IMPROVEMENTS RELATING TO DISPERSIONS

Abstract

A dispersion comprising a solid particulate component such as a pigment, a dispersing agent and one or more solvents is disclosed. The dispersing agent comprises a reaction product of (a) an epoxidised carboxylic acid ester; (b) a compound including at least one reactive alcohol and/or amino functional group; and (c) a derivatising agent. Such a dispersion shows excellent long-term stability. A method of producing such a dispersion having long-term stability, and a use of the dispersing agent to provide a dispersion having long-term stability are also described.

Claims

1. A liquid dispersion comprising: a solid particulate component; a dispersing agent; and one or more solvents; wherein the dispersing agent comprises a reaction product of: (a) an epoxidized carboxylic acid ester; (b) a compound including at least one reactive alcohol and/or amino functional group; and (c) a derivatising agent.

2. A method of producing a dispersion having long-term stability, the method comprising the steps of: (a) mixing together a dispersing agent and one or more solvents; and (b) adding a solid particulate component to form a dispersion; wherein the dispersing agent comprises a reaction product of: (i) an epoxidized carboxylic acid ester; (ii) a compound including at least one reactive alcohol and/or amino functional group; and (iii) a derivatizing agent.

3. Use of a dispersing agent to provide long-term stability to a dispersion comprising a solid particulate component and one or more solvents, wherein the dispersing agent comprises a reaction product of: (a) an epoxidized carboxylic acid ester; (b) a compound including at least one reactive alcohol and/or amino functional group; and (c) a derivatizing agent.

4. A method or use according to claim 2, wherein the dispersing agent prevents flocculation of the solid particulate component.

5. The dispersion according to claim 1 wherein the dispersing agent comprises a reaction product of (c) a derivatizing agent with a reaction product of (a) an epoxidized carboxylic acid ester and (b) a compound including at least one reactive alcohol and/or amino functional group.

6. The dispersion according claim 1 wherein said epoxidized carboxylic acid ester (a) comprises an ester of formula RCOOR.sup.1 in which R is a hydrocarbyl group including an epoxy functional group and R.sup.1 is a hydrocarbyl group.

7. The dispersion according to claim 1 wherein said epoxidized carboxylic acid ester (a) comprises an epoxidized soybean oil fatty acid ester.

8. The dispersion according to claim 1 wherein said compound (b) comprises a compound of formula (I): ##STR00013## wherein n is 0 or a positive integer; each X is independently O or NH; each group R.sup.4 is independently an optionally substituted alkylene, alkenylene or arylene group; and R.sup.5 is hydrogen or an optionally substituted alkyl, alkenyl, aryl, alkaryl or aralkyl group provided that n is not 0 when R.sup.5 is hydrogen.

9. The dispersion, according to claim 1 wherein said compound (b) comprises an alkoxylated compound.

10. The dispersion according to claim 1 wherein said derivatizing agent (c) comprises a compound including at least one reactive alcohol or amino functional group and one tertiary amino group.

11. The dispersion according to claim 1 wherein said derivatizing agent (c) comprises a compound of formula (III): ##STR00014## wherein p is 0 or a positive integer, each X.sup.3 is independently O or NR.sup.11, X.sup.4 is O or NR.sup.12, each R.sup.9 is independently an optionally substituted alkylene, alkenylene or arylene group, and each of R.sup.10, R.sup.11 and R.sup.12 is independently hydrogen or an optionally substituted alkyl, alkenyl, aryl, alkaryl or aralkyl group.

12. The dispersion according to claim 11 wherein p is at least 10, each X.sup.3 is O, X.sup.4 is O, each R.sup.9 is an unsubstituted alkylene or alkenylene group, and R.sup.10 is hydrogen or an unsubstituted alkyl or alkenyl group.

