POLYMERS, PROCESSES, COMPOSITIONS & USES

Abstract

The invention relates to a polymer comprising certain specific units. The invention further relates to processes for making the polymer of the invention. The invention further relates to a binder and compositions comprising the polymer, preferably to compositions suitable for paints and coatings. The invention relates in particular to water-borne, solvent-borne and powder coating compositions and preferably to curable water-borne, curable solvent-borne and curable powder coating compositions. The invention further relates to cured compositions. The invention further relates to objects, in particular coatings prepared from the compositions of the invention. The invention further relates to processes for making the compositions of the invention. The invention further relates to articles having coated thereon the compositions of the invention. The invention further relates to articles having coated and cured thereon the compositions of the invention. The invention further relates to various uses of the polymer of the invention, the binder of the invention, the composition of the invention, the cured composition of the invention and various uses of articles having coated and optionally cured thereon the compositions of the invention.

Claims

1. A polymer having: a) an acid value (AV) measured titrimetrically according to ISO 2114 of at least 105 and at most 180 mg KOH/g, and b) a glass transition temperature (T.sub.g) measured via Differential Scanning calorimetry as described in the description, of at least 30 and at most 140 C. and wherein the polymer comprises one or more units selected from the group consisting of S1, S2, S3 S4, and combinations thereof, wherein each of S1, S2, S3, and S4 is represented by the following corresponding formula: ##STR00044## wherein i) k is an integer equal to or higher than 0, and ii) m is an integer equal to or higher than 0, and iii) n is an integer equal to or higher than 0, and iv) p is an integer equal to or higher than 0, and v) the sum of k, m, n and p is equal to or higher than 1, and vi) X is selected from the group consisting of L4, L6, L7, L8, L9, L10, L11, L12, L13, L18, L19, L20, L23, L24, L25, L26, L27, L28, L29, L30, and L31 as each of L4 to L31 is defined below, and wherein the black bold dots shown in the formulae of any one of L4 to L31 represent the attachment points of each of L4 to L31 to the S1, and wherein the attachment points are carbon atoms, vii) Y is selected from the group consisting of L4, L6, L7, L8, L9, L10, L11, L12, L13, L18, L19, L20, L23, L24, L25, L26, L27, L28, L29, L30, and L31 as each of L4 to L31 is defined below, and wherein the black bold dots shown in the formulae of any one of L4 to L31 represent the attachment points of each of L4 to L31 to the S2, and wherein the attachment points are carbon atoms, viii) Z is selected from the group consisting of L4, L6, L7, L8, L9, L10, L11, L12, L13, L18, L19, L20, L23, L24, L25, L26, L27, L28, L29, L30, and L31 as each of L4 to L31 is defined below, and wherein the black bold dots shown in the formulae of any one of L4 to L31 represent the attachment points of each of L4 to L31 to the S3, and wherein the attachment points are carbon atoms, ix) T is selected from the group consisting of L4, L6, L7, L8, L9, L10, L11, L12, L13, L18, L19, L20, L23, L24, L25, L26, L27, L28, L29, L30, and L31 as each of L4 to L31 is defined below, and wherein the black bold dots shown in the formulae of any one of L4 to L31 represent the attachment points of each of L4 to L31 to the S4, and wherein the attachment points are carbon atoms, ##STR00045## ##STR00046## ##STR00047## wherein R.sub.1, R.sub.2 is independently selected from the group consisting of H and CH.sub.3, and R.sub.3, is a CH.sub.2 or C.sub.2-C.sub.34 optionally-substituted-hydrocarbylene, and R.sub.4R.sub.5R.sub.6R.sub.7 is independently selected from the group consisting of H, CH.sub.3, and C.sub.2-C.sub.34 optionally-substituted-hydrocarbyl, R.sub.8, R.sub.9 is independently selected from C.sub.1-C.sub.34 optionally-substituted-hydrocarbyl, and R.sub.10, R.sub.11 is independently selected from C.sub.1-C.sub.12 saturated-hydrocarbyl, and R.sub.12 is C.sub.4-C.sub.34 unsaturated-acyclic-hydrocarbyl.

