Effect pigments coated with organic binders for powders paints, and a method for producing said coated effect pigments and their use

Abstract

The invention relates to coated effect pigments, wherein the coating comprises a binder which is suitable for powder paints. They comprise a crystalline and an amorphous fraction which is determined by C.sup.13 NMR MAS relaxation measurements, the relaxation of the .sup.13C cores being fitted as a biexponential relaxation according to the formula (II) and the degree of crystallinity c being in a range between 40 to 85%, and relaxation having a short average relaxation time T.sub.1.sup.S and a long average relaxation time T.sub.1.sup.l, and T.sub.1.sup.l being in a range of from 65 to 130 s. The effect pigments coated according to the invention have at least one endothermic peak with a maximum from a range of T.sub.max=100 to 150° C. and an enthalpy ΔH associated with said peak from a range of 15 J/g to 80 J/g in DSC at a feed speed of 5° C./min, the enthalpy being calculated relative to the amount of the binder. The binders are applied to the effect pigment by way of spontaneous precipitation.

Claims

1. A method for producing a coated effect pigment comprising a platelet-shaped substrate and a coating applied thereon comprising a binder for powder coating, the method comprising: a1) dissolving a binder for powder coating which is spontaneously precipitable in an organic solvent or solvent mixture within a first time span timespan of t.sub.sol at a temperature T.sub.sol, b1) subsequently adding and dispersing an effect pigment in the solvent or solvent mixture from a1), c1) coating the effect pigment with the binder within a second timespan t.sub.insol at a temperature T.sub.insol, to prepare a coated effect pigment, or a2) dispersing an effect pigment in an organic solvent or solvent mixture, b2) subsequently adding a binder for powder coating which is spontaneously precipitable to the solvent or solvent mixture which has a temperature T.sub.sol, c2) coating the effect pigment with the binder within a time span t.sub.insol at a temperature T.sub.insol to prepare a coated effect pigment, d) removing the coated effect pigment from the solvent or solvent mixture, and e) optionally drying out the coated effect pigment, wherein the difference ΔT=T.sub.insol−T.sub.sol is in a range from 0 to 5° C. and there is spontaneous precipitation.

2. The method for producing a coated effect pigment as claimed in claim 1, wherein the temperature T.sub.insol for step c1) or c2) is a range from 10° C. to 5° C. below the boiling temperature of the organic solvent or solvent mixture.

3. The method for producing a coated effect pigment as claimed in claim 1, wherein t.sub.insol in step c1) or c2) is in a range from 0.5 h to 12 h.

4. The method for producing a coated effect pigment as claimed in claim 1, wherein the organic solvent or solvent mixture comprises one or more acetone, methyl ethyl ketone, and ethyl acetate.

5. The method for producing a coated effect pigment as claimed in claim 1, wherein after the step a2) an additive is added as precipitation assistant.

6. A coated effect pigment formed by the method according to claim 1.

7. The method for producing a coated effect pigment as claimed in claim 5, wherein the additive is a comb polymer based on maleic anhydride and a vinyl-containing aromatic.

8. The method for producing a coated effect pigment as claimed in claim 5, wherein the additive is a comb polymer based on maleic anhydride and styrene.

Description

LIST OF THE FIGURES

(1) FIG. 1: DSC diagrams recorded at 5° K/min in a temperature range from 30 to 210° C. in a representation against the temperature. The diagram shows only the lines toward higher temperatures, and no backward lines.

(2) - (Continuous line): preliminary test example 1: powder coating CC 4540-0 after precipitation from acetone,

(3) -⋅-⋅-⋅ (dash, dot line): preliminary test comparative example 1: powder coating CC 4540-0 as obtained from the manufacturer

(4) - ⋅⋅ - ⋅ - ⋅ (dash, dot, dot line): preliminary test example 1b: powder coating CC 4540-0 after precipitation, 2.sup.nd scan directly after 1.sup.st scan

(5) FIG. 2: schematic representation of the pulse sequences used for the .sup.13C MAS NMR overview measurements (FIG. 2a) and for the .sup.13C NMR MAS relaxation measurements (FIG. 2b).

(6) FIG. 3: PXRD of preliminary test example 1 (CC 4540-0) for the amorphous phase as per preliminary test comparative example 1 (top) and semicrystalline phase as per preliminary test example 1 (middle, dashed line) and also for the coated aluminum particles of example 1 (bottom, dotted line).

(7) The measurement was made on a STOE StadiP diffractometer in Debye-Scherrer geometry with Cu.sub.Kα1 radiation (Ge(111) monochromator). SiO.sub.2 capillaries with a diameter of 0.3 mm were used. For better overview, the measurement data for the amorphous samples and for the semicrystalline samples were shifted upward by 50 000 and 25 000 counts. The very sharp and high peaks for example 1 are attributable to reflections of the aluminum substrate.

(8) FIG. 4: .sup.13C CP MAS spectra of the binder CC 4540-0 for the amorphous phase as per preliminary test comparative example 1 (bottom, labeled “AGM”; v.sub.rot=12.5 kHz), for the semicrystalline phase as per preliminary test example 1 (middle, labeled “ND 10%”; v.sub.rot=12.5 kHz), and for the coated aluminum particles as per example 1 (top, labeled “50/50” Alu pigment”; v.sub.rot=8 kHz). Rotational sidebands are marked with an asterisk and the isotropic chemical shifts were assigned to the characteristic chemical structural units of the acid and alcohol components of the polyester.

(9) FIG. 5: plot of the extent of relaxation against the waiting time for the .sup.13C resonance of the methylene group of the semicrystalline polymer from preliminary test example 1 (binder CC 4540-0). The two different time constants for the amorphous fraction and the crystalline fraction are reflected in two regions having significantly different slopes.

(10) FIG. 6: .sup.13C CP MAS spectra of the binder CC 2506 for the amorphous phase as per preliminary test comparative example 10 (bottom, labeled “AGM”; v.sub.rot=6 kHz) and for the semicrystalline phase as per preliminary test example 1 (middle, labeled “ND”; v.sub.rot=6 kHz). Rotational sidebands are marked with an asterisk and the isotropic chemical shifts were assigned to the characteristic chemical structural units.

(11) FIG. 7: plot of the extent of relaxation against the waiting time for the .sup.13C resonance of the methylene group of the semicrystalline polymer from preliminary test example 10 (binder CC 2506-1). The two different time constants for the amorphous fraction and the crystalline fraction are reflected in two regions having significantly different slopes.

ASPECTS

(12) The invention further relates to subject matter comprising coated effect pigments according to one of the claims or aspects.

(13) According to an aspect 1, the present invention relates to a coated effect pigment comprising a platelet-shaped substrate and a coating applied thereon and comprising a binder for powder coating material;

(14) characterized,

(15) in that the binder has a crystalline and an amorphous fraction which is determined by means of .sup.13C NMR MAS relaxation measurements, the relaxation of the .sup.13C nuclei being fitted as a biexponential relaxation according to the formula

(16) $M (t, M_{0}, a, c, T_{1}^{s}, T_{1}^{l}) = M_{0} .Math. [(1 - c) .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{s}})}) + c .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{l}})})]$

(17) where the degree of crystallinity c is in a range between 40% to 85% and where there are a short average relaxation time T.sub.1.sup.s and a long average relaxation time T.sub.1.sup.l and where T.sub.1.sup.l is in a range from 65 to 130 s.

(18) According to an aspect 2 of the present invention, the coated effect pigment according to aspect 1 preferably comprises a binder having a degree of crystallinity c of 45% to 75%.

(19) According to an aspect 3 of the present invention, in the coated effect pigment according to any of aspects 1 and 2, the long average relaxation time T is preferably in a range from 70 to 110 s.

(20) According to an aspect 4 of the present invention, in the coated effect pigment of aspects 1 to 3, the binder is preferably not an LCST or UCST polymer.

(21) According to an aspect 5 of the present invention, in the coated effect pigment according to any of the preceding aspects, the binder in the PXRD diffractogram in Debye-Scherrer geometry (capillary 0.3 mm diameter) preferably has structured peaks with full widths at half maximum in the range from 0.7 to 2.0° (in 2°), using Cu Kα1 as x-ray source and using germanium(111) with a slit width of 0.5 mm as monochromator.

(22) According to an aspect 6 of the present invention, in the coated effect pigment according to the preceding aspects, in a DSC diagram at a rate of advance of 5° C./min, preferably has at least one endothermic peak having a maximum from a range of T.sub.max=100 to 150° C. and also having an enthalpy ΔH associated with this peak from a range from 15 J/g to 80 J/g, the enthalpy being calculated on the amount of the binder.

