preferably 20 - 80 wt%, and most preferably 30 - 70 wt%, based on the total amount of polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), and optional catalyst (D), pot life extender (E), reactive diluent (F), and / or anti-sagging agent (G).

[0114] Optionally, the crosslinkable composition of the present invention comprises at least one polyol (B) different from polyacrylate polyol (A1) and containing at least two free hydroxyl groups.

[0115] The optionally present polyol (B) is preferably selected from polyester polyols, polyacrylate polyols (or (meth)acrylate polyols), polycarbonate polyols, polyether polyols, polyurethane polyols, amino resin polyols, and mixtures (or hybrids) thereof. Such polymers are generally known to those skilled in the art and are commercially available. More preferably, the polyol (B) is selected from polyester polyols, polyacrylate polyols, and mixtures (or hybrids) thereof.

[0116] Suitable polyester polyols (B) can be obtained, for example, by a polycondensation reaction of one or more di- and / or higher-functional hydroxyl compounds with one or more di- and / or higher-functional carboxylic acids, optionally in combination with one or more monofunctional carboxylic acids and / or hydroxyl compounds. Non-limiting examples of monocarboxylic acids are linear or branched alkyl carboxylic acids containing 4 - 30 carbon atoms, preferably, for example, stearic acid, 2-ethylhexanoic acid, or isononanoic acid. As non-limiting examples, the di- and / or higher-functional hydroxyl compounds can be one or more alcohols selected from the following: ethylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, isosorbide, spiroglycol, trimethylolpropane, glycerol, tri(2-hydroxyethyl) isocyanurate, and pentaerythritol. As non-limiting examples, the difunctional and / or higher-functional carboxylic acids are one or more selected from the following: succinic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic acid, terephthalic acid, isophthalic acid, phthalic acid, and their functional equivalents. The polyester polyol can be prepared from di- and / or higher-functional hydroxyl compounds and from carboxylic acids and / or acid anhydrides and / or C1 - C4 alkyl esters of the acids.

[0117] Suitable (meth)acrylic polyols (or polyacrylate polyols) (B) can be obtained, for example, by (co)polymerizing a hydroxy-functional (meth)acrylic monomer with other ethylenically unsaturated comonomers in the presence of a free radical initiator. As non-limiting examples, the (meth)acrylic polyols can include residues formed by the polymerization of one or more hydroxyalkyl esters of (meth)acrylic acid, such as 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.(Meth)acrylic polyols further preferably contain monomers without hydroxyl groups, such as methyl (meth)acrylate, tert-butyl (meth)acrylate, (substituted) cyclopentyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, (substituted) cycloheptyl (meth)acrylate, isomers of limonene (meth)acrylate, isomers of carvone (meth)acrylate, isomers of pinene (meth)acrylate, isosorbide (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, esters of (meth)acrylic acid and hydroxylated (substituted) naphthalane, esters of (meth)acrylate and hydroxylated (substituted) bicycloalkyl, isomers of dimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of ethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of ethyldimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of diethylmethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of trimethylbicyclo[2.2.1]heptyl (meth)acrylate, isomers of trimethylbicyclo[3.1.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenemethanol and isomers of (meth)acrylic acid, isobornyl (meth)acrylate, (substituted) norbornyl (meth)acrylate, isomers of bicyclo[2.2.1]hept-5-en-2-ylmethyl (meth)acrylate, (substituted) adamantyl (meth)acrylate, (substituted) dicyclopentadiene (meth)acrylate, (substituted) bicyclo[2.2.2]octyl (meth)acrylate, (substituted) bicyclo[4.2.0]octyl (meth)acrylate, and (substituted) polycyclopentadienyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylic acid; more preferably methyl (meth)acrylate, tert-butyl (meth)acrylate, (substituted) cyclopentyl (meth)acrylate, (substituted) cyclohexyl (meth)acrylate, (substituted) cycloheptyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (substituted) norbornyl (meth)acrylate, isomers of bicyclo[2.2.1]hept-5-en-2-ylmethyl (meth)acrylate, (substituted) adamantyl (meth)acrylate, (substituted) dicyclopentadiene (meth)acrylate, and (substituted) polycyclopentadienyl (meth)acrylate, isobutyl (meth)acrylate, (meth)acrylic acid. (Meth)acrylic polyols optionally contain non-(meth)acrylate monomers, such as styrene, vinyltoluene or other substituted styrene derivatives, vinyl esters of (branched) monocarboxylic acids, maleic acid, fumaric acid, itaconic acid, crotonic acid and monoalkyl esters of maleic acid.Preferably, relative to the total monomer composition of the polyacrylate polyol (B), the amount of the (substituted) alicyclic (meth)acrylate monomer is less than 15%, more preferably less than 10%, and most preferably less than 5%.

[0118] If present, the weight average molecular weight Mw of the polyester polyol (B) used in the composition of the present invention is preferably at least 600 daltons, more preferably at least 800 daltons. The weight average molecular weight Mw of the polyester polyol (B) used in the composition of the present invention is preferably less than 10,000 daltons, more preferably less than 9,000 daltons. The number average molecular weight Mn of the polyester polyol (B) is preferably higher than 500 daltons, more preferably higher than 600 daltons. The number average molecular weight Mn of the polyester polyol (B) is preferably at most 6,000 daltons, more preferably at most 5,000 daltons.

[0119] If present, the weight average molecular weight Mw of the polyacrylate polyol (B) used in the composition of the present invention is preferably at least 800 daltons, more preferably at least 1,000 daltons, and most preferably at least 1,200 daltons. The weight average molecular weight Mw of the polyacrylate polyol (B) used in the composition of the present invention is preferably less than 10,000 daltons, more preferably less than 9,000 daltons. The number average molecular weight Mn of the polyacrylate polyol (B) is preferably higher than 500 daltons, more preferably higher than 600 daltons, and most preferably higher than 700 daltons. The number average molecular weight Mn of the polyacrylate polyol (B) is preferably at most 6,000 daltons, more preferably at most 5,000 daltons.

[0120] The polydispersity (defined as Mw / Mn) of the optional polyol (B) used in the composition of the present invention is preferably less than 5, more preferably less than 4, and most preferably less than 3.

[0121] The glass transition temperature Tg of the optional polyol (B) used in the composition of the present invention is preferably higher than -70 °C, more preferably higher than -60 °C, and most preferably higher than -50 °C. The glass transition temperature of the polyol (B) is preferably not more than 90 °C, more preferably not more than 75 °C. Tg is measured using a Mettler DSC 3+ calorimeter according to DIN EN ISO 16805 and ISO 11357.

[0122] If present, the hydroxyl value of the polyol (B) used in the composition of the present invention is preferably 40 - 400 mg KOH / g of the polyol (B), more preferably 50 - 300 mg KOH / g of the polyol (B), and most preferably 80 - 250 mg KOH / g of the polyol (B). The hydroxyl value is measured according to the standard method ASTM E222-17.

[0123] The acid value (AV) of the optional polyol (B) used in the composition of the present invention is preferably less than 20 mg KOH / g of polyol (B), preferably less than 15 mg KOH / g of polyol (B), and more preferably less than 10 mg KOH / g of polyol (B).

[0124] If present, the hydroxyl value of the polyol (B) used in the composition of the present invention is preferably 40 - 400 mg KOH / g of polyol (B) and / or the acid value is preferably 0 - 20 mg KOH / g of polyol (B).

[0125] If present, the content of polyol (B) in the composition is preferably 0 - 90 wt%, more preferably 10 - 80 wt%, and most preferably 20 - 70 wt%, based on the total amount of polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), and optional catalyst (D), pot life extender (E), reactive diluent (F), and / or anti - sag agent (G).

[0126] The crosslinking agent (C) generally comprises an oligomeric or polymeric compound having at least two functional groups capable of reacting with polyacrylate polyol (A1) and / or optional polyol (B) and / or optional reactive diluent (F).

[0127] The crosslinking agent (C) is preferably selected from isocyanates, blocked isocyanates, amino resins such as melamine - formaldehyde resins and formaldehyde - free resins, and mixtures of amino resins with (blocked) isocyanates.

[0128] Melamine - formaldehyde resins are well - known and have long been commercialized, and can be obtained under the trade names and from allnex. These melamine - formaldehyde resins, optionally in solution in the corresponding organic solvents, and include products having different degrees of hydroxymethylation, etherification, or condensation (monocyclic or polycyclic). Preferred melamine - formaldehyde resins are the resins sold under the following names: 202, 232, 235, 238, 254, 266, 267, 272, 285, 301, 303, 325, 327, 350, 370, 701, 703, 736, 738, 771, 1141, 1156, 1158, 1168, NF 2000, NF 2000A, US-132BB-71, US-134BB-57, US-138BB-70, US-144BB-60, US-146BB-72, US-148BB-70 or a mixture thereof. Particularly preferred is US-138BB-70, 327, NF 2000, NF 2000A or a mixture thereof.