2. The polymer according to claim 1, wherein the AV is at most 170 mg KOH/g.

3. The polymer according to claim 1, wherein the AV is at least 110 and at most 170 mg KOH/g.

4. The polymer according to claim 1, wherein the AV is at least 130 and at most 170 mg KOH/g.

5. The polymer according to claim 1, wherein the T.sub.g is at least 40 and at most 95 C.

6. The polymer according to claim 1, wherein the T.sub.g is at least 40 and at most 85 C.

7. The polymer according to claim 1, wherein the polymer has a MRQ of at least 1 and at most 1.4, and wherein the MRQ is $M.Math..Math.R.Math..Math.Q=\frac{S_{\mathrm{total}}}{S_{\mathrm{specific}}}=\frac{S_{\mathrm{specific}}+S_{\mathrm{rest}}}{S_{\mathrm{specific}}}$ wherein S.sub.total=S.sub.specific+S.sub.rest, and S.sub.specific=(total moles S1)+(total moles S2)+(total moles S3)+(total moles S4), and S.sub.rest=the total moles of all the units of a polymer wherein said units are not any one of S1, S2, S3, S4, and wherein the MRQ is determined is determined via NMR spectroscopy, as described in the description.

8. The polymer of claim 7, wherein the MRQ is at most 1.3, preferably at most 1.2.

9. The polymer according to claim 1 wherein the polymer has: i) a number average molecular weight (M.sub.n) of at least 810.sup.2 and at most 10.sup.4 Da, and ii) a polydispersity (D) (D=M.sub.w/M.sub.n) of at least 1 and at most 10, and iii) a T.sub.g of at least 40 and at most 85 C., and iv) an AV of at least 110 and at most 170 mg KOH/g, and v) a hydroxyl value (OHV) of at least 0 and at most 400 mg KOH/g, and vi) a functionality (f) of at least 3 and at most 25, wherein M.sub.w is the weight average weight and is measured via Gel Permeation Chromatography according to the description, and M.sub.n is measured via Gel Permeation Chromatography according to the description, and OHV is measured titrimetrically via ISO 4629, and f is as defined and measured in the description.

10. The polymer according to claim 1, wherein the polymer is an acid-functional polyester.

11. The polymer according to claim 1, wherein the polymer is ionic.

12. A process for making a polymer as defined in claim 1, comprising the steps of a. providing: a-i) a mono-epoxide selected from the group consisting of E4, E6, E7, E8, E9, E10, E11, E12, E13, E18, E19, E20, E23, E24, E25, E26, E27, E28, E29, E30, E31 and mixtures thereof, as each of E4 to E31 is represented by the following corresponding formula: ##STR00048## ##STR00049## ##STR00050## wherein R.sub.1, R.sub.2 is independently selected from the group consisting of H and CH.sub.3, and R.sub.3, is a CH.sub.2 or C.sub.2-C.sub.34 optionally-substituted-hydrocarbylene, and R.sub.4R.sub.5R.sub.6R.sub.7 is independently selected from the group consisting of H, CH.sub.3, and C.sub.2-C.sub.34 optionally-substituted-hydrocarbyl, R.sub.8, R.sub.9 is independently selected from C.sub.1-C.sub.34 optionally-substituted-hydrocarbyl, and R.sub.10, R.sub.11 is independently selected from C.sub.1-C.sub.12 saturated-hydrocarbyl, and R.sub.12 is C.sub.4-C.sub.34 unsaturated-acyclic-hydrocarbyl, and wherein none of R.sub.1 to R.sub.12 comprises any anhydride group, and a-ii) a reagent A selected from the group consisting of trimellitic acid anhydride, trimellitic acid, citric acid anhydride, citric acid and mixtures thereof, and a-iii) optionally a catalyst A, and a-iv) optionally an organic solvent, and a-v) optionally a reagent B selected from the group comprising of anhydride A, cyclic ester and mixtures thereof, and b. charging a-i) to a-v) provided in step a. into a reaction vessel to form a reaction mixture, and c. polymerizing the reaction mixture, c-i) at a temperature of at least 60 and at most 200 C., and c-ii) for a time of at least 0.5 hours and at most 200 hours, and c-iii) removing water by applying vacuum, if water is formed during the polymerization of the reaction mixture, and c-iv) optionally applying pressure with the proviso that vacuum and pressure are not applied at the same time, to afford the polymer, and d. discharging the polymer from the reaction vessel and collecting said polymer, and wherein the molar ratio L between the moles of monoepoxide as defined in a-i) and the moles of reagent A as defined in a-ii), Molar ratio L=moles of monoepoxide/moles of reagent A is at least 0.1 and at most 2.9, preferably at least 0.3 and at most 2.8.

