US20130041103A1

US20130041103A1 - Heat-curable powder coating compositions, which after the coating has cured result in a matt surface and simple method for producing same

Info

Publication number: US20130041103A1
Application number: US13/583,252
Authority: US
Inventors: Werner Grenda; Emmanouil Spyrou; Thomas Weihrauch; Christoph Lammers; Holger Loesch; Klaus Behrendt
Original assignee: Evonik Degussa GmbH
Current assignee: Evonik Operations GmbH
Priority date: 2010-03-11
Filing date: 2011-03-10
Publication date: 2013-02-14
Also published as: US8476376B2; WO2011110640A1; RU2012143306A; US9096774B2; DE102011005369A1; AU2011226101B2; EP2545115A1; US20110288202A1; US20140316056A1; US20110224378A1; KR20130039715A; US8524837B2; JP2013522383A; MX2012010450A; AU2011226101A1; HK1177945A1; JP5730336B2; CN102782032A; CN102782032B; BR112012022874A2

Abstract

The invention relates to heat-curable powder coating compositions, which after the coating has cured result in a matt surface and to a simple method for producing same

Description

The invention relates to thermosetting powder coating compositions which have a matt surface after the coating is cured, and also to a simple method for their production.
Heat-curable powder coating materials do not emit any organic solvents on application, and therefore clearly possess environmental advantages over liquid paints. Crosslinking under hot conditions takes place via polyaddition reactions or polycondensation reactions between the functional groups present in the binders. Typical binder systems are epoxy resins with curing agents based on amines, amidines, acids, anhydrides; carboxyl polyesters or polyacrylates with curing agents based on epoxides; hydroxyl polyesters or polyacrylates with crosslinkers based on blocked isocyanates; polyacrylates containing epoxide groups with dicarboxylic acids as crosslinkers, carboxyl polyesters or polyacrylates with crosslinkers based on β-hydroxyalkylamides, etc. As well as the technical coatings properties, the various binder systems differ particularly in the stability to outdoor weathering. The pure binder systems lead in general to highly glossy surfaces, with a gloss of >80 scale divisions (DIN 67530/ISO 2813, incident angle 60°), when they are processed in a one-shot process with only one co-reactant, e.g., crosslinker and resin, and are induced to cure.
There is considerable interest in coating systems which endow a substrate with a uniformly even and matt surface. The reason for this is primarily practical. Glossy surfaces require a far higher degree of cleaning than do matt surfaces. Furthermore, it may be desirable on safety grounds to avoid highly reflecting surfaces. In wide areas of application in the powder coatings industry, such as architectural, automotive, and metal-furnishing segments, etc., there is a rise in demand in matt (10-30 units) and semimatt (30-50 units) surfaces, measured as reflectometer values to DIN 67530/ISO 2813 at an incident angle of 60°.
The most simple principle for obtaining a matt surface is to admix the powder coating material with smaller or greater amounts—depending on the extent of the desired matt effect—of fillers, such as chalk, finely divided silicon dioxide or barium sulfate, for example. These additions, though, produce a deterioration in the technical coatings film properties, such as adhesion, flexibility, impact strength, and chemicals resistance.
Although the addition of substances incompatible with the coating material, such as waxes or cellulose derivatives, for example, does produce a distinct matting, slight changes during extrusion lead to fluctuations in the surface gloss and to a “fade-out” effect in dark shades. The reproducibility of the matt effect is not guaranteed. EP 0698645 describes the production of matt powder coatings by dry-blending of at least two separately produced hydroxylalkylamide powder coating materials. U.S. Pat. No. 3,842,035 therefore proposes producing matt powder coatings by dry-blending ready-made powder coating materials having sufficiently different reactivities, i.e., powder coating materials having very short and very long gelling times. The binders used are acrylic resins, alkyd resins, and—preferably—epoxy resins. WO-A-89/06674 describes the production of satin-gloss or matt surfaces by dry blending, in other words physical blends of ready-made powder coating materials, which are composed of different binder systems.
DE 2 324 696 proposes a method for producing matt coatings by using a specialty curing agent reacting with epoxide groups—the salt of cyclic amidines with certain polycarboxylic acids. According to this method, the powder coating material undergoes crosslinking with different reactivity at different temperatures, thus forming, on the surface, microstructures which exhibit a matt surface. The application of this method, however, is confined to epoxide and carboxyl polyester/epoxide powder coating materials, meaning that this method cannot be used to produce coatings with sufficient weathering stability.
EP 366 608 likewise proposes a method for producing powder coatings having matt surfaces. It relates to powder coating materials based on epoxy resins or epoxide compounds, such as triglycidyl isocyanurate (TGIC), for example, with carboxyl-terminated polyester resins and mixtures of di-, tri- or tetrakis(β-carboxyethyl)cyclohexanones or -cyclopentanones. The matt effect here is attributed to the difference in reactivity between the aliphatic carboxylate groups of the crosslinker and the aromatic carboxylate groups of the carboxyl-terminated polyester resin.
Another patent specification, DE 3 232 463, describes powder coatings with matt surfaces by joint extrusion of hydroxyl-terminated polyester resins, epoxide compounds, such as TGIC, for example, and special, reversibly blocked polyisocyanates having free carboxylate groups.
U.S. Pat. No. 4,801,680 (EP 322 834) describes a heat-curable powder coating material which consists of a particulate mixture comprising a polyester containing carboxylate groups and a β-hydroxyalkylamide. Following application to a substrate, this powder coating material leads to glossy film surfaces. According to example 2 of U.S. Pat. No. 4,801,680, the resulting film surfaces exhibit no film-surface deterioration after an accelerated weathering test has been carried out and using UV irradiation EP 520429 describes a resin composition comprising polyesters having different hydroxyl numbers. The resin composition described necessarily comprises a substantially ungelled polyester A, a substantially ungelled polyester B, tetramethoxymethylglycoluril as curing agent, and an organic sulfonic acid as catalyst.
Numerous further publications have appeared concerning the possibilities for matting hydroxyalkylamide powder coatings, examples being R. Franiau, “Advances in β-Hydroxyalkylamide crosslinking chemistry” ECJ, (2002) 10, p 409ff; D. Fink, U. Kubilius, “Optimising the Matting of Powder Coatings”, Powder Coatings Europe 2002, and R. Guida, “A Novel Approach to Produce Reduced Gloss β-Hydroxyl Alkylamide Powder Coatings” Powder Coating 2002 PCI Conference; D. Beccaria et al. “Modeling Gloss Control in Polyester/β-Hydroxyalkylamide Powder Coatings Based on SPM Structure-Property Relationship”, Waterborne, High-Solids and Powder Coatings Symposium, Feb. 26-28, 2003, New Orleans, La., USA.
Laid-open specification KR 10-2009-0111720 (application number 10-2008-0037454), with translated title “CYCLOALKANE DICARBOXAMIDE COMPOUNDS, THEIR PREPARATION AND APPLICATION” (see also J. Korean Ind. Eng. Chem., vol. 20, No. 2, April 2009, 195-200), discloses in particular in example 1 the therein-named compound N¹,N¹,N⁴,N⁴-tetrakis(2-hydroxyethyl)cyclohexane-1,4-dicarboxamide (formula 3). This compound according to FIG. 2 has only one peak according to DSC analysis, with a maximum peak at approximately 190° C. A cis/trans content for the compound is not stated. Furthermore, polyesters containing carboxyl groups, which are not precisely defined but instead are indicated only by broad ranges of certain parameters (polyesters not unambiguously characterized and unknown on the market with this viscosity), are crosslinked with this compound and compared with the known β-hydroxyalkylamide, in this case named in example 3 as [N¹,N¹,N⁶,N⁶-tetrakis(2-hydroxyethyl)adipamide] (available as VESTAGON HAA 320 or PRIMID XL 552), in other words with curing agents from the prior art, and with long-established market products, which are known to lead to glossy surfaces on the coatings produced. In FIGS. 3 and 4, the metal panels are shown. There is no description to the effect that the coatings in question are matt. Nor is this possible, since the coatings obtained with the conventional curing agents are glossy.
Therefore, for matt and semimatt (<50 gloss units) powder coating compositions with hydroxylalkylamides, state of the art is what are called dry blends; in other words, the separate preparation of two hydroxyalkylamide powder coating materials is required, based on β-hydroxyalkylamides, plus resins (polymers) with different acid numbers, which are then supplied in the form of a dry blend to the grinding operation. This involves considerable extra cost and effort and, in the event of deviation in a binder component, results in gloss deviations which take considerable extra cost and effort to correct. Furthermore, these dry blends undergo separation, including at the premises of the end customer, with a resultant shift in gloss if the powder coating, as is usual, is to be recycled.
It was an object of the invention to find thermosetting powder coating composition which after the coating is cured exhibit a matt surface, and also a simple method for their production.
This object is achieved by the new β-hydroxyalkylamides of the invention as crosslinkers (curing agents), and also by the method of the invention.
The invention provides a powder coating composition substantially comprising

A) at least one polymer containing carboxylate groups and having an acid number of 5 to 350 mg KOH/g and a glass transition temperature T_gof greater than 40° C.,
and
B) at least one β-hydroxyalkylamide having two or three or four β-hydroxyalkylamide groups per molecule of the formula I

where
R¹and R²are, independently of one another, identical or different radicals selected from alkyl radical, cycloalkyl radical, aryl radical, aralkyl radical or alkenyl radical having 1-24 carbon atoms, it being possible for the radicals also to contain heteroatoms and/or functional groups,
and where R¹may also be hydrogen,
and where R²may also be

and
A is

where radicals R³are, independently of one another, identical or different radicals selected from hydrogen, alkyl radical, cycloalkyl radical, aryl radical, aralkyl radical or alkenyl radical having 1-24 carbon atoms, it being possible for the radicals also to contain heteroatoms and/or functional groups, and where two or more substituents R³may be linked with one another to form rings;
where the β-hydroxyalkylamides are present in solid form below 150° C.;
C) optionally auxiliaries and/or additives;
where the ratio of β-hydroxyalkylamide groups to the carboxylate groups is between 0.5:1 to 1.5:1.