[0129] The crosslinking agent component (C) may further include an isocyanate compound having at least two free -NCO (isocyanate) groups. Isocyanate crosslinking agents are well known and have been widely described in the art. Isocyanate compounds are generally selected from aliphatic, cycloaliphatic, and aromatic polyisocyanates containing at least 2 -NCO groups and mixtures thereof. The crosslinking agent (C) is preferably selected from hexamethylene diisocyanate, 2,4,4 - trimethylhexamethylene diisocyanate, 1,2 - cyclohexylene diisocyanate, 1,4 - cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl - 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, m - and p - phenylene diisocyanate, 1,3 - and 1,4 - bis(isocyanatomethyl)benzene, xylene diisocyanate, α,α,α',α'-tetramethylxylene diisocyanate 1,5 - dimethyl - 2,4 - bis(isocyanatomethyl)benzene, 2,4 - and 2,6 - tolylene diisocyanate, 2,4,6 - tolylene triisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl diisocyanate, naphthalene - 1,5 - diisocyanate, isophorone diisocyanate, 4 - isocyanatomethyl - 1,8 - octamethylene diisocyanate, and mixtures of the above polyisocyanates. Other preferred isocyanate crosslinkers are adducts of polyisocyanates, such as biurets, isocyanurates, imino - oxadiazinediones, urethanes, uretdiones, or mixtures thereof. Examples of such adducts are adducts of 2 molecules of hexamethylene diisocyanate or isophorone diisocyanate with a diol such as ethylene glycol, adducts of 3 molecules of hexamethylene diisocyanate with 1 molecule of water, adducts of 1 molecule of trimethylolpropane with 3 molecules of isophorone diisocyanate, adducts of 1 molecule of pentaerythritol with 4 molecules of tolylene diisocyanate, isocyanurate of hexamethylene diisocyanate (available under the trade name (E)N3390 or HDT - LV), mixtures of uretdione and isocyanurate of hexamethylene diisocyanate (trade name N3400), urethane of hexamethylene diisocyanate (available under the trade name LS2101), and isocyanurate of isophorone diisocyanate (available under the trade name T1890). In addition, (co)polymers of isocyanate - functional monomers such as α,α’ - dimethyl - m - isopropenylbenzyl isocyanate are also suitable. If desired, hydrophobically or hydrophilically modified polyisocyanates can also be used to impart specific properties to the coating.

[0130] When a blocking agent having a sufficiently low deblocking temperature is used to block any of the above polyisocyanate crosslinker components (C), the crosslinker component (C) can also include blocked isocyanates. In that case, the crosslinker component (C) is substantially free of unblocked isocyanate - containing compounds, and the crosslinkable composition can be formulated as a one - component formulation. Blocking agents that can be used to prepare the blocked isocyanate component are well known to those skilled in the art.

[0131] The content of the crosslinker (C) in the composition is preferably 10 - 90 wt%, more preferably 20 - 80 wt%, and most preferably 30 - 70 wt%, based on the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinker (C), and optional catalyst (D), pot - life extender (E), reactive diluent (F), and / or anti - sag agent (G).

[0132] The crosslinkable composition of the present invention preferably comprises a polyacrylate polyol (A1), an optional polyol (B), an optional reactive diluent (F), and a polyisocyanate crosslinking agent (C), in amounts such that the equivalent ratio of isocyanate groups to hydroxyl groups is preferably from 0.5 to 4.0, more preferably from 0.7 to 3.0, and most preferably from 0.8 to 2.5.

[0133] The crosslinkable composition may optionally comprise a catalyst (D) for catalyzing the reaction between the -OH groups in the polyacrylate polyol (A1) and / or the optional polyol (B) and / or the optional reactive diluent (F) and the crosslinking agent (C). Those skilled in the art will know that the type of catalyst (D) generally depends on the type of crosslinking agent component.

[0134] In one embodiment, the catalyst (D) is an organic acid, more particularly selected from sulfonic acids, carboxylic acids, phosphoric acids and / or acidic phosphates. Preferred is a sulfonic acid. Examples of suitable sulfonic acids are dodecylbenzenesulfonic acid (DDBSA), dinonylnaphthalenedisulfonic acid (DNNSA), p-toluenesulfonic acid (pTSA). The acid catalyst can also be used in blocked form. Thus, as is known, the shelf life of a composition containing a blocked catalyst is improved. Examples of suitable reagents for blocking the acid catalyst are amines, such as preferably tertiary alkylated amines or heterocyclic amines. The blocked sulfonic acid catalyst can be, for example, blocked DDBSA, blocked DNNSA or blocked p-TSA. Such blocking of the sulfonic acid catalyst occurs, for example, also with amines, such as preferably tertiary alkylated or heterocyclic amines, such as 2-amino-2-methylpropanol, diisopropanolamine, dimethyloxazoline or trimethylamine. Alternatively, NH3, optionally dissolved in an organic solvent or in water, can be used to block the sulfonic acid catalyst. Covalently blocked sulfonic acid catalysts can also be used. In this case, for example, covalently bonding blocking agents such as epoxides or epoxy-isocyanate compounds are used for blocking. These types of blocked sulfonic acid catalysts are described in detail in the patent publication US Patent No. 5102961. The catalyst can be obtained, for example, under the trade name (allnex) or obtained and can be used directly in the composition of the present invention.

[0135] In another embodiment, the catalyst (D) is a metal-based catalyst. Preferred metals in the metal-based catalyst include tin, bismuth, zinc, zirconium, and aluminum. Preferred metal-based catalysts (D) are carboxylates or acetylacetonate complexes of the above metals. Preferred metal-based catalysts (D) optionally used in the present invention are tin carboxylates, bismuth carboxylates, or zinc carboxylates, more particularly preferably dimethyltin dilaurate, dimethyltin didecanoate, dimethyltin dioleate, dibutyltin dilaurate, dioctyltin dilaurate, tin octoate, zinc 2-ethylhexanoate, zinc neodecanoate, bismuth 2-ethylhexanoate, or bismuth neodecanoate. Also suitable are dialkyltin maleates or dialkyltin acetates. Mixtures and combinations of metal-based catalysts, mixtures of (blocked) acid catalysts, or mixtures of metal-based catalysts with (blocked) acid catalysts can also be used.

[0136] Generally, the content of the catalyst (D) in the composition of the present invention is 0-10%, preferably 0.001-5%, more preferably 0.002-5%, even more preferably 0.002-3%, and most preferably 0.005-1% by weight of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), and optional catalyst (D), pot life extender (E), reactive diluent (F), and / or anti-sagging agent (G).

[0137] Optionally, the crosslinkable composition of the present invention comprises at least one pot life extender (E). This can be any type of pot life extender, and many different types of pot life extenders are known to those skilled in the art. Well-known pot life extenders are, for example, of the β-diketone, β-ketoester and α-hydroxyketone types. Examples of such compounds are 2,4-pentanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, 2,4-hexanedione, 2,4-heptanedione, 5-methyl-2,4-hexanedione 2,4-octanedione, 5,5-dimethyl-2,4-hexanedione, 3-ethyl-2,4-pentanedione, 2,4-decanedione, 2,2-dimethyl-3,5-nonanedione, 3-methyl-2,4-pentanedione, 2,4-tridecanedione, 1-1-cyclohexyl-1,3-butanedione, 5,5-dimethyl-1,3-cyclohexanedione, 1,3-cyclohexanedione, 1-phenyl-1,3-butanedione, 1-(4-biphenyl)-1,3-butanedione, 1-phenyl-1,3-pentanedione, 3-benzyl-2,4-pentanedione, 1-phenyl-5,5-dimethyl-2,4-hexanedione, 1-phenyl-2-butyl-1,3-butanedione, 1-phenyl-3-(2-methoxyphenyl)-1,3-propanedione, 1-(4-nitrophenyl)-1,3-butanedione, 1-(2-furyl)-1,3-butanedione, 1-(tetrahydro-2-furyl)-1,3-butanedione, dibenzoylmethane, methyl acetoacetate, ethyl acetoacetate, α-methylethyl acetoacetate, α-n-butylethyl acetoacetate, α-sec-butylethyl acetoacetate, α-ethylethyl acetoacetate, α-acetyl-butyrolactone, dimedone and 1-hydroxyanthraquinone, benzoin, acetoin and α-hydroxyacetophenone. Particularly preferred pot life extender compounds from this group are 2,4-pentanedione.

[0138] Another type of pot life extender (E) that is particularly suitable for the crosslinkable compositions of the present invention is a carboxylic acid, preferably a monofunctional carboxylic acid such as acetic acid, butyric acid, propionic acid, acrylic acid, methacrylic acid, phenylacetic acid, benzoic acid, p-methylbenzoic acid, p-nitrobenzoic acid, p-chlorobenzoic acid, p-methoxybenzoic acid, isononanoic acid, 2-ethylhexanoic acid, valeric acid, 3-methylbutyric acid, neodecanoic acid, tertiary carbonic acid, 3-hydroxy-2,2-dimethylpropionic acid, 2,2-bis(hydroxymethyl)propionic acid, abietic acid, 1-methylcyclohexanecarboxylic acid, dimethylmalonic acid, ethylmethylmalonic acid, diethylmalonic acid, 2,2-dimethylsuccinic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2,2-dimethylpropionic acid, 2,2-dimethylbutyric acid, 2-ethyl-2-methylbutyric acid, 2,2-diethylbutyric acid, 2,2-dimethylvaleric acid, 2-ethyl-2-methylvaleric acid, 2,2-diethylvaleric acid, 2,2-dimethylhexanoic acid, 2,2-diethylhexanoic acid, 2,2-dimethyloctanoic acid, 2-ethyl-2,5-dimethylhexanoic acid, 3-methylisocitric acid, 4,4-dimethylaconitic acid, 1-methylcyclopentanecarboxylic acid, 1,2,2-trimethyl-1,3-cyclopentanedicarboxylic acid, 1-methylcyclohexanecarboxylic acid, 2-methylbicyclo[2.2.1]-5-heptene-2-carboxylic acid, 2-methyl-7-oxabicyclo[2.2.1]-5-heptene-2-carboxylic acid, 1-adamantanecarboxylic acid, bicyclo[2.2.1]heptane-1-carboxylic acid, bicyclo[2.2.2]octane-1-carboxylic acid or mixtures thereof. Preferred are acetic acid, propionic acid, isononanoic acid, benzoic acid or any tertiary acid, or mixtures thereof.

