Epoxy resins for waterborne dispersions

Abstract

The present invention relates to compounds comprising the epoxide functional reaction product of: (a) at least one molecule comprising two terminal epoxy-reactive moieties; with (b) two molecules comprising two epoxide moieties; wherein, said compound comprises, pendent to the residue of (a) (i.e. as a side chain of the molecule), one or more polyoxyalkylene or polyoxyalkylene alkyl ether radical(s) having a weight average molecular weight of at least 400. Also provided are aqueous coating compositions comprising such compounds.

Claims

1. A compound comprising the epoxide functional reaction product of: (a) at least one molecule comprising two terminal epoxy-reactive moieties; with (b) two molecules comprising two epoxide moieties; wherein said compound comprises, pendent to the residue of (a), one or more polyoxyalkylene alkyl ether radical(s) having a weight average molecular weight of at least 400; wherein said compound is represented by Formula (I) or (II):
A-(X-A-).sub.y-X-AFormula (I)
X-(A-X-).sub.z-AFormula (II) wherein: each A independently represents: (i) an epoxy terminated monovalent radical formed from one or more diglycidyl ether compounds comprising a cycloaliphatic and/or an aromatic hydrocarbylene moiety; or (ii) a divalent radical formed by opening of the terminal epoxy of (i); each X independently represents: a divalent radical of a polyester represented by Formula (VIII) or Formula (IX): ##STR00007## wherein R represents a C.sub.5-12 alkyl group; R represents H or a C.sub.1-5 alkyl group; q represents 0 or 1; r represents 0 or an integer from 1 to 10; t represents an integer from 15 to 200; and n represents an integer from 5 to 200; y represents an integer from 0 to 10; and z represents an integer from 1 to 10.

2. The compound according to claim 1, wherein said compound has an epoxy equivalent weight from 400 to 200,000.

3. The compound according to claim 1, wherein A represents a monovalent or divalent radical derived from a compound according to Formula (V) or Formula (VI): ##STR00008## wherein R.sup.1 represents C.sub.1-10 alkylene, C.sub.1-10 haloalkylene, C.sub.4-10 cycloalkylene, carbonyl, sulfonyl, oxygen, sulphur or a direct bond; R.sup.2 represents C.sub.1-3 alkyl or halogen; each b independently represents 0 or 1; each m independently represents 0 or an integer from 1 to 4; and r represents 0 or an integer from 1 to 40.

4. The compound according to claim 1, wherein each X represents a monovalent or divalent radical of a polyester.

5. The compound according to claim 1, wherein said polyoxyalkylene alkyl ether is selected from a polyethylene glycol C.sub.1-4 alkyl ether, polypropylene glycol C.sub.1-4 alkyl ether, and mixtures thereof.

6. A compound according to claim 1, which is formed from a polyester and is represented by Formula (XI) or (XII): ##STR00009## ##STR00010## wherein each R represents a C.sub.5-12 alkyl group; R represents H or a C.sub.1-5 alkyl group; each m represents 0 or an integer from 1 to 40; p represents an integer from 1 to 20; q represents 0 or 1; r represents 0 or an integer from 1 to 10; t represents an integer from 15 to 200; and n represents an integer from 5 to 200.

7. A compound according to claim 1, wherein said compound has a weight average molecular weight from 2000 to 25000.

8. An aqueous coating composition comprising a compound according to claim 1.

9. The aqueous coating composition as claimed in claim 8, further comprising one or more anionic surfactants.

10. The compound according to claim 1, wherein the polyoxyalkylene alkyl ether radical(s) have a weight average molecular weight of 500 to 4000, as measured by gel permeation chromatography.

Description

EXAMPLES

(1) The following examples demonstrate a surprising reduction in observable foaming in aqueous dispersions comprising epoxy resin compounds of the present invention. Further, in preferred examples, the presence of one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals is shown to result in a surprising reduction in the melting viscosity of the epoxy resins, which is believed to be indicative of a higher dispersing efficiency.