13. The dispersion according to claim 11 wherein p is 1, X.sup.3 is NR.sup.11, X.sup.4 is NH, R.sup.9 is an unsubstituted C.sub.1 to C.sub.8 alkylene group, and R.sup.10 and R.sup.11 are independently an unsubstituted C.sub.1 to C.sub.4 alkyl group.

14. The dispersion according to claim 11 wherein the solid particulate component comprises an organic pigment.

15. The dispersion according to claim 11 wherein the solid particulate component comprises an inorganic pigment.

16. The dispersion according to claim 11 wherein the solid particulate component is present in an amount of from 50 to 95 wt % based on the total weight of solids in the dispersion.

17. The dispersion according to claim 11 wherein the dispersing agent is present in an amount of from 5 to 30 wt % based on the total weight of solids in the dispersion.

18. The dispersion according to claim 11 wherein the dispersion comprises one or more further components selected from resins, pH modifiers, humectants, binders, solvents, antifoaming agents, surfactants, biocides, rheology modifiers, extenders, silicones, UV stabilisers, catalysts, fillers, driers, and anti-settling agents.

19. The dispersion according to claim 11 wherein the one or more solvents comprise water.

20. A paint, ink, polymer or coating composition comprising the dispersion according to claim 1 and one or more further components.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0259] For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which:

[0260] FIG. 1 shows the viscosity of Examples 5, 6 and 7 over time.

[0261] FIGS. 2a and 2b show the particle size analysis of Examples 5 and 6, respectively.

[0262] FIG. 3 shows the flow cup analysis of Examples 8, 9 and 10 over time.

[0263] FIG. 4 shows the viscosity of Examples 8, 9 and 10 after 197 days.

[0264] FIG. 5 shows the flow cup analysis of Examples 11, 12 and 13 over time.

[0265] FIG. 6 shows the viscosity of Examples 11, 12 and 13 after 196 days.

[0266] FIGS. 7a and 7b show the particle size analysis of Examples 11 and 12, respectively.

[0267] FIG. 8 shows the viscosity of Examples 14 and 15 over time.

[0268] FIGS. 9a and 9b show the particle size analysis of Examples 14 and 15, respectively.

[0269] FIG. 10 shows the viscosity of Examples 16 and 17 over time.

[0270] FIGS. 11a and 11b show the particle size analysis of Examples 16 and 17, respectively.

[0271] FIG. 12 shows the viscosity of Examples 18 and 19 over time.

EXAMPLES

Example 1

[0272] Reaction of epoxidised methyl soyate with polyethylene glycol 1500 molecular weight

[0273] 99.1 grams of epoxidised soyate with an epoxide value of 210 mg KOH/g was placed into a flask. 300.9 grams of 1500 molecular weight polyethylene glycol (1:1 equivalents epoxy to hydroxy) was then added. The mixture was dried to a water content of <0.1%, then cooled to 60° C. 0.32 grams of boron tetrafluoride etherate catalyst was added, and the reaction was cooled to maintain the temperature below 80° C. The reaction was continued until the epoxide value of the mixture was <1 mg KOH/g.

Example 2

[0274] Reaction of epoxidised methyl soyate with polyethylene glycol 600 molecular weight

[0275] 180.7 grams of epoxidised soyate with an epoxide value of 227 mg KOH/g was placed into a flask. 219.3 grams of 600 molecular weight polyethylene glycol (1:1 equivalents epoxy to hydroxy) was then added. The mixture was dried to a water content of <0.1%, then cooled to 30° C. 0.32 grams of boron tetrafluoride etherate catalyst was added, and the reaction was cooled to maintain the temperature below 60° C. The reaction was continued until the epoxide value of the mixture was <1 mg KOH/g.

Example 3

[0276] Derivatisation of example 2 by transesterification of the ester group with a methyl initiated poly ethylene glycol of 1000 molecular weight (MPEG1000)

[0277] 162.9 grams of example 2 was placed in a flask. 237.1 grams of MPEG1000 was then added. The mixture was dried to a water content of <0.1%, then cooled to 60° C. 1% of 20% sodium methoxide catalyst was then added, and vacuum was applied to distil the methanol from the catalyst and by-product from the reaction. The reaction mixture was slowly heated until distillation stopped.