[0139] Another type of pot life extender (E) that is particularly useful in the crosslinkable compositions of the present invention is a compound of the general formula R-SH, where R can be an alkyl, alkenyl, aryl or aralkyl group. The -SH group can be a primary, secondary or tertiary -SH group. R can be a linear, cyclic or branched group and can contain one or more other functional groups such as hydroxyl, primary amine, secondary amine or tertiary amine groups, silane or siloxane groups, ether groups, ester groups, carboxylic acid groups. Preferably R is a linear or branched alkyl group of the general formula -C n H2 n+1 where n is from 4 to 40, more preferably from 8 to 30. Examples are n-C 12 H 25 SH, n-C 16 H 33 SH, of the formula C 11 H 23 SH, C 12 H 25 SH and C 13 H 27Linear or branched molecules of SH and their mixtures, and (CH3)2(iPr)C-C(CH3)2-C(CH3)2SH. If R contains more than one other functional group, these functional groups can be different or the same. Hydroxyl or ester groups are particularly preferred as other functional groups. In the case where R contains an ester group, R preferably has the general formula -(CH2) n (C=O)O-R'. Here, n can be selected in the range of 1 - 20, preferably in the range of 1 - 10, and particularly preferably n is 1 or 2. R' can be any alkyl, alkenyl, aryl or aralkyl group, preferably containing 1 - 24 carbon atoms, such as butyl, 2-ethylhexyl, isooctyl, tridecyl, octadecyl. Particularly preferred is the chelating agent of the formula HS-(CH2) n (C=O)O-R', where n is 1 or 2, and where R' is an alkyl group containing 3 to 20 carbon atoms.

[0140] When selected from the R-SH type, the pot life extender (E) can contain multiple -SH groups. Preferred are compounds of the formula HS-(CH2) x -SH, where x = 1 - 20, compounds of the formula (HSCH2) 4-m C(CH2SCH2CH2SH) m where m = 1 - 4, and similar compounds, such as those described in patents EP 0665219 and EP 0435306. Particularly preferred other chelating agents (E) are SH-functional acids, especially esters of SH-functional carboxylic acids and polyols. It is not necessarily limited to synthesis by condensation reaction, and such products can be obtained by forming (poly)ester bonds between, for example, HS(CH2) n COOH (where n = 1 - 20) and polyols. Preferred are those reaction products of carboxylic acids of the formula HS(CH2) n COOH (where n is 1 - 20) with polyols having 2 or greater OH functionality. In this case, the polyol usually has 2 or greater OH functionality and can be monomeric, oligomeric or polymeric. Non-limiting examples of such polyols can be ethylene glycol, glycerol, trimethylolpropane, neopentyl glycol, pentaerythritol, dipentaerythritol, ethoxylated trimethylolpropane, tris(hydroxyethyl)isocyanurate, castor oil, OH-functional polyesters, OH-functional polyacrylates, polycaprolactones, OH-functional polycarbonates, polymers based on dithiolane monomers as described in patent US 6486298.

[0141] Mixtures of different types of pot life extenders (E) can be used, such as mixtures of carboxylic acids and compounds of the formula R-SH.

[0142] Preferably, the content of the pot life extender (E) in the composition is 0-10 wt%, more preferably 0.1-5 wt%, and most preferably 0.2-2 wt%, based on the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C) and optional catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G).

[0143] Optionally, the crosslinkable composition may further comprise a reactive diluent (F). Reactive diluents are typically monomers, oligomeric or polymeric compounds that are used to reduce the viscosity of the polyacrylate polyol (A1) and / or optional polyol (B), and that can react with the polyacrylate polyol (A1), polyol (B) and / or crosslinking agent (C). Preferably, the reactive diluent (F) is non-volatile and thus does not contribute to the total volatile organic compound content of the composition.

[0144] Preferably, the reactive diluent (F) has a number average molecular weight of 62-4000 daltons, more preferably 62-2000 daltons, most preferably 62-1000 daltons, a polydispersity Mw / Mn of 1-3, preferably 1-1.5, more preferably 1-1.3, even more preferably 1-1.25, and an average hydroxyl functionality of 1-6, preferably 1.5-4, more preferably 1.8-3.5.

[0145] Preferred reactive diluents are monomers, oligomeric or polymeric compounds containing one -OH group, or monomers, oligomeric or polymeric compounds containing 2 - 5 -OH groups, or mixtures thereof, which can react with the polyacrylate polyol (A1), polyol (B), and / or crosslinking agent (C), and which preferably react with the crosslinking agent (C) usually under the influence of a catalyst (D), and which are used to reduce the viscosity of the polyacrylate polyol (A1) and / or optionally the polyol (B). Preferred types of reactive diluents (F) are monohydric alcohols, diols or triols containing 1, 2 or 3 -OH groups respectively. Preferably, the reactive diluent (F) is of the type of diol or triol and is a liquid compound containing 2 - 40 carbon atoms, preferably 2 - 20 carbon atoms, more preferably 2 - 12 carbon atoms. Examples of such diol or triol reactive diluents (F) are ethylene glycol, diethylene glycol, triethylene glycol, 1,2 - propanediol, 1,3 - propanediol, 1,1 - dimethyl - 1,2 - ethanediol, dipropylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1,4 - butanediol, 1,5 - pentanediol, 2 - ethyl - 1,3 - propanediol, 2 - methyl - 1,3 - propanediol, 2 - methyl - 1,5 - pentanediol, 2 - ethyl - 1,4 - butanediol, 2 - ethyl - 1,3 - hexanediol, 2,4 - diethyloctane - 1,3 - diol, 1,3 - bis(hydroxymethyl)cyclohexane, 1,3 - cyclohexanediol, glycerol, poly-THF with a molar weight between 162 - 4500, preferably between 250 - 2000, poly-1,3 - propanediol (or polypropylene glycol) with a molar weight between 134 - 4000, or polyethylene glycol with a molar weight between 200 - 2000, or mixtures thereof. Also suitable are commercially available diols sold under the name CARBOWAX TM such as poly(ethylene glycol) and poly(propylene glycol) with an average molecular weight of about 300 - 700. In another preferred embodiment, the reactive diluent (F) can include oligomeric or polymeric polyols. Such reactive diluents (F) are well-known and are commercially available, for example, under the trade name 1406. The reactive diluent (F) can also include a mixture of an oligomeric or polymeric polyol and one or more of the above diols, triols and / or any liquid monohydric alcohol, preferably a mixture of an oligomeric or polymeric polyol and one or more of the above diols or triols.

[0146] Most preferred are those reactive diluents (F) of the diol type having a melting point above -60 °C, preferably above -50 °C and a boiling point above 200 °C, preferably above 220 °C and having 5 - 12 carbon atoms, preferably 6 - 10 carbon atoms.

[0147] Preferably, the content of the reactive diluent (F) in the crosslinkable composition is 0 - 20 wt%, more preferably 0 - 15 wt%, and most preferably 5 - 15 wt%, based on the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), and optional catalyst (D), pot life extender (E), reactive diluent (F), and / or anti-sagging agent (G).

[0148] The composition of the present invention may optionally contain one or more volatile organic compounds. Generally, these are compounds having a boiling point of 200 °C or lower at atmospheric pressure, and they are used to dilute the composition to a viscosity suitable for applying the composition. Thus, if desired, a viscosity suitable for applying the composition can be obtained by using the reactive diluent (F) or by using volatile organic compounds, or a mixture of the reactive diluent (F) and volatile organic compounds.

[0149] Preferably, the (uncolored) crosslinkable composition contains less than 460 g / l, more preferably less than 420 g / l, and most preferably less than 400 g / l of volatile organic compounds based on the total composition.

[0150] Examples of suitable volatile organic compounds are hydrocarbons such as toluene, xylene, 100, ketones, terpenes such as dipentene or turpentine, halogenated hydrocarbons such as dichloromethane, ethers such as ethylene glycol dimethyl ether, esters such as ethyl acetate, ethyl propionate, n-butyl acetate, or ether esters such as methoxypropyl acetate or ethoxyethyl propionate. In addition, mixtures of these compounds can be used.

[0151] If desired, one or more so-called "exempt solvents" can be included in the composition of the present invention. Exempt solvents refer to volatile organic compounds that do not participate in atmospheric photochemical reactions to form smog. It can be an organic solvent, but since it takes a long time to react with nitrogen oxides in sunlight, the U.S. Environmental Protection Agency considers its reactivity negligible. Examples of exempt solvents approved for paints and coatings include acetone, methyl acetate, p-chlorobenzotrifluoride (which can be commercially available under the name 100) and volatile methyl siloxanes. In addition, tert-butyl acetate is also considered an exempt solvent.

[0152] Preferably, the non-volatile content (referred to as the solids content) of the composition of the present invention at the application viscosity is higher than 54 wt%, more preferably higher than 56 wt%, even more preferably higher than 58 wt%, or most preferably higher than 60 wt% based on the total composition.

[0153] In the present application, the solids content of the (uncolored) composition refers to the amount of material produced after applying and curing (or crosslinking) the composition and after subsequent evaporation of volatile organic compounds. The solids content at the application viscosity can be calculated by the following equation, Equation (I):

[0154] Solids content [wt%] = {[(polyacrylate polyol (A1) + optional polyol (B) + crosslinking agent (C) + optional catalyst (D) + optional pot life extender (E) + optional reactive diluent (F) + optional anti-sag agent (G) + sum of the weights of the non-volatile parts of optional coating additives)] / [(total weight of the sprayable composition - weight of the pigment - weight of the filler)]} * 100

[0155] The crosslinkable compositions of the present invention can be used and applied with very small amounts of volatile components, preferably less than 15%, more preferably less than 10%, most preferably less than 5% or even no volatile components, relative to the total weight of the (uncolored) crosslinkable composition, especially when using one or more reactive diluents (F) as described above and / or in applications where a higher application viscosity is required.

[0156] Methods for determining the application viscosity (i.e., the viscosity suitable for applying the composition) are known to those skilled in the art. It is obvious to those skilled in the art to select a suitable method according to the required coating application.

[0157] In addition to the above components, other compounds may be present in the crosslinkable compositions of the present invention. Such compounds may be binders other than polyacrylate polyol (A1), polyol (B) and / or reactive diluent (F), and may contain reactive groups that can crosslink with the above polyacrylate polyol (A1), polyol (B), optional reactive diluent (F) and / or crosslinking agent (C). Examples of such other compounds are ketone resins and latent amino-functional compounds such as oxazolines, ketimines, aldimines and diimines. These and other compounds are known to those skilled in the art and are especially mentioned in US5214086.