(2) Measurement of Melting Viscosity of Epoxy Resins:

(3) Throughout the following examples, the melting viscosity of epoxy resins was measured in a conventional manner using a TA Instruments AR-2000 parallel plate rheometer (New Castle, Del.). In this method, 2 to 4 g of the sample resin is placed on the lower, stationary plate which is heated and maintained at 80 C. for the duration of the test, thereby melting the sample resin. An upper, rotatable plate (50 mm 0) is then positioned above the lower plate such that the interplate separation provides a 1,000 m gap in which the sample to be tested is located. Following positioning of the upper plate, the plate is manually rotated such that the centrifugal force applied to the sample facilitates the creation of a homogenous layer of resin between the upper and lower plates before any excess resin protruding from the sides of the plates is removed. The automated test procedure is then initiated and the upper plate is rotated under computational control. Sample viscosity, measured in cP, is then computationally derived, using software included in the rheometer hardware, via conversion of the measured resistance to upper plate rotation into a viscosity value. Sample analysis is conducted over a 25 minute timescale, with a total of 250 viscosity data points being recorded. Upon completion of the test procedure, the recorded data points are averaged in order to arrive at a final melting viscosity value, in centipoise (cP), for each sample.

(4) Measurement of Foaming, Stability and Viscosity of Epoxy Dispersions:

(5) Dispersion viscosities, in centipoise (cP), were measured at room temperature, i.e. from about 20 to 25 C. using a Brookfield DV-I Prime Viscometer (Middleboro, Mass.). During sample viscosity determination, appropriately sized spindles were selected based upon the suitable viscosity measuring ranges of each spindle. Similarly, appropriate spindle rotation speeds were selected based upon the viscosity of the sample and the utilized spindle.

(6) Stability analysis was conducted immediately following the formation of the epoxy resin-containing dispersions. In order to carry out such tests, 15 ml of the dispersions, which comprise approximately fifty weight percent epoxy resin (based on the total weight of the composition, including water), were placed into 20 ml clear glass vials which were located on a stable horizontal surface. At various time intervals, the degree of separation of water and resin was visually observed, with the depth of the uppermost phase comprising clear liquid which appeared to be free of resin, which results from settling out of the resin, being measured with a ruler and recorded as an indication of stability. The size of phase separation together with the time taken to achieve such separation indicates dispersion stability, with a small separation measured over a long timescale being indicative of highly stable dispersions. As the dispersions contained approximately 50 percent solids, it is apparent that if one half of the height of the composition appears to be free of resin, the resin should be considered to have completely separated from the water.

(7) The degree of foaming observed on the surface of such dispersions was recorded concurrently with stability analysis. The degree of foaming was visually observed upon placing 15 ml samples of each dispersion within 25 ml clear glass vials located on a stable horizontal surface, with each dispersion being allocated a Foam Rating ranging from 1 to 5. The final rating score took into consideration both the degree of foaming and the time taken for said foam to dissipate. As a guide, the following Foam Ratings relate to the following: 1no foaming was observed; 2a small amount of foam was initially observed but quickly dissipated; 3significant foaming was initially observed but quickly dissipated; 4significant foaming was initially observed and did not dissipate within 1 hour; 5complete foaming of the dispersion was observed and did not dissipate within 1 hour.

(8) Measurement of Acid Number:

(9) Throughout the following examples, the acid number of the synthesised resins and precursors thereof were measured via a conventional titration method. In this method, a pre-weighed sample is dissolved in 50 ml acetone and combined with 5 drops of phenolphthalein indicator solution. The resultant solution is then subjected to titration with 0.1N aqueous sodium hydroxide solution, wherein the stoichiometric point for the sample is recorded as the volume of titrant required for the indicator to undertake a pink colouration. A control titration is carried out in an analogous fashion, wherein the stoichiometric point for a solution of acetone and phenolphthalein is recorded. For accuracy, samples are analysed at least in duplicate, with the mean average stoichiometric point being used to calculate the acid number according to the following formula:

(10) $\mathrm{acid}\mathrm{number}\left(\mathrm{wt}\%\right)=\frac{45.02N\left(V2-V1\right)}{10w}$
wherein N represents the Normality of titrant, i.e. sodium hydroxide, solution; V2 represents the volume of titrant required to reach the stoichiometric point during the sample test; V1 represents the volume of titrant required to reach the stoichiometric point during the control test; and w represents the weight of the tested sample.

Example 1

(11) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with Tegomer was conducted in a 250 ml 4-neck round bottom flask equipped with a nitrogen inlet, mechanical stirrer, condenser and a temperature regulator. 99.2 g of Tegomer was charged to the flask, maintained under nitrogen and heated to a temperature of 130 C. prior to addition of 42.4 g 2-dodecene-1-ylsuccinic anhydride through a 50 ml syringe over a 5 minute timescale, during which the mixture was subjected to continual stirring. The resultant mixture was then heated to 140 C. and maintained at this temperature for 450 minutes, by which time the acid number was stabilized at 5.80%.

