COMB POLYMER AND USE THEREOF AS DISPERSING AGENT

Abstract

The invention relates to a comb polymer having repeating units of at least one of the structures of formulae (I) to (IV) wherein R.sup.1 represents a polyoxyalkylene group and A represents an organic group, and wherein the comb polymer has end groups of the general formula (V) wherein R.sup.2 and R.sup.3 independent of each other are selected from a) organic groups having 1 to 24 carbon atoms and b) R.sup.1.

##STR00001##

Claims

1. A comb polymer having repeating units of at least one of the structures of formulae (I) to (IV) ##STR00006## wherein R.sup.1 represents a polyoxyalkylene group and A represents an organic group, and wherein the comb polymer has end groups of the general formula (V) ##STR00007## wherein R.sup.2 and R.sup.3 independent of each other are selected from a) organic groups having 1 to 24 carbon atoms and b) R.sup.1.

2. The comb polymer according to claim 1, wherein at least one of R.sup.2 and R.sup.3 is a hydroxyalkyl group having 2 to 4 carbon atoms.

3. The comb polymer according to claim 1, wherein R.sup.2 is equal to R.sup.1 and R.sup.3 is a group of formula (VI) ##STR00008## wherein R.sup.4 is an organic group having 2 to 20 carbon atoms and selected from hydrocarbyl groups, ether groups and ester groups.

4. The comb polymer according to claim 1, wherein R.sup.1 comprises repeating units from at least one of oxyethylene, oxypropylene, and oxybutylene.

5. The comb polymer according to claim 1, wherein R.sup.1 is terminated by a hydrocarbyl group having 1 to 10 carbon atoms.

6. The comb polymer according to claim 1, wherein A comprises at least one ether group.

7. The comb polymer according to claim 1, wherein A consists of ether groups and hydrocarbyl groups.

8. The comb polymer according to claim 1, wherein the sum of the repeating units of the structures of formulae (I), (II), (III), and (IV) is in the range of 3 to 25.

9. The comb polymer according to claim 1, wherein the comb copolymer has a number average molecular weight in the range of 6000 to 50000 g/mol.

10. The comb polymer according to claim 1, wherein the comb polymer has an epoxide equivalent weight of at least 10000 g/mol.

11. The comb polymer according to claim 1, wherein the comb polymer is substantially free of epoxide groups and wherein the comb polymer is substantially free of primary and secondary amine groups.

12. The comb polymer according to claim 1, wherein at least a part of the tertiary amino groups of the repeating units of the structures of formulae (I) to (IV) are present in salt form.

13. The comb polymer according to claim 1, wherein at least a part of the tertiary amino groups of the repeating units of the structures of formulae (I) to (IV) have been converted to quaternary ammonium groups.

14. A process for preparing a comb polymer, the process comprising reacting a) a diepoxide and a primary monoamine of the formula R.sup.1—NH.sub.2, wherein the molar ratio of epoxide groups to amine active hydrogens of the primary monoamine is not equal to 1:1, and b) a monoepoxide of the formula (VII) ##STR00009## if a molar excess of amine active hydrogens is employed in a), or a secondary amine of the formula HNR.sup.2R.sup.3, if a molar excess epoxide groups is employed in a), wherein R.sup.1 represents a polyoxyalkylene group, R.sup.2 and R.sup.3 independent of each other are selected from a) organic groups having 1 to 24 carbon atoms and b) R.sup.1, and R.sup.4 is an organic group having 2 to 20 carbon atoms and selected from hydrocarbyl groups, ether groups and ester groups.

15. A composition comprising solid particles and the comb polymer according to claim 1.

16. The composition according to claim 15, wherein the solid particles comprise at least one of pigments and fillers.

17. A process of dispersing solid particles in a dispersion medium comprising a) Mixing solid particles and the comb polymer according to claim 1 in a dispersion medium, and b) Exerting shear force to the mixture prepared in a).