(23) According to an aspect 7 of the present invention, the coated effect pigment according to the preceding aspects is produced preferably by the method according to aspects 19 to 33.

(24) According to an aspect 8 of the present invention, in the coated effect pigment according to any of the preceding aspects, the binder preferably has polyester functions and is prepared via a melt polymerization.

(25) According to an aspect 9 of the present invention, in the coated effect pigment according to aspect 8, the binder is preferably a polyester containing acid and alcohol components and as acid components a main fraction is taken from monomers of the group consisting of isophthalic acid and terephthalic acid and mixtures thereof.

(26) According to an aspect 10 of the present invention, in the coated effect pigment according to aspect 8 or 9, the binder comprises preferably as acid component at least 14 mol % of isophthalic acid, based on all the acid components.

(27) According to an aspect 11 of the present invention, in the coated effect pigment according to any of aspects 8 to 10, the binder comprises preferably as alcohol component a fraction of neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of 50 to 100 mol %, based on all the alcohol components.

(28) According to an aspect 12 of the present invention, in the coated effect pigment according to aspect 11, with regard to the alcohol components of the polyester, the polyester preferably has a molar ratio of ethylene glycol and/or diethylene glycol to neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of less than 20%.

(29) According to an aspect 13 of the present invention, in the coated effect pigment according to any of aspects 6 to 12, the binder preferably has a ratio of the endothermic enthalpies of fusion ΔH/ΔH.sub.AGM, which can be determined by means of the run of a DSC measurement at a rate of advance of 5° C./min and which are based on the amount of binder, after the precipitation (ΔH) in relation to the binder before the precipitation (ΔH.sub.AGM), in a range from 2 to 10.

(30) According to an aspect 14 of the present invention, in the coated effect pigment according to any of aspects 6 to 13, the binder preferably exhibits an increase of ΔT.sub.Max in the DSC from the crystallized state in comparison to the uncrystallized state from a range from 40 to 75° C.

(31) According to an aspect 15 of the present invention, in the coated effect pigment according to any of the preceding aspects, the platelet-shaped substrate is preferably taken from the group consisting of metallic effect pigments, pearlescent pigments, and interference pigments, and also mixtures thereof.

(32) According to an aspect 16 of the present invention, in the coated effect pigment according to any of the preceding aspects, the platelet-shaped substrate is preferably a pearlescent pigment or is a metallic effect pigment coated with a metal oxide.

(33) According to an aspect 17 of the present invention, in the coated effect pigment according to aspect 16, the metal oxide is preferably taken from the group consisting of silicon (di)oxide, silicon oxide hydrate, silicon hydroxide, aluminum oxide, aluminum oxide hydrate, aluminum hydroxide, and mixtures thereof.

(34) According to an aspect 18 of the present invention, in the coated effect pigment according to either of aspects 16 and 17, the platelet-shaped substrate is preferably an SiO.sub.2-coated aluminum effect pigment.

(35) According to an aspect 19, the present invention relates to a method for producing coated effect pigments comprising a platelet-shaped substrate and a coating applied thereon for powder coating material, comprising the following steps:

(36) a1) dissolving a binder which is spontaneously precipitatable in an organic solvent or solvent mixture within a first time span of t.sub.sol, at a temperature T.sub.sol,

(37) b1) subsequently adding an effect pigment to the solvent or solvent mixture from a1), with dispersion of the effect pigment,

(38) c1) coating the effect pigment with the binder within a second timespan t.sub.insol at a temperature T.sub.insol or

(39) a2) dispersing an effect pigment in a solvent or solvent mixture,

(40) b2) subsequently adding a binder which is spontaneously precipitable to the solvent or solvent mixture which has a temperature T.sub.sol,

(41) c2) coating the effect pigment with the binder within a timespan t.sub.insol, at a temperature T.sub.insol d) removing the coated effect pigment from the solvent or solvent mixture, and e) optionally drying out the coated effect pigment.

(42) According to an aspect 20 of the present invention, in the method according to aspect 22 the method is preferably characterized in that the difference ΔT=T.sub.insol−T.sub.sol, is in a range from 0 to 5° C. and there is spontaneous precipitation.

(43) According to an aspect 21 of the present invention, in the method according to aspect 19 or 20, the method is preferably characterized in that the temperature T.sub.insol for step c1) or c2) is in a range from 10° C. to 5° C. below the boiling temperature of the solvent or solvent mixture.

(44) According to an aspect 22 of the present invention, in the method according to aspect 21, the method is preferably characterized in that the temperature T.sub.insol for step c1) or c2) is in a range from 18° C. to 30° C.

(45) According to an aspect 23 of the present invention, in the method according to aspect 219 to 22, the method is preferably characterized in that the temperature T.sub.sol for step a1) or b2) is in a range from 10° C. to 5° C. below the boiling temperature of the solvent or solvent mixture.

(46) According to an aspect 24 of the present invention, in the method according to aspect 23, the method is preferably characterized in that the temperature T.sub.sol, for step a1) or b2) is in a range from 18° C. to 30° C.

(47) According to an aspect 25 of the present invention, in the method according to any aspects 19 to 24, the method is preferably characterized in that t.sub.insol in step c1) or c2) is in a range from 0.5 h to 12 h.

(48) According to an aspect 26 of the present invention, in the method according to any of aspects 19 to 25, the method is preferably characterized in that the organic solvent is selected from the group consisting of acetone, methyl ethyl ketone, ethyl acetate, and also mixtures thereof.

(49) According to an aspect 27 of the present invention, in the method according to any of aspects 19 to 26, the method is preferably characterized in that the binder is not an LCST or UCST polymer.

(50) According to an aspect 28 of the present invention, in the method according to any of aspects 19 to 27, the method is preferably characterized in that the binder has polyester functions and is prepared via a melt polymerization.

(51) According to an aspect 29 of the present invention, in the method according to aspect 28, the method is preferably characterized in that the binder is a polyester containing acid and alcohol components and as acid components a main fraction is taken from monomers of the group consisting of isophthalic acid and terephthalic acid and mixtures thereof.

(52) According to an aspect 30 of the present invention, in the method according to aspect 28 or 29, the method is preferably characterized in that the binder comprises as acid component at least 14 mol % of isophthalic acid, based on all the acid components.

(53) According to an aspect 31 of the present invention, in the method for producing a coated effect pigment according to any of aspects 28 to 30, the method is preferably characterized in that the binder comprises as alcohol component a fraction of neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of 50 to 100 mol %, based on all the alcohol components.

(54) According to an aspect 32 of the present invention, in the method for producing a coated effect pigment according to aspect 31, the method is preferably characterized in that with regard to the alcohol components of the polyester it has a molar ratio of ethylene glycol and/or diethylene glycol to neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of less than 20%.

(55) According to a further aspect 33 of the present invention, in accordance with any of aspects 19 to 32, after step a2) an additive is added as precipitation assistant, the additive preferably being a comb polymer based on maleic anhydride and a vinyl-containing aromatic, preferably styrene.

(56) According to a further aspect 33 of the present invention, in accordance with any of aspects 19 to 33, the effect pigment after step a2) and before the addition of binder, and optionally the addition of additive, is treated with an adhesion promoter.

(57) According to an aspect 34 of the present invention, the coated effect pigments according to aspect 1 to 18 are used in paints, powder coatings, printing inks, toners or plastics.

(58) According to a further aspect 35, the present invention relates to a coated effect pigment comprising a platelet-shaped substrate and a coating applied thereon and comprising a binder for powder coating material;

(59) characterized

(60) in that in a DSC diagram at a rate of advance of 5° C./min, preferably has at least one endothermic peak having a maximum from a range of T.sub.max=100 to 150° C. and also having an enthalpy ΔH associated with this peak from a range from 15 J/g to 80 J/g, the enthalpy being calculated on the amount of the binder.

(61) According to an aspect 36 of the present invention, in the coated effect pigment according to aspect 35, the binder preferably has a ratio of the endothermic enthalpies of fusion ΔH/ΔH.sub.AGM, which can be determined by means of the run of a DSC measurement at a rate of advance of 5° C./min and which are based on the amount of binder, after the precipitation (ΔH) in relation to the binder before the precipitation (ΔH.sub.AGM), in a range from 2 to 10.

(62) According to an aspect 37 of the present invention, in the coated effect pigment according to any of aspect 35 or 36, the binder preferably exhibits an increase of ΔT.sub.Max in the DSC from the crystallized state in comparison to uncrystallized state from a range from 40 to 75° C.