Example 4

[0278] Derivatisation of example 2 by amidation of the ester group with dimethylaminopropylamine (DMAPA)

[0279] 342.8 grams of example 2 was placed in a flask and dried to <0.1% water content. 57.2 grams of DMAPA was then added (10% molar excess). The temperature was adjusted to 60° C., then 1% of 20% sodium methoxide catalyst was added, and the reaction mixture was slowly heated to 140° C. to distil the methanol from the catalyst and by-product from the reaction until distillation stopped. Once methanol distillation stopped, vacuum was applied and the reaction mixture was heated to 150° C. until the distillation of the excess DMAPA was complete.

[0280] Method of Preparation of Dispersions

[0281] Each formulation was prepared and mixed to form a mill-base using a high-speed stirrer. The pigment was slowly added to all the other components over a 10-minute period at a speed of 1000 rpm. The mill-base was then mixed for a further 5 minutes. Once the mill base was prepared the second stage of preparation was then carried out using a laboratory size beadmill. The dispersion was prepared using an Eiger Torrance bead mill set at 2000 rpm for 60 minutes.

[0282] Viscosity and Stability of Dispersions

[0283] The viscosity analysis was carried out by a combination of methods depending on the initial viscosity. For low viscosity dispersions flow cups DIN6 and DIN4 were used, while for medium viscosities a Brookfield cone and plate were used. Viscosities were periodically tested over reasonable time period, in order to determine the average storage stability.

[0284] Colour Analysis

[0285] Each pigment dispersion was incorporated into a styrene/butyl acrylate emulsion.

[0286] 2.5 g of dispersion was added to 100 g of emulsion and then mixed thoroughly. The solution was then drawn down on a card and allowed to dry. The colour was then measured using a Konica-Minolta CM-5 to assess the CIELAB colour. The CIELAB color space (also known as CIE L*a*b* or sometimes abbreviated as simply “Lab” colour space) is a colour space defined by the International Commission on Illumination (CIE) in 1976. It expresses colour as three values: L* for the lightness from black (0) to white (100), a* from green (−) to red (+), and b* from blue (−) to yellow (+). CIELAB was designed so that the same amount of numerical change in these values corresponds to roughly the same amount of visually perceived change.

[0287] Flocculation Assessment

[0288] A known weight of each dispersion was added to a low-quality paint and the rub-out test was performed to assess the level of flocculation.

[0289] The paint is applied to a test card and after a short drying time (flash-off) the rub-out test was carried out by rubbing the paint film with a finger while it was still damp but already starting to dry. The instability or stability of the pigment dispersion was shown by the degree of colour difference evident between the rubbed area and the surrounding coating material.

[0290] Particle Size Analysis Each dispersion was tested for particle size distribution by using a Mastersizer 2000.

[0291] Performance Examples

[0292] Formulation:

TABLE-US-00001 Example 5 (Comparative) Example 6 Example 7 Pigment 50   50   50   Red 112 Lansperse 10   — — DS200W.sup.1 Example 3 — 10   — Example 4 — — 8   Defoamer  0.06  0.06  0.06 Biocide  0.07  0.07  0.07 Water 39.87 39.87 41.87 .sup.1Standard ethoxylated polyaromatic dispersing agent

[0293] Viscosity Analysis

[0294] The viscosity of Examples 5, 6 and 7 was measured at intervals over an extended period of time. The results are shown in FIG. 1. Examples 6 and 7 exhibited lower viscosity than conventional Example 5.

[0295] Colour Analysis

TABLE-US-00002 Example 5 (Comparative) Example 6 Example 7 L 48.60 47.68 48.94 a 61.22 62.54 60.59 b 29.46 33.02 28.71

[0296] Comparable colour strength was observed when comparing Example 6 and Example 7 against an industry standard.