13. A heat-curable powder coating composition comprising a binder in an amount of at least 1 and at most 100 pph composition, and wherein the binder comprises: a) a polymer as defined in claim 1, in an amount of at least 10 and at most 99 pph binder, and b) an acid-functional copolymerizable polymer A which is an acid functional polyester B, in an amount of at least 10 and at most 99 pph, and c) a copolymerizable agent able to react with the polymer and the acid-functional copolymerizable polymer A, in an amount of at least 1 and at most 90 pph binder, and wherein the acid-functional polyester B is different from the polymer, and the difference between the AV of the polymer and the AV of the copolymerizable polymer A (DeltaAV) each of the AV measured titrimetrically according to ISO 2114 is at least 30 mg KOH/g, and wherein the AV of the copolymerizable polymer A is lower than the AV of the polymer.

14. The heat-curable powder coating composition of claim 13, wherein the DeltaAV is at least 75 mg KOH/g.

15. The heat-curable powder coating composition of claim 13, wherein the DeltaAV is at least 100 mg KOH/g.

16. The heat-curable powder coating composition according to any one of claims 13 to 15, wherein the Weight Ratio R (WR) $\mathrm{Weight}.Math..Math.\mathrm{Ratio}.Math..Math.R=\frac{\begin{array}{c}\mathrm{Weight}.Math..Math.\mathrm{of}.Math..Math.\mathrm{acid}-\\ \mathrm{functional}.Math..Math.\mathrm{copolymerizable}.Math..Math.\mathrm{polymer}.Math..Math.A\end{array}}{\mathrm{Weight}.Math..Math.\mathrm{of}.Math..Math.\mathrm{polymer}}$ is at least 1 and most 10.

17. The heat-curable powder coating composition of claim 16, wherein the WR is at least 2 and at most 8.

18. The heat-curable powder coating composition according to claim 13, wherein the acid-functional copolymerizable polymer A has an AV measured titrimetrically according to ISO 2114 of at least 15 and at most 40 mg KOH/g, and a T.sub.g measured via Differential Scanning calorimetry as described in the description, of at least 40 and at most 80 C.

19. The heat-curable powder coating composition according to claim 13, wherein the copolymerizable agent is a BHA compound in an amount of at least 2 and at most 15 pph binder.

20. A cured composition as the composition is defined in claim 13.

21. An article having coated a composition as the composition is defined in claim 13.

22. An article having coated and cured thereon a composition as the composition is defined in claim 13.

23. (canceled)

24. A product which comprises the polymer according to claim 1, wherein the product is selected from the group consisting of paints, polishes, inks, adhesives, pastes, 3D-printing materials, automotive products, marine products, aerospace products, medical products, defense products, sports/recreational products, architectural products, bottling products, household products, machinery products, can products, coil products, energy products, textiles and electrical products.

Description

EXAMPLES

[0655] The invention is explained in more detail with reference to the following non-limiting examples.

1 Chemicals, Raw Materials; Analytical Methods and Techniques

1.1 Chemicals & Raw Materials

[0656] Cardura E10P (supplied by HEXION; glycidyl ester of Versatic Acid 10, is a synthetic saturated monocarboxylic acid of highly branched C.sub.10 isomers of the following formula:

##STR00043##

wherein each of Q1 and Q2 is a short chain alkyl group and wherein the total number of carbon atoms of both of these alkyl groups is 7. Primid XL-552 (T.sub.m=120-124 C., OHV=620-700 mg KOH/g) is a BHA-compound supplied from EMS Chemie and it was used as a crosslinker. Kronos 2360 is titanium dioxide (white pigment) supplied from Kronos Titan GmbH. Resiflow PV 5 is a flow control agent from Worle-Chemie GmbH. Benzoin was used as degassing agent. Any other chemicals mentioned in the Examples and not explicitly mentioned in this paragraph, were supplied by Aldrich and they were used as supplied.

1.2 Analytical Methods and Techniques

[0657] The acid value (AV) was measured titrimetrically according to ISO 2114. The AV is given as the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of the tested substance and is used as a measure of the concentration of carboxylic acid groups present.

[0658] The hydroxyl value (OHV) was measured titrimetrically according to ISO 4629. The OHV is given as the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of the tested substance and is used as a measure of the concentration of hydroxyl groups present.

[0659] The glass transition temperature (T.sub.g) of the Polymer was measured by Differential Scanning calorimetry (DSC) at a heating rate of 5 C./min in N.sub.2 atmosphere at a flow rate of 50 mL/minute, on a a TA instruments DSC Q2000 apparatus according to the following method: a sample of 100.5 mg was weight and placed in the DSC cell at a temperature between 20 and 25 C. The sample was cooled down to 50 C. and the temperature was kept at 50 C. for time enough for the sample to reach equilibrium; upon equilibration the sample was heated up from 50 C. up to 160 C. at a heating rate of 5 C./minute; the sample was kept at that temperature for 2 minutes and it was subsequently cooled down to 50 C. at a cooling rate of 20 C./min; once the sample reached 50 C. the temperature was maintained for 5 minutes; subsequently, the sample was heated up from 50 C. up to 220 C. at a heating rate of 5 C./minute (thermograph A). The T.sub.g was measured from this last thermograph (thermograph A) as the inflection point of the DSC signal (DSC thermograph, Heat Flow vs. Temperature) The processing of the DSC signal and the determination of the T.sub.g was carried out using Universal Analysis 2000 software version 4.5a provided by TA instruments.