(63) According to an aspect 38 of the present invention, in the coated effect pigment of aspects 35 to 37, the binder is preferably not an LCST or UCST polymer.

(64) According to an aspect 39 of the present invention, in the coated effect pigment according to either of the preceding aspects 37 to 38, the binder in the PXRD diffractogram in Debye-Scherrer geometry (capillary 0.3 mm diameter) preferably has structured peaks with full widths at half maximum in the range from 0.7 to 2.0° (in 2θ), using Cu Kα1 as x-ray source and using germanium(111) with a slit width of 0.5 mm as monochromator.

(65) According to an aspect 40 of the present invention, in the coated effect pigment according to preceding aspects 35 to 39, the binder preferably has a crystalline and amorphous fraction which is determined by means of .sup.13C NMR MAS relaxation measurements, the relaxation of the .sup.13C nuclei being fitted as a biexponential relaxation according to the formula

(66) $M (t, M_{0}, a, c, T_{1}^{s}, T_{1}^{l}) = M_{0} .Math. [(1 - c) .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{s}})}) + c .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{l}})})]$

(67) where the degree of crystallinity c is in a range between 40% to 85% and where there are a short average relaxation time T.sub.1.sup.s and a long average relaxation time T.sub.1.sup.l and where T.sub.1.sup.l is in a range from 65 to 130 s.

(68) According to an aspect 41 of the present invention, the coated effect pigment according to aspect 40 preferably comprises a binder having a degree of crystallinity c of 45% to 75%.

(69) According to an aspect 42 of the present invention, in the coated effect pigment according to any of aspects 40 and 41, the long average relaxation time T.sub.1.sup.l is preferably in a range from 70 to 110 s.

(70) According to an aspect 43 of the present invention, the coated effect pigment according to preceding aspects 34 to 42 is preferably produced by the method according to aspects 19 to 33.

(71) According to an aspect 44 of the present invention, in the coated effect pigment according to any of the preceding aspects 34 to 43, the binder preferably has polyester functions and is prepared via a melt polymerization.

(72) According to an aspect 45 of the present invention, in the coated effect pigment according to aspect 44, the binder is preferably a polyester containing acid and alcohol components and as acid components a main fraction is taken from monomers of the group consisting of isophthalic acid and terephthalic acid and mixtures thereof.

(73) According to an aspect 46 of the present invention, in the coated effect pigment according to aspect 44 or 45, the binder comprises preferably as acid component at least 14 mol % of isophthalic acid, based on all the acid components.

(74) According to an aspect 47 of the present invention, in the coated effect pigment according to any of aspects 44 to 46, the binder comprises preferably as alcohol component a fraction of neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of 50 to 100 mol %, based on all the alcohol components.

(75) According to an aspect 48 of the present invention, in the coated effect pigment according to aspect 47, with regard to the alcohol components of the polyester, the polyester preferably has a molar ratio of ethylene glycol and/or diethylene glycol to neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of less than 20%.

(76) According to an aspect 49 of the present invention, in the coated effect pigment according to any of the preceding aspects 34 to 48, the platelet-shaped substrate is preferably taken from the group consisting of metallic effect pigments, pearlescent pigments, and interference pigments, and also mixtures thereof.

(77) According to an aspect 50 of the present invention, in the coated effect pigment according to aspect 49, the platelet-shaped substrate is preferably a pearlescent pigment or is a metallic effect pigment coated with a metal oxide.

(78) According to an aspect 51 of the present invention, in the coated effect pigment according to aspect 50, the metal oxide is preferably taken from the group consisting of silicon (di)oxide, silicon oxide hydrate, silicon hydroxide, aluminum oxide, aluminum oxide hydrate, aluminum hydroxide, and mixtures thereof.

(79) According to an aspect 52 of the present invention, in the coated effect pigment according to either of aspects 50 and 16, the platelet-shaped substrate is preferably an SiO.sub.2-coated aluminum effect pigment.

(80) According to an aspect 53 of the present invention, the coated effect pigments according to one of aspects 34 to 52 are used in paints, powder coatings, printing inks, toners or plastics.

(81) A further subject of the present invention is a polymer according to the following aspects.

(82) According to aspect 54 of the present invention, is preferably a polymer which may be a binder and has polyester functions and is precipitated spontaneously in a solvent or solvent mixture.

(83) According to aspect 55 of the present invention, the polymer according to aspect 54 is preferably a binder for powder coating.

(84) According to an aspect 56 of the present invention, the polymer according to either of aspects 54 and 55 is preferably characterized in that the binder is a polyester containing acid and alcohol components and as acid components a main fraction is taken from monomers of the group consisting of isophthalic acid and terephthalic acid and mixtures thereof.

(85) According to an aspect 57 of the present invention, the polymer according to any of aspects 54 to 56 is preferably characterized in that the binder comprises as acid component at least 14 mol % of isophthalic acid, based on all the acid components.

(86) According to an aspect 58 of the present invention, the polymer according to any of aspects 54 to 57 is preferably characterized in that the binder comprises as alcohol component a fraction of neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of 50 to 100 mol %, based on all the alcohol components.

(87) According to an aspect 59 of the present invention, the polymer according to aspect 58 is preferably characterized in that with regard to the alcohol components of the polyester, the polyester has a molar ratio of ethylene glycol and/or diethylene glycol to neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of less than 20%.

(88) According to an aspect 60 of the present invention, the polymer according to any of aspects 54 to 59 preferably has a crystalline and amorphous fraction which is determined by means of .sup.13C NMR MAS relaxation measurements, the relaxation of the .sup.13C nuclei being fitted as a biexponential relaxation according to the formula

(89) $M (t, M_{0}, a, c, T_{1}^{s}, T_{1}^{l}) = M_{0} .Math. [(1 - c) .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{s}})}) + c .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{l}})})]$

(90) where the degree of crystallinity c is in a range between 40% to 85% and where there are a short average relaxation time T.sub.1.sup.s and a long average relaxation time T.sub.1.sup.l and where T.sub.1.sup.l is in a range from 65 to 130 s.

(91) According to an aspect 61 of the present invention, the polymer according to aspect 60 preferably has a degree of crystallinity c of 45% to 75%.

(92) According to an aspect 62 of the present invention, the polymer according to either of aspects 60 and 61 the long average relaxation time T.sub.1.sup.l is preferably in a range from 70 to 110 s.

(93) According to an aspect 63 of the present invention, the polymer of aspects 54 to 62 the binder is preferably not an LCST or UCST polymer.

(94) According to an aspect 64 of the present invention, the polymer according to any of preceding aspects 54 to 63 is preferably the polymer in the PXRD diffractogram in Debye-Scherrer geometry (capillary 0.3 mm diameter) preferably has structured peaks with full widths at half maximum in the range from 0.7 to 2.0° (in 2θ), using Cu Kα1 as x-ray source and using germanium(111) with a slit width of 0.5 mm as monochromator.

(95) According to an aspect 65 of the present invention, the polymer according to preceding aspects 54 to 64 preferably, in a DSC diagram at a rate of advance of 5° C./min, has at least one endothermic peak having a maximum from a range of T.sub.max=100 to 150° C. and also having an enthalpy ΔH associated with this peak from a range from 15 J/g to 80 J/g, the enthalpy being calculated on the amount of the binder.

(96) According to an aspect 66 of the present invention, the polymer is prepared preferably by a method according to any of aspects 69 to 81.

(97) According to an aspect 67 of the present invention, the polymer according to any of aspects 73 to 85, the organic solvent is preferably selected from the group consisting of acetone, methyl ethyl ketone, ethyl acetate, and also mixtures thereof.

(98) According to an aspect 68 of the present invention, the polymer according to any of aspects 54 to 67 is preferably used for the coating of platelet-shaped effect pigments.

(99) According to an aspect 69, the present invention relates to a method for producing a polymer, comprising the following steps:

(100) c1) dissolving a binder which is spontaneously precipitable in an organic solvent or solvent mixture within a first timespan of t.sub.sol at a temperature T.sub.sol,

(101) c2) subsequently precipitating the polymer within a second timespan t.sub.insol at a temperature T.sub.insol where the difference ΔT=T.sub.insol−T.sub.sol, is in a range from 0 to 5° C. and there is spontaneous precipitation,

(102) d1) removing the polymer from the solvent or solvent mixture, and

(103) e) optionally drying out the polymer.

(104) According to an aspect 70 of the present invention, in the method according to aspect 69, the method is preferably characterized in that the temperature T.sub.insol for step c1) or c2) is in a range from 10° C. to 5° C. below the boiling temperature of the solvent or solvent mixture.