[0158] The crosslinkable compositions of the present invention may also contain other ingredients, (coating) additives or auxiliaries commonly used in coating compositions, such as pigments, dyes, surfactants, pigment dispersion aids, leveling agents, wetting agents, anti-cratering agents, defoamers, matting agents, anti-sag agents, antioxidants, radical scavengers, heat stabilizers, light stabilizers, UV absorbers violet, radical inhibitors, scratch-resistant additives and fillers.

[0159] Preferably, the crosslinkable composition further comprises one or more anti-sag agents (G).

[0160] The anti-sagging agent (G) is a rheologically active compound that provides thixotropy to the crosslinkable composition. These anti-sagging agents (G) are well-known and are generally selected from clay anti-sagging agents, silica-based anti-sagging agents, microgel anti-sagging agents, amide-based anti-sagging agents, or anti-sagging agents based on polyurea products. If the crosslinkable composition of the present invention contains an anti-sagging agent (G), preferably, the crosslinkable composition contains an anti-sagging agent based on polyurea products (referred to as polyurea anti-sagging agent (G1) in this specification).

[0161] If present, the content of the anti-sagging agent (G) in the composition is preferably 0-10 wt%, more preferably 0.2-5 wt%, even more preferably 0.3-3 wt%, or most preferably 0.5-2.5 wt%, based on the total amount of polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), and optional catalyst (D), pot life extender (E), reactive diluent (F), and / or anti-sagging agent (G).

[0162] The polyurea anti-sagging agent (G1) is generally prepared by the reaction of a polyisocyanate, its isocyanurate, biuret, uretdione, or other condensation derivatives with at least one monoamine, or by the reaction of an effective monoisocyanate (including a diisocyanate that has been selectively reacted on one side) with a polyamine. The prefix "poly" for polyisocyanate and polyamine indicates that at least two of the above functional groups are present in the respective "poly" compounds. Note that when preparing the polyurea anti-sagging agent (G1) by the reaction of an amine with a polyisocyanate, it is preferred to prepare a biurea product or a triurea product.

[0163] The polyisocyanate is preferably selected from aliphatic, cycloaliphatic, aralkylidene, and aryl polyisocyanates, more preferably selected from substituted or unsubstituted linear aliphatic polyisocyanates (and their isocyanurates, biurets, uretdiones) and substituted or unsubstituted aralkylidene and cyclohexylene polyisocyanates. Optionally, the polyisocyanate may contain other functional groups, such as ether functional groups, ester functional groups, or urethane functional groups.

[0164] There are usually 2-40, preferably 4-12 carbon atoms between the NCO groups of the polyisocyanate. The polyisocyanate preferably contains at most four isocyanate groups, more preferably at most three isocyanate groups, and most preferably two isocyanate groups. Even more preferably, a symmetric aliphatic or cyclohexylene diisocyanate is used.

[0165] Suitable examples of the diisocyanates are preferably selected from butylene-1,4-diisocyanate, hexamethylene-1,6-diisocyanate (HMDI), trans-cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,5-dimethyl-(2,4-ω-diisocyanatomethyl)benzene, 1,5-dimethyl(2,4-ω-diisocyanatoethyl)benzene, 1,3,5-trimethyl(2,4-ω-diisocyanatomethyl)benzene, 1,3,5-triethyl(2,4-ω-diisocyanatomethyl)benzene, m-xylylene diisocyanate, p-xylylene diisocyanate, dicyclohexyl-dimethylmethane-4,4'-diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate and diphenylmethane-4,4'-diisocyanate (MDI).

[0166] Other suitable polyisocyanates are preferably selected from HMDI-based polyisocyanates, including condensation derivatives of HMDI, such as uretidione, biuret, isocyanurate (trimer) and asymmetric trimer, etc., many of which are N and HDB and HDT for sale. Particularly preferred polyisocyanates are selected from HMDI, its isocyanurate trimer, its biuret (or other condensation derivatives), trans-cyclohexylene-1,4-diisocyanate, p- and m-xylylene diisocyanate and toluene diisocyanate.

[0167] Most preferably, HMDI, its isocyanurate or other condensation derivatives are selected.

[0168] As will be understood by those skilled in the art, conventional blocked polyisocyanates that generate two or more isocyanates in situ can also be used, provided that the blocking agent does not prevent the formation of the rheology modifiers of the present invention after cleavage. In this document, the term "polyisocyanate" is used to name all polyisocyanates and compounds that generate polyisocyanates.

[0169] A preferred embodiment of the present invention, the amine for preparing the polyurea anti-sagging agent (G1) includes monoamines. Many monoamines can be used in combination with polyisocyanates to produce polyurea reaction products. Aliphatic amines and aromatic amines, as well as primary amines and secondary amines, can be used. According to the present invention, primary amines are preferably used, and n-alkylamines and ether-substituted n-alkylamines are particularly useful. Optionally, the amine can contain other functional groups, such as hydroxyl groups, ester groups, urethane groups. Preferred monoamines include n-aliphatic amines, especially n-alkylamines, such as hexylamine, cyclohexylamine, benzylamine, 3-methoxypropylamine, S-α-methylbenzylamine, and 2-phenylethylamine, and mixtures thereof. Particularly preferred polyurea anti-sagging agents (G1) are adducts of HMDI (condensation derivatives thereof) and benzylamine or S-α-methylbenzylamine or mixtures of benzylamine and S-α-methylbenzylamine, and adducts of HMDI (condensation derivatives thereof) and 3-methoxypropylamine. Using diamines (such as ethylenediamine) as a component second only to monoamines can also be an option for preparing high-melting-point polyureas. The monoamine or a part of the monoamine used for preparing the polyurea anti-sagging agent (G1) can be a chiral monoamine, and the polyurea anti-sagging agent described in US8207268 is considered to be a part of the present invention.

[0170] The polyurea formation reaction can be carried out in the presence of an inert solvent such as acetone, methyl isobutyl ketone, N-methylpyrrolidone, benzene, toluene, xylene, butyl acetate, aliphatic hydrocarbons such as petroleum ether, alcohols, water, or mixtures thereof, or in the presence of a binder for the final composition or any other coating formulation component. Here, the term "inert" means that the solvent does not significantly interfere with the polyurea formation process, which means that the amount of polyurea formed in the presence of the solvent is at least 80% of the amount produced in the absence of the solvent.

[0171] Obviously, if the binder present during the preparation of the polyurea anti-sagging agent (G1) has high reactivity with the amine or isocyanate, then this binder and this particular sensitive compound cannot be premixed. The term "high reactivity" herein means that more than 30% of the sensitive amine or isocyanate reacts with the binder before mixing the amine and isocyanate to prepare the polyurea anti-sagging agent (G1).

[0172] According to a preferred embodiment of the present invention, the polyurea sag resist agent (G1) is prepared in the presence of a polyacrylate polyol (A1), a polyol (B) and / or a reactive diluent (F). This can be accomplished by mixing a mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and an isocyanate with an amine component (i.e., by adding the amine component to the mixture of the polyol (A1), the polyol (B) and / or the reactive diluent (F) and the isocyanate), or by mixing an isocyanate with a mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and an amine component (i.e., by adding the isocyanate to the mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and the amine component), or by mixing a (one) mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and an amine component with a (one) mixture of the polyacrylate polyol (A1), the polyol (B) and / or or the reactive diluent (F) and an NCO-component (i.e., by adding the mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and the amine component to the mixture of the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F) and the NCO-component).

[0173] Also, a small amount of a co-reactive component can be deliberately used as a crystallization modifier in the preparation reaction of the polyurea sag resist agent (G1), more specifically, to change the crystal size upon precipitation or the colloidal stability of the resulting crystals. Similarly, a dispersant and other auxiliaries can be present in any of these introduction steps. The preparation of the polyurea sag resist agent (G1) can be carried out in any convenient manner, usually in a batch or continuous method with vigorous stirring of the reactants. The amine component can be added to the isocyanate, or the isocyanate can be added to the amine component, whichever is most convenient.

[0174] Alternatively, the polyurea sag resist agent (G1) can be formed in a separate reaction and mixed with the polyacrylate polyol (A1), usually with appropriate stirring, to form the polyol component (A) or the crosslinkable composition of the present invention.

[0175] The relative molar ratio of amine / isocyanate is usually between 0.9 and 1.1, preferably between 0.95 and 1.05.

[0176] As determined according to ISO 1524, the particle size of the polyurea sag resist agent (G1) is preferably less than 15 μm.

[0177] Scratch-resistant additives are usually additives used to improve important coating properties such as car wash resistance, scratch resistance, or abrasion resistance. These scratch-resistant additives are well-known and are usually selected from waxes, silicone-modified polyolefins, organic or inorganic polysiloxanes, silane-modified components such as silane-modified polyols, or silane-modified crosslinkers such as silane-modified melamine or isocyanates), or scratch-resistant agents based on nanoparticle technology. If the crosslinkable composition of the present invention contains a scratch-resistant additive, it is preferred that the crosslinkable composition contains a scratch-resistant agent based on nanoparticle technology, more preferably based on modified nanoparticles with an average diameter of 1-400 nanometers, and most preferably based on the nanoparticles described in EP2106424B1. A particularly preferred combination is polyacrylate polyol (A1), a pot life extender (E) of the R-SH type, and nanoparticles as described in EP2106424B1, optionally containing flow and leveling agents known to those skilled in the art.

[0178] The coating composition of the present invention preferably comprises:

[0179] - 10-90 wt%, preferably 20-80 wt%, more preferably 30-70 wt% of polyacrylate polyol (A1),

[0180] - Optionally, 0-90 wt%, preferably 10-80 wt%, more preferably 20-70 wt% of polyol (B),

[0181] - 10-90 wt%, preferably 20-80 wt%, more preferably 30-70 wt% of polyisocyanate crosslinker (C),

[0182] - Optionally, 0-10 wt%, preferably 0.001-5 wt%, more preferably 0.002-5 wt%, even more preferably 0.002-3 wt%, most preferably 0.005-1 wt% of catalyst (D),

[0183] - Optionally, 0-10 wt%, preferably 0.1-5 wt%, more preferably 0.2-2 wt% of pot life extender (E),

[0184] - Optionally, 0-20 wt%, preferably 0-15 wt%, more preferably 5-15 wt% of reactive diluent (F), and

[0185] - Optionally, 0-10 wt%, preferably 0.2-5 wt%, more preferably 0.3-3 wt%, or even more preferably 0.5-2.5 wt% of anti-sag agent (G), preferably polyurea anti-sag agent (G1),

[0186] Based on the total amount of polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C) and optional catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G).