[0660] The glass transition temperature (T.sub.g) of the Binder is measured by Differential Scanning calorimetry (DSC) at a heating rate of 5 C./min in N.sub.2 atmosphere at a flow rate of 50 mL/minute, on a a TA instruments DSC Q2000 apparatus according to the following method: a sample of 100.5 mg is weight and placed in the DSC cell at a temperature between 20 and 25 C. The sample is cooled down to 50 C. and the temperature is kept at 50 C. for time enough for the sample to reach equilibrium; upon equilibration the sample is heated up from 50 C. up to 220 C. at a heating rate of 5 C./minute (thermograph A). The T.sub.g was measured from this last thermograph (thermograph A) as the inflection point of the DSC signal (DSC thermograph, Heat Flow vs. Temperature) The processing of the DSC signal and the determination of the T.sub.g was carried out using Universal Analysis 2000 software version 4.5a provided by TA instruments.

[0661] The number average molecular weight (M.sub.n) and the weight average molecular weight (M.sub.w) were measured via gel permeation chromatography (GPC) calibrated with a set of polystyrene standards with a molecular weight range of from 500 up to 710.sup.6 g/mol and using as eluent stabilized tetrahydrofuran (THF) modified with 0.8% acetic acid at a flow rate of 1 mL/min at 40 C. The GPC measurements were carried out on a Waters Alliance system equipped with: i) an Waters Alliance 2414 refractive index detector at 40 C., and ii) a Waters Alliance 2695 separation module equipped with two consecutive PL-gel columns of Mixed-C type with l/d=300/7.5 mm and filled with particles having a particle size of 10 m (supplied by the Polymer Laboratories).

[0662] The polydispersity (D) was calculated according to the following equation:

D=M.sub.w/M.sub.n.

[0663] .sup.1H-NMR or .sup.13C-NMR or .sup.31P-NMR spectroscopy or combinations thereof were used to characterize chemical entities shown herein. .sup.1H-NMR spectra were recorded on a Varian Mercury Vx (400 MHz) spectrometer or on a Bruker Advance (400 MHz) spectrometer at 25 C. in chloroform-d1 unless stated otherwise and referenced versus residual solvent shifts. .sup.13C-NMR spectra were recorded on a Varian Mercury Vx (100 MHz) spectrometer or on a Bruker Advance (100 MHz) spectrometer at 25 C. in chloroform-d1 unless stated otherwise and referenced versus residual solvent shifts. .sup.31P-NMR spectra were recorded on a Varian Mercury Vx (162 MHz) spectrometer or on a Bruker Advance (162 MHz) spectrometer at 25 C. in chloroform-d1: pyridine (70:30 v/v) and referenced versus residual solvent shifts (the .sup.31P-NMR method according to P. Dais and A. Spyros described in Magnetic Resonance in Chemistry 2007; 45:367, may be used).

[0664] The coating (film) thickness of the cured coatings, was measured with a PosiTector 6000 coating thickness gauge from DeFelsko Corporation according to EN ISO 2808:2007.

[0665] Gloss 60 of the powder coatings derived upon curing of the corresponding heat-curable powder coating compositions on ALQ-46 panels were measured according to ASTM D523 with a BYK-Gardner GmbH Haze-Gloss meter. The gloss was measured at a film thickness of 505 m on ALQ-46 panels, recorded at an angle of 60, and it was reported in gloss units.

[0666] The physical storage stability (PSS) is tested at 23 C. for 3 weeks. Prior to assessing the PSS the heat-curable powder coating composition is left to cool down to room temperature for about 3 hours. The greater the extend of agglomeration or sintering the poorer the PSS, thus the lower its ranking according to the following scale. The extent of agglomeration is visually assessed and ranked according to the following rating on a 1-10 scale (1 representing the worst PSS and 10 the best PSS):

10: No change.
9: No agglomeration, very good fluidity.
8: No agglomeration, good fluidity.
7: Very low agglomeration; agglomeration can be dispersed by one light tap into a fine powder.
6: Very low agglomeration; agglomeration can be dispersed by several taps into a fine powder.
5: Low agglomeration; agglomeration can be dispersed by hand pressure into a fine powder.
4: Low agglomeration; agglomeration cannot be dispersed by hand pressure in a fine powder.
3: Severe agglomeration into several large lumps, material is pourable.
2: Severe agglomeration into several large lumps, material is not pourable.
1: product sintered to one lump, volume reduced.