Surprisingly it has been found that through the use of the new β-hydroxyalkylamides of formula I of the invention as crosslinkers it is possible to obtain coatings having matt (10-30 units) and semimatt (30-50 units) surfaces, measured as reflectometer values to DIN 67530/ISO 2813 at an incident angle of 60°.
Surprisingly it has been found that through the method of the invention, in a one-shot operation, in other words by joint extrusion of all of the components, it is possible to obtain the powder coating composition of the invention, based on polymers containing carboxylate groups and β-hydroxyalkylamides of the invention as crosslinkers.
In the context of this invention the terms crosslinker and curing agent are used synonymously.
There is no requirement for costly and involved dry blending of at least two powder coating materials which differ in reactivity, on the basis of β-hydroxyalkylamides as crosslinkers. Furthermore, there is also no need for a polyester mixture or polyacrylate mixture of at least two resins having different reactivities.
Co-reactants contemplated for the β-hydroxyalkylamide compounds used in accordance with the invention for preparing the powder coating composition are polymers A) containing carboxylate groups. Polymers which can be used are addition polymers, polycondensates, and polyaddition compounds. In principle it is possible to use any polymer which contains at least two carboxylate groups and has a glass transition temperature T_ggreater than 40° C. Polymers containing carboxylate groups that are suitable for the powder coating materials of the invention are those which have acid numbers of 5-350 mg KOH/g, preferably 15-150 mg KOH/g, with OH numbers <15 mg KOH/g. These polymers preferably have at least two terminal carboxylate groups.
Particularly preferred in the context of the invention are polyacrylates and/or polyesters containing carboxylate groups.
The polyesters A) containing carboxylate groups are preferably polyester polycarboxylic acids prepared from polyols and polycarboxylic acids and/or derivatives thereof. The glass transition temperature T_gof these acidic polyesters is situated in a range from 40 to 80° C., preferably 40 to 70° C.; their acid number varies from 5-250 mg KOH/g, preferably from 10 to 150 mg KOH/g, more preferably 12 to 120 mg KOH/g. The OH numbers are below 15 mg KOH/g. They have an average molecular weight M_Wof 1000 to 10 000 g/mol, preferably 1500 to 9000 g/mol, more preferably of 2000 to 8000 g/mol.
The polyesters containing carboxylate groups for use in accordance with the invention are prepared using polycarboxylic acids, such as oxalic, succinic, adipic, 2,2,4(2,4,4)-trimethyladipic, azelaic, sebacic, decanedicarboxylic, dodecanedicarboxylic, fumaric, phthalic, isophthalic, terephthalic, trimellitic, pyromellitic acid, for example. For the acidic polyesters, polyols used are, by way of example, the following: ethylene glycol, 1,2- and 1,3-propanediol, 1,2-, 1,3-, 1,4- and 2,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,12-dodecanediol, 2,2,4(2,4,4)-trimethyl-1,6-hexanediol, trimethylolpropane, glycerol, pentaerythritol, 1,4-bishydroxymethylcyclohexane, cyclohexane-1,4-diol, diethylene glycol, triethylene glycol, and dipropylene glycol. It is of course also possible for hydroxyl-containing polyesters, prepared by known methods from polycarboxylic acids and polyols, to be reacted with polycarboxylic acids and/or polycarboxylic anhydrides to give the polyester polycarboxylic acids.
The polyester resins containing carboxylate groups are prepared by known methods, by esterification or transesterification of dihydric and/or polyhydric linear or branched, aliphatic or cycloaliphatic polyols with polybasic, preferably dibasic or polybasic aliphatic, cycloaliphatic or aromatic carboxylic acids or their anhydrides or esters thereof, in the presence of an esterification or transesterification catalyst at temperatures up to about 250° C. and under reduced pressure toward the end.
Preferred polyols are 2,2-dimethyl-1,3-propanediol (neopentyl glycol), ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-dimethylolcyclohexane, 2,2-[bis(4-hydroxycyclohexyl)]propane, diethylene glycol, dipropylene glycol, glycerol, pentaerythritol etc. The polyol component preferably includes a high fraction of neopentyl glycol in order to obtain very high glass transition temperatures. Preferred polybasic carboxylic acids are terephthalic acid, isophthalic acid, trimellitic acid, adipic acid, and/or 1,4-cyclohanedicarboxylic acid. The functionality of the preferred polyester resins containing carboxylate groups is adjusted via the ratio of dibasic to more-than-dibasic carboxylic acids.
Suitable acrylate polymers containing carboxylate groups possess an acid number of 10-350 mg KOH/g, preferably 20 to 300 mg KOH/g, and a glass transition temperature T_gof greater than 40° C., preferably of 45 to 100° C., prepared by homopolymerization or copolymerization of a monomer mixture.
The polyacrylate comprises carboxylic acid groups and may be a homopolymer or a copolymer.
Monomers which can be used are acrylic acid and/or methacrylic acid, C₁-C₄₀alkyl esters and/or cycloalkyl esters of methacrylic acid and/or acrylic acid, hydroxyalkyl acrylates and/or hydroxyalkyl methacrylates, glycidyl methacrylate, glycidyl acrylate, 1,2-epoxybutyl acrylate, 1,2-epoxybutyl methacrylate, 2,3-epoxycyclopentyl acrylate, 2,3-epoxycyclopentyl methacrylate, and also the analogous amides, where styrene and/or derivatives thereof may also be present.
Preference is given to using butyl acrylate and/or butyl methacrylate, 2-hydroxyethyl acrylate and/or 2-hydroxyethyl methacrylate, methyl methacrylate, styrene (meth)acrylic acid, and, optionally, further unsaturated monomers, with at least one monomer containing carboxylate groups being used.
Further suitable monomers are (cyclo)alkyl esters of acrylic or methacrylic acid having 2 to 18 carbon atoms in the (cyclo)alkyl radical. Examples of suitable and preferentially suitable monomers are ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl methacrylate, neopentyl methacrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, and stearyl methacrylate.
Examples of monomers contemplated include styrene, vinyltoluene, and ethylstyrene. Examples of are acrylic acid and methacrylic acid, which are also used preferably, and also crotonic acid, itaconic acid, fumaric acid, maleic acid, and citaconic acid.
The polyacrylate preferably possesses an OH number of less than 10 mg KOH/g, an acid number of 5 to 350 mg KOH/g, preferably 20 to 300 mg KOH/g, more preferably of 30 to 250 mg KOH/g, a Tg of 40 to 110° C., preferably 45 to 100° C., an M_wof 500 to 50 000 g/mol, preferably 1000 to 30 000 g/mol, more preferably of 1500 to 20 000 g/mol.
As co-crosslinkers it is also possible to use epoxy resins. Those contemplated include, for example, glycidyl ethers and glycidyl esters, aliphatic epoxides, diglycidyl ethers based on bisphenol A, and glycidyl methacrylates. Examples of epoxides of these kinds are triglycidyl isocyanurate (TGIC trade name: e.g., ARALDIT PT 810, Huntsman; TEPIC G, Nissan; Taida TGIC, Anhui Taida), mixtures of diglycidyl terephthalate and triglycidyl trimellitate (trade names, e.g., ARALDIT PT 910 and PT 912, Huntsman), glycidyl esters of Versatic acid (trade name, e.g., CARDURA E10, Shell), 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (ECC), diglycidyl ethers based on bisphenol A (trade name, e.g., EPIKOTE 828, Shell), ethylhexyl glycidyl ether, butyl glycidyl ether, pentaerythritol tetraglycidyl ether, (trade name, e.g., POLYPDX R16, UPPC AG), and also other Polypox types having free epoxy groups. Mixtures can also be used. Preference is given to using TEPIC G or ARALDIT PT 910 and 912. Co-crosslinkers of these kinds can be used at up to 50% by weight of the curing agent mixture that is used, composed of β-hydroxyalkylamide of the invention (matt curing agent) and co-crosslinker.
Surprisingly it has been found that β-hydroxyalkylamides having a cyclohexane ring in the framework, the β-hydroxyalkylamides being present in solid form below 150° C., as crosslinkers for carboxyl-containing polymers in powder coating materials, lead to matt surfaces after curing.
The β-hydroxyalkylamides B) may be prepared from various starting materials. A known reaction is that of β-hydroxyalkylamines with esters of carboxylic acids, the latter generating the parent structure (A). Depending on the selection of the starting materials, the β-hydroxyalkylamides of the invention can be generated in this way.
Alternative but less preferred methods are based on other carboxylic acid derivatives, such as carboxylic acids, carbonyl chlorides, carboxylic anhydrides or other activated carboxylic acid derivatives, for example, as starting materials, which are reacted with β-hydroxyalkylamines.
Suitable β-hydroxyalkylamines are those which have alkyl groups having at least 2 to 10 carbon atoms in the hydrocarbon framework. The alkyl groups may be linear, branched or else cyclic. The alkyl groups may likewise be substituted by heteroatoms, preferably oxygen, nitrogen. Furthermore, these alkyl groups may also contain functional groups, preferably carbonyl groups, carboxyl groups, amino groups, amide groups, urethane groups, and may carry an additional alkyl radical on the nitrogen.
Preferably in this invention the β-hydroxyalkylamides are prepared from N-alkyl-1,2-alkanolamines and/or from N,N-bis-2-hydroxyalkylamines and esters of cyclohexanedicarboxylic acids.
Particular preference is given to using β-hydroxyalkylamines of the formulae II and/or III:
where
R¹is hydrogen, methyl, ethyl, propyl,
R²is methyl;
where radicals R¹simultaneously or independently of one another are hydrogen, methyl, ethyl, propyl.
Particular preference in accordance with the invention is given to using the following compounds as starting materials for preparing β-hydroxyalkylamides: diethanolamine (DEA), di-isopropropanolamine (DIPA), di-sec-butanolamine, N-methylethanolamine, N-methylisopropanolamine.
Suitable starting compounds for the substituent A in the β-hydroxyalkylamides of the invention are 1,2-, 1,3-, and 1-4-cyclohexanedicarboxylic acid derivatives, more particularly dialkyl esters of cyclohexanedicarboxylic acids. These starting compounds may have any desired cis/trans content.
Preference is given to using compounds of the formula IV
where radicals R⁴simultaneously or independently of one another are methyl, ethyl, propyl, butyl.
Particular preference is given to using 1,4-substituted cyclohexanedicarboxylic esters, very preferably dimethyl 1,4-cyclohexyldicarboxylate.
The β-hydroxyalkylamides that are particularly preferred in accordance with the invention, formed from dialkyl 1,4-cyclohexyldicarboxylates, preferably from dimethyl 1,4-cyclohexyldicarboxylate, have a trans content, based on the position of the carboxyl groups on the cyclohexyl ring, of greater than or equal to 70 mol %, preferably greater than 80 mol %, more preferably of greater than 85 mol %. For preparing the preferred β-hydroxyalkylamides it is possible in this case to use dialkyl 1,4-cyclohexyldicarboxylates having any desired trans content.
The β-hydroxyalkylamides (I) of the invention are present in solid form below 150° C., preferably below 170° C., more preferably below 180° C.
Particularly preferred β-hydroxyalkylamides of the invention have the following formulae:
where
R²is methyl,
or
where R^1Ais hydrogen and R^1Bis methyl, ethyl, propyl,
or
R^1Ais methyl, ethyl, propyl and R¹⁸is hydrogen;
and
A is a 1,4-disubstituted cyclohexane ring of the formula
where the trans content of A is ≧70 mol %;
and where the β-hydroxyalkylamides are present in solid form below 150° C.
The β-hydroxyalkylamide that is particularly preferred in accordance with the invention, formed from dimethyl 1,4-cyclohexyldicarboxylate and diethanolamine with four β-hydroxyalkylamide groups per molecule of the formula XII,
has a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, preferably greater than 80 mol %, and more preferably of greater than 85 mol %.
In order to achieve good technical coatings properties for the powder coating composition, the ratio of β-hydroxyalkylamide groups to the carboxylate groups of the polymers containing carboxylate groups is preferably between 0.5 to 1.5:1, more preferably between 0.8 to 1.2:1.
The powder coating composition may be admixed with the auxiliaries and additives C) that are customary in powder coating technology, such as flow control agents, e.g., polysilicones or acrylates, light stabilizers, e.g., sterically hindered amines and/or absorbers, degassing agents (e.g., benzophenone), modified phenolic resins, catalysts and/or other auxiliary agents, as described in EP 669 353, for example, in a total amount of 0.1% to 10% by weight. Fillers and pigments such as titanium dioxide, for example, can be added in an amount of up to 50% by weight of the overall composition.
In quantitative terms the constitution of the powder coating compositions is as follows:


	% by weight

	Inventive β-hydroxyalkylamide	0.5 to 20
	(matt curing agent B)
	preferably	1 to 15
	Optional HAA curing agent	0 to 10
	preferably	0 to 8
	Polymers A) containing	35 to 96
	carboxylate groups
	preferably	50 to 80
	Optionally co-crosslinker(s)	0 to 5
	preferably	0 to 3
	Additives, fillers, pigments etc. C)	0.1 to 50
	preferably	5 to 40

The powder coating compositions of the invention exhibit good storage stability in the storage test customary for powder coating materials, in accordance with DIN EN ISO 8130-8, at temperatures of 30±1 and 40±1° C., and are storable for >30 days.
In the particularly preferred embodiment of the invention, the powder coating compositions of the invention comprise:

- at least one polyester containing carboxylate groups and having an acid number of 15 to 150 mg/KOH/g and a glass conversion temperature of at least 40° C.,
- at least one β-hydroxyalkylamide of the invention having at least two or more, preferably four, β-hydroxyalkylamide groups, or else mixtures thereof having the same and/or different functionality,
- and also, optionally, further additives and auxiliaries customary for powder coating materials, such as, for example, wetting, flow control or degassing agents, heat stabilizers or UV stabilizers, pigments, dyes, fillers, co-crosslinkers.

The invention provides a method for producing a powder coating composition substantially comprising

A) at least one polymer containing carboxylate groups and having an acid number of 5 to 250 mg KOH/g and a glass transition temperature T_gof greater than 40° C.,
and
B) at least one β-hydroxyalkylamide having two or three or four β-hydroxyalkylamide groups per molecule of the formula I

and
A is

where radicals R³are, independently of one another, identical or different radicals selected from hydrogen, alkyl radical, cycloalkyl radical, aryl radical, aralkyl radical or alkenyl radical having 1-24 carbon atoms, it being possible for the radicals also to contain heteroatoms and/or functional groups, and where two or more substituents R³may be linked with one another to form rings; where the β-hydroxyalkylamides are present in solid form below 150° C.;
C) optionally auxiliaries and/or additives;
where the ratio of β-hydroxyalkylamide groups to the carboxylate groups is between 0.5:1 to 1.5:1;
in the melt by joint extrusion of all the components at temperatures between 80 to 150° C.

The invention also provides a method for producing a powder coating composition, comprising N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to formula XIIA as component B)
which has the following parameters:

- 1. a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present,
- and
- 2. two endothermic peaks according to DSC analysis (differential scanning calorimetry), where peak 1 is situated in the region of 140-170° C. with a maximum of 155-165° C., and peak 2 is situated in the region of 170-210° C. with a maximum of 175-207° C.,
- and
- 3. the ratio of the enthalpies of the endothermic peak 1 to the endothermic peak 2 is 1:1 to 1:5,
- and
- 4. the XRPD spectrum of the powder sample in the x-ray diffractometer, measured with Cu Kα radiation (1.541 Å), has the following peaks:


	Degrees 2theta ±
Peak #.	0.2 degree 2theta	d (Å)

1	14.90	5.94
2	16.70	5.31
3	17.40	5.09
4	21.20	4.19
5	21.60	4.11
6	26.00	3.43

The invention also provides a method for producing a powder coating composition, comprising N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B)
which has the following parameters:

- 5. and which, according to x-ray structural analysis of a single crystal, has the following parameters:


Crystal system:	Orthorhombic
Space group:	Pbca
Unit cell dimensions:	a = 10.06350(10) Å	α = 90°.
	b = 11.85290(10) Å	β = 90°.
	c = 14.6275(2) Å	γ = 90°.
Volume:	1744.79(3) Å³

The powder coating composition of the invention is produced preferably in the melt by joint extrusion of all the components A) to C) at temperatures between 80 to 150° C. The extrudate is subsequently cooled, ground, and sieved off or classified to a particle size of <120 μm, preferably <100 μm. The heat-curable and toxicologically flawless powder coating composition produced in accordance with the invention therefore consists of a matrix obtained by joint extrusion of all the components.
In order to obtain the effect in accordance with the invention, namely the formation of matt surfaces having a gloss to DIN 67530/ISO 2813 of <50 at an incident angle of 60°, it is possible to use numerous polymers containing carboxylate groups, more particularly carboxylate-group-terminated polyesters or polyacrylates, which differ in their functionality and reactivity. The desired gloss can therefore be selected via the selected binder partner (polyester) in conjunction with the hydroxyalkylamide of the invention within a considerable spectrum (examples 1-7), with the formulation being otherwise the same. Example (8) with the polyacrylate deviates from this, since more crosslinker is needed for the increased acid number, and a lower level of pigmentation was selected in view of the anticipated greater brittleness.
The use of and the application of the powder coating materials for producing coatings take place in accordance with methods customary for powder coating materials, preferably by means of an electrostatic powder coating sprayer device in accordance with the triboelectric or corona method or in accordance with the fluid-bed method.
At standard ambient temperatures, the powder coating compositions produced in accordance with the invention possess good storage stability and, after crosslinking between 150 to 220° C., exhibit good technical coatings properties, surfaces which flow out well in optical terms, and the low gloss levels described.
In contrast to the prior art, the coatings obtained with the powder coating compositions of the invention have visually very attractive surfaces with good leveling (PCI evaluation table 8-10), which, however, are matt (10-30 units) and/or semimatt (30-50 units), measured as reflectometer values to DIN 67530/ISO 2813 at an incident angle of 60°, with no need for a dry blend or a polyester mixture or polyacrylate mixture (one-shot blend).
Beyond this variation, the possibility additionally exists of shifting the measured reflectometer value, to DIN 67530/ISO 2813 at an incident angle of 60°, to higher levels, up to the re-acquisition of the high gloss of >80 scale divisions at the 60° angle. This is accomplished by partially replacing the matt curing agent B) of the invention with a standard commercial β-hydroxyalkylamide having two or more than two β-hydroxyalkylamide groups, or mixtures thereof having different functionalities.
The invention provides the use of a powder coating composition substantially comprising

- A) at least one polymer containing carboxylate groups and having an acid number of 5 to 350 mg KOH/g and a glass transition temperature T_gof greater than 40° C.,
- and
- B) at least one β-hydroxyalkylamide having two or three or four β-hydroxyalkylamide groups per molecule of the formula I

- where
- R¹and R²are, independently of one another, identical or different radicals selected from alkyl radical, cycloalkyl radical, aryl radical, aralkyl radical or alkenyl radical having 1-24 carbon atoms, it being possible for the radicals also to contain heteroatoms and/or functional groups, and where R¹may also be hydrogen,
- and where R²may also be

- and
- A is

- where radicals R³are, independently of one another, identical or different radicals selected from hydrogen, alkyl radical, cycloalkyl radical, aryl radical, aralkyl radical or alkenyl radical having 1-24 carbon atoms, it being possible for the radicals also to contain heteroatoms and/or functional groups, and where two or more substituents R³may be linked with one another to form rings; where the β-hydroxyalkylamides are present in solid form below 150° C.;
- C) optionally auxiliaries and/or additives;
- where the ratio of β-hydroxyalkylamide groups to the carboxylate groups is between 0.5:1 to 1.5:1;
- for producing coatings having matt surfaces, having a gloss to DIN 67530/ISO 2813 of <50 at an incident angle of 60.