[0187] The coating composition preferably comprises 50 - 100 wt% in total of polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C) and optional catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G), based on the total amount of the coating composition.

[0188] For one-component compositions, the crosslinkable composition can be suitably prepared by a method comprising mixing the polyol component (A) with optional polyol (B), crosslinking agent (C), optional catalyst (D), optional reactive diluent (F) and / or anti-sagging agent (G). Alternatively, for two-component compositions, the crosslinkable composition can be prepared by a method comprising mixing the polyol component (A) with optional polyol (B), optional catalyst (D), optional pot life extender (E), optional reactive diluent (F) and / or anti-sagging agent (G) to form a binder component and mixing the binder component with the crosslinking agent (C).

[0189] Generally, in the case where the crosslinking agent (C) is an isocyanate-functional crosslinking agent, for a crosslinkable composition comprising a hydroxyl-functional binder and an isocyanate-functional crosslinking agent, the composition of the present invention has a limited pot life. Thus, the composition can be suitably provided as a multi-component composition, for example as a two-component composition or as a three-component composition, where on the one hand the polyol component (A), optional polyol (B) and optional reactive diluent (F) and on the other hand the crosslinking agent (C) are parts of at least two different components.

[0190] Accordingly, the present invention also relates to a multi-part kit for preparing a crosslinkable composition, which comprises:

[0191] i. A binder module, which comprises:

[0192] - At least one polyacrylate polyol (A1) of the present invention, and

[0193] - Optionally: at least one solvent (A2), at least one additive (A3), at least one polyol (B), at least one catalyst (D), at least one pot life extender (E), at least one reactive diluent (F), and / or at least one anti-sagging agent (G); and

[0194] ii. A crosslinking agent module, which comprises at least one crosslinking agent (C).

[0195] Alternatively, the kit may comprise three components, including:

[0196] i. A binder module, comprising:

[0197] - At least one polyacrylate polyol (A1) of the present invention, and

[0198] - Optionally: at least one solvent (A2), at least one additive (A3) and / or at least one polyol (B); and

[0199] ii. A crosslinker module, comprising at least one crosslinker (C), and

[0200] iii. A diluent module, comprising a volatile organic diluent,

[0201] wherein, optionally, at least one catalyst (D), at least one pot life extender (E), at least one reactive diluent (F) and / or at least one anti-sag agent (G) may be distributed on module i), ii) or iii), and wherein at least one module optionally contains a catalyst (D).

[0202] In the case where the crosslinker (C) does not readily react with the polyacrylate polyol (A1) and / or polyol (B) and / or reactive diluent (F) at the storage temperature, for example when the crosslinker (C) comprises a melamine-formaldehyde resin and / or a blocked isocyanate group, all components (A) to (G) may be supplied in part.

[0203] As long as the modules exhibit the required storage stability, the other components in the crosslinkable composition may be distributed on the modules in different ways as described above. The components in the crosslinkable composition that react with each other during storage are preferably not combined in one module. If necessary, the components in the coating composition may be distributed on more modules, such as 4 or 5 modules.

[0204] The crosslinkable composition of the present invention provides a coating with improved leveling and appearance, exhibits excellent anti-sag properties, and provides other related coating properties with good balance, such as hardness, chemical resistance, flexibility and durability. The composition is very suitable for formulation in the case of extremely low volatile organic compound content and no highly toxic substances.

[0205] The crosslinkable composition of the present invention can be applied to any substrate. The substrate can be, for example, metal (such as iron, steel, tinplate and aluminum), plastic, wood, glass, synthetic material, paper, leather, concrete or other coatings. Other coatings can be composed of the coating composition of the present invention or can be different coating combinations. The coating composition of the present invention can be particularly used as varnish, primer, colored topcoat, primer and filler.

[0206] The crosslinkable composition of the present invention is very suitable for use as a varnish. The varnish is substantially free of pigments and is transparent to visible light. However, the varnish composition may contain a matting agent, such as a silica-based matting agent, to control the gloss of the coating.

[0207] When the crosslinkable composition of the present invention is a varnish, it is preferably applied over a basecoat that imparts color and / or effect. In this case, the varnish forms the top layer of a multi-layer paint coating, such as a coating typically applied to the exterior of a motor vehicle. The basecoat can be an aqueous basecoat or a solvent-based basecoat. The crosslinkable composition of the present invention is also suitable as a colored topcoat for coating objects such as bridges, pipelines, industrial plants or buildings, oil and gas installations or ships. The composition is particularly suitable for the refinishing and repair of motor vehicles and large transport vehicles such as trains, trucks, buses and aircraft. In general, the crosslinkable composition of the present invention can be applied by spraying, brushing, spreading, overspray-free application based on jet streams or drop-on-demand techniques, or any other method of transferring the composition onto a substrate.

[0208] Accordingly, the present invention also relates to a method of providing a coating, preferably providing the coating onto at least a part of a substrate (e.g., at least a part of the outer surface of a transport vehicle), wherein the method comprises applying the coating composition of the present invention onto at least a part of the substrate (e.g., applying it onto at least a part of the outer surface of a transport vehicle), and preferably curing the applied coating composition at a temperature of 5 - 180 °C. Those skilled in the art will know that the curing temperature depends on the type of crosslinking agent (C) used, and for certain applications known to those skilled in the art, curing can be carried out, for example, at 5 - 70 °C, more preferably at 10 - 65 °C, or even more preferably at 15 - 45 °C, or, for other applications known to those skilled in the art, at 80 - 180 °C, more preferably at 100 - 160 °C, or more preferably at about 140 °C (depending on the crosslinking agent (C) used). It is obvious to those skilled in the art to select a suitable curing temperature according to the crosslinking agent (C) used and the desired coating application.

[0209] An important trend in the art on the market (especially for OEM varnishes) is the desire to bake these varnishes using methods that require less thermal energy. The typical baking temperatures for methods known in the art that require less thermal energy are generally in the range of 70 - 110 °C, preferably 80 - 100 °C, while for traditional baking methods used in the art for OEM varnishes, the baking temperature is most preferably at about 140 °C. It is well known that baking OEM clear coats using such methods known in the art that require less thermal energy results in deterioration of the chemical resistance of the coating and a reduction in hardness, especially when the solids content of the formulation is high. However, the present applicant has now found that the present invention is particularly suitable (for) methods that require less thermal energy. Accordingly, the present invention provides a method:

[0210] 1) Apply the crosslinkable composition of the present invention to a substrate (such as the outer surface of a vehicle), the crosslinkable composition comprising:

[0211] - a polyacrylate polyol (A1),

[0212] - optionally, at least one polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups,

[0213] - at least one polyisocyanate crosslinker (C) preferably containing free isocyanate groups, and

[0214] - optionally, at least one catalyst (D) for catalyzing the reaction between the hydroxyl groups in the polyacrylate polyol (A1), the optional polyol (B), the optional reactive diluent (F) and the isocyanate groups of the crosslinker (C), the amount of the catalyst (D) present being 0 - 10 wt%, preferably 0 - 3 wt% of the total amount of the polyacrylate polyol (A1), the optional polyol (B), the crosslinker (C), the optional catalyst (D) and the optional pot life extender (E), the reactive diluent (F) and / or the anti-sag agent (G);

[0215] - optionally one or more pot life extenders (E),

[0216] - optionally, at least one reactive diluent (F),

[0217] - optionally, at least one anti-sag agent (G), preferably a polyurea anti-sag agent (G1), the at least one anti-sag agent (G) being preferably present in the polyacrylate polyol (A1), the polyol (B) and / or the reactive diluent (F), and

[0218] 2) Cure the applied crosslinkable composition at a temperature of 70 - 110 °C, preferably 80 - 100 °C.

[0219] Preferably, the step of curing the applied crosslinkable composition is carried out within a time interval of 15 minutes to 1 hour, preferably 20 - 40 minutes, more preferably about 30 minutes.

[0220] Another important trend in the art in the market, especially for OEM varnishes, is the desire to reduce the number of coating layers and the number of baking and curing steps. In fact, compared to the standard application methods known in the art, where a primer layer is typically applied over an electrodeposited coating, followed by a first baking and curing step, and subsequent steps of applying an aqueous basecoat, flash drying, applying a varnish layer, and performing a second baking and curing, methods and processes with reduced baking and curing steps are more economical in terms of paint volume and energy consumption. Baking and curing in these standard methods known in the art, which include at least two baking and curing steps, is typically carried out at a temperature of at least 80 °C, preferably at least 120 °C, most preferably at about 140 °C. The baking and curing steps are typically carried out over a time interval of 15 minutes to 1 hour. Compared to the standard processes known in the art, methods with reduced baking and curing steps are typically characterized by eliminating the step of applying a primer layer and the step of performing the first baking and curing.

[0221] Now, it has surprisingly been found that the coating compositions of the present invention are particularly suitable for use in crosslinkable varnish compositions for methods and processes with a reduced number of baking and curing steps compared to such standard processes as described above. Accordingly, the present invention also provides a method of providing a coating to at least a portion (preferably at least a portion of the outer surface of a transport vehicle) of a substrate, the method comprising the steps of applying a first aqueous color coat over a metallic substrate (metal layer) or an electrodeposited layer (the electrodeposited layer being applied over the metallic substrate), then flash drying, applying an aqueous basecoat, flash drying again, then applying a varnish layer comprising the coating composition of the present invention, and subsequently performing (only) one baking and curing step on all the layers simultaneously (together). The flash drying time is short, more particularly the flash drying is carried out for less than 1 hour, preferably less than 30 minutes, more preferably the flash drying is carried out for 5 - 20 minutes, most preferably 5 - 10 minutes, and at a low temperature, preferably at a temperature below 90 °C, more preferably at 80 °C. The single baking and curing is carried out at a temperature of 125 - 180 °C, preferably 125 - 160 °C, more preferably 130 - 150 °C, even more preferably 130 - 145 °C, most preferably 135 - 145 °C. The baking and curing step is carried out over a time interval of 15 minutes to 1 hour, preferably 20 - 40 minutes, more preferably about 30 minutes.