18. A particle dispersion comprising the comb polymer according to claim 1, a dispersion medium, and solid particles.

Description

EXAMPLES

[0064] Raw Materials Used:

[0065] Epikote 828 is an aromatic diepoxide from Hexion

[0066] Jeffamine M 2070 is a polyetheramine from Huntsman Corporation

[0067] DABCO is a catalyst from Air products

[0068] 2,2′-Iminodiethanol supplied by BASF SE

[0069] Dibutylamine supplied by Sigma Aldrich

[0070] Dibenzylamine supplied by Sigma Aldrich

[0071] N-benzylmethylamine supplied by Sigma Aldrich

[0072] Epalloy 5001LC is an aliphatic diepoxide from Emerald Performance Materials

[0073] Grilonit RV 1814 is an C13/C15 alkyl glycidylether from EMS Griltech

[0074] Oxirane, 2-[(2-methylphenoxy)methyl]- is supplied by Dow

Termination with Secondary with Secondary Amine

Preparation Example 1

[0075] 45 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until only two epoxide groups were detected per polymer by 1H-NMR (integrated). After two hours, 0.25 g DABCO were added as catalyst. Afterwards, 5 g 2,2′-Iminodiethanol are were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

Preparation Example 2

[0076] 45 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until only two epoxide groups were detected per polymer by 1H-NMR (integrated). After two hours, 0.25 g DABCO were added as catalyst. Afterwards, 6 g dibutylamine were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

Preparation Example 3

[0077] 45 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until only two epoxide groups were detected per polymer by 1H-NMR (integrated). After two hours, 0.25 g DABCO were added as catalyst. Afterwards, 5 g dibenzylamine were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

Preparation Example 4

[0078] 45 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until only two epoxide groups were detected per polymer by 1H-NMR (integrated). After two hours, 0.25 g DABCO were added as catalyst. Afterwards, 6 g N-benzylmethylamine were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

Preparation Example 5

[0079] 32 g Epalloy 5001LC and 124 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until only two epoxide groups were detected per polymer by 1H-NMR (integrated). After two hours, 0.15 g DABCO were added as catalyst. Afterwards, 3.2 g 2,2′-Iminodiethanol are were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

[0080] In preparation Examples 1 to 5 the molar ratio of epoxide groups to amine active hydrogens of the primary monoamine to the amine active hydrogens of the secondary amine was 10:8:2.

Termination with Monoepoxide

Preparation Example 6

[0081] 30 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until no epoxide groups were detected per polymer by 1H-NMR (integrated). Afterwards, 4.5 g Grilonit RV 1814 were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

Preparation Example 7

[0082] 30 g Epikote 828 and 193 g Jeffamin M 2070 were combined and stirred for 6 hours at 140° C. under N.sub.2-atmosphere until no epoxide groups were detected per polymer by 1H-NMR (integrated). Afterwards, 2.3 g Oxirane, 2-[(2-methylphenoxy)methyl]- were added and the reaction mixture was stirred for an additional 6 hours at 140° C. until no epoxide groups were detected by 1H-NMR. An amber, clear, viscous polymer was obtained.

[0083] All examples had the same ratio of epoxide groups belonging to the diepoxide to amine active hydrogens of the primary monoamine to epoxide groups belonging to the monoepoxide (8:10:2).

Comparative Preparation Examples

[0084] (1) According to patent EP 1 745 104 B1, preparation 7 (Huntsman)

[0085] (2) Material described in EP 1 486 524 B1 was prepared by combining 30 g Epikote 828, 193 g Jeffamin M 2070 and 0.2 g DABCO. The reactants were stirred for 12 hours at 140° C. under N2-atmosphere until no epoxide groups were detected per polymer by 1H-NMR (integrated). An amber, clear, viscous polymer was obtained. The ratio of epoxide groups to amine active hydrogens was 10:12.

Application Examples

[0086] To evaluate the effectiveness of the inventive polymers as pigment dispersants, they were tested in different coating compositions.

Application Example 1: Laropal Dispersion

[0087] As first step, pigment concentrates with different pigments were made with an inorganic pigment (Bayferrox 130M) and a carbon black pigment (Special Black 4). The components shown in Table 1 were combined and dispersed in a Lau-Disperser with 1 mm glass beads to create the pigment concentrates (2 hours for Bayferrox 130M, 4 hours for Special Black 4).