(105) According to an aspect 71 of the present invention, in the method according to aspect 70, the method is preferably characterized in that the temperature T.sub.insol for step c2) is in a range from 18° C. to 30° C.

(106) According to an aspect 72 of the present invention, in the method according to aspect 69 to 71, the method is preferably characterized in that the temperature T.sub.sol, for step c1) is preferably in a range from 10° C. to 5° C. below the boiling temperature of the solvent or solvent mixture.

(107) According to an aspect 73 of the present invention, in the method according to aspect 72, the method is preferably characterized in that the temperature T.sub.sol for step c1) is in a range from 18° C. to 30° C.

(108) According to an aspect 74 of the present invention, in the method according to any aspects 69 to 73, the method is preferably characterized in that t.sub.insol in step c2) is in a range from 0.5 h to 12 h.

(109) According to an aspect 75 of the present invention, in the method according to any of aspects 69 to 74, the method is preferably characterized in that the organic solvent is selected from the group consisting of acetone, methyl ethyl ketone, ethyl acetate, and also mixtures thereof.

(110) According to an aspect 76 of the present invention, in the method according to any of aspects 69 to 74, the method is preferably characterized in that the binder is not an LCST or UCST polymer.

(111) According to an aspect 77 of the present invention, in the method according to any of aspects 69 to 76, the method is preferably characterized in that the binder has polyester functions and is prepared via a melt polymerization.

(112) According to an aspect 78 of the present invention, in the method according to aspect 77, the method is preferably characterized in that the binder is a polyester containing acid and alcohol components and as acid components a main fraction is taken from monomers of the group consisting of isophthalic acid and terephthalic acid and mixtures thereof.

(113) According to an aspect 79 of the present invention, in the method according to aspect 77 or 78, the method is preferably characterized in that the binder comprises as acid component at least 14 mol % of isophthalic acid, based on all the acid components.

(114) According to an aspect 80 of the present invention, in the method for producing a coated effect pigment according to any of aspects 77 to 79, the method is preferably characterized in that the binder comprises as alcohol component a fraction of neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of 50 to 100 mol %, based on all the alcohol components.

(115) According to an aspect 81 of the present invention, in the method for producing a coated effect pigment according to aspect 80, the method is preferably characterized in that with regard to the alcohol components of the polyester it has a molar ratio of ethylene glycol and/or diethylene glycol to neopentyl glycol and/or 2-butyl-2-ethyl-1,3-propanediol of less than 20%.

EXAMPLES

A1 Preliminary Tests 1 to 15

(116) In the preliminary tests, a wide variety of different polyester binders, offered commercially as powder coating binders, were dissolved in solvents such as acetone, methyl ethyl ketone (MEK) or ethyl acetate at room temperature and then investigated for a possible spontaneous precipitation. For this purpose, the solvent was charged to a glass beaker, the temperature was adjusted if necessary, and the binder powder (typically around ⅙ of the amount of the solvent) was added with stirring.

(117) All binders which exhibited the spontaneous precipitation were first of all dissolved without residue, but in that case took the form of a slightly grayish solution, suggesting an at least partly colloidal state. Binders not displaying spontaneous precipitation (comparative examples) always dissolved in a colorless clear solution.

(118) The spontaneous precipitation took place in different times: these times may have amounted to several minutes up to around 48 hours. The precipitated polymers were isolated via a VWR filter paper 454 (particle retention: 12-15 μm) and dried in a vacuum drying cabinet at 50° C. for 6 h.

(119) These polymer powders could then be analyzed further.

(120) Systematic investigations on a number of selected polymers showed that the precipitation accomplished was at least 90%, and in the majority of cases largely quantitative.

(121) All results in this regard are summarized in table 1.

(122) Preliminary Test Comparative Examples 1 to 3:

(123) The binders CC 340, CC 2818-0 (both Allnex), and Uralac P 1580 (DSM) were dissolved in acetone, ethyl acetate or methyl ethyl ketone, but no longer precipitated.

(124) These binders are therefore not spontaneously precipitable in the sense of this invention.

(125) Preliminary Test Comparative Examples 4 to 6:

(126) In preliminary tests, an attempt was made to dissolve the semicrystalline powder coating polyester resins UVCOAT 9010, Additol P791, and Crylcoat-8078-0 (all from Allnex) in ethyl acetate, acetone, and methyl ethyl ketone, at room temperature and also at various temperatures up to 5° C. below the respective boiling temperature. The resins, however, could not be dissolved to a sufficient degree corresponding to the invention.

(127) These binders are therefore not spontaneously precipitable in the sense of this invention.

(128) These resins, and analysis could be carried out, were investigated for their monomer composition (see table 1) and characterized by DSC (see table 2).

A2 Structure of Binders

(129) The binders were analyzed for their monomer composition by customary methods of polymer analysis such as, for example, GC-mass spectroscopy, IR spectra, and NMR (.sup.1H, .sup.13C, and also 2-D NMR). In these analyses, some of the acid monomer components present in very small amount were subsumed collectively under “other acids”.

(130) Table 1 provides an overview of the binders investigated. Also reported here, very generally, are the precipitation time and also the results of the monomer constituent analysis. For each sample here, the amounts of isophthalic or of terephthalic acid (preliminary test comparative example 3) were taken as 100 parts in each case, and all other components were expressed in proportion to them.

(131) In further preliminary test examples, the procedure of example 1 was repeated, using a wide variety of different polyester resins suitable for powder coatings.

(132) The results of the dissolution tests in acetone at room temperature, and also the analytically determined monomer compositions, are shown in table 1. Similar results were also obtained in solvents such as ethyl acetate or methyl ethyl ketone (MEK).

(133) In very apolar solvents such as chloroform, the binders dissolved completely, to give a clear solution. There was, however, no precipitation.

(134) All in all, out of twenty-one polyester binders investigated, fifteen displayed the behavior of spontaneous precipitation (preliminary test examples 1-15), while three binders, though dissolving in the solvent, no longer underwent spontaneous precipitation (preliminary test comparative examples 1-3) and three further binders were not soluble (preliminary test comparative examples 4-6).

(135) The majority of these binders were also tested in ethyl acetate and also in methyl ethyl ketone, leading to similar results.

(136) TABLE-US-00001 TABLE 1 **Dissolution behavior in acetone and analytical monomer composition of the polyester binders of preliminary tests Analytically determined relative amount of monomers (based on 100 parts isophthalic acid or terephthalic acid) Iso- Tere- Trimethylol- Manu- Precipitation phthalic phthalic Other Neopentyl propane Ethylene glycol/ Example Binder facturer time acid acid acids glycol (TMP) diethylene glycol Preliminary CC* 4540-0 Allnex <3 h 100 1.8 — 92.1 2.5 4.8 test example 1 Preliminary Uralac P 3480 DSM <3 h 100 3 0.2 94 2 test example 2 Preliminary Uralac P 3495 DSM <20 h 100 362 9 442 test example | 3 Preliminary CC 2578-0 Allnex <42 h 100 450 4 505 8 test example 4 Preliminary CC 4420-0 Allnex <20 h 100 82 7 test example | 5 Preliminary Uralac P800 DSM <1 min 100 5.2 98.3 0.9 2.3 test example 6 Preliminary CC 4626-0 Allnex <1 min 100 1.3 92.5 test example 7 Preliminary Uralac P6800 DSM <3 h 100 1.5 84.5 5 7.6 test example | 8 Preliminary CC 4655-2 Allnex <3 h 100 <1 87.7 3.6 5.9 test example 9 Preliminary CC 2506-1 Allnex <3 h 100 435.8 508.2 test example 10 Preliminary CC 2505-4 Allnex <3 h 100 545 17 587 47.2 test example 11 Preliminary P 3486 Allnex <42 h 100 592.3 653.2 6 11.1 test example 12 Preliminary CC 4890-0 Allnex <3 h 100 1.6 112 3 7.5 test example 13 Preliminary Sirales 7499 SIR <3 h 100 2.6 98.2 test example 14 Preliminary Uralac P 5500 DSM <3 h 100 12.4 90.7 1.8 test example 15 Preliminary CC 340** Allnex No precipitation 100 82.1 27.5 test comparative example 1 Preliminary Uralac P 1580 DSM No precipitation 100 67 18 15 test comparative example 2 Preliminary CC 2818 Allnex No precipitation 0 100 0 14.7 89.6 test comparative example 3 Preliminary UVCOAT 9010 Allnex No dissolution 100.5*** 100 to 105 test (Ethylene glycol) example 4 Preliminary Additol***** DSM No dissolution **** test P791 example 5 Preliminary CC-8079-0 Allnex No dissolution 100***** 2.4 trans-1,4- test dimethylolcyclo- example 6 hexane: 61.0; cis-1,4- dimethylolcyclo- hexane: 34.1 *The code CC stands for “Crylcoat” **Binders of the examples from EP 1 699 884 B1 ***Dodecanoic acid ****This product dissolved only in minimal amounts in DMSO and no analysis could therefore be conducted. It is an ester of 1,12-dodecanoic acid. *****Adipic acid

(137) The binders of preliminary test comparative examples 1-3 showed a high fraction of ethylene glycol and/or of trimethylolpropane in comparison to neopentyl glycol.