[0222] In the present invention, it has surprisingly been found that the polyacrylate polyol (A1) of the present invention is particularly suitable for formulating crosslinkable compositions, preferably varnish compositions, when combined with a polyol (B), a crosslinking agent (C) and an optional catalyst (D), a pot life extender (E), a reactive diluent (F) and / or an anti-sagging agent (G). When such crosslinkable compositions are used in the above-described process with a reduced number of baking and curing steps, the coatings obtained have a good appearance, excellent anti-sagging properties and very good chemical resistance. Furthermore, it has particularly surprisingly been found that when the polyacrylate polyol (A1) is combined with a polyol (B), a crosslinking agent (C) preferably of the melamine-formaldehyde resin type, a catalyst (D) preferably of the blocked sulfonic acid type, a reactive diluent (F) and a polyurea anti-sagging agent (G1), the coatings obtained have a good appearance, excellent anti-sagging properties, very good chemical resistance and low VOCs.

[0223] The present invention also relates to coatings and coated substrates obtained by using the compositions of the present invention or by the process of the present invention as described above. Such coatings combine a very good appearance with other properties such as hardness, chemical resistance, flexibility and durability, making them particularly suitable for automotive applications. Examples

[0224] In the examples, the glass transition temperature Tg was determined using a Mettler DSC 3+ calorimeter in accordance with DIN EN ISO 16805 and ISO 11357. More specifically, first, 7 - 15 mg of the sample was heated above Tg at 120 °C. This temperature was maintained for 5 minutes, then the temperature was lowered to -20 °C at a cooling rate of 30 °C / min. The sample was then cooled at -20 °C for 5 minutes, and subsequently the sample was heated to 120 °C at a heating rate of 10 °C / min. Tg is the temperature at the intersection of the tangent to the baseline and the tangent to the maximum negative slope in the graph of heat flow versus temperature.

[0225] The molecular weight and molecular weight distribution are determined by gel permeation chromatography according to ASTM D 3593 using polystyrene standards, more particularly by size exclusion chromatography. The size exclusion apparatus used is an Alliance system consisting of a pump, an autosampler and a helium degasser (Degasys DG-1210 from Uniflows), equipped with a PLgel 5μm MIXED-C 600x 7.5mm chromatographic column and a Plgel 5μm guard column (50x 7.5mm - Polymer Laboratories). The column oven (Separations Analytical Instruments) is set at 30°C. Tetrahydrofuran (THF - Extra Dry, Biosolve 206347) + 2% acetic acid (Baker 6052) is used as the eluent at a flow rate of 0.8 ml / min. Carbon disulfide (Backer) is used as the marker. A Waters 410 refractive index is used as the detector. The injection volume is 100 μl and the concentration is 1.5 mg / ml. Polystyrene standards (Polymer Laboratories, Easical PS-1, 2010-0501 (M is 580 - 8500000 g / mol) and Easical PS-2, 2010-0601 (M is 580 - 400000 g / mol)) are used for calibration using a third-order polynomial. The software used for data analysis is Empower (Waters). In the graph of the elution weight fraction against the molecular weight thus obtained, Mn is the molecular weight at which 50% of the molecules have been eluted, and Mw is the molecular weight at which 50% of the total mass has been eluted.

[0226] Example 1

[0227] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 0.3 parts of acrylic acid, 35.1 parts of hydroxyethyl methacrylate, 7.5 parts of butyl acrylate, 22.5 parts of butyl methacrylate, 21.1 parts of norbornenyl acrylate, 1.1 parts of methyl methacrylate and 12.3 parts of styrene. It has a hydroxyl value of 145 mg KOH / g (based on non-volatile content), an acid value of 6.0 mg KOH / g (based on non-volatile content), Mw of 1735 Dalton and Mn of 943 Dalton (GPC, polystyrene standard) and Tg of 15 °C. After polymerization is completed, 42.5 parts of a polyester resin are added, which has an Mw of 2189 Dalton and an Mn of 1146 Dalton (GPC, polystyrene standard), a Tg of -11 °C, a hydroxyl value of 172 mg KOH / g, and an acid value of 8 mg KOH / g. The (meth)acrylic polyol-polyester polyol mixture is dissolved in butyl acetate to obtain a solution with a non-volatile content of 78 wt%. When diluted with butyl acetate to a non-volatile content of 70 wt%, the viscosity at 100 s -1 is 310 mPa·s according to ASTM D4287.

[0228] Comparative Example 2

[0229] The (meth)acrylic polyol is prepared by polymerization of a mixture of 0.3 parts of acrylic acid, 30.2 parts of hydroxyethyl methacrylate, 7.5 parts of butyl acrylate, 24.8 parts of butyl methacrylate and 36.1 parts of styrene. It has a hydroxyl value of 132 mg KOH / g (based on non-volatile content), an acid value of 2.4 mg KOH / g (based on non-volatile content), Mw of 2867 and Mn of 1303 (GPC, polystyrene standard) and Tg of -4 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 78 wt%.

[0230] Example 3

[0231] In a 5-liter glass container equipped with a temperature jacket and a stirrer, the resin from Example 1 is charged and heated to 30 °C. Then benzylamine is added to the reaction vessel, and the mixture is homogenized for 10 - 15 minutes, followed by cooling with ice water. The stirrer speed is increased to 750 rpm, and hexamethylene diisocyanate diluted with butyl acetate is added. The reaction mixture is stirred for 30 minutes and further diluted with butyl acetate to a solid content of 73.5%. The resulting resin contains 7.5 wt% of a polyurea anti-sagging agent and 66.0 wt% of a polyacrylate polyol. It is found that the particle size of the polyurea anti-sagging agent measured by the ISO 1524 method is less than 15 μm.

[0232] Comparative Example 4

[0233] Example 3 was repeated, except that the resin of Comparative Example 2 was used instead of the resin of Example 1. The resulting resin had a solids content of 67.1%, contained 7.1 wt% of a polyurea sag control agent and 60.0 wt% of a polyacrylate polyol. It was found that the particle size of the polyurea sag control agent measured using the ISO 1524 method was less than 15 μm.

[0234] Table 1

[0235]

[0236] 1406 is a microbranched polyester polyol.

[0237] 327 resin is a methylated high imino melamine crosslinking agent provided in isobutanol.

[0238] NF 2000A resin is a unique trifunctional melamine-based crosslinking agent containing reactive urethane functional groups provided in n-butanol.

[0239] 600 is a strong acid catalyst based on dodecylbenzenesulfonic acid provided in isopropanol.

[0240] 315N is a solution of polyester-modified polymethylalkylsiloxane in 2-phenoxyethanol and 2-methoxy-1-methylethyl acetate.

[0241] 310 is a silicone-containing surface additive.

[0242] Paints were prepared according to the data in Table 1, subsequently diluted with butyl acetate, and at different addition amounts, the solids content was calculated according to Equation (I), and the viscosity at 1000 s -1 was measured. The results are as Figure 1 shown, showing the relationship between the viscosity and the calculated solids content of the paints in Example 5 (triangles) and Comparative Example 6 (circles). It can be clearly seen from these results that at the same solids content, the viscosity of the paint in Example 5 is much lower than that of Comparative Example 6.

[0243] Subsequently, the paint was diluted to 105 mPa·s (1000 s -1 ). The solids content was calculated according to Equation (I), and was also determined by diluting 1 g of the paint with 3 ml of butyl acetate to 105 mPa·s (1000 s -1 ), mixing and heating at 140 °C for 0.5 h. Subsequently, the weight of the residue was measured and correlated with the starting weight of the diluted paint.

[0244] These formulations were then used in a process with a reduced number of baking curing steps: Commercial waterborne base 1 was sprayed, and after a 3-minute flash at room temperature, black commercial base 2 was applied wet-on-wet. After a 7-minute flash at room temperature, the system was heated to 80°C for 10 minutes. Subsequently, the clearcoat formulation was applied, followed by a 5-minute flash at room temperature, and the entire system was then cured at 140°C for 24 minutes. Appearance properties such as Wb, Wd, DOI, long wave and short wave were determined using a Byk Wavescan Dual.

[0245] The sag limit is determined by spraying the crosslinkable composition onto 5 tinplate panels of 47 x 30 cm. At half the length, the test panel contains 13 holes with a diameter of 1 cm and a distance of 2.5 cm between the holes. The crosslinkable formulation is sprayed onto this test panel with increasing layer thickness from left to right. After the coating has cured, the length of each tear below the hole and the layer thickness above each hole are determined. The sag resistance is determined as the layer thickness (μm) at which the (interpolated) tear length is 5 mm.

[0246] Xylene resistance was determined by placing a cotton wool ball soaked in xylene on the dried coating for 5 minutes. The cotton wool ball was then removed and the coating was wiped with a clean cloth. Protrusions and softening of the coating were visually determined by scraping the exposed portion with a scraper. Both protrusions and softening were rated on a scale of 1 (good) to 5 (poor).

[0247] The results are shown in Table 2.

[0248] Table 2

[0249]

[0250] The data in Table 2 show that, most importantly, the paint of Example 5 has a higher solid content at the same viscosity compared to Comparative Example 6. In particular, the measured solid content of the paint of Comparative Example 6 is too low to obtain a VOC-compliant paint (i.e., VOC compliance means a VOC content below 420 g / l), while the paint of Example 5 is VOC-compliant. In addition, the coating obtained from Example 5 has a better appearance, as observed from the lower values measured for Wb, Wd, long wave, short wave and the higher value for DOI. In addition, similarly better xylene resistance was measured for the coating obtained with the paint from Example 5. In summary, the paint of Example 5 shows improved performance and has a higher solid content than the paint in Comparative Example 6.