TABLE-US-00001 TABLE 1 Composition of the pigment concentrates. Laropal A 81 is an aldehyde resin from BASF SE, GARAMITE 7305 is a clay-based rheology additive from BYK-Chemie GmbH, Bayferrox 130M is a micronized iron oxide red pigment from LANXESS, Special Black 4 is a carbon black pigment from Orion Engineered Carbon. Pigment Pigment Concentrate Concentrate Raw material 130M Sp. Black 4 Laropal A 81 60% 12.50 10.60 2-Propanol, 1- 22.60 27.40 methoxy-, acetate Inventive or 4.50 4.00 comparative polymers GARAMITE 7305 0.40 Bayferrox 130M 60.00 Special Black 4 8.00 100.00 50.00

[0088] The viscosities of the pigment concentrates were measured one day after grinding. The viscosities and the particle size of the pigment concentrates using the polymers of preparation examples 1 and 5 (present invention) and comparative example 1 are shown in Table 2 below. The viscosity was measured with an Anton Paar rheometer ((25 mm 0, 1°, 23° C.) at high shear rates.

TABLE-US-00002 TABLE 2 Viscosities of samples of pigment concentrate Bayferrox 130M for high (100 1/s) shear rates. mPa s at 100 1/s— after 1 d RT Pigment Concentrate Polymer sample 130M Comp. Example 1 431.4 Example 1 282.4 Example 5 148.8

[0089] The inventive samples showed a better viscosity reduction than the comparative example for the pigment concentrate with the inorganic exemplary pigment.

TABLE-US-00003 TABLE 3 Viscosities of samples of pigment concentrates Special Black 4 for high (100 1/s) shear rates. mPa s at 100 1/s—after 1 d RT Pigment Concentrate Polymer sample Sp. Black 4 Comparative Example 1 42.7 Example 1 29.8 Example 5 22.6

[0090] The viscosity for carbon black also improved with the inventive products indicating that the dispersion ability improved also for the exemplary organic pigment.

[0091] Letdown

[0092] To form the final coating composition, the pigment concentrate was combined with the letdown and hardener with the composition shown in table 4 and 5. The mixing ratio of the three components is shown in table 6. After application on the panel, the coating is cured for 30 min at 60° C. after 60 minutes flash off time.

TABLE-US-00004 TABLE 5 Composition of hardener Component Ratio Desmodur N75 25.00 Butyl acetate 8.70 Solvent naphtha 8.80 (petroleum), light arom. 2-Propanol, 1-methoxy-, 2.50 acetate Xylene 5.00 50.00

TABLE-US-00005 TABLE 4 Composition of letdown Component Ratio Macrynal SM 510 75.00 Xylol 6.60 Solvent Naphtha 5.00 Butyl acetate 8.00 2-Propanol, 1- 5.00 methoxy-, acetate BYK-066N 0.30 BYK-306 0.10 100.00

[0093] Macrynal SM 510 is an acrylic resin from Allnex, BYK-066N is a silicone defoamer from BYK-Chemie GmbH, BYK-306 is a surface-active additive from BYK-Chemie GmbH, Desmodur N75 is an isocyanate hardener from Covestro AG.

[0094] Mixing Ratio

TABLE-US-00006 TABLE 6 Mixing ratio of Pigment concentrate, letdown and hardener. Pigment Concentrate Let-Down 130M SBlack 4 Hardener Sum 130M 17.3 4.0 8.7 30.0 Sp. Black 4 18.1 2.8 9.1 30.0

[0095] Results

[0096] To evaluate the efficiency of dispersion of the pigment concentrates, the transparency was assessed and haze as well as gloss were measured. The transparency was assessed by visual valuation. The coating was applied on a PET-foil (50 μm wire bar) and held against a light source. Haze and gloss of the coating was measured on the same foil with a BYK haze-gard for the haze measurement and the BYK-micro-haze plus for the gloss (20° angle). The results are summarized in table 7.

TABLE-US-00007 TABLE 7 Results of transparency, transmission, haze and gloss measurement for Special Black 4 coating. Transparency Haze Gloss Coating sample Sp. Black 4 Sp. Black 4 Sp. Black 4 Comparative Example 1 3 19 85 Example 1 1-2 16 86 Example 5 1-2 16 86

[0097] The transparency improved significantly with the inventive products, showing that the dispersion quality increased. The haze of the coating is low while the gloss is good in all cases.

[0098] To evaluate the efficiency of dispersion of the pigment concentrate 130M, a rub out test was performed. After storage, the paint is applied on a contrast test chart by use of a frame applicator (100 μm wire bar). The Rub-up-test is carried out by rubbing a finger on the surface of the paint (about ⅓ of the applied area) until there is a certain resistance against the rubbing and the color difference between the rubbed and the untreated area reaches the highest value and stays constant. After drying, an evaluation of the color difference is performed with a Spectro Guide Sphere Gloss (20° Angle).