(138) Three further binders, sold by their manufacturers as semicrystalline powder coating binders, could not be sufficiently dissolved (preliminary test comparative examples 4-6). These binders as their acid component had a main fraction of adipic acid (preliminary test example 5) or of 1,12-dodecanoic acid. The alcohol components present, where analyzable, included no detectable amounts of neopentyl glycol, but instead were ethylene glycol (preliminary test example 4) or a mixture of cis- and trans-dimethylolcyclohexane.

(139) Evidently these binders already have a crystalline fraction which is such that they cannot be dissolved and consequently also no longer exhibit any “spontaneous polymerization”.

(140) DSC Investigations on Binders of the Preliminary Tests:

(141) For inventive examples of the preliminary tests, DSC investigations were additionally conducted. In these investigations, small, defined amounts (a few mg) both of the precipitated and dry binder (preliminary test examples) and also, for comparison, of the unprecipitated, dry binder, as obtained from the manufacturer (preliminary test comparative examples), were weighed out and DSC measurements were conducted (instrument manufacturer: Netzsch, Germany; model STA 449 F3 Jupiter; comparison standard: indium). The rate of advance here was 5° K/min and the temperature range extended in general from 30° C. to 250° C. The sample, without a waiting time, was subsequently cooled at 5 K/min down to 40° C. and, after a waiting time of 20 minutes at this temperature, a second temperature run was recorded at 5 K/min up to 250° C. The measurements took place under air, since no reactivity with oxygen could be ascertained.

(142) In these investigations, in the case of the unprecipitated comparison samples, there was in each case an endothermic peak having a maximum in a region of above 60 to around 75° C., and with a corresponding T.sub.onset of around 55 to below 70° C. Situated below these peaks, as a general rule, is a glass transition temperature T.sub.9, which in a DSC is known to be manifested in a shift in the baseline. This glass transition temperature can be assigned primarily to the amorphous fractions of the polymer. This behavior in DSC is known for these polyester binders and is entirely customary. The peak may well be attributable to the melting of certain small crystalline fractions.

(143) In the case of the spontaneously precipitated samples, in contrast, substantially larger endothermic peaks were found, having a maximum T.sub.max in a range from around 120 to around 135° C. and having a corresponding T.sub.onset of around 100 to 124° C. Here again, there may also be a glass transition temperature below the peak. The backward temperature run of all samples was always substantially without structure, with no distinctly identifiable peaks.

(144) This is a clear indication that the strongly shifted and enlarged endothermic peaks are attributable to a substantial increase in the crystalline fractions of the polyester resins investigated, as a result of the spontaneous precipitation.

(145) Where a second measurement after the first temperature cycle was conducted for the spontaneously precipitated samples, the behavior found was always similar to that of the unprecipitated samples.

(146) FIG. 1 shows by way of example the forward temperature runs for preliminary test example 1.

(147) The unprecipitated polymer as obtained from the manufacturer (preliminary test comparative example 1) exhibits an endothermic peak with a maximum at 70.1° C. The precipitated polymer, in contrast, exhibits an endothermic peak at 126.2° C. and a much higher enthalpy (preliminary test example 1). If a DSC spectrum is again recorded for this polymer, after the backward run to 30° C., the subsequent DSC scan is highly comparable with that of the unprecipitated polymer (preliminary test comparative example 1b, T.sub.max at 71.5° C.). The crystalline structure obtained as a result of the spontaneous precipitation has evidently been destroyed irreversibly at higher temperatures.

(148) If, however, this polymer were to be redissolved in the solvent and spontaneously precipitated, then again a DSC curve resembling that of preliminary test example 1 would be obtained (not shown in FIG. 1). The crystallization procedure is in this sense reversible.

(149) For all of the DSC tests, TGA measurements were carried out simultaneously. For some samples, decreases in mass in the range from 1 to around 2 wt % were found. It was generally possible here to observe a first step at a temperature of around 50° C. This step can be interpreted as the removal at this point of residual traces of the solvent from the precipitated polymer.

(150) The peaks were integrated in order to calculate the associated enthalpy ΔH. Table 2 gives an overview of the measurement data obtained. It shows the onset temperatures T.sub.onset, the maximum temperatures T.sub.max and also the enthalpies ΔH associated with the peaks (following subtraction of a customary background correction) of the endothermic peaks for the unprecipitated binder samples (preliminary test comparative examples) and also for the precipitated samples (preliminary test examples). Also shown are the shifts of these parameters, for which in each case the value for the unprecipitated binder was subtracted from that for the precipitated binder. In the case of the enthalpies, a ratio was formed of the precipitated to the unprecipitated polyester resin.

(151) This massive temperature shift in the T.sub.max values, and also the sharp increase of the associated enthalpy of the endothermic peaks, can be attributed to a substantial increase in the crystalline fractions of the polymers, as a result of the spontaneous precipitation.

(152) TABLE-US-00002 TABLE 2 T.sub.onset, T.sub.max and ΔH parameters from DSC measurements on precipitated binders (preliminary test examples) and unprecipitated binders (preliminary test comparative examples) Unprecipitated binder (preliminary Precipitated binder Comparison test comparative (inventive preliminary (precipitated minus examples) test examples) unprecipitated binder) T.sub.onset T.sub.max ΔH.sub.AGM T.sub.onset T.sub.max ΔH/ ΔT.sub.onset ΔT.sub.max ΔH.sub.precip/ Example Binder [° C.] [° C.] [J/g] [° C.] [° C.] [J/g] [° C.] [° C.] ΔH.sub.AGM Preliminary CC 4540-0 65.6 70.1 9.4 100.5 126.2 55.0 34.9 56.1 5.9 test example 1 Preliminary P 3480 66.9 71.2 8.0 104.5 128.8 44.0 37.6 57.6 5.5 test example 2 Preliminary P 3495 64.6 71.1 5.1 105.4 129 30.9 40.8 57.9 6.0 test example 3 Preliminary CC 2578-0 70.1 73.5 6.9 107.1 130.5 32.2 37.0 57 4.7 test example 4 Preliminary CC 4420-0 64 71.3 7.4 105.7 123.4 38.2 41.7 51.7 5.2 test example 5 Preliminary P800 65.4 69.3 7.9 124 132.5 38.2 58.6 67.2 6.1 test example 6 Preliminary CC 4626-0 63.8 67.7 10.1 127 134.1 51.4 63.2 66.4 5.1 test example 7 Preliminary P 6800 63.8 66.6 8.5 115.8 124.5 42.2 52.0 57.9 5.0 test example 8 Preliminary CC 4655-2 67.8 72 8.5 117 125.3 41.9 49.2 53.3 4.9 test example 9 Preliminary CC 2506-1 68.3 71.7 6.2 106.2 132.2 35.0 37.9 60.6 5.6 test example 10 Preliminary CC 2505-4 64.8 68.9 6.0 110.1 130.7 32.8 45.3 61.8 5.5 test example 11 Preliminary P 3486 64.6 67.1 5.2 110.2 134.5 35.6 45.6 67.4 6.8 test example 12 Preliminary CC 4890-0 66.8 69.8 8.7 105.4 125.9 43.0 38.6 56.1 4.9 test example 13 Preliminary Sir 7499 66.8 69.9 8.3 106.8 126.7 45.3 40.0 56.8 5.5 test example 14 Preliminary P 5500 59.6 62.7 9.0 103.4 120 38. 43.8 53.3 4.2 test example 15 Preliminary UVCOAT 79.5 84.1 105.1 — — — — — — test 9010 example 4 Preliminary Additol 86.5 94.3 191.1 — — — — — — test P791 example 5 Preliminary Crylcoat- 86.4 92.5/99.7 34.6 — — — — — — test 8079-0 example 6

(153) The very high values for the melting range from 120 to more than 132° C. are known similarly in the literature only for the so-called “semicrystalline” polyesters (EP 0 521 992 B1, U.S. Pat. No. 4,217,426). There, similar enthalpy values are also reported.