[0667] The reverse impact resistance (RIR) (inch/lbs, 1 inch/lbs=0.055997 m/kg) was tested according to ASTM D 2794, with a ball at 60 inch/lbs and at a film thickness of 505 m on ALQ-46 panels, one day after the coating was applied, cured at 200 C. for 15 minutes and subsequently cooled at room temperature. If the coating withstood the impact of 60 inch/lbs, then this result was reported as a pass; if the coating did not withstand the impact of 60 inch/lbs then this result was recorded as fail.

[0668] The chemical resistance (CR) of the coatings was assessed via acetone double rubs (ADR). With one acetone double rub (ADR) is meant one continuous back and forward movement, in a cycle time of about one second, over the surface of a coating having a thickness of 505 microns using a cotton cloth drenched in acetone, which cotton cloth covers a hammer head having a weight of about 980 grams and a contact surface area with the coating of about 2 cm.sup.2. Every 10 rubs the cloth was drenched in acetone. The measurement was carried out at room temperature, and it was performed on coatings that were left at room temperature for 168 hours before been tested, and within 2 h from the lapse of the time period of 168 hours; the measurement was continued either until the coating was removed and the number of ADR at which the coating was removed was reported, or until 500 ADR were reached. For example, a result reported as 200 ADR indicates that there was no coating left after 200 ADR.

[0669] By the term Molar Ratio Q (abbreviated as MRQ and referring to a polymer comprising units selected from the group consisting of S1, S2, S3, S4, and combinations thereof, as each of S1, S2, S3 and S4 is disclosed herein) is meant herein:

[00006]$M.Math..Math.R.Math..Math.Q=\frac{S_{\mathrm{total}}}{S_{\mathrm{specific}}}=\frac{S_{\mathrm{specific}}+S_{\mathrm{rest}}}{S_{\mathrm{specific}}}$

wherein
S.sub.total=S.sub.specific+S.sub.rest, and
S.sub.specific=(total moles S1)+(total moles S2)+(total moles S3)+(total moles S4), and
S.sub.rest=the total moles of all the units of a polymer wherein said units are not any one of S1, S2, S3, S4.
The MRQ is by definition equal to or higher than 1.
The MRQ can be determined by a combination of well-known analytical techniques and a methodology such as those described just below.
At first, one may determine the composition of the polymer via high resolution NMR spectroscopy e.g. .sup.1H-NMR (400 MHz), .sup.13C-NMR (100 MHz), .sup.31P-NMR (162 MHz) [after phosphorylation reaction of the hydroxyl and carboxylic acid groups with 2-chloro-4,4,5,5-tetramethyldioxaphospholane (I) and the related derivative product (II); see method as reported by P. Dais and A. Spyros in Magnetic Resonance in Chemistry 2007, 45:367], or combinations thereof may be used; this is to say that the kind of constitutional units that make up the polymer e.g. monomer residues, or groups of atoms that form distinct residues, and their corresponding amounts are determined. Various well-known 2D NMR techniques such as COSY (homonuclear correlation spectroscopy), HSQC (heteronuclear single-quantum correlation spectroscopy) and HMBC (heteronuclear multiple-bond correlation spectroscopy) may be applied.

[0670] Subsequently, and having determined the polymer composition as described above, one may determine: [0671] i) the total mol of ester groups ( . . . OC(O) . . . ) originating from the units S1, S2, S3, S4, and [0672] ii) the total mol of any other repeating unit from sequences of monomer residues or group of atoms that form distinct residues, wherein each of said units is different than those of S1, S2, S3, S4.

[0673] The determination of i) can be carried out by .sup.13C-NMR spectroscopy assisted by the co-employment of .sup.1H-NMR and .sup.31P-NMR spectroscopies, focusing on:

[0674] ia) all the carbon atoms present in respectively S1, S2, S3 and S4 (excluding the carbon atoms belonging to X, Y, Z and T) and;

[0675] ib) the first carbon atom of X, Y, Z and T that is directly connected to the ester group of S1, S2, S3, S4, respectively.