Provided especially preferably by the invention is a powder coating composition which has the compound N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B),
which has the following parameters:

- 1. a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present, and
- 2. two endothermic peaks according to DSC analysis (differential scanning calorimetry), where peak 1 is situated in the region of 140-170° C. with a to maximum of 155-165° C., and peak 2 is situated in the region of 170-210° C. with a maximum of 175-207° C.,
- and
- 3. the ratio of the enthalpies of the endothermic peak 1 to the endothermic peak 2 is 1:1 to 1:5, and
- 4. the XRPD spectrum of the powder sample in the x-ray diffractometer, measured with Cu Kα radiation (1.541 Å), has the following peaks:

Description of the Particularly Preferred Component B):
Provided more preferably by the invention is a powder coating composition comprising the β-hydroxyalkylamide N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B), having a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, preferably greater than 80 mol %, and more preferably of greater than 85 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present.
Additionally this β-hydroxyalkylamide of the invention used as component B), N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA, has two endothermic peaks according to DSC analysis (differential scanning calorimetry): first a peak with a maximum (peak 1) of about 160° C., and a further, second peak with a maximum (peak 2) of about 190° C.; see the figures relating to the examples. Preferably, the first peak is situated in the range of 140-170° C. with a maximum of 155-165° C. and the second peak is situated in the range of 170-210° C. with a maximum of 175-207° C.
More preferably, the first peak is situated in the range of 155-170° C. with a maximum of 158-165° C., and the second peak is situated in the range of 170-210° C. with a maximum of 180-205° C.
The ratio of the enthalpies of the endothermic peak 1 (˜160° C.) to the endothermic peak 2 (˜190° C.) may be 1:1 to 1:5, preferably 1:1 to 1:3.
The DSC measurements were carried out in accordance with DIN EN ISO 11357-1 of March 2010. A heat flow difference calorimeter from the manufacturer Mettler-Toledo, model DSC 821, was used. The samples are run once from −30° C. to 250° C. at 10 K/min.
The XRPD measurements on powder samples were carried out in an x-ray diffractometer using Cu Kα radiation (1.541 Å). In accordance with FIG. 9, the following significant and characteristic 6 peaks of the β-hydroxyalkylamide N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA were found:


	Degrees 2theta ±
Peak #	0.2 degree 2 theta	d (Å)

1	14.90	5.94
2	16.70	5.31
3	17.40	5.09
4	21.20	4.19
5	21.60	4.11
6	26.00	3.43

Especially preferred as component B) is the β-hydroxyalkylamide N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA having a trans content on the cyclohexyl ring of greater than or equal 92 mol %, preferably greater than 94 mol %, and more preferably of greater than 96 mol %, and very preferably of greater than 98 mol %, based on the total amount of all of the isomers of N,N,N′,W-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present.
The β-hydroxyalkylamide of the formula XIIA of the invention that is used as component B) is present in solid form below 175° C., preferably below 180° C., and more preferably of below 185° C.
The β-hydroxyalkylamide of the formula XIIA of the invention that is used as component B), having the features 1. to 4, was investigated by means of x-ray structural analysis of a single crystal. Comprehensive details relating to the measurement are summarized in annex 1. The x-ray structural analysis of a single crystal gave the following result for the structure:

The values within the brackets indicate the measurement accuracy, in each case in plus and minus, for the corresponding last digit or last two digits, respectively.
Provided with very particular preference by the invention is a powder coating composition which comprises the compound N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B)
which has the following parameters:

- 1. a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present,
- and
- 2. two endothermic peaks according to DSC analysis (differential scanning calorimetry), where peak 1 is situated in the region of 140-170° C. with a maximum of 155-165° C., and peak 2 is situated in the region of 170-210° C. with a maximum of 175-207° C.,
- and
- 3. the ratio of the enthalpies of the endothermic peak 1 to the endothermic peak 2 is 1:1 to 1:5, and
- 4. the XRPD spectrum of the powder sample in the x-ray diffractometer, measured with Cu Kα radiation (1.541 Å), has the following peaks:

Preparation

The particularly preferred N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA which is used as component B) is obtainable by various methods:
First of all, as described precisely earlier on above, the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA is prepared, preferably solventlessly, in an extruder, intensive compounder, intensive mixer or static mixer, preferably in an extruder. For this preparation, temperatures of 100 to 180° C. are employed. This is followed by recrystallization from a suitable solvent, preferably water. After dissolution at temperatures of 20-100° C. and crystallization, the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA is obtained with the above-stated parameters. It can then, subsequently, be washed with alcohols, preferably methanol, and dried. Drying takes place preferably at temperatures of 20-90° C., and can also take place under reduced pressure.
Another variant of the preparation takes place as described precisely earlier on above, by the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA being prepared in an extruder, intensive compounder, intensive mixer or static mixer, preferably in an extruder, preferably solventlessly. In this case temperatures of 100 to 180° C. are employed. This is followed by a thermal conditioning at temperatures of 50-100° C., preferably at temperatures of 70-85° C. The time is more than 6 hours, preferably more than 12 hours. Thermal conditioning may also take place under reduced pressure.
The particularly preferred N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA that is used as component B) may also take place discontinuously in a solvent, in other words in a batch method.
The reaction is carried out in customary reactors. Operation may be unpressurized, using a reflux condenser, or under pressure, with a closed reactor.
The synthesis is carried out in a solvent, preferably in alcohols, preferably methanol. The amount of solvent added is greater than 10% by weight, preferably greater than 15% by weight, based on the total amount of all the reactants (starting materials) used. This operation may take place under reflux, or else at relatively low temperatures, and also relatively high temperatures, under pressure. The preparation takes place at temperatures of 20 to 120° C., preferably at 60 to 90° C., more preferably at 70 to 85° C.
After crystallization has taken place, the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA is obtained, with the parameters stated above.
Furthermore, the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA can be prepared in closed apparatus under pressure at temperatures of 60 to 140° C. without addition of solvents.
The N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA prepared in this way in a batch method can be recrystallized from suitable solvents, preferably from water or alcohols, preferably from methanol.
Furthermore, the preparation of the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA may also take place discontinuously without solvents.
The reaction is carried out in customary reactors. It is possible here to operate using a reflux condenser. The preparation takes place preferably at temperatures of 20 to 140° C., preferably 60 to 90° C., more preferably at 70 to 85° C. The β-hydroxyalkylamide obtained in this way in a batch method is then recrystallized from suitable solvents, preferably from water or alcohols, preferably from methanol. After crystallization has taken place, the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA is obtained, with the parameters stated above.
The concentration of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide in the end product after its preparation is 75% by mass, preferably 80% by mass, and more preferably 85% by mass.
This β-hydroxyalkylamide characterized and described here, N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide of the formula XIIA, produces far-reaching matting in powder coatings, with a gloss of less than 50 scale divisions at the 60° angle, as has been shown in the examples. This product of the formula XIIA therefore differs clearly from the β-hydroxyalkylamide disclosed in accordance with laid-open specification KR 10-2009-0111720 (and from the β-hydroxyalkylamide from Korean Ind. Eng. Chem., vol. 20, No. 2, April 2009, 195-200), as demonstrated there in FIG. 2 on page 15, which has only one peak according to DSC analysis at about 190° C., and, as shown by comparative example 4c, does not lead to coatings having matt surfaces.
The invention also provides the use of a powder coating composition as described above, comprising N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to formula XIIA as a component
which has the following parameters:

Degrees 2theta ±

Peak #. 0.2 degree 2theta d (Å)

1 14.90 5.94

2 16.70 5.31

3 17.40 5.09

4 21.20 4.19

5 21.60 4.11

6 26.00 3.43

for producing coatings having matt surfaces with <50 gloss units, measured as reflectometer values to DIN 67530/ISO 2813 with an incident angle of 60°.
The invention also provides the use of a powder coating composition as described above, comprising N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B)
which has the following parameters:

1. a trans content on the cyclohexyl ring of greater than or equal to 70 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present, and
2. two endothermic peaks according to DSC analysis (differential scanning calorimetry), where peak 1 is situated in the region of 140-170° C. with a maximum of 155-165° C., and peak 2 is situated in the region of 170-210° C. with a maximum of 175-207° C.,
and
3. the ratio of the enthalpies of the endothermic peak 1 to the endothermic peak 2 is 1:1 to 1:5,
and
4. the XRPD spectrum of the powder sample in the x-ray diffractometer, measured with Cu Kα radiation (1.541 Å), has the following peaks:

5. and which, according to x-ray structural analysis of a single crystal, has the following parameters:

Crystal system: Orthorhombic

Space group: Pbca

Unit cell dimensions: a = 10.06350(10) Å α = 90°.

b = 11.85290(10) Å β = 90°.

c = 14.6275(2) Å γ = 90°.