(154) It is striking here, however, that on the basis of the monomer composition, the binders are known more as “amorphous” binders (e.g., U.S. Pat. No. 6,660,398 B1). The degree of crystallization achieved through the spontaneous precipitation is seemingly very high.

(155) The enthalpy values of the preliminary test comparative examples 4 and 5 (measured only in the first scan), at 105.1 and 191.1 J/g, were higher still than all of the measured enthalpy values of the inventive examples after the precipitation. This appears to reflect an even higher degree of crystallization. These binders are evidently so highly crystalline that they cannot be dissolved in the solvents used here and therefore do not enter into spontaneous crystallization.

B Coating of Effect Pigments

Example 1

(156) An open 1-liter jacketed reactor was used, cooled with a cryostat to 15° C. 60.0 g of SiO.sub.2 coated aluminum effect pigment (STANDART® PCS 3500, available from Eckart GmbH) with an average particle size D.sub.50 of 35 μm were introduced and suspended in 250 g of acetone. Via a vibratory chute, over a time of 60 min, 63.0 g of a carboxyl-group-containing, saturated polyester resin with the designation Crylcoat 4540-0 (manufacturer: Allnex S.à.r.l.) were added to the suspension. After the end of the addition, the suspension was stirred for 2 hours and then discharged via a suction filter. The precipitate obtained was dried for an hour in a heatable Duplex kneader (model HKD-T06D, from IKA-Werke GmbH & Co. KG) under reduced pressure at 80 mbar and 35° C., and then sieved through a sieve having a mesh size of below 100 μm.

Example 2

(157) The procedure of example 1 was repeated, but using as the polyester resin the resin with the designation Sirales PE 7499 (manufacturer: SIR Industriale SpA) (corresponding to preliminary test 14).

Example 3

(158) The procedure of example 1 was repeated, but using as the polyester resin the resin with the designation CC 2506-1 (manufacturer: Allnex S.à.r.l.) (corresponding to preliminary test 10).

Example 4

(159) The procedure of example 1 was repeated, but using, as effect pigment, 60.0 g of SiO.sub.2 coated gold bronze pigment Dorolan Reichbleichgold 17/0.

Example 5

(160) The procedure of example 1 was repeated, but using, as effect pigment, 60.0 g pearlescent pigment Luxan E221 (from Eckart GmbH, Germany).

Example 6

(161) The procedure of example 1 was repeated, but using ethyl acetate instead of acetone as solvent and, before the addition of the binder, adding 1.0 g of Disperbyk 2060 to the metallic effect pigment suspension and stirring for 1 h before the binder was added. After the end of the addition, the suspension was stirred for 2 hours and thereafter the suspension was left to stand for 1 h. An only slightly turbid solvent supernatant was formed, while the coated metallic effect pigment underwent sedimentation.

(162) If a corresponding procedure was adopted with the formula according to example 1 without addition of additive, then the supernatant was much more turbid. In light micrographs and also in SEM micrographs it could be seen that the metallic effect pigment in the case of example 6 was coated better and more uniformly with polymer than in the case of example 1, for which some secondary precipitation was observed.

Example 7

(163) The procedure of example 6 was repeated, but before the addition of Disperbyk 2060 to the suspension of the metallic effect pigment, it was admixed with 2.0 g of Dynasylan Glymo (from Evonik Industries AG) and stirred at room temperature for 1 h.

(164) The quantity of polymer precipitation was comparable with example 6.

Comparative Example 1 (Based on EP 1 699 884 B1)

(165) 195 g of the polyester resin Crylcoat 2818-0 (from Allnex S.à.r.l.) and also, as curing component, 105 g of a polyisocyanate adduct with the designation Vestagon BF 1320 (manufacturer: Evonik) were dissolved in 1800 g of acetone, and 200 g of SiO.sub.2 coated aluminum effect pigment (STANDART® PCS 3500, available from Eckart GmbH) were dispersed. The dispersion was sprayed in a spray drier at a rate of 30 g/min with a spraying pressure of 2.5 bar in an air stream whose temperature was 55° C. After drying, a yield of 380 g of coated effect pigment was obtained.

Comparative Example 2

(166) Coating as in comparative example 1, but using 200 g of pearlescent pigment Luxan E221 (from Eckart GmbH, Germany) as substrate.

Comparative Example 3: Use of a UCST Polymer Based on DE 102 43 438 A1

(167) The metallic effect pigment was suspended as in example 1, but using 250 g of deionized water as solvent. The polymer added was 63 g of LUVITEC® VPC 55 K 65 W (UCST polymer from BASF with cloud point temperature of around 65° C. in water). The temperature was then raised to 75° C. over the course of an hour, and the mixture was left at this temperature for an hour. Subsequently, the dispersion was filtered while still hot.

(168) In contrast to the inventive examples, the resulting precipitate was highly tenacious, attributable to substantial agglomeration of the pigment particles. The agglomeration proved to be so substantial that further testing of the pigments did not appear useful.

(169) In further comparative tests, the precipitation temperature was varied, and ethyl acetate instead of water was used as solvent; however, agglomerates were always produced.

B1 Performance Properties

(170) B 1.1 Storage Stability Tests:

(171) In a method based on DIN EN ISO 8130-8, 50 g of pigment powder from the inventive examples and the comparative examples were introduced in each case into a sealable aluminum can and stored in a heating cabinet at 60° C. for 28 days. After the end of the time, the consistency was assessed and scored on the criteria below, relative to a comparison sample stored at room temperature.

(172) TABLE-US-00003 TABLE 3 The storage tests were based on the following evaluation system: Index Extent of solidification or agglomeration 0 No change 1 Slight signs of solidification; agglomerates could easily be disrupted. 2 Significant solidification. Some effort is required to disperse the powder coating. Agglomerates can be disrupted by manual pressure. 3.sup.1) Considerable solidification, making it difficult or impossible to disperse the powder coating. Agglomerates are very stable and require the application of machine means for disruption. .sup.1)If a product is classed with the index 3, it should be considered whether further examination is necessary, since the powder coating probably cannot be used to satisfaction.

(173) TABLE-US-00004 TABLE 4 Results of the storage tests: Storage test Sample index Example 1 0 Example 2 0 Example 3 0 Example 4 0 Example 5 0 Example 6 0 Example 7 0 Comparative 3 example 1 Comparative 3 example 2

(174) All of the inventive examples and also comparative examples 2 to 5 showed outstanding storage stability (index 0). The storage stability of comparative examples 1 and 2 was evaluated only as of index 3, however.

(175) The improved storage stability is very probably attributable to the increased degree of crystallization of the binder coatings of the inventive examples.

(176) B 1.2: Robustness of Adhesion of the Polymer Coat

(177) An important criterion of the product of the invention is the adhesion of the resin coat on the effect pigment surface. The resin coat is subject to severe exposure during the production steps of drying and sieving and also in the further processing steps by the user of the products of the invention.

(178) In order to determine the adhesion to the resin coat on the effect pigment surface, the specimens of inventive examples 1, 6 and 7 were subjected to determination of the particle number and particle size. In this case, size measurements were performed in a Sysmex FPIA-3000S. The CE.sub.50 is the size value for which 50% of the equivalent circle size of the measured particles in a cumulative size distribution are smaller than this value (number average). The instrument had an ultrasound unit for dispersing the specimens. This dispersing amounts to 15 watts with adjustable amplitude and at a frequency of 30 kHz.

(179) The specimens were measured without ultrasound exposure and, in order to simulate mechanical loads during processing steps, were measured with ultrasound at 20% and 60% amplitude.

(180) Table 5 below illustrates the results:

(181) TABLE-US-00005 TABLE 5 CE.sub.50 values and measured particle number (determined using Sysmex FPIA 3000S): Ultrasound 15 W, frequency 30 kHz Amplitude Parameters Sample none 20% 60% CE.sub.50/μm Example 7 3.20 1.98 1.80 Example 6 2.79 1.64 1.58 Particle Example 7 1958 5482 7066 number Example 6 2810 8484 10992

(182) The samples of example 6 consistently showed lower CE.sub.50 values and higher particle numbers than those of example 7. This is attributable to increased secondary precipitation of the polymer coating. This secondary precipitation is usually substantially smaller than the effect pigments.

(183) With increasing amplitude and hence increasing energy input in the ultrasound treatment, the CE.sub.50 values fall in both cases. Here, evidently, the pigments are reduced in size and/or there is partial abrasion of the polymer coating.

(184) Accordingly, the polymer coating in the case of example 7 is bonded better on the pigment surface than in the case of example 6, which is probably attributable to the mediation of adhesion by the epoxy silane.