If a carbon atom is a tertiary carbon atom, then only .sup.13C-NMR; if a carbon atom is primary or secondary .sup.1H-NMR may be also applied and assist the analysis from the .sup.13C-NMR spectroscopy. Typically, .sup.31P-NMR is used to determine the type of present carboxylic acid and hydroxyl groups present in these units. Various well-known 2D (see above) and/or 3D NMR techniques (e.g. experiments consisting of 2D experiments after another, the triple resonance experiments, etc.) may be used alone or in combination. Upon the completion of this part of the analysis, one is able to determine the total mol of S1, S2, S3 and S4 units, and thus the S.sub.specific.

[0676] The determination of ii) can be carried out by .sup.13C-NMR spectroscopy assisted by the co-employment of .sup.1H-NMR and .sup.31P-NMR spectroscopies, focusing on the carbon atoms present in the sequences of monomer residues or group of atoms that that form distinct residues, and especially to the carbon atoms which are immediately next to the bonds connecting the various units together.

If a carbon atom is a tertiary carbon atom, then only .sup.13C-NMR; if a carbon atom is primary or secondary .sup.1H-NMR may be also applied and assist the analysis from the .sup.13C-NMR spectroscopy. Typically, .sup.31P-NMR is used to determine the type of present carboxylic acid and hydroxyl groups present in these units. Various well-known 2D (see above) and/or 3D NMR techniques (e.g. experiments consisting of 2D experiments after another, the triple resonance experiments, etc.) may be used alone or in combination. Upon the completion of this part of the analysis, one is able to determine the total mol of any unit other than S1, S2, S3 and S4 units, and thus the S.sub.rest.

[0677] Subsequently, given the values for the S.sub.specific and S.sub.rest, one is able to calculate the MRQ by factoring in the equation concerning the MRQ (see above in this paragraph) the values for the S.sub.specific and S.sub.rest.

2 Example of a Polymer According to the Invention and Example of a Process (According the Invention) for Making Said Polymer.

2.1 Example 1: Preparation of a Polymer According to 1.1 Consisting of One S1 Unit, Wherein X is L30

(PEX1)

[0678] Cardura E10P (228.33 g 1.00 mol) and trimellitic anhydride (192.13 g, 1.00 mol) were charged and mixed into a reactor vessel under a nitrogen flow to form a mixture. The mixture was subsequently polymerized at a temperature ranging from 130 to 150 C. for 2.5 hours. The progress of the polymerization reaction was being tracked via measurements of the acid and hydroxyl values. Once an acid value of 147 mg KOH/g was reached, the obtained polymer was discharged from the reaction vessel and collected. The polymer (an acid-functional PolymerCS P) was characterized as follows: solid, MRQ=1, T.sub.g=48 C., M.sub.n=2189 Da, D=5.3, AV=147 mg KOH/g, OHV=6 mg KOH/g; .sup.31P-NMR (, ppm, 162 MHz; chloroform-d1:pyridine=:70:30 v/v): 135.5-136.0 (br, m; three groups of resonances, one of them is attributed to the carboxylic acid group of the S1 unit).

3. Examples of Comparative Polymers

3.1 Example 2: Preparation of a Comparative Polymer Comprising One S1, One S2, One S3 and One S4 Unit, Wherein X is L30

(CPEX1)

[0679] Cardura E10P (490 g, 2.15 mol) and citric acid (192 g, 1.00 mol) as reagent A were charged and mixed into a reactor vessel under a nitrogen flow to form a mixture. The mixture was subsequently polymerized at a temperature of 120 C. for 3 hours. Subsequently, after cooling the reaction mixture to 80 C., isophorone diisocyanate (78 g, 0.35 mol) was added thereto and reacted for 6 hours at 80 C. Furthermore, trimellitic anhydride (115 g, 0.60 mol) as reagent A was added and reacted for 1 hour at 180 C. The progress of the polymerization reaction was being tracked via measurements of the acid and hydroxyl values. Once an acid value of 65 mg KOH/g was reached, the obtained polymer was discharged from the reaction vessel and collected. The polymer was characterized as follows: solid, MRQ=1.8, T.sub.g=19.6 C., M.sub.n=1536 Da, D=2.2, AV=65 mg KOH/g, OHV=113 mg KOH/g).

[0680] This example represented an effort to reproduce the example 8 of U.S. Pat. No. 7,838,076 B2 (=example 8 of EP 1788049 A1). Although the same monomers and amounts were used and the same process was applied, it was not possible to fully reproduce the polymer of example 8 of U.S. Pat. No. 7,838,076 B2 as far as its properties AV and OHV were concerned (the AV and OHV reported by the U.S. Pat. No. 7,838,076 B2 (=EP 1788049 A1) for the polymer of example 8 were 80 and 67 mg KOH/g, respectively.