[0297] Flocculation Assessment

[0298] Example 6 was added at 2% to chalk paint, which was applied to a test card. Virtually no flocculation was observed when carrying out the rub-out test.

[0299] Particle Size Analysis

[0300] The particle size distributions of Examples 5 and 6 are shown in FIG. 2. The dispersions had comparable particle size distributions.

[0301] Formulation:

TABLE-US-00003 Example 8 (Comparative) Example 9 Example 10 Pigment 45   45   45   Yellow 74 Lansperse  8.75 — — DS200W Example 3 —  8.75 — Example 4 — — 7   Defoamer  0.06  0.06  0.06 Biocide  0.07  0.07  0.07 Water 46.12 46.12 47.87

[0302] Viscosity Analysis

[0303] Flow cup analysis was carried out on Examples 8, 9 and 10 at intervals over an extended period of time. The results are shown in FIG. 3. The viscosity of Examples 8, 9 and 10 was measured after 197 days. The results are shown in FIG. 4. Examples 9 and 10 exhibited lower viscosity than comparative Example 8.

[0304] Colour Analysis

TABLE-US-00004 Example 8 (Comparative) Example 9 Example 10 L 77.26 77.18 77.17 a −9.42 −9.40 −9.32 b 48.61 48.52 46.1 

[0305] Examples 8, 9 and 10 demonstrated comparable colour strength.

[0306] Flocculation Assessment

[0307] Example 9 was added at 2% to chalk paint, which was applied to a test card. Virtually no flocculation was observed when carrying out the rub-out test.

[0308] Formulation:

TABLE-US-00005 Example 11 (Comparative) Example 12 Example 13 Pigment 40   40   40   Yellow 110 Lansperse  8.75 — — DS200W Example 3 —  8.75 — Example 4 — — 7   Defoamer  0.06  0.06  0.06 Biocide  0.07  0.07  0.07 Water 51.12 51.12 52.87

[0309] Viscosity Analysis

[0310] Flow cup analysis was carried out on Examples 11, 12 and 13 at intervals over an extended period of time. The results are shown in FIG. 5. The viscosity of Examples 11, 12 and 13 was measured after 197 days. The results are shown in FIG. 6. The dispersions exhibited comparable viscosities.

[0311] Colour Analysis

TABLE-US-00006 Example 11 (Comparative) Example 12 L 75.10 73.60 a  2.02  2.34 b 42.23 40.87

[0312] Examples 11 and 12 demonstrated comparable colour strength.

[0313] Particle Size Analysis

[0314] The particle size distributions of Examples 11 and 12 are shown in FIG. 7. The dispersions had comparable particle size distributions.

[0315] Formulation:

TABLE-US-00007 Example 14 (Comparative) Example 15 Black 7 41   41   Lansperse 11.25 — DS200W Example 3 — 11.25 Monoethanolamine 0.8 0.8 Defoamer  0.06  0.06 Biocide  0.07  0.07 Water 46.82 46.82

[0316] Viscosity Analysis

[0317] The viscosities of Examples 14 and 15 were measured at intervals over an extended period of time. The results are shown in FIG. 8. Example 15 exhibited lower viscosity than comparative Example 14.

[0318] Colour Analysis

TABLE-US-00008 Example 14 (Comparative) Example 15 L 34.59 34.62 a  1.17  1.22 b  0.62  0.73

[0319] Examples 14 and 15 demonstrated comparable colour strength.

[0320] Particle Size Analysis

[0321] The particle size distributions of Examples 14 and 15 are shown in FIG. 9. The dispersions had comparable particle size distributions.