B2 Analytical Investigations

(185) B 2.1 DSC Measurements:

(186) In analogy to the preliminary tests, DSC investigations were performed using an instrument from Netzsch (model STA 449 F3 Jupiter) on the inventive examples. The binder contents of the coated effect pigments were analyzed. The curve profiles in the DSC measurements corresponded to those of the preliminary tests. The positions of the onset temperatures and maximum temperatures in the endothermic peaks corresponded largely to those of the corresponding preliminary tests. The enthalpies of the endothermic peaks were converted for these amounts of binder. A very good match was found with the preliminary tests, with deviations in the range of +/−5%.

(187) B 2.2 PXRD Powder Diffractograms

(188) All powder diffraction measurements were taken on a STOE StadiP diffractometer in Debye-Scherrer geometry in transmission at room temperature. The diffractometer is equipped with copper radiation and a germanium monochromator (111), so that only the Cu.sub.Kα1 band (λ=1.5406 Å) is used for the diffraction. The generator power was set at 40 kV and 40 mA in order to ensure an optimum ratio of background to Bragg scattering. To limit the beam divergence, a 0.5 mm collimator was used in front of the sample. All measurements were carried out in a 20 range between 5 and 70° using a Mythen detector (from Dectris) with a detection window at 64×8 mm, corresponding to an opening angle of 19° in 2Θ. The detector was operated in 0.2° steps with an exposure time of 90 s for each step. The individual measurements are summated. This leads to a measuring time of 8 h and 8 min for each sample. The samples were prepared in 0.3 mm borosilicate glass capillaries (from Hilgenberg, Mark-tubes).

(189) B 2.3 C.sup.13 MAS NMR Overview Measurements

(190) All high-resolution one dimensional .sup.13C NMR spectra (e.g., FIGS. 4 and 6) were recorded on an Avance III HD Fourier-transform NMR spectrometer from Bruker. The spectrometer is equipped with three channels and a “wide bore” magnet (cryomagnet) with a magnetic field strength of 9.4 T. This corresponds to Larmor frequencies of 400.13 MHz for .sup.1H nuclei and of 100.62 MHz for .sup.13C nuclei. The samples were placed in 4 mm zirconium dioxide rotors and transferred into a 4 mm MAS double resonance sample head from Bruker. During the measurements, the rotational frequency of the sample holder was 12.5 kHz for the pure polymers (preliminary test examples 1, 10 and 15 and also preliminary test comparative examples 1, 10 and 15) and 8.0 kHz for the coated aluminum particles (example 1). Excitation was effected by cross-polarization, using a CW pulse on the .sup.13C channel and a shape pulse on the .sup.1H channel. By means of the shape pulse, the .sup.1H polarization was transferred in a customary way to the .sup.13C nuclei. FIG. 2a outlines the pulse sequences used. During the shape pulse, the pulse amplitude was increased linearly by a factor of two during the Hartmann-Hahn block. The initiating proton-90° pulse was adjusted to a length of 2.5 s, and the nutation frequencies of .sup.1H and .sup.13C during the Hartmann-Hahn block were 65 kHz (averaged over shape) and 53 kHz. The Hartman-Hahn condition for the transfer of the magnetizations from protons to the .sup.13C nuclei is, as is known, as follows: <ν(.sup.1H)>−ν(.sup.13C)=n*ν.sub.rot with n generally=±1. A 3 ms duration of the Hartmann-Hahn block (contact time) yielded optimum transfer efficiencies. The repeat time of 1 s was selected so as to allow more than 90% of the proton magnetization to relax into the thermal equilibrium in all cases. The recording of the FID was accompanied by broadband proton decoupling by means of a SPINAL64 sequence (described in B. M. Fung, A. K. Khitrin, K. Ermolaev, J. Magn. Reson. 2000, 142, 97-104), in which the proton nutation frequency was adjusted to 73 kHz and the time interval between the individual phase shifts was adjusted to 7.2 μs. In an acquisition time of 40 ms, 4096 points were recorded for the FID (Free Induction Decay). While 4096 transients were accumulated for the pure polymer samples (preliminary tests), the low sensitivity in the case of the coated aluminum particles (example 1) necessitated 51 600 repetitions. The 1D spectra were obtained by subsequent Fourier transformation with a “zero filling” of 4096 points and with folding using a Lorentz line with a full width at half maximum of 10 Hz. All chemical shifts for .sup.13C are reported relative to the standard TMS (0 ppm).

(191) .sup.13C MAS NMR overview measurements were prepared for the polymer samples of preliminary test examples 1, 10 and 17 (spontaneously precipitated polymers) and also of the corresponding preliminary test comparative examples 1, 10 and 17 (polymer samples in the original state) and also for example 1. FIG. 4 shows by way of example the spectra of example 1, preliminary test example 1, and preliminary test comparative example 1. The figure also includes the chemical formulae of the structural elements of the polyester and their assignment to the peaks in the NMR spectrum.

(192) FIG. 6 shows by way of example the spectra of example 10, preliminary test example 10, and preliminary test comparative example 10. More clearly in comparison to FIG. 4 it is possible to make out a double structure in the region of 130 ppm, owing to the high terephthalic acid fraction of the binder.

(193) The precipitated, semicrystalline polymers in each case show clearly more effectively structured .sup.13C NMR spectra than the unprecipitated, amorphous polymers. In the case of the coated aluminum pigment (example 1), the structures are not entirely too pronounced as in the case of the pure polymer (preliminary test example 1). This may be due to the greater susceptibility differences in this sample.

(194) The full widths at half maximum of the .sup.13C MAS spectra were between 250 and 350 Hz for the amorphous samples (preliminary test comparative examples 1, 10 and 17) and between 100 and 180 Hz for the semicrystalline polymers (preliminary test examples 1, 10 and 17). That of the coated Al particles (example 1) was between 180 and 270 Hz.

(195) Since it was not possible from the full widths at half maximum alone to determine the degree of crystallization, .sup.13C NMR MAS relaxation measurements were conducted as well.

(196) B 2.4.sup.13C NMR MAS Relaxation Measurements:

(197) All of the measurements of the .sup.13C spin-lattice relaxation (T.sub.1) were carried out on an Avance II Fourier-transform NMR spectrometer from Bruker. This spectrometer is equipped with three channels and a “wide bore” magnet with a magnetic field strength of 7.05 T. This corresponds to Larmor frequencies for .sup.1H and .sup.13C of 300.15 MHz and 75.48 MHz. The samples were introduced into 7 mm zirconium dioxide rotors and transferred into a 7 mm MAS triple resonance sample head from Bruker. During the measurements, the rotational frequency of the sample holder was 6 kHz. The low rotational frequency was selected so as to minimize the effect of the rotational frequency on the spin-lattice relaxation by quenching of the spin diffusion in the proton bath. Recording took place with a saturation sequence. The saturation block contained ten .sup.13C-90° pulses with a length of 3.5 μs for the pure polymers of the preliminary test examples and comparative examples, and 7.0 μs for the coated Al particles (example 1), and also a dephasing interval of 20 ms between them. At the end of the saturation block, the residual magnetization was less than 0.1%, with the greatest fraction of the falling magnetization having been caused by the rapid relaxation of the methyl resonance. The saturation block was followed by a variable waiting time of between 100 μs and 1400 s, in which the longitudinal magnetization builds up again, depending on this waiting time and on the time constant T.sub.1. The waiting times were selected with an exponential difference such that six values were measured in each full decade. For detection of the re-established polarization, the latter was converted into transverse, observable magnetization by means of a 90° read pulse on the .sup.13C channel with a length of, again, 3.5 μs and 7.0 μs. The resulting FID was recorded with an acquisition time of 15 ms and with 2048 points under broadband proton decoupling with a SPINAL64 sequence. For the latter, the proton nutation frequency was 75 kHz and the time interval between the individual phase shifts was 7.4 s. In the case of the pure polymer samples (preliminary test examples and comparative examples), 64 transients were recorded for each FID at each waiting time. For the coated Al particles (example 1), the number of repetitions for each FID was 1200. FIG. 2b gives a schematic overview of the pulse sequences used.