(12) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 58.4 g DER 330 to the flask, which caused a temperature reduction to 138 C., followed by addition of 0.08 g A1 catalyst to the resultant mixture. The mixture was then heated to 140 C. and kept at this temperature for 160 minutes, by which time the acid number had reduced to 0.02%. As a final step, 0.056 g methyl p-toluene sulfonate (MPTS) was added into the mixture under stiffing. The absolute yield of epoxy resin was 180 g, which corresponded to a fractional yield of 100%. The EEW, measured via titration according to ASTM D1652-11e1 (2011), was 1319, and the epoxy percentage, calculated using the formula

(13) $\frac{43}{\mathrm{EEW}}100,$
was 3.26.

Example 2

(14) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with YmerN120 was conducted substantially in accordance with the method of Example 1 in identical apparatus to that used in Example 1. 100.04 g YmerN120 was charged to the flask, maintained under nitrogen and heated to a temperature of 108 C. prior to addition of 47.74 g 2-dodecene-1-ylsuccinic anhydride through a 50 ml syringe over a 5 minute timescale, during which the mixture was subjected to continual stiffing. The resultant mixture was then heated to 142 C. and maintained at this temperature for 450 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1864 cm.sup.1, which corresponds to an anhydride specific absorption peak.

(15) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 65.71 g DER 330 to the flask, which caused a temperature reduction to 120 C., followed by addition of 0.085 g A1 catalyst to the resultant mixture. The mixture was then heated to 144 C. and kept at this temperature for 120 minutes, by which time the acid number had reduced to 0.01%. As a final step, 0.056 g MPTS was added into the mixture under stirring. The absolute yield of epoxy resin was 190 g, which corresponded to a fractional yield of 100%. The EEW was 1150, and the epoxy percentage was 3.74.

Example 3

(16) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with Diol A was conducted substantially in accordance with the method of Example 1 in identical apparatus to that used in Example 1. 114.78 g Diol A was charged to the flask, maintained under nitrogen and heated to a temperature of 110 C. prior to addition of 27.92 g 2-dodecene-1-ylsuccinic anhydride through a 50 ml syringe over a 5 minute timescale, during which the mixture was subjected to continual stirring. The resultant mixture was maintained at 110 C. for 180 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1864 cm.sup.1.

(17) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 57.30 g DER 330 to the flask which caused a temperature increase to 120 C., followed by the addition of 0.08 g A1 catalyst to the resultant mixture. The mixture was then heated to 149 C. and kept at this temperature for 240 minutes, by which time the acid number had reduced to 0.01%. As a final step, 0.056 g MPTS was added into the mixture under stirring. The absolute yield of epoxy resin was 190 g, which corresponded to a fractional yield of 100%. The EEW was 821, and the epoxy percentage was 5.24.

Example 4

(18) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with Diol B was conducted substantially in accordance with the method of Example 1 in identical apparatus to that used in Example 1. 94.05 g Diol B was charged to the flask, maintained under nitrogen and heated to a temperature of 110 C. prior to addition of 44.58 g 2-dodecene-1-ylsuccinic anhydride through a 50 ml syringe over a 5 minute timescale, during which the mixture was subjected to continual stirring. The resultant mixture was maintained at 110 C. for 120 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1864 cm.sup.1.

(19) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 61.36 g DER 330 to the flask which caused a temperature increase to 120 C., followed by the addition of 0.08 g A1 catalyst to the resultant mixture. The mixture was then heated to 145 C. and kept at this temperature for 330 minutes, by which time the acid number had reduced to 0.01%. As a final step, 0.056 g MPTS was added into the mixture under stirring. The absolute yield of epoxy resin was 190 g, which corresponded to a fractional yield of 100%. The EEW was 815, and the epoxy percentage was 5.27.

Example 5

(20) Polycarboxylic acid formation via esterification of pyromellitic dianhydride with MPEG 550 was conducted substantially in identical apparatus to that used in Example 1. The flask was charged with 100.0 g MPEG 550 which was subsequently dried for a period of 120 minutes under nitrogen bubbling at 120 C. prior to addition of 19.47 g of pyromellitic dianhydride. The resultant mixture was then heated to 148 C. and maintained at this temperature for 360 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1851 cm.sup.1, which corresponds to an anhydride specific absorption peak.

(21) Epoxy resin synthesis was then conducted following polycarboxylic acid formation, by the addition of 93.97 g of DER 330 to the flask, which caused a temperature reduction to 130 C., followed by the addition of 0.11 g of A1 catalyst to the resultant mixture. The mixture was then heated to 148 C. and kept at this temperature for 90 minutes, by which time the acid number had reduced to less than 0.01%. The absolute yield of epoxy resin was 200 g, which corresponded to a fractional yield of 100%. The EEW was 636, and the epoxy percentage was 6.76.