Volume: 1744.79(3) Å³

for producing coatings having matt surfaces with <50 gloss units, measured as reactometer values to DIN 67530/ISO 2813 at an incident angle of 60°.

EXAMPLES

The following examples and tables 1, 2, and 3 characterize the composition of the coating system and the properties of the respective coating after its application and curing.

Materials Used:

1) β-Hydroxyalkylamide

- a) β-Hydroxyalkylamide (matt cutting agent) based on 1,4-cyclohexanedicarboxylic acid and diethanolamine, having four β-hydroxyalkylamide groups per molecule, of the formula XII has a trans content on the cyclohexyl ring of >90% (Evonik Degussa GmbH, D).


trans-N,N,N′,N′-tetrakis(2-hydroxyethyl)	% by mass	95.30
cyclohexyl-1,4-diamide¹
cis-N,N,N′,N′-tetrakis(2-hydroxyethyl)	% by mass	0.28
cyclohexyl-1,4-diamide¹
Σ N,N,N′,N′-tetrakis(2-hydroxyethyl)	% by mass	95.58
cyclohexyl-1,4-diamide¹
DEA¹	% by mass	0.18
OH number	mg KOH/g	616
Base number	mg KOH/g	3
Melting range	° C.	194-201

¹Analytical values by GC
OH number: DIN 53240
Base number: DIN 53176
Melting range: DIN EN ISO 3146

- b) VESTAGON® HA 320, OH number: 660-740 mg KOH/g, melting range: 115-130° C., (Evonik Degussa GmbH, D)

2) Polymers Containing Carboxylate Groups—Resins

- a) Amorpher polyester:
  - Crylcoat® 2617-3, AN number: 33 mg KOH/g, Tg: 61° C., (Cytec Inc., USA)
  - Crylcoat® 2618-3, AN number: 35 mg KOH/g, Tg: 61° C., (Cytec Inc., USA)
  - Crylcoat® E 36988, AN number: 30 mg KOH/g, Tg: 54° C., (Cytec Inc., USA)
  - Uralac® P 800, AN number: 28 mg KOH/g, Tg: 61° C., DSM Resins B.V., NL)
  - Uralac® P 865, AN number: 35 mg KOH/g, Tg: 56° C., (DSM Resins B.V., NL)
  - Pulverol® 8120, AN number: 33 mg KOH/g, Tg: 60° C., (Neochimiki LV s.a., GR)
  - Pulverol® 8123, AN number: 33 mg KOH/g, Tg: 60° C., (Neochimiki LV s.a., GR)
- b) Polyarclate
  - Joncryl® 819, AN number: 75 mg KOH/g, Tg: 57° C., (BASF AG., D)

3) Co-Crosslinker

- a) Triglycidyl isocyanurate:
  - TEPIC®G, Epoxy equiv: <110 g/eq, Melting range: 90-125° C., (Nissan Chemical Ind. Ltd., J)

4) Other Formulating Ingredients:

- Titanium dioxide, Kronos® 2160, (Kronos Titan GmbH, D),
- Resiflow® PV 88, (Worlée-Chemie GmbH, D),
- Benzoin, (Merck-Schuchard, D).

Powder Coating Material and Coating

The powder coating material was produced first by mixing all of the components as per tables 1 and 2 at room temperature in a MIT mixer at 500 rpm for 120 seconds and then, second, by joint extrusion in the melt at a temperature (barrel) of 90° C. (about 130° C. melt temperature). The stoichiometric ratio of acid groups of the polyester or polyacrylate to OH groups of the β-hydroxyalkylamides (curing agents) was about 1:1. When co-crosslinkers were used, they were taken into account stoichiometrically in respect of the amount of curing agent.
The extrudate was subsequently cooled, ground, and sieved to a particle size of <100 μm. The powder coating material produced in this way was applied using an electrostatic powder spraying unit at 60 KV to degreased steel panels (deep-drawn steel from Krüppel 210×70×0.8 mm) and/or aluminum panels (Q-panel AL-36 5005 H 14/08 0.8 mm) and baked in a forced-air drying oven at between 160 to 220° C. The cured coating films had a film thickness of about 55-65 μm. The example data relate to a baking time of 20 minutes at 200° C.

TABLE 1

Testing according to characteristics of different polyesters and polyacrylate
Formulating examples with inventive β-hydroxyalkylamide 1a (matt cutting agent)
and different resins

Example

	1	2	3	4	5	6	7	8

β-Hydroxyalkylamide	% by wt.	3.00	3.00	3.00	3.00	3.00	3.00	3.00	7.80
1a
CRYLCOAT ® 2618-3	% by wt.	60.70	—	—	—	—	—	—	—
CRYLCOAT ® E 36988	% by wt.	—	60.70	—	—	—	—	—	—
PULVEROL ® 8120	% by wt.	—	—	60.70	—	—	—	—	—
URALAC ® P 800	% by wt.	—	—	—	60.70	—	—	—	—
URALAC ® P 865	% by wt.	—	—	—	—	60.70	—	—	—
CRYLCOAT ® 2617-3	% by wt.	—	—	—	—	—	60.70	—	—
PULVEROL ® 8123	% by wt.	—	—	—	—	—	—	60.70	—
JONCRYL ® SCX 819	% by wt.	—	—	—	—	—	—	—	66.00
KRONOS ® 2160	% by wt.	35.00	35.00	35.00	35.00	35.00	35.00	35.00	25.00
RESIFLOW ® PV 88	% by wt.	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
Benzoin	% by wt.	0.30	0.30	0.30	0.30	0.30	0.30	0.30	0.20
Curing at 200° C.	min		20	20	20	20	20	20	20	30
Film thickness	μm	67-71	57-66	57-59	57-61	66-73	54-60	52-59	58-62
Erichsen cupping	mm	>8	4	>8	5	>8	>8	>8	6
Ball impact direct	in lb	>80	>80	>80	>80	>80	>80	>80	20
Ball impact reverse	in lb	60	60	80	50	80	60	80	<10
Gloss 60°	units	36	53	44	51	30	33	45	33
Gloss 85°	units	44-48	62-67	53-59	60-64	39-43	41-43	55-61	59-65

By replacing the inventive β-hydroxyalkylamide 1a) by a standard commercial β-hydroxyalkylamide, such as VESTAGON HA 320 1b), or else by mixtures with other commercial products with the same and/or different functionality, it is possible to retain the gloss, at low levels of admixture, or, if desired, to shift it to higher values, with increased additivation or replacement. This is shown here in examples 9 to 13 by reference to a polyester.
Formulating examples with inventive β-hydroxyalkylamide 1a (matt curing agent) and different resins, and with commercial β-hydroxyalkylamide 1b)

	TABLE 2

	Example

	9	10	11	12	13

β-Hydroxyalkylamide	% by wt.	1.90	1.75	1.50	1.00	0.25
1a
VESTAGON HA 320	% by wt.	1.10	1.25	1.50	2.00	2.75
1b
CRYLCOAT ® 2617-3	% by wt.	60.70	60.70	60.70	60.70	60.70
KRONOS ® 2160	% by wt.	35.00	35.00	35.00	35.00	35.00
RESIFLOW ® PV 88	% by wt.	1.00	1.00	1.00	1.00	1.00
Benzoin	% by wt.	0.30	0.30	0.30	0.30	0.30
Curing at 200° C.	min		20	20	20	20	20
Film thickness	μm	57-66	57-59	57-61	66-73	54-60
Erichsen cupping	mm	>8	>8	>8	>8	>8
Ball impact direct	in lb	>80.00	>80.00	>80.00	>80.00	>80.00
Ball impact reverse	in lb	80	>80	>80	>80	>80
Gloss 60°	units	53	57	62	83	94

As co-crosslinkers it is also possible to use epoxy resins. Examples contemplated include glycidyl ethers and glycidyl esters, aliphatic epoxides, diglycidyl ethers based on bisphenol A, and glycidyl methacrylates. Examples of such epoxides are triglycidyl isocyanurate (TGIC trade names, e.g., ARALDIT PT 810, Huntsman; TEPIC G, Nissan; Taida TGIC, Anhui Taida), mixtures of diglycidyl terephthalate and triglycidyl trimellitate (trade names, e.g., ARALDIT PT 910 and PT 912, Huntsman), glycidyl esters of Versatic acid (trade name, e.g., CARDURA E10, Shell), 3,4-epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (ECC), diglycidyl ethers based on bisphenol A (trade name, e.g., EPIKOTE 828, Shell), ethylhexyl glycidyl ether, butyl glycidyl ether, pentaerythritol tetraglycidyl ether, (trade name, e.g., POLYPDX R 16, UPPC AG), and also other Polypox types having free epoxy groups. Mixtures can also be used. Preference is given to using TEPIC G or ARALDIT PT 910 and 912.
Co-crosslinkers of these kinds can be used at up to 50% by weight of the curing agent mixture used, composed of matt curing agent and co-crosslinker.
Formulating examples with inventive β-hydroxyalkylamide 1a (matt curing agent) and co-crosslinker

	TABLE 3

	Example

	14	15	16	17

β-Hydroxyalkylamide	% by wt.	2.95	2.90	2.80	2.50
1a
TEPIC ® G 3a	% by wt.	0.05	0.10	0.20	0.50
CRYLCOAT ® 2617-3	% by wt.	60.70	60.70	60.70	60.70
KRONOS ® 2160	% by wt.	35.00	35.00	35.00	35.00
RESIFLOW ® PV 88	% by wt.	1.00	1.00	1.00	1.00
Benzoin	% by wt.	0.30	0.30	0.30	0.30
Curing at 200° C.	min		20	20	20	20
Film thickness	μm	50-56	50-55	53-62	45-51
Erichsen cupping	mm	>8	>8	>8	>8
Ball impact direct	in lb	60	>80	>80	>80
Ball impact reverse	in lb	<10	>80	>80	>80
Gloss 60°	units	32	44	45	53
Gloss 85°	units	40-45	58-62	57-59	65-67

Examples 3a, b; 4a, b, c, d; 5

The DSC Measurements

The DSC measurements were carried out in accordance with DIN EN ISO 11357-1 of March 2010.
A heat flow difference calorimeter from the manufacturer Mettler-Toledo, model: DSC 821 with serial number 5116131417 was used. The samples are run once from −30° C. to 250° C. at 10 K/min.