[0251] Example 7

[0252] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 0.3 parts of acrylic acid, 35.1 parts of 2-hydroxyethyl methacrylate, 6.9 parts of butyl acrylate, 23.2 parts of butyl methacrylate, 21.1 parts of norbornene acrylate, 1.1 parts of methyl methacrylate and 12.3 parts of styrene. It has a hydroxyl value of 135 mg KOH / g (based on non-volatile content), an acid value of 0 mg KOH / g (based on non-volatile content), Mw of 1846 and Mn of 1155 (GPC, polystyrene standard) and Tg of 17 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 78 wt%. When diluted with butyl acetate to a non-volatile content of 70 wt%, the viscosity at 100 s -1 is 290 mPa·s according to ASTM D 4287.

[0253] Example 8

[0254] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 31.0 parts of 2-hydroxyethyl methacrylate, 17.7 parts of butyl acrylate, 10.8 parts of isobutyl methacrylate, 20.0 parts of isobornyl acrylate and 20.5 parts of styrene. It has a hydroxyl value of 133 mg KOH / g (based on non-volatile content), an acid value of 2.0 mg KOH / g (based on non-volatile content), Mw of 2797 and Mn of 1592 (GPC, polystyrene standard) and Tg of 12 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 74 wt%.

[0255] Example 9

[0256] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 31.0 parts of 2-hydroxyethyl methacrylate, 17.7 parts of butyl acrylate, 10.8 parts of isobutyl methacrylate, 20.0 parts of 3,3,3-trimethylbicyclo[2.2.1]heptyl acrylate and 20.5 parts of styrene. It has a hydroxyl value of 133 mg KOH / g (based on non-volatile content), an acid value of 1.9 mg KOH / g (based on non-volatile content), Mw of 2751 and Mn of 1574 (GPC, polystyrene standard) and Tg of 13 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 74 wt%.

[0257] Example 10

[0258] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 30.6 parts of 2-hydroxyethyl methacrylate, 17.5 parts of butyl acrylate, 10.7 parts of isobutyl methacrylate, 20.9 parts of (octahydro-4,7-methano-1H-indenyl)methyl methacrylate and 20.3 parts of styrene. It has a hydroxyl value of 132 mg KOH / g (based on non-volatile content), an acid value of 2.2 mg KOH / g (based on non-volatile content), Mw of 2681 and Mn of 1496 (GPC, polystyrene standard) and a Tg of 14 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 74 wt%.

[0259] Example 11

[0260] The (meth)acrylic polyol of the present invention is prepared by polymerization of a mixture of 29.8 parts of 2-hydroxyethyl methacrylate, 17.0 parts of butyl acrylate, 10.4 parts of isobutyl methacrylate, 23.1 parts of octahydro-4,7-methano-1H-indenemethanol monoacrylate and 19.7 parts of styrene. It has a hydroxyl value of 128 mg KOH / g (based on non-volatile content), an acid value of 2.0 mg KOH / g (based on non-volatile content), Mw of 2723 and Mn of 1574 (GPC, polystyrene standard) and a Tg of 13 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 74 wt%.

[0261] Comparative Example 12

[0262] The (meth)acrylic polyol is prepared by polymerization of a mixture of 0.3 part of acrylic acid, 35.1 parts of 2-hydroxyethyl methacrylate, 1.2 parts of methyl methacrylate, 7.5 parts of butyl acrylate, 22.5 parts of butyl methacrylate and 33.5 parts of styrene. It has a hydroxyl value of 153 mg KOH / g (based on non-volatile content), an acid value of 2.2 mg KOH / g (based on non-volatile content), Mw of 2123, Mn of 1285 (GPC, polystyrene standard) and a Tg of 1 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 78 wt%. When diluted to a non-volatile content of 70 wt% with butyl acetate, the viscosity at 100 s according to ASTM D 4287 -1 is 420 mPa·s.

[0263] Comparative Example 13

[0264] Resin A of US20190106527 is prepared, with Mn of 1650, Mw of 3100 and Tg of 31 °C. When diluted to a non-volatile content of 70 wt% with butyl acetate, at 100 s according to ASTM D4287 -1The viscosity under [condition] is 2200 mPa.s.

[0265] Table 3

[0266]

[0267] In Table 3:

[0268] 91796SS-69 is a thermosetting hydroxylated acrylic resin, modified with an anti-sagging agent

[0269] US-138BB-70 is a non-plasticized melamine resin solution with extremely high reactivity

[0270] 5414 is a polymeric blocked sulfonate catalyst

[0271] 384-2 is a hydroxy phenyl benzotriazole liquid UV absorber

[0272] TINUVIN 123 is a liquid HALS stabilizer based on amino ether functional groups.

[0273] Solvesso 100 and Solvesso 150 are mixtures of aromatic solvents.

[0274] Prepare the paint according to Table 3, calculate the solid content, and measure the DinCup 4 viscosity.

[0275] The results are shown in Table 4.

[0276] Table 4

[0277]

[0278]

[0279] The data in Table 4 clearly show that at this high solid content, the paints obtained from Examples 14 - 18 are at spraying viscosity and do not require further dilution. However, the paints obtained from Comparative Examples 19 - 21 are too viscous and need to be further diluted to reach spraying viscosity. But if this is done, the VOC will become too high (i.e., higher than 420 g / l), so these paints were not further studied.

[0280] Spray the paints of Examples 14 - 18 on tinplate pre-coated with a black solvent-based primer, and then cure at 140 °C for 30 minutes. It was found that both the hardness and appearance were very good, and the gloss was excellent.

[0281] Comparative Example 22

[0282] (Meth)acrylic polyol is prepared by polymerization of a mixture of 0.7 parts of acrylic acid, 26.1 parts of hydroxyethyl methacrylate, 8.0 parts of hydroxyethyl acrylate, 4.6 parts of butyl acrylate, 30.6 parts of isobutyl methacrylate and 30 parts of styrene. It has a hydroxyl value of 150 mg KOH / g (non-volatile content), an acid value of 9 mg KOH / g (non-volatile content), Mw of 3790, Mn of 1800 (GPC, polystyrene standard) and Tg of 10 °C. The (meth)acrylic polyol is dissolved in butyl acetate to obtain a solution with a non-volatile content of 75 wt%.

[0283] Comparative Example 23

[0284] (Meth)acrylic polyol is prepared by polymerization of a mixture of 0.75 parts of acrylic acid, 15 parts of hydroxyethyl methacrylate, 30 parts of butyl acrylate, 14.25 parts of butyl methacrylate and 40 parts of styrene. It has a hydroxyl value of 65 mg KOH / g (based on non-volatile content), an acid value of 5.8 mg KOH / g (based on non-volatile content), Mw of 8759, Mn of 2241 (GPC, polystyrene standard) and Tg of 13 °C. The (meth)acrylic polyol is dissolved in a mixture of butyl acetate and xylene to obtain a solution with a non-volatile content of 80 wt%.

[0285] Table 5

[0286]

[0287]

[0288] The solvent mixture is a mixture of 58.8 parts of xylene, 39.2 parts of methoxypropyl acetate and 2 parts of 2-ethyl-1,3-hexanediol.

[0289] Ti-PURE TM R-706 is a rutile type titanium dioxide pigment.

[0290] 6577 is a wetting and dispersing agent for solvent-containing systems.

[0291] VXL 4930 is a modified silicone used to improve the leveling and surface smoothness of solvent-based paints and water-based paints.

[0292] DBTDL is dibutyltin dilaurate.

[0293] 292 is a liquid hindered amine light stabilizer developed specifically for coatings.

[0294] 1130 is a liquid ultraviolet absorber of the hydroxyphenyl benzotriazole type.

[0295] TOLONATE TM HDT-90 is an aliphatic polyisocyanate, based on HDI-trimer (isocyanurate), supplied at 90% solids content in a mixture of butyl acetate / high flash aromatic solvent (1:1 weight).

[0296] Prepare the paint according to Table 5, dilute the paint with butyl acetate to 20 s DinCup 4, and calculate the solids content. The results are shown in Table 6.

[0297] Table 6

[0298]

[0299] The data in Table 6 clearly show that the solids content of the coatings obtained from Examples 24 - 25 is much higher compared to the solids content of the paints obtained from Comparative Examples 26 - 27. In addition, it was observed that the xylene resistance of the coatings obtained from Examples 24 - 25 is much better than that of the coating obtained from Comparative Example 27. Moreover, particularly surprisingly, the gloss of Examples 24 - 25 is significantly higher than that obtained in Comparative Example 26. In summary, the paints of Examples 24 - 25 of the present invention are better balanced and, importantly, meet more stringent VOC regulations.

[0300] Prepare the paint according to Table 7. Spray the paint according to ASTM G 53 and then expose it to UV-B light. Measure the gloss regularly. The data in Table 8 show that Example 28 of the present invention shows better resistance to UV-B light compared to Comparative Example 29 which is not of the present invention.

[0301] Table 7

[0302]

[0303] Table 8: Gloss (20°) development during UV exposure

[0304]

[0305]

Claims

1. A polyol component (A) comprising 35 - 100 wt% of at least one polyacrylate polyol (A1), based on the total weight of the polyol component (A), wherein the polyacrylate polyol (A1) is obtained from: 10 - 60 wt% of a hydroxyalkyl (meth)acrylate monomer (a1), wherein the hydroxylated alkyl contains 1 - 20 carbon atoms; 10 - 60 wt% of a linear or branched alkyl (meth)acrylate monomer (a2), wherein the alkyl contains 1 - 20 carbon atoms; 10 - 60 wt% of a vinyl monomer (a3); 5 - 50 wt% of an alicyclic (meth)acrylate monomer (a4); and Optionally, 0 - 5 wt% of (meth)acrylic acid (a5); Based on the sum of (a1), (a2), (a3), and (a4) and optionally present (a5); Wherein the polyacrylate polyol (A1) has a number average molecular weight Mn of 500 - 2000 daltons, a weight average molecular weight Mw of 1000 - 2900 daltons, and an acid value of less than 10 mg KOH / g of the polyacrylate polyol (A1), wherein the weight average molecular weight Mw and the number average molecular weight Mn are determined by gel permeation chromatography using polystyrene standards according to ASTM D 3593 standard.