[0322] Formulation:

TABLE-US-00009 Example 16 (Comparative) Example 17 Pigment 50   50   Blue 15.3 Lansperse 10   — DS200W Example 4 — 8   Defoamer  0.06  0.06 Biocide  0.07  0.07 Water 39.87 41.87

[0323] Viscosity Analysis

[0324] The viscosities of Examples 16 and 17 were measured at intervals over an extended period of time. The results are shown in FIG. 10. The viscosity of Examples 16 and 17 was comparable.

[0325] Colour Analysis

TABLE-US-00010 Example 16 (Comparative) Example 17 L 47.87 48.42 a −7.44 −7.56 b −37.33  −38.38 

[0326] Examples 16 and 17 demonstrated comparable colour strength.

[0327] Particle Size Analysis

[0328] The particle size distributions of Examples 16 and 17 are shown in FIG. 11. The dispersions had comparable particle size distributions.

[0329] Formulation:

TABLE-US-00011 Example 18 (Comparative) Example 19 Pigment 20   20   Yellow 74 Solsperse 39000.sup.1 2.4 — Example 4 —  2.88 Solsperse 22000.sup.2  0.48 — DPGDA.sup.3 77.12 77.12 .sup.1Dispersant 2Synergist .sup.3Dipropylene glycol diacrylate

[0330] Viscosity Analysis

[0331] The viscosities of Examples 18 and 19 were measured at intervals over an extended period of time. The results are shown in FIG. 12. Example 19 demonstrated comparable viscosity to Example despite not including a synergist (e.g. Solsperse 22000).

[0332] Colour Analysis

TABLE-US-00012 Example 18 (Comparative) Example 19 L 87.35 87.37 a  8.74  8.63 b 61.65 60.43

[0333] Examples 18 and 19 demonstrated comparable colour strength.

[0334] The example embodiments described above may provide dispersions with excellent long-term stability.

[0335] Conventional dispersions containing solid particulate components such as pigments may encounter problems regarding the stability of the dispersions over time. Furthermore, conventional dispersing agents cannot be produced from renewable sources. These problems may be addressed by example embodiments as described herein.

[0336] In summary, a dispersion comprising a solid particulate component, a dispersing agent and one or more solvents is disclosed. The dispersing agent comprises a reaction product of: [0337] (a) an epoxidised carboxylic acid ester; [0338] (b) a compound including at least one reactive alcohol and/or amino functional group; and [0339] (c) a derivatising agent.

[0340] Such a dispersion shows excellent long-term stability. A method of producing such a dispersion having long-term stability, and a use of the dispersing agent to provide a dispersion having long-term stability are also described. The performance of these dispersing agents and the dispersions containing them is comparable to or better than the performance of known dispersing agents. This advantageous performance is achieved in addition to the dispersing agents of the present invention having an improved environmental and safety profile compared to known dispersing agents. Therefore these dispersing agents allow the production of a concentrate liquid, a paint, coating, polymer or ink with an improved environmental profile without having to sacrifice dispersing performance and therefore the quality of these compositions.

[0341] Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0342] Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of” or “consists essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention. Typically, when referring to compositions, a composition consisting essentially of a set of components will comprise less than 5% by weight, typically less than 3% by weight, more typically less than 1% by weight of non-specified components.

[0343] The term “consisting of” or “consists of” means including the components specified but excluding addition of other components.

[0344] Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to encompass or include the meaning “consists essentially of” or “consisting essentially of”, and may also be taken to include the meaning “consists of” or “consisting of”.

[0345] For the avoidance of doubt, wherein amounts of components in a composition are described in wt % based on the total weight of solids, this means the weight percentage of the specified component in relation to the whole composition referred to, except for solvents. For example, “wherein the solid particulate component is present in the dispersion in an amount of from 50 to 95 wt % based on the total weight of the solids in the dispersion” means that 50 to 95 wt % of the solid (i.e. non-volatile) components in the dispersion is provided by the solid particulate component.

[0346] The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

[0347] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0348] All of the features disclosed in this specification (including any accompanying claims, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0349] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0350] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.