Comprehensive Description of the Measurement Method:

- 1. Type (heat flow difference calorimeter or power-compensated calorimeter), model and manufacturer of the DSC instrument used;
- 2. Material, nature, and type, and also, when necessary, mass of the crucibles used;
- 3. Nature, purity, and volume flow rate of the flushing gas used;
- 4. Nature of the calibration method and details of the calibrating substances used, including source, mass, and other properties significant for calibration;
- 5. Details concerning sampling, sample preparation, and conditioning
  1: Heat flow difference calorimeter
- Manufacturer: Mettler-Toledo
- Model: DSC 821
- Serial number: 5116131417

2: Crucible Material: Ultrapure Aluminum

- Size: 40 μl, without pin,
- Mettler order No.: ME-26763
- Mass including lid: about 48 mg

3: Flushing Gas: Nitrogen

- Purity: 5.0 (>99.999% by volume)
- Volume flow rate: 40 ml/min

4: Calibrating Method: Single

- Material 1: indium
- Mettler calibrating set ME-51119991
- Mass: about 6 mg per weighing
- Calibration of temperature (onset) and heat flow
- Material 2: deionized water
- Taken from in-house system
- Mass: about 1 mg per weighing
- Calibration of temperature (onset)
  5: Sampling: from Supplied Sample Vials
- Sample weighing mass: 8 to 10 mg
- Sample preparation: pressed on the crucible base using die
- Crucible lid: perforated
- Measurement program: −30 to 250° C. 10 K/min 1×

Description of the XRPD Measurement:

The powder sample is pressed into a powder holder and is measured in a Philips PW1800 x-ray diffractometer using Cu Kα radiation (1.541 Å) under the following conditions:

Excitation: 40 kV, 45 mA

Measuring range: 3°≦2θ≦40°
Step size: 0.1° (2Theta)
Time per step: 20 s
Rotation: ¼ revolution/sec
Receiving slit: coarse
Divergence slit: automatic

Examples 3a, b; 4a, b, c, d


	Product description,
Substances used	manufacturer

Diethanolamine (DEA)	Dow Chemical
Dimethyl
1,4-cyclohexyldicarboxylate	Dimethylester of 1,4-
(DMCD) (distilled) trans content	cyclohexanedicarboxylic acid,
15-35 mol %	EASTMAN
Sodium methoxide	30% strength in methanol

Example 3a

A three-neck flask with reflux condenser and glass stirrer is charged with 92.24 g of dimethyl 1,4-cyclohexyldicarboxylate with 96.91 g of diethanolamine, 10.84 g of 30% strength sodium methoxide in methanol, and 52 g of methanol. A homogeneous solution is formed.
The batch is boiled in an oil heating bath under reflux with stirring for six hours (bath temperature 80° C.). The product begins to precipitate after about 0.5 hour.
The reaction mixture is left to cool, during which further product crystallizes out. The precipitated product is subsequently separated from methanol by filtration and then dried. The yield is more than 80% of theory. Table 3a
Obtained accordingly is an N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to formula XIIA having two endothermic peaks (1st at about 160° C. and 2nd at about 190° C.) in the DSC as per FIG. 1 and the XRPD spectrum as per FIG. 5 and table 5. This product thus produced produces far-reaching matting in powder coatings, with a gloss of less than 50 scale divisions at a 60° angle, table 3a.

Example 3b

The product produced in 3a is dissolved in boiling water, then slowly cooled again and, after crystallization has taken place, briefly washed with methanol. Table 3a This product exhibits the two endothermic peaks, see FIG. 2, with matting effect present in the resultant powder coatings, of 29 scale divisions at the 60 degree angle, table 3a.

TABLE 3A

End products from batch preparation examples 3a-3b and their characterization by GC analysis¹⁾

Example

	3a	3b

Starting material	—	3a
Preparation	Batch preparation as	Boil 3a in deionized water
	described in example	cool slowly
	3a	crystallize
		wash with methanol
		dry under vacuum

¹⁾DEA	% by mass	1.22	<0.1
¹⁾trans-N,N,N′,N′-Tetrakis(2-hydroxyethyl)cyclohexyl-1,4-	% by mass	89.34	91.81
diamide
¹⁾cis-N,N,N′,N′-Tetrakis(2-hydroxyethyl)cyclohexyl-1,4-	% by mass	0.74	0.00
diamide
Σ N,N,N′,N′-Tetrakis(2-hydroxyethyl)cyclohexyl-1,4-	% by mass	90.08	91.81
diamide
Ratio of ¹⁾trans-N,N,N′,N′-tetrakis(2-	mol %	99.2	1000
hydroxyethyl)cyclohexyl-1,4-diamide
to ¹⁾cis-N,N,N′,N′-tetrakis(2-	mol %	0.8	0.0
hydroxyethyl)cyclohexyl-1,4-diamide
OH number	mg KOH/g	629	—
Base number	—	22	—
DSC: 1^stendo. peak - Δ H	° C. - J/g	159-54	164-63
DSC: 2^ndendo. peak - Δ H	° C. - J/g	186-89	203-124

¹⁾Analytical values by GC GC after silylation with Silyl 991 (BSTFA-TMCS 99: 1) from Macherey and Nagel order

No. 701.490.150. Silylation: 1 ml Silyl 991, 1 ml pyridine, 35 mg reaction product, 35 mg C-18 hydrocarbon as internal

standard, heat for 30 minutes at 80° C. in a closed ampoule.

Powder coating data

PC experiment number

		3a	3b

HAA crosslinker	% by mass	3.00	3.00
CRYLCOAT ® 2617-3	% by mass	60.70	60.70
KRONOS ® 2160	% by mass	35.00	35.00
RESIFLOW ® PV 88	% by mass	1.00	1.00
Benzoin	% by mass	0.30	0.30
Total	% by mass	100.00	100.00
Curing	min @° C.	30 @ 200	30 @ 200
Film thickness	μm	64-70	70-73
Gloss at 60°	Sc. div.	30	29

OH number: DIN 53240

Base number: DIN 53176

Preparation Example A

Preparation of a β-hydroxyalkylamide of the formula XIIA from dimethyl-1,4-cyclohexyldicarboxylate and diethanolamine in an extruder


	Product description,
Substances used	manufacturer

Diethanolamine (DEA)	Dow Chemical
Dimethyl
1,4-cyclohexyldicarboxylate	Dimethylester of 1,4-
(DMCD) trans content 15-35 mol %	cyclohexanedicarboxylic acid,
	EASTMAN
Sodium methoxide	30% strength in methanol

Operation Took Place with Three Streams:
Stream 1 consisted of DMCD
Stream 2 consisted of DEA
Stream 3 consisted of the catalyst, the methanolic sodium methoxide solution.

The streams were metered so that the molar ratio between dimethyl 1,4-cyclohexyldicarboxylate and diethanolamine was 1:1.95.
The total amount of catalyst (only sodium methoxide, calculated on solvent-free basis), based on the total formula, was 0.50% to 3.0%.
Stream 1 was fed at a rate of 10.0 kg/h into the first barrel of a twin-extruder (ZSK 30, 32 d) (stream temperature 80 to 130° C.).
Stream 2 was fed in at a rate of 9.9 kg/h (stream temperature 65 to 145° C.).
Stream 3 was introduced through a nozzle from entry into the extruder into stream 2 (0.5 to 2.0 kg/h).
The extruder used consisted of 8 barrels, which were separately heatable and coolable. Barrels 1-5: 160° C., barrels 6-8: 120-160° C.
Barrels 3, 5, and 8 were provided with a vacuum dome (100 to 600 mbar).
The extruder screws were fitted with conveying elements. Ahead of the vacuum domes, kneading blocks were installed.
All of the temperatures represented setpoint temperatures. Regulation took place via electrical heating or water cooling. The extruder head was likewise heated electrically (100-160° C.).
The screw speed was 300 rpm. The reaction product was conveyed out of the extruder using a gear pump. The total throughput was 20 kg/h.
The end product was cooled via a pipe section or via an extruder and was guided onto a cooling belt, and cooled further.