(198) In order to enable frequency-resolved evaluation of the spin-lattice relaxation, the pseudo-2D data obtained were Fourier-transformed along the F2 domain. For this purpose, a “zero filling” of 2048 points and a fold with a Lorentz line with a full width at half maximum of 50 Hz was used. All chemical shifts for .sup.13C are again reported relative to the standard TMS (0 ppm). The spectra thus obtained were baseline-corrected by adapting the spectra using a “cubic spline” interpolation for the shortest waiting time which still contained no significant spectral intensity. The resulting fitted curve was then subtracted from all other spectra. This was followed by integration over the resonances of the characteristic chemical structural units, by summation of the intensities. The baseline correction and integration were conducted using the program package Matlab version R2014b (8.4.0.150421) from MathWorks. The following spectral ranges were integrated: 17-28 ppm (Me-), 61-78 ppm (—CH.sub.2—), 30-40 ppm (C.sub.q), 124-140 ppm (—C.sub.aromatic—), and 160-170 ppm (—CO.sub.2—). The integral intensities.sup.1 were adapted biexponentially as a function of the waiting time t by means of equation (1). This was done using a Levenberg-Marquardt algorithm in its implementation in the program gnuplot (version 4.6 patch level 5) with a weighting of 1.0 for each data point in the sum of the least square errors.

(199) $\begin{matrix} M (t, M_{0}, a, c, T_{1}^{s}, T_{1}^{l}) = M_{0} .Math. [(1 - c) .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{s}})}) + c .Math. (1 - a .Math. e^{- (\frac{t}{T_{1}^{l}})})] & (II) \end{matrix}$

(200) The equilibrium magnetization M.sub.0 was adapted separately as the mean of the intensities for the greatest waiting times, and was no longer altered in the overall refinements. In the case of the Levenberg-Marquardt algorithm used, only the variables a, c, T.sub.1.sup.s and T.sub.1.sup.l were changed. For this purpose, with regard to the measurements, it is necessary to bear in mind that the intensities no longer rise systematically, at least for the last three measurement values. Parameter a takes account of nonzero initial magnetizations and can therefore be viewed as a technical variable for the refinement that is otherwise not relevant for determining the crystalline fraction in the polymers and coated Al particles. Parameter a reflects the efficiency of the saturation block and of the baseline correction, and ought to be close to 1.0 on complete elimination of the magnetization at t=0. For the measurements carried out here, a varied between 0.92 and 1.1.

(201) For the determination of the degree of crystallinity there are therefore three variables remaining—the two time constants of the spin-lattice relaxation, T.sub.1.sup.s and T.sub.1.sup.l, and also the weighting c. T.sub.1.sup.s and T.sub.1.sup.l differed very significantly and were therefore easy to separate. Together with the powder diffractograms (FIG. 3), this suggests a heterogeneous nature to the samples, in which an unordered (amorphous) and an ordered (crystalline) region can be distinguished. The rapid spin-lattice relaxation with the time constant T.sub.1.sup.s is assigned, on the basis of the more efficient relaxation, to the amorphous region, where greater dynamism is expected.

(202) Correspondingly, T.sub.1.sup.l is characteristic for the crystalline region. The constant c describes, correspondingly, the fraction of the crystalline regions in atom percent. FIGS. 5 and 7 show by way of example the typical profile of the extent of relaxation Φ=(M.sub.0−M(t))/M.sub.0 against the waiting time t. The y-axis is plotted logarithmically, and so the individual relaxation components appear as straight lines.

(203) The results of the evaluations of the relaxation measurements carried out are set out in tab. 6. In this case, the signals of the methyl groups were disregarded, since, as is known, they relax very rapidly owing to the spin-rotation relaxation between C atoms and adjacent H atoms, meaning that no difference can be detected between crystalline and amorphous fractions.

(204) TABLE-US-00006 TABLE 6 Results of the evaluations of the .sup.13C MAS relaxation measurements Means of determined Parameter parameters c, Binder/sample: determined —CO.sub.2— C.sub.ar —CH.sub.2— Cq T.sub.1.sup.s and T.sub.1.sup.l CC 4540-0 “AGM” M.sub.0 2.02 6.49 1.75 1.06 (amorphous) a 1.00 1.00 1.00 1.00 Preliminary test c 0.66 0.81 0.64 0.64 0.69 comparative T.sub.1.sup.s/s 16 7.2 2.1 4.8 7.5 example 1 T.sub.1.sup.l/s 73 45.9 28 22 42.2 (CC 2506-1 M.sub.0 3.12 8.33 2.82 1.87 “AGM”) a 1.00 0.99 0.98 0.99 Preliminary test c 0.73 0.74 0.66 0.4 0.63 comparative T.sub.1.sup.s/s 12.2 4.4 1.2 8.3 6.5 example 10 T.sub.1.sup.l/s 55.4 43.2 24.1 36 39.7 (Sirales PE 7499 M.sub.0 2.28 6.01 2.09 1.18 “AGM”) a 1.00 1.00 0.98 1.00 Preliminary test c 0.79 0.75 0.65 0.79 0.75 comparative T.sub.1.sup.s/s 11.5 9.4 1.6 1.6 6.0 example 15 T.sub.1.sup.l/s 71.4 61.1 35.9 22.8 47.8 CC 4540-0 “Nd” M.sub.0 1.15 3.15 0.76 0.59 Preliminary test a 1.10 1.00 1.00 1.03 example 1 c 0.77 0.54 0.47 0.33 0.5275 T.sub.1.sup.s/s 1.6 14 9.6 7.2 8.1 T.sub.1.sup.l/s 93 140 83 77 98.25 CC 4540-0 coated M.sub.0 7.5 19.8 2.8 3.4 Al substrate a 1.002 0.964 0.95 1.02 Example 1 c 0.69 0.76 0.73 0.65 0.7075 T.sub.1.sup.s/s 14.9 8.8 0.5 1.3 6.4 T.sub.1.sup.l/s 123 84.6 57 29.8 73.6 CC 2506-1 “Nd” M.sub.0 2.49 6.25 2.11 1.29 Preliminary test a 1.00 0.99 0.99 0.99 example 10 c 0.73 0.62 0.72 0.33 0.6 T.sub.1.sup.s/s 10.2 12.5 2.1 7.4 8.1 T.sub.1.sup.l/s 105 103 50.1 47 76.3 Sirales PE 7499 M.sub.0 1.79 4.27 1.58 0.86 “ND” a 1.00 0.99 0.98 0.99 Preliminary test c 0.68 0.63 0.75 0.7 0.69 example 15 T.sub.1.sup.s/s 16.8 14.8 2.1 4 9.4 T.sub.1.sup.l/s 116 114 57 23.4 77.6

(205) For the evaluation, the relaxations of the .sup.13C nuclei of the acid groups (for short —CO.sub.2—), of the aromatic group of the acid component (C.sub.ar for short), and also the methylene groups (for short —CH.sub.2—) and the quaternary C atom (for short C.sub.q) of the neopentyl alcohol component were employed in each case. The methyl groups were not used, owing to their familiar, very rapid relaxation, as is known. For the values c, T.sub.1.sup.s and T.sub.1.sup.l determined, the means of all individual groups were used in each case, corresponding to the usual procedure of this method.

(206) There is a distinct difference between the short relaxation frequencies assigned to the amorphous fraction and the long relaxation frequencies assigned to the crystalline fraction. Inventive example 1 and preliminary test examples 1, 10 and 15 exhibit much higher relaxation times T.sub.1.sup.l (73.6 to 98.25 s) than the corresponding preliminary test comparative examples (39.7 to 47.8 s). In the parameter c, however, there are no clear delimitations apparent as in the case of the parameter T.sub.1.sup.l. All of the samples investigated have degrees of crystallization c of around 70%.

(207) Overall, these findings can be interpreted to mean that the unprecipitated binder polymers already have a certain preorder with a very low spatial extent. In the case of the precipitated binder polymers, however, the ordered regions increase sharply spatially, leading to longer relaxation times T.sub.1.sup.l.

(208) Because the .sup.13C NMR relaxation measurements outlined here are a method that is extremely sensitive at a molecular level, it is also possible for regions with a very low order to result in high c values. Using the method, local orders in the polymer are detected from as little as around 3 to 4 unit cells.

(209) These interpretations of the NMR findings fit very well with the results of the PXRD investigations. There, the unprecipitated samples of the preliminary test comparative examples consistently showed unstructured spectra. A preorder of the polymers already present here was in evidence, though insufficiently pronounced in spatial terms to give signals in the Debye-Scherrer geometry. With this method, which is based on more long-distance interactions, structured signals are obtained only when there are at least around twenty unit cells of the crystalline regions present. The precipitated polymers gave clearly structured spectra in the case both of the pure polymer samples (preliminary test examples) and of the polymer precipitated onto the Al platelets (example 1). In the case of the NMR relaxation tests, the sharply increased domain size of the crystalline fractions of the precipitated polymers resulted in the higher relaxation times T.sub.1.sup.l observed.

Effect pigments coated with organic binders for powders paints, and a method for producing said coated effect pigments and their use

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