Example 6

(22) Polycarboxylic acid formation via esterification of pyromellitic dianhydride with MPEG 750 was conducted substantially in accordance with the method of Example 5 in identical apparatus to that used in Example 5. The flask was charged with 100.0 g MPEG 750 which was subsequently dried for a period of 120 minutes under nitrogen bubbling at 120 C. prior to addition of 14.99 g of pyromellitic dianhydride. The resultant mixture was then heated to 151 C. and maintained at this temperature for 310 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1851 cm.sup.1.

(23) Epoxy resin synthesis was then conducted following polycarboxylic acid formation, by the addition of 60.24 g of DER 330 to the flask, which caused a temperature reduction to 129 C., followed by the addition of 0.087 g of A1 catalyst to the resultant mixture. The mixture was then heated to 151 C. and kept at this temperature for 80 minutes, by which time the acid number had reduced to less than 0.01%. The absolute yield of epoxy resin was 165 g, which corresponded to a fractional yield of 100%. The EEW was 872, and the epoxy percentage was 4.93.

Example 7

(24) Polycarboxylic acid formation via esterification of pyromellitic dianhydride with MPEG 2000 was conducted substantially in accordance with the method of Example 5 in identical apparatus to that used in Example 5. The flask was charged with 100.0 g MPEG 2000 which was subsequently dried for a period of 120 minutes under nitrogen bubbling at 120 C. prior to addition of 5.04 g of pyromellitic dianhydride. The resultant mixture was then heated to 144 C. and maintained at this temperature for 100 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1851 cm.sup.1.

(25) Epoxy resin synthesis was then conducted following polycarboxylic acid formation, by the addition of 59.91 g of DER 330 to the flask, which caused a temperature reduction to 120 C., followed by the addition of 0.082 g of A1 catalyst to the resultant mixture. The mixture was then heated to 146 C. and kept at this temperature for 50 minutes, by which time the acid number had reduced to less than 0.01%. The absolute yield of epoxy resin was 150 g, which corresponded to a fractional yield of 100%. The EEW was 586, and the epoxy percentage was 7.33.

Example 8

(26) Polycarboxylic acid formation via esterification of pyromellitic dianhydride with MPEG 5000 was conducted substantially in accordance with the method of Example 5 in identical apparatus to that used in Example 5. The flask was charged with 100.0 g MPEG 5000 which was subsequently dried for a period of 120 minutes under nitrogen bubbling at 120 C. prior to addition of 2.3 g of pyromellitic dianhydride. The resultant mixture was then heated to 151 C. and maintained at this temperature for 380 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1851 cm.sup.1.

(27) Epoxy resin synthesis was then conducted following polycarboxylic acid formation, by the addition of 33.17 g of DER 330 to the flask, which caused a temperature reduction to 120 C., followed by the addition of 0.082 g of A1 catalyst to the resultant mixture. The mixture was then heated to 146 C. and kept at this temperature for 70 minutes, by which time the acid number had reduced to less than 0.01%. The absolute yield of epoxy resin was 120 g, which corresponded to a fractional yield of 100%. The EEW was 810, and the epoxy percentage was 5.31.

Comparative Example 1

(28) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with PEG 1450 was conducted in a 1000 ml glass reactor equipped with an oil heated jacket, and a 4-neck containing flange equipped with a nitrogen inlet, mechanical stirrer, condenser and a temperature regulator. 320.31 g of PEG 1450 was charged to the flask, maintained under nitrogen and heated to a temperature of 130 C. prior to addition of 117.7 g 2-dodecene-1-ylsuccinic anhydride through a 100 ml syringe over a 30 minute timescale, during which the mixture was subjected to continual stirring. The resultant mixture was then heated to 140 C. and maintained at this temperature for 250 minutes, by which time the acid number was stabilized at 4.85%.

(29) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 161.9 g of DER 330 to the flask which caused a temperature reduction to 117 C., followed by addition of 0.24 g of A1 catalyst to the resultant mixture. The mixture was then heated to 140 C. and kept at this temperature for 180 minutes, by which time the acid number had reduced to 0.02%. As a final step, 0.168 g of MPTS was added into the mixture under stiffing. The absolute yield of epoxy resin was 560 g, which corresponded to a fractional yield of 100%. The EEW was 1350, and the epoxy percentage was 3.19.