3.2 Example 3: Preparation of a Comparative Polymer Comprising One S1 Unit, Wherein X is L13

(CPEX2)

[0681] Trimellitic anhydride (192.13 g, 1.00 mol) was charged and mixed into a reactor vessel with xylene (290 g) under a nitrogen flow to form a mixture. Cyclohexene oxide (98.14 g, 1.00 mol) was added dropwise to the reactor. The mixture was subsequently polymerized at a temperature ranging from 130 to 150 C. for 5 hours. The progress of the polymerization reaction was being tracked via measurements of the acid and hydroxyl values. Once an acid value of 280 mg KOH/g was reached, the solvent was removed by applying vacuum and the obtained polymer was discharged from the reaction vessel and collected. The polymer, after drying, was characterized as follows: solid, MRQ=1, T.sub.g=80 C., AV=280 mg KOH/g, OHV=0.5 mg KOH/g).

4. Example of a Copolymerizable Polymer A

4.1 Example 4: Preparation of an Acid-Functional Polyester (POL1)

[0682] The polyester resins POL1 was prepared via a two phase (or two step) polycondensation reaction. At the end of the first step a hydroxyl functional polyester (mentioned herein as precursor) was obtained; next the hydroxyl functional polyester was reacted further with excess of carboxylic acid functional monomers to obtain the carboxylic acid functional polyester POL1. More particularly: A reactor vessel fitted with a thermometer, a stirrer and a distillation device for the removal of water formed during the synthesis, was filled with butyl stannoic acid (0.25 g) (catalyst), neopentyl glycol (432.4 g, 4.15 mol). The vessel was heated up to 150 C. until the mixture was molten. Then terephthalic acid (501.6 g, 3.02 mol) and isophthalic acid (122.4 g, 0.74 mol) were added and under a nitrogen flow the temperature was gradually increased to 260 C. while distilling off the reaction water, until the reaction mixture was clear and the acid value of the precursor of the polyester was between 5 and 15 mg KOH/g; that marked the completion of the first step. For the second step the reaction mixture was cooled to 200 C. and subsequently the adipic acid (40.9 g, 0.28 mol) and isophthalic acid (50.3 g, 0.30 mol) were added. The temperature was raised to 250 C. while distilling off water; subsequently vacuum was applied until the polyester reached the desired acid value range (25 mg KOH/g). Subsequently, the vacuum was stopped and the polyester was cooled down to 195 C. (marking the end of the second step), prior being discharged onto an aluminum foil that was kept at room temperature. The polyester (acid-functional one) was characterized as follows: T.sub.g=60 C., AV=25 mg KOH/g, OHV=4 mg KOH/g, M.sub.n=3901 Da, D=2.7).

5. Preparation of Heat-Curable Powder Coating Compositions According to the Invention (Inventive) and Coatings Thereof

[0683] PEX1 (which was prepared according to the process of the invention) was used to prepare:

[0684] i) four (individual) 1K white heat-curable inventive powder coating compositions namely PCCA1, PCCA2, PCC3, and PCCA4 (see Table 1), and

[0685] ii) white inventive powder coatings PCA1, PCA2, PCA3 and PCA4 derived upon heat curing of the PCCA1, PCCA2, PCCA3 and PCCA4, respectively.

[0686] The composition of each of the 1K white heat-curable inventive powder coating compositions PCCA1, PCCA2, PCCA3 and PCCA4 is shown in Table 1.

6. Preparation of Heat-Curable Comparative Powder Coating Compositions not According to the Invention (Comparative) and Coatings Thereof

[0687] CPEX1 and CPEX2 were each used to prepare:

[0688] i) two (individual) 1K white heat-curable comparative powder coating compositions namely PCCC1 and PCCC2 (see Table 1), and

[0689] ii) white comparative powder coatings PCC1 and PCC2 derived upon heat curing of the PCCC1 and PCCC2, respectively.

[0690] The composition of each of the 1K white heat-curable comparative powder coating compositions PCCC1 and PCCC2 is shown in Table 1.

[0691] Each one of the comparative and inventive 1K white heat-curable powder coating compositions was prepared by mixing its components in a blender and subsequently extruding the obtained mixture in a PRISM TSE16 PC twin screw at 125 C. in which the screw speed was adapted to have a high torque (>80%) to ensure good mixing. The extrudate was allowed to cool at room temperature and it was then chopped into chips. The chips were milled in a Retsch ZM100 with a 0.5 mm ring sieve at 18.000 rpm and then sieved. The sieve fraction with particle size below 90 m was collected, to afford each of the comparative and inventive powder coating compositions. Subsequently, each of the comparative and inventive powder coating compositions was individually and separately electrostatically sprayed (corona, 60 kV) onto 0.8 mm thick chromate aluminium Q-panels (type: ALQ-46) to a coating thickness of 505 m and cured at 200 C. for 15 minutes in an air-circulation oven (Heraeus Instruments UT6120) at atmospheric pressure to afford the white comparative and inventive powder coatings.