TABLE-US-00008 TABLE 8 Results of Rub-Out (Delta-E, b*-value and Gloss) for Bayferrox 130M coating Delta-E Gloss Coating sample Bayferrox 130M Bayferrox 130M Comparative Example 1 1.13 93 Example 1 0.96 93 Example 5 0.68 93

[0099] The dispersion quality and thus the Delta-E values of the Rub-Out improved with the inventive products. Especially Example 5 shows a low delta-e value and thus a good dispersion and stabilization of the pigment. The gloss is good in all cases.

Application Example 2: Epoxy Coating System

[0100] For the second type of coating composition, all liquid components (Epikote 1001 X75, exemplary polymer and BYK-052 N) were combined in a pot and located under a grinding vessel (4 cm tooth plate). The solid components (Bayferrox 130M, Blanc Fixe N and GARAMITE 7305) were stirred in with a low mixing rate. After complete addition, the components were dispersed for 30 minutes at 50° C. and 8500 rpm. Afterwards, the solvent mixture was added. The curing agent was added before application of the coating composition.

TABLE-US-00009 TABLE 9 Coating composition of epoxy coating example. Epikote 1001 X75 is a solid epoxy resin from Hexion, BYK-052 N is a defoamer from BYK-Chemie GmbH, Blanc Fixe N is a barium sulfate whit pigment from Solvay, MIBK is a solvent from Eastman, iso-Butanol is a solvent from Dow, Epikure 3115 X70 is a polyamide based curing agent from Hexion. 2-pack- Epoxy Raw materials Coating Epikote 1001 X75 128.00 Inventive or comparative 1.80 polymers BYK-052 N 1.00 Bayferrox 130M 15.00 Blanc Fixe N 110.60 GARAMITE 7305 1.60 Grinding vessel, 50° C., 30 min, 8500 rpm, 4 cm- Tooth plate MIBK/iso-BuOH 7:3 42.00 300.00 Epikure 3115 X70 45.00 345.00

[0101] Viscosity

[0102] The viscosities of the coating composition without the curing agent using dispersant examples 1, 5 (present invention) and comparative examples 1 and 2 are shown in Table 10 below. The viscosity was measured with an Anton Paar rheometer ((25 mm 0, 1°, 23° C.) at different shear rates. The measurement was repeated after 7 d and the quotient of the viscosities for a shear rate 100 1/s recorded as storage index.

TABLE-US-00010 TABLE 10 Viscosities of samples for high (100 1/s), medium (10 1/s) and low (1 1/s) shear rates. mPa s at 1 mPa s at 10 mPa s at 100 Storage 1/s—after 1/s—after 1/s—after Index at Sample 1 d RT 1 d RT 1 d RT 100 1/s Comparative 2869 1467 1037 1.13 Example 1 Comparative 2564 2027 1734 0.86 Example 2 Example 1 2156 1708 1465 1.04 Example 5 1658 1295 1084 1.08

[0103] The viscosity of the inventive examples is lower for low shear rates. That leads to a better handling even with “bad” grinding conditions. The storage stability of the coating is furthermore enhanced which is reflected by the storage index. The same tendencies are found for low shear rates.

[0104] To evaluate the efficiency of dispersion of the pigment concentrate 130M, a rub out test was performed. After storage, the paint is applied on a contrast test chart by use of a frame applicator (100 μm wire bar). The Rub-Out-test is carried out by rubbing a finger on the surface of the paint (about ⅓ of the applied area) until there is a certain resistance against the rubbing and the color difference between the rubbed and the untreated area reaches the highest value and stays constant. After drying, an evaluation of the color difference is performed with a Spectro Guide Sphere Gloss.

TABLE-US-00011 TABLE 11 Results of Rub-Out for the epoxy coating. Sample Delta-E Comparative Example 1 1.02 Comparative Example 2 0.58 Example 1 0.54 Example 5 0.51

[0105] The Delta-E values show that the Rub-Out and thus the dispersion efficiency is improved with the inventive polymers.

Application Example 3: Aqueous Ink

[0106] Water, biocide, defoamer and inventive or comparative polymer were combined and dispersed in a Lau-Disperser with 1 mm glass beads for 16 hours to prepare pigment concentrates.