Example 4a and 4b

4a
An N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide with the product data 4a is prepared in the same way as described in example A in an extruder (Werner and Pfleiderer ZSK 30, 32 d). Table 4
4b
This product, described and produced as in example 4a, is recrystallized. For this purpose, the product from example 4a is dissolved in deionized water at boiling and then slowly cooled and crystallized, to convert it back into the solid form. It is subsequently washed with methanol and dried in a vacuum drying oven at 50° C. and about 20 mbar. Table 4
Obtained accordingly is an N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide having two endothermic peaks (1^stat about 160° C. and 2^ndat about 190° C.) in the DSC. This product with the two peaks in the DSC as per FIG. 3 and the XRPD spectrum as per FIG. 7 produces far-reaching matting in powder coatings, with a gloss of 30 scale divisions at a 60° angle. Table 4.

Comparative Example 4c

A noninventive N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide with the DSC as per FIG. 4 was prepared.
This product shows only one endothermic peak in the DSC, at about 190° C., as per FIG. 4, and an XRPD spectrum as per FIG. 6 and table 6. The powder coating material produced from it does not exhibit far-reaching matting, but instead has a gloss of 95 scale divisions at the 60 degree angle. Table 4

Example 4d

An N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide of the formula XIIA with the product data 4d is prepared in the same way as described in example 1 in an extruder (Werner and Pfleiderer ZSK 30, 32 d). Table 4
This product thus produced is run onto a cooling belt and collected. This material is then conditioned thermally under reduced pressure in a drying cabinet at 80° C. for 24 hours, and the resulting product is subsequently comminuted.
This product produces far-reaching matting in powder coating materials, with a gloss of 40 scale divisions at the 60° angle. Table 4

TABLE 4

End products from continuous preparation, examples 4a-4b, and their characterization by GC analysis¹⁾

Product examples

	4a	4b	4d

Starting material	—	SK 988
Preparation	Extruder setting as	Dissolve 4a in deionized	Extruder setting as
	described in	water	described in example 1
	example 1	cool slowly	thermal conditioning
		crystallize	24 h 80° C. vacuum
		wash with methanol
		dry under vacuum

¹⁾DEA fraction	% by mass	2.17	0.11	1.2
¹⁾trans-N,N,N′,N′-Tetrakis(2-	% by mass	84.25	93.72	91.3
hydroxyethyl)cyclohexyl-1,4-diamide
¹⁾cis-N,N,N′,N′-Tetrakis(2-	% by mass	1.60	0.11	0.66
hydroxyethyl)cyclohexyl-1,4-diamide
Σ N,N,N′,N′-Tetrakis(2-	% by mass	85.85	93.83	91.96
hydroxyethyl)cyclohexyl-1,4-diamide
Ratio of ¹⁾trans-N,N,N′,N′-tetrakis(2-	mol %	98.1	99.9	99.3
hydroxyethyl)cyclohexyl-1,4-diamide
to ¹⁾cis-N,N,N′,N′-tetrakis(2-	mol %	1.9	0.1	0.7
hydroxyethyl)cyclohexyl-1,4-diamide
OH number	mg KOH/g	641	625
Base number	—	24	1.1
DSC: 1^stendo. peak - Δ H	° C. - J/g		162-61	158-50
DSC: 2^ndendo. peak - Δ H	° C. - J/g		200-128	188-115

¹Analytical values by GC. GC after silylation with Silyl 991 (BSTFA-TMCS 99: 1) from Macherey and Nagel order

standard, heat for 30 minutes at 80° C. in a closed ampoule.

Powder coating data

PC experiment number

		4b	4d

HAA crosslinker	% by mass	3.00	3.00
CRYLCOAT ® 2617-3	% by mass	60.70	60.70
KRONOS ® 2160	% by mass	35.00	35.00
RESIFLOW ® PV 88	% by mass	1.00	1.00
Benzoin	% by mass	0.30	0.30
Total	% by mass	100.00	100.00
Curing	Min @° C.	30 @ 200	30 @ 200
Film thickness	μm	52-55	58-68
Gloss at 60°	Sc. div.	29-30	40

OH number: DIN 53240

Base number: DIN 53176

End products from preparation of comparative examples 4c and

characterization by GC analysis¹⁾and powder coating material

	Comparative example
	4c

Starting material
Preparation	- allow to cool at RT

¹⁾DEA	% by mass	2.87
¹⁾trans-N,N,N′,N′-tetrakis(2-	% by mass	64.11
hydroxyethyl)cyclohexyl-1,4-
diamide
¹⁾cis-N,N,N′,N′-tetrakis(2-	% by mass	15.84
hydroxyethyl)cyclohexyl-1,4-
diamide
Σ N,N,N′,N′-tetrakis(2-	% by mass	79.95
hydroxyethyl)cyclohexyl-1,4-
diamide
Ratio of ¹⁾trans-N,N,N′,N′-	mol %	80.19
tetrakis(2-hydroxyethyl)cyclohexyl-
1,4-diamide
to ¹⁾cis-N,N,N′,N′-tetrakis(2-	mol %	19.81
hydroxyethyl)cyclohexyl-1,4-
diamide
OH number	mg KOH/g sample	—
Base number	—	—
DSC: 1^stendo. peak - ΔH	° C. - J/g
DSC: 2^ndendo. peak - ΔH	° C. - J/g	171-87

Powder coating data

		PC experiment number
		4c

HAA crosslinker	% by mass	3.00
CRYLCOAT ® 2617-3	% by mass	60.70
KRONOS ® 2160	% by mass	35.00
RESIFLOW ® PV 88	% by mass	1.00
Benzoin	% by mass	0.30
Total	% by mass	100.00
Curing	min @° C.	30 @ 200
Film thickness	μm	65-78
Gloss at 60°	Sc. div.	95

Example 5

A β-hydroxyalkylamide of the formula XIIA was prepared as in example 3a. From it a single crystal was grown. The inventive of the formula XIIA was investigated by x-ray structural analysis of a single crystal. Comprehensive details relating to the measurement are compiled in annex 1.

Annex 1

Single-Crystal X-Ray Structural Analysis

Analytical method: Single Crystal X-ray Structure Analysis “2012-0573602-06D”

Report: WHC 11/11 EKS

Receipt of sample: 2011-02-22
Report date: 2011-02-25
Objective: Determination of single crystal structure.
Compound: N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide, formula XIIA
Crystallization: by the chemist.
Crystal dimensions: colorless block, 0.50×0.40×0.40 mm³
Code: vesta
Comments: The asymmetric unit comprises half a molecule.

Experimental Details

The single crystal structure was determined using an instrument from Oxfor Diffraction which was equipped with a CCD detector (Ruby model), a conventional x-ray tube with Cu_Kαradiation, Osmic mirror as monochromator, and a low-temperature unit of the Cryojet type (T=100 K). Data collection was carried out in phi and omega scans. Data collection and reduction took place using Crysalis (Oxford Diffraction 2007).
Structural resolution and refinement took place using SHELXTL (V. 6.10, Sheldrick, University of Göttingen, 2000). All non-hydrogen atoms were refined anisotropically. The hydrogen atoms were refined as riding groups.

Tables

TABLE A

Crystal data and data relating to structural refinement for vesta.

Identification code	vesta
Empirical formula	C16H30N2O6
Formula weight	346.42
Temperature	100 K
Wavelength	1.54178 Å
Crystal system	Orthorhombic
Space group	Pbca
Unit cell	a = 10.06350(10) Å = 90°.
	b = 11.85290(10) Å = 90°.
	c = 14.6275(2) Å = 90°.
Volume	1744.79(3) Å³
Z	4
Density (calculated)	1.319 Mg/m³
Absorption coefficient	0.832 mm⁻¹
F(000)	752
Crystal dimensions	0.50 × 0.40 × 0.40 mm³
Theta range for data collection	6.05 to 65.68°.
Index range	−11 ≦ h ≦ 10, −12 ≦ k ≦ 14,
	−14 ≦ l ≦ 17
Number of reflections collected	9191
Symmetry-independent reflections	1482 [R(int) = 0.0345]
Completeness to theta = 65.68°	98.5%
Correction for absorption	Crysalis
Refinement	Full-matrix least-squares on F²
Data/restraints/parameters	1482/0/111
Goodness-of-fit on F²	1.065
Final R values [I > 2sigma(I)]	R1 = 0.0316, wR2 = 0.0792
R values (all data)	R1 = 0.0358, wR2 = 0.0817
Largest difference peaks	0.199 and −0.189 e · Å⁻³

TABLE B

Bond lengths [Å] and angles [°] for vesta.

	O(1)—C(4)	1.2478(15)
	O(2)—C(6)	1.4221(15)
	O(3)—C(8)	1.4205(16)
	N(1)—C(4)	1.3479(16)
	N(1)—C(5)	1.4741(15)
	N(1)—C(7)	1.4727(15)
	C(1)—C(3)#1	1.5291(17)
	C(1)—C(2)	1.5398(16)
	C(2)—C(4)	1.5189(17)
	C(2)—C(3)	1.5405(16)
	C(3)—C(1)#1	1.5291(17)
	C(5)—C(6)	1.5182(16)
	C(7)—C(8)	1.5159(17)
	C(4)—N(1)—C(5)	124.59(10)
	C(4)—N(1)—C(7)	117.87(10)
	C(5)—N(1)—C(7)	117.54(9)
	C(3)#1—C(1)—C(2)	110.62(10)
	C(4)—C(2)—C(1)	111.04(10)
	C(4)—C(2)—C(3)	108.67(10)
	C(1)—C(2)—C(3)	110.09(10)
	C(1)#1—C(3)—C(2)	111.18(10)
	O(1)—C(4)—N(1)	119.97(11)
	O(1)—C(4)—C(2)	120.15(10)
	N(1)—C(4)—C(2)	119.84(10)
	N(1)—C(5)—C(6)	113.66(9)
	O(2)—C(6)—C(5)	110.97(10)
	N(1)—C(7)—C(8)	113.52(10)
	O(3)—C(8)—C(7)	113.31(10)

	Symmetry operations for generating equivalent atoms:
	#1 −x + 1, −y + 1, −z

TABLE C

Torsional angles [°] for vesta.