[0692] The object of the invention was to provide for powder coatings that have all of the following very desired properties: [0693] i) excellent chemical resistance, and [0694] ii) excellent reverse impact resistance, and [0695] iii) low gloss 60 (matt finish), and [0696] iv) (their corresponding 1K powder coating compositions have) good physical storage stability.

[0697] By the term matt finish or matt powder coatings or low gloss powder coatings' is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating having a gloss 60as gloss 60 is defined and measured hereinof at most 50, preferably at most 48, more preferably at most 46, most preferably at most 45, especially at most 43, more especially at most 41, even more especially at most 40, most especially at most 38, for example at most 37, for example at most 36, for example at most 35, for example at most 33, for example at most 32, for example at most 30, for example at most 28, for example at most 26, for example at most 25, for example at most 24, for example at most 22, for example at most 20, for example at most 18, for example at most 16, for example at most 15, for example at most 12, for example at most 10, for example at most 8, for example at most 6.

[0698] By the term very low gloss powder coatings is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating having a gloss 60as gloss 60 is defined and measured hereinof at most 20.

[0699] By the term excellent physical storage stability (or equally excellent storage stability) (when referring to powder coating compositions) is meant herein that a white heat-curable powder coating composition has a physical storage stability (PSS) of at least 9, on a scale from 1 (very poor storage stability) up to 10 (excellent storage stability), as the PSS is defined and measured herein.

[0700] By the term good physical storage stability (or equally good storage stability) (when referring to powder coating compositions) is meant herein that a white heat-curable powder coating composition has a physical storage stability (PSS) of at least 7 and at most 8, on a scale from 1 (very poor storage stability) up to 10 (excellent storage stability), as the PSS is defined and measured herein.

[0701] By the term poor physical storage stability (or equally poor storage stability) (when referring to powder coating compositions) is meant herein that a white heat-curable powder coating composition has a physical storage stability (PSS) of at most 6, on a scale from 1 (very poor storage stability) up to 10 (excellent storage stability), as the PSS is defined and measured herein.

[0702] By the term good reverse impact resistance (RIR) (or equally without compromising the reverse impact resistance) is meant herein that a white heat-curable powder coating composition scored a pass on the relevant test for measuring the reverse impact resistance as this is defined and measured herein.

[0703] By the term poor reverse impact resistance (RIR) (or equally compromising the reverse impact resistance) is meant herein that a white heat-curable powder coating composition scored a fail on the relevant test for measuring the reverse impact resistance as this is defined and measured herein.

[0704] By the term excellent chemical resistance is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating has a chemical resistance of at least 160 ADR, as the chemical resistance is defined and measured herein.

[0705] By the term good chemical resistance is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating has a chemical resistance of at least 141 and at most 159 ADR, as the chemical resistance is defined and measured herein.

[0706] By the term mediocre chemical resistance is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating has a chemical resistance of at least 100 and at most 140 ADR, as the chemical resistance is defined and measured herein.

[0707] By the term poor chemical resistance is meant herein a white powder coating having a thickness of 505 m that is obtained upon low bake curing of a white heat-curable powder coating composition, said white powder coating has a chemical resistance of at most 100 ADR, as the chemical resistance is defined and measured herein.

[0708] It was surprisingly found (see Table 1) that only the polymers of the invention (and the compositions of the invention) were able to afford powder coatings that had a unique combination of four very desired properties, such as:

[0709] i) excellent chemical resistance, and

[0710] ii) excellent reverse impact resistance, and

[0711] iii) low gloss 60 (matt coatings), and

[0712] iv) good physical storage stability.

Each of the comparative polymers and their compositions failed to afford powder coatings that combined all of the four above-mentioned properties. The reason being the CPEX1 had an AV (65 mg KOH/g) and a T.sub.g (19.6 C.) outside of the claimed range, whilst the CPEX2 had an AV (280 mg KOH/g) outside of the claimed range.

[0713] Therefore, only the inventive polymers (and their powder compositions) offered a surprising solution to the problem of improving on the reverse impact resistance (RIR) and the chemical resistance of low gloss (matt) powder coatings by maintaining at the same time a good physical storage stability of their corresponding powder coating compositions.