TABLE-US-00012 TABLE 13 Composition of the pigment concentrate for aqueous inks. Acticide MBS is a biocide from Lanxess, BYK-019 is a defoamer from BYK-Chemie GmbH, Emperor 1800 is a carbon black pigment from the Cabot Corporation. Component Pigment Concentrate Water 37.25 Inventive or comparative polymers 5.00 Acticide MBS 0.05 BYK-019 0.20 Emperor 1800 7.50 50.00

[0107] The viscosities and the particle size of the pigment concentrates using dispersant examples 1, 2, 3, 4, 6, 7 (present invention) and comparative example 2 are shown in Table 14 below. The viscosity was measured with an Anton Paar rheometer (measurement system CP 50, T=25° C.) at a constant shear rate of 100 s.sup.−1. The particle size of the pigment concentrates was measured with a NanoPlus DLS particle analyzer micromeritics). For this purpose 0.05 g of the pigment concentrate was diluted with 12.5 g water.

TABLE-US-00013 TABLE 14 Viscosity and Particle Size of the pigment concentrate. Particle Viscosity size after after initial storage Storage storage mPas mPas Index D50 [nm] Comparative Example 2 14.3 12.4 0.87 62 Example 1 11.0 10.8 0.98 59 Example 2 12.1 11.5 0.95 60 Example 3 11.5 11.1 0.97 59 Example 4 11.5 10.9 0.95 56 Example 6 12.7 12.7 1.00 60 Example 7 10.3  9.9 0.96 62

[0108] As can be seen, the polymer of the invention is much more effective at dispersing carbon black than the comparative example, as reflected by a lower viscosity. Furthermore, the storage stability improved significantly with the inventive products even without having a resin in the pigment paste. The particle size is comparable or better in most cases.

Application Example 4: Aqueous Carbon Black Dispersion

[0109] For the pigment concentrate, the raw materials shown in table 15 are mixed while stirring and the pH adjusted to 8.2-8.5 with Dimethylethylamine (10% solution in water) before grinding. The mixture is ground in a LAU Disperser DAS 200 for 4 hours with glass beads (1.0-1.2 mm) ratio=1:1 (by weight). After grinding, the pH is checked and if needed again adjusted to 8.2-8.5 with Dimethylethylamine (10% solution in water).

TABLE-US-00014 TABLE 15 Composition of pigment concentrate. BYK-011 is a defoamer from BYK-Chemie GmbH, Raven 5000 UIII is a carbon black pigment from Birla Carbon. [%] Deionized water 82.2 Inventive or 7.0 comparative polymers BYK-011 0.8 Raven 5000 UIII 10.0 100.0

[0110] The letdown is prepared by combining the raw materials shown in table 16 while stirring. The pigment concentrate is added to the letdown and the viscosity is adjusted to the spray out viscosity with demineralized water (˜700 mPa*s Brookfield Viscometer at 50 rpm). The mixing ratio of pigment concentrate and letdown is shown in table 17.

TABLE-US-00015 TABLE 16 Composition of letdown. Setaqua 6801 is an acrylic binder from Allnex, Setaqua 6802 is an acrylic binder from Allnex, BYK-028 is a defoamer from BYK-Chemie GmbH, BYK- 348 is a silicone surfactant from BYK-Chemie GmbH, BYK-425 is a rheology additive from BYK-Chemie GmbH. Let-down [%] Setaqua 6801 23.8 Setaqua 6802 44.9 BYK-028 0.6 Dimethylethylamine 2.0 10% in water Deionized water 13.5 Butylglykol 5.7 BYK-348 0.5 BYK-425 9.0 5% in water 100.0

TABLE-US-00016 TABLE 17 [%] Pigment Concentrate 13.3 Let-down 86.7 100.0

[0111] The base coat is applied by hand on coil-primed aluminum panels with a spray gun (HVLP 3000, 1.3 mm nozzle) at 2 bar. The panel is cured by 30 min flash off at RT.

[0112] To evaluate the quality of dispersion, the jetness of the base coat was measured with a BYK-Gardner spectro guide 45/0.

TABLE-US-00017 My dM Mc Comparative Example 2 259 10 269 Example 1 264 11 275 Example 2 264 10 274 Example 7 266  9 274

[0113] It can be seen, that the Mc as well as the My values are higher for the inventive samples, indicating a good dispersion. The Undertone dM which is a indicator for the bluishness of the coating is good for all samples.