	C(3)#1—C(1)—C(2)—C(4)	177.11(9)
	C(3)#1—C(1)—C(2)—C(3)	56.72(14)
	C(4)—C(2)—C(3)—C(1)#1	−178.85(9)
	C(1)—C(2)—C(3)—C(1)#1	−57.04(14)
	C(5)—N(1)—C(4)—O(1)	176.19(10)
	C(7)—N(1)—C(4)—O(1)	−3.65(16)
	C(5)—N(1)—C(4)—C(2)	−6.21(16)
	C(7)—N(1)—C(4)—C(2)	173.95(10)
	C(1)—C(2)—C(4)—O(1)	−54.62(14)
	C(3)—C(2)—C(4)—O(1)	66.61(14)
	C(1)—C(2)—C(4)—N(1)	127.78(11)
	C(3)—C(2)—C(4)—N(1)	−110.98(12)
	C(4)—N(1)—C(5)—C(6)	80.57(13)
	C(7)—N(1)—C(5)—C(6)	−99.58(12)
	N(1)—C(5)—C(6)—O(2)	61.92(13)
	C(4)—N(1)—C(7)—C(8)	86.25(13)
	C(5)—N(1)—C(7)—C(8)	−93.60(12)
	N(1)—C(7)—C(8)—O(3)	73.97(13)

	Symmetry operations for generating equivalent atoms:
	#1 −x + 1, −y + 1, −z

FIG. 11:

Calculated powder diffractogram based on the single crystal structural determination of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide (vesta sample)

Claims

1. A powder coating composition, comprising:

A) a polymer comprising a carboxylate group and having an acid number of 5 to 250 mg KOH/g and a glass transition temperature T_gof greater than 40° C.;

and

B) a β-hydroxyalkylamide having two or three or four β-hydroxyalkylamide groups per molecule of the formula I

wherein:

R¹and R²are, independently of one another, identical or different radicals selected from the group consisting of an alkyl radical, a cycloalkyl radical, an aryl radical, an aralkyl radical and an alkenyl radical having 1-24 carbon atoms, said radicals optionally comprising a heteroatom, a functional group, or both, and where R¹may also be hydrogen, such that R²is optionally:

A is A¹, A²or A³:

such that radicals R³are, independently of one another, identical or different radicals selected from the group consisting of hydrogen, an alkyl radical, a cycloalkyl radical, an aryl radical, an aralkyl radical and an alkenyl radical having 1-24 carbon atoms, said radicals optionally comprising a heteroatom, a functional group, or both, such that two or more substituents R³are optionally linked with one another to form rings; and

the β-hydroxyalkylamide is present in solid form below 150° C.;

C) optionally auxiliaries additives, or both;

wherein a ratio of the β-hydroxyalkylamide groups to the carboxylate groups is between 0.5:1 to 1.5:1.

2. The powder coating composition of claim 1, wherein the β-hydroxyalkylamide derives from β-hydroxyalkylamines comprising alkyl groups having at least 2 to 10 carbon atoms in the hydrocarbon framework as starting materials, said alkyl groups being linear, branched or cyclic and optionally substituted by at least one heteroatom, and optionally comprising at least one functional group such that the β-hydroxyalkylamines optionally comprise an additional alkyl radical on the nitrogen.

3. The powder coating composition of claim 1, comprising β-hydroxyalkylamides of N-alkyl-1,2-alkanolamines and/or of N,N-bis-2-hydroxyalkylamines and esters of cyclohexanedicarboxylic acids.

4. The powder coating composition of claim 1, wherein the β-hydroxyalkylamines are hydroxylamines of the formulae II and/or III:

wherein

R¹is hydrogen, methyl, ethyl, or propyl,

R²is methyl;

wherein radicals R¹simultaneously or independently of one another are hydrogen, methyl, ethyl, or propyl.

5. The powder coating composition of claim 1, wherein the following compounds are starting materials for preparing the β-hydroxyalkylamide: diethanolamine (DEA), di-isopropropanolamine (DIPA), di-sec-butanolamine, N-methylethanolamine, N-methylisopropanolamine.

6. The powder coating composition of claim 1, wherein the substituent A derives from 1,2-substituted, 1,3-substituted, and 1-4-substituted cyclohexanedicarboxylic acid derivatives.

7. The powder coating composition of claim 1, wherein

the β-hydroxyalkylamide is prepared from compounds of the formula IV:

wherein radicals R⁴simultaneously or independently of one another are methyl, ethyl, propyl, or butyl.

8. The powder coating composition of claim 1, wherein at least one 1,4-substituted cyclohexanedicarboxylic ester is a starting compound.

9. The powder coating composition of claim 1, wherein the β-hydroxyalkylamide B) has at least one of the following formulae:

wherein:

R²is methyl,

or

where R^1Ais hydrogen and R^1Bis methyl, ethyl, or propyl,

or

R^1Ais methyl, ethyl, or propyl and R^1Bis hydrogen;

A is a 1,4-disubstituted cyclohexane ring of the formula:

a trans content of A is ≧70 mol %; and

at least one β-hydroxyalkylamide B) is present in solid form below 150° C.

10. The powder coating composition of claim 1, comprising β-hydroxyalkylamides of dialkyl 1,4-cyclohexyldicarboxylates, with a trans content, based on the position of the carboxyl groups on the cyclohexyl ring, of greater than or equal to 70 mol %.

11. The powder coating composition of claim 1, wherein:

the β-hydroxyalkylamide consists of dimethyl 1,4-cyclohexyldicarboxylate and diethanolamine having four β-hydroxyalkylamide groups per molecule of the formula XII:

having a trans content on the cyclohexyl ring of greater than or equal to 70 mol.

12. The powder coating composition of claim 1, wherein the β-hydroxyalkylamide is present in solid form below 150° C.

13. The powder coating composition of claim 1, comprising a polyester A) comprising at least one carboxylate group and having:

a glass transition temperature T_gin a range from 40 to 80° C.

an acid number varied from 5-250 mg KOH/g;

an OH number of less than 15 mg KOH/g; and

an average molecular weight M_wof 1000 to 10 000 g/mol.

14. The powder coating composition of claim 1, comprising an acrylate polymer A) comprising at least one carboxylate group and having:

an OH number of less than 10 mg KOH/g;

an acid number of 10 to 350 mg KOH/g;

a Tg of 40 to 110° C.; and

an M_Wof 500 to 50 000 g/mol.

15. The powder coating composition of claim 1, comprising at least one co-crosslinker based on epoxy resins and/or β-hydroxyalkylamides different from the β-hydroxyalkylamide B).

16. A method for producing the powder coating composition of claim 1, the method comprising

conducting joint extrusion of all the components in a melt at temperatures between 80 to 150° C.

17. A process for producing a coating for a matt surface, the process comprising applying the powder coating composition of claim 1 to a surface, wherein the coating has

a gloss to DIN 67530/ISO 2813 of <50 at an incident angle of 60.

18. The powder coating composition of claim 1, comprising a N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide according to the formula XIIA as component B),

having the following parameters:

a trans content on the cyclohexyl ring of the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide of greater than or equal to 70 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present;

two endothermic peaks according to DSC analysis (differential scanning calorimetry), where peak 1 is situated in the region of 140-170° C. with a maximum of 155-165° C., and peak 2 is situated in the region of 170-210° C. with a maximum of 175-207° C.;

a ratio of the enthalpies of the peak 1 to the peak 2 is 1:1 to 1:5; and

the following peaks in the XRPD spectrum of the powder sample in the x-ray diffractometer, measured with Cu Kα radiation (1.541 Å):

Degrees 2theta ± Peak #. 0.2 degree 2theta d (Å) 1 14.90 5.94 2 16.70 5.31 3 17.40 5.09 4 21.20 4.19 5 21.60 4.11 6 26.00 3.43.

19. The powder coating composition of claim 18, having a trans content on the cyclohexyl ring of greater than or equal to 92 mol %, based on the total amount of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide that are present.

20. The powder coating composition of claim 18, wherein the β-hydroxyalkylamide of the formula XIIA is present in solid form below 175° C.

21. The powder coating composition of claim 18, wherein a concentration of all of the isomers of N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide in the end product after its production is 75% by mass.

22. The powder coating composition of claim 18, wherein a ratio of the enthalpies of the peak 1 to the peak 2 is 1:1 to 1:3.

23. The powder coating composition of claim 18, wherein the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide,

according to x-ray structural analysis of a single crystal, has the following parameters:

Crystal system: Orthorhombic Space group: Pbca Unit cell dimensions: a = 10.06350(10) Å α = 90°[[.]] b = 11.85290(10) Å β = 90°[[.]] c = 14.6275(2) Å γ = 90°[[.]] Volume: 1744.79(3) Å³.

24. A process for producing a coating for a matt surface, the process comprising applying the powder coating composition of claim 18 to a surface, wherein the coating has

matt surfaces with <50 gloss units, measured as reflectometer values to DIN 67530/ISO 2813 with an incident angle of 60°.

25. The process of claim 24, wherein the N,N,N′,N′-tetrakis(2-hydroxyethyl)cyclohexyl-1,4-diamide,

Crystal system: Orthorhombic Space group: Pbca Unit cell dimensions: a = 10.06350(10) Å α = 90°. b = 11.85290(10) Å β = 90°. c = 14.6275(2) Å γ = 90°. Volume: 1744.79(3) Å³.

26-27. (canceled)