2. The polyol component according to claim 1, wherein the polyacrylate polyol (A1) is a random copolymer containing on average at least 2 free hydroxyl groups.

3. The polyol component according to claim 1 or 2, wherein the hydroxyalkyl (meth)acrylate monomer (a1) used to obtain the polyacrylate polyol (A1) is hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, or a mixture thereof.

4. The polyol component according to claim 1 or 2, wherein the alicyclic (meth)acrylate monomer (a4) is isobornyl (meth)acrylate, norbornyl (meth)acrylate, 2,6,6 - trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3 - trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro - 4,7 - methano - 1H - indenyl)methyl (meth)acrylate, octahydro - 4,7 - methano - 1H - indenedimethanol and esters of isomers of (meth)acrylic acid, cyclohexyl (meth)acrylate, or a mixture thereof.

5. The polyol component according to claim 1 or 2, wherein the polyacrylate polyol (A1) has a polydispersity of less than 4 and a glass transition temperature of higher than - 15 °C, and contains 5 - 50 wt% of the alicyclic (meth)acrylate monomer (a4), based on the sum of (a1), (a2), (a3), and (a4) and optionally present (a5).

6. The polyol component according to claim 5, wherein the alicyclic (meth)acrylate monomer (a4) is 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, norbornenyl (meth)acrylate, or a mixture thereof.

7. The polyol component according to claim 1 or 2, wherein the polyacrylate polyol (A1) has an Mn of 500 - 1600 daltons, a polydispersity of less than 4, and a glass transition temperature of higher than -15 °C, and contains 5 - 50 wt% of the alicyclic (meth)acrylate monomer (a4), based on the sum of (a1), (a2), (a3), and (a4) and optionally present (a5).

8. The polyol component according to claim 7, wherein the hydroxyalkyl (meth)acrylate monomer (a1) is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or a mixture thereof, and wherein the alicyclic (meth)acrylate monomer (a4) is isobornyl (meth)acrylate, 2,6,6-trimethylbicyclo[3.1.1]heptyl (meth)acrylate, 1,3,3-trimethylbicyclo[2.2.1]heptyl (meth)acrylate, (octahydro-4,7-methano-1H-indenyl)methyl (meth)acrylate, esters of octahydro-4,7-methano-1H-indenedimethanol and isomers of (meth)acrylic acid, cyclohexyl (meth)acrylate, or a mixture thereof.

9. The polyol component according to claim 8, wherein the alicyclic (meth)acrylate monomer (a4) is isobornyl (meth)acrylate.

10. The polyol component according to claim 1 or 2, comprising: 35 - 100 wt% of a polyacrylate polyol (A1), 0 - 50 wt% of a solvent (A2), 0 - 10 wt% of an additive (A3) selected from the group consisting of surfactants, leveling agents, wetting agents, anti-cratering agents, defoaming agents, heat stabilizers, light stabilizers, UV absorbers, and antioxidants, 0 - 40 wt% of at least one polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups, 0 - 5 wt% of a pot life extender (E), 0 - 20 wt% of a reactive diluent (F), and / or 0 - 15 wt% of an anti-sagging agent (G), relative to the total weight of the polyol component (A), wherein the sum of the components in the polyol component (A) is 100%.

11. The polyol component according to claim 10, comprising: 35 - 100 wt% of a polyacrylate polyol (A1), and 10 - 40 wt% of a solvent (A2), and / or 0 - 10 wt% of an additive (A3) selected from the following: surfactants, leveling agents, wetting agents, anti-cratering agents, defoamers, heat stabilizers, light stabilizers, UV absorbers, and antioxidants, 0 - 40 wt% of a polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups, 0 - 5 wt% of a pot life extender (E), 0 - 20 wt% of a reactive diluent (F), 0 - 15 wt% of an anti-sag agent (G), relative to the total weight of the polyol component (A), wherein the sum of the components in the polyol component (A) is 100%.

12. The polyol component according to claim 10, comprising: 40 - 90 wt% of a polyacrylate polyol (A1), and 15 - 30 wt% of a solvent (A2), and / or 0.1 - 7 wt% of an additive (A3) selected from the following: surfactants, leveling agents, wetting agents, anti-cratering agents, defoamers, heat stabilizers, light stabilizers, UV absorbers, and antioxidants, 5 - 25 wt% of a polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups, 0.1 - 2 wt% of a pot life extender (E), 1 - 10 wt% of a reactive diluent (F), 1 - 8 wt% of an anti-sag agent (G), relative to the total weight of the polyol component (A), wherein the sum of the components in the polyol component (A) is 100%.

13. A crosslinkable composition, comprising: a) the polyol component (A) according to any one of claims 1 - 12; b) optionally, at least one polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups; c) at least one crosslinking agent (C) comprising functional groups capable of reacting with the polyacrylate polyol (A1), the optional polyol (B), and / or the optional reactive diluent (F); and d) optionally, at least one catalyst (D) for catalyzing the reaction between the hydroxyl groups in the polyacrylate polyol (A1), the optional polyol (B), the optional reactive diluent (F) and the functional groups in the crosslinking agent (C), the amount of the catalyst (D) being 0 - 10 wt% of the total amount of the polyacrylate polyol (A1), the optional polyol (B), the crosslinking agent (C), the optional catalyst (D), and the optional pot life extender (E), reactive diluent (F), and / or anti-sag agent (G); e) optionally, at least one pot life extender (E); f) optionally, at least one reactive diluent (F) having a number average molecular weight Mn of 62 - 4000 daltons, a polydispersity Mw / Mn of 1 - 3, and an average hydroxyl functionality of 1 - 6, wherein the weight average molecular weight Mw and the number average molecular weight Mn are determined by gel permeation chromatography using polystyrene standards according to ASTM D3593 standard; g) optionally, at least one anti-sag agent (G).

14. The crosslinkable composition according to claim 13, wherein the content of the polyacrylate polyol (A1) is 10-90 wt% based on the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), optional catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G).

15. The crosslinkable composition according to claim 13 or 14, wherein a polyol (B) is present and is selected from polyester polyols, polyacrylate polyols and mixtures or hybrids thereof.

16. The crosslinkable composition according to claim 13 or 14, wherein the at least one crosslinking agent (C) is selected from isocyanates, blocked isocyanates, amino resins, and mixtures of amino resins and isocyanates.

17. The crosslinkable composition according to claim 13 or 14, wherein a reactive diluent (F) is present and is a monofunctional alcohol, diol or triol, and the reactive diluent (F) is a liquid compound containing 2-40 carbon atoms.

18. The crosslinkable composition according to claim 13 or 14, wherein a reactive diluent (F) is present and is of the glycol type having a melting point above -60 o °C, a boiling point above 200 o °C and 5 to 12 carbon atoms.

19. The crosslinkable composition according to claim 13 or 14, which comprises: 10-90 wt% of a polyacrylate polyol (A1), optionally, 0-90 wt% of a polyol (B), 10-90 wt% of a polyisocyanate crosslinking agent (C), optionally, 0-10 wt% of a catalyst (D), optionally, 0-10% of a pot life extender (E), optionally, 0-20 wt% of a reactive diluent (F), and optionally, 0-10 wt% of an anti-sagging agent (G), based on the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C) and optional catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G).

20. An adhesive module, which comprises at least one polyacrylate polyol (A1) according to any one of claims 13-19, optionally at least one solvent (A2), at least one additive (A3), polyol (B), catalyst (D), pot life extender (E), reactive diluent (F) and / or anti-sagging agent (G), wherein the additive (A3) is selected from surfactants, leveling agents, wetting agents, anti-cratering agents, defoaming agents, heat stabilizers, light stabilizers, UV absorbers and antioxidants.

21. A method of providing a coating, which comprises the following steps: applying the crosslinkable composition according to any one of claims 13-19 to at least a part of a substrate, and curing the applied crosslinkable composition at a temperature of 5-180 °C.

22. The method according to claim 21, which comprises the following steps: 1) applying the crosslinkable composition according to any one of claims 13-19 to at least a part of a substrate, the crosslinkable composition comprising: a polyacrylate polyol (A1); optionally, at least one polyol (B) different from the polyacrylate polyol (A1) and containing at least two free hydroxyl groups; at least one polyisocyanate crosslinking agent (C); and Optionally, at least one catalyst (D) for catalyzing the reaction between the hydroxyl groups in the polyacrylate polyol (A1), optional polyol (B), and optional reactive diluent (F) and the isocyanate groups in the crosslinking agent (C), wherein the amount of the catalyst (D) present is 0 - 10 wt% of the total amount of the polyacrylate polyol (A1), optional polyol (B), crosslinking agent (C), optional catalyst (D), and optional pot life extender (E), reactive diluent (F), and / or anti-sagging agent (G); Optionally, one or more pot life extenders (E); Optionally, at least one reactive diluent (F); Optionally, at least one anti-sagging agent (G); and 2) Curing the applied crosslinkable composition at a temperature of 70 - 110°C.

23. The method according to claim 21, comprising the following steps: Applying a first aqueous color coat on a metallic substrate or an electrodeposition layer, Performing subsequent steps of flash-off, applying an aqueous primer coat, and flash-off again, Applying a clear coat layer comprising the crosslinkable composition according to any one of claims 13 - 19, and Performing a single baking and curing step on all layers simultaneously, wherein the flash-off is carried out at a temperature below 90°C for less than 1 hour, and the baking and curing step is carried out at a temperature of 125 - 180°C.

24. The method according to claim 23, wherein the polyacrylate polyol (A1) is combined with the polyol (B), crosslinking agent (C), catalyst (D), reactive diluent (F), and polyurea anti-sagging agent (G1).

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