Comparative Example 2

(30) Polyester formation via esterification of 2-dodecene-1-ylsuccinic anhydride with PEG 4600 was conducted substantially in accordance with the method of Comparative Example 1 in identical apparatus to that used in Comparative Example 1. 390.52 g of PEG 4600 was charged to the flask, maintained under nitrogen and heated to a temperature of 130 C. prior to addition of 45.46 g of 2-dodecene-1-ylsuccinic anhydride through a 100 ml syringe over a 30 minute timescale, during which the mixture was subjected to continual stirring. The resultant mixture was then heated to 140 C. and maintained at this temperature for 200 minutes, by which time the acid number was stabilized at 2.01%.

(31) Epoxy resin synthesis was then conducted following polyester formation, by the addition of 162.01 g of DER 330 to the flask, which caused a temperature reduction to 117 C., followed by the addition of 0.24 g of A1 catalyst to the resultant mixture. The mixture was then heated to 140 C. and kept at this temperature for 120 minutes, by which time the acid number had reduced to 0.02%. As a final step, 0.168 g of MPTS was added into the mixture under stiffing. The absolute yield of epoxy resin was 560 g, which corresponded to a fractional yield of 100%. The EEW was 837, and the epoxy percentage was 5.14.

Comparative Example 3

(32) Polycarboxylic acid formation via esterification of pyromellitic dianhydride with MPEG 350 was conducted substantially in accordance with the method of Example 5 in identical apparatus to that used in Example 5. The flask was charged with 70.0 g MPEG 350 which was subsequently dried for a period of 120 minutes under nitrogen bubbling at 120 C. prior to addition of 22.49 g of pyromellitic dianhydride. The resultant mixture was then heated to 150 C. and maintained at this temperature for 210 minutes, by which time FTIR spectral analysis of the resultant polyester confirmed that no peak was observable at 1851 cm.sup.1.

(33) Epoxy resin synthesis was then conducted following polycarboxylic acid formation, by the addition of 108.79 g of DER 330 to the flask, which caused a temperature reduction to 130 C., followed by the addition of 0.10 g of A1 catalyst to the resultant mixture. The mixture was then heated to 146 C. and kept at this temperature for 100 minutes, by which time the acid number had reduced to less than 0.01%. The absolute yield of epoxy resin was 190 g, which corresponded to a fractional yield of 100%. The EEW was 533, and the epoxy percentage was 8.07.

(34) Following synthesis, the melt viscosity of each of the above epoxy resins was experimentally determined in accordance with the procedure detailed above, with the results summarised in Table 1 below. The data clearly indicates that epoxy resins according to the present invention have a reduced melt viscosity in comparison with epoxy resins which do not possess one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals, i.e. Comparative Examples 1 and 2, and in comparison with epoxy resins which possess one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals having a molecular weight below 400, i.e. Comparative Example 3.

(35) TABLE-US-00001 TABLE 1 Melt Final Viscosity/ Final EEW % Epoxy M.sub.w M.sub.n cP Example 1 1319 3.26 7,556 4855 526 Example 2 1150 3.74 16766 3420 1180 Example 3 821 5.24 15829 3919 347 Example 4 815 5.27 12,320 3179 470 Example 5 636 6.76 8174 2462 632 Example 6 872 4.93 9385 3166 819 Example 7 586 7.33 4805 2223 260 Example 8 810 5.31 11754 7641 1516 Comparative 1350 3.19 6,395 1,840 1227 Example 1 Comparative 837 5.14 6,980 987 3085 Example 2 Comparative 533 8.07 18323 2101 1875 Example 3

(36) In order to demonstrate the antifoaming effect of the resins according to the present invention, each of the synthesized resins were incorporated into aqueous compositions comprising DER 331, and an epoxy resin which, in itself, does not form a stable dispersion in water. For each resin, an aqueous composition was prepared containing 5 weight percent of said resin and 45 weight percent DER 331, wherein said weight percentages are based on total weight (including water) of the aqueous composition. Once combined, the aqueous compositions were thoroughly mixed using a high speed centrifugal mixer system (SpeedMixerDAC 150, 1FVZ-K) which was spun the compositions at 3500 rpm for 10 minutes, thereby forming an aqueous dispersion.

(37) The particle size of each dispersion was experimentally measured immediately following completion of the mixing process by laser diffraction using a commercially available laser diffraction particle size analyzer, specifically the LS 13 320 MW particle size analyzer manufactured and supplied by Beckman Coulter, Inc. (Brea, Calif.). The Foam Rating, viscosity and stability of each dispersion was measured according to the procedures detailed above. A dispersion is considered to have acceptable stability if the experimentally derived value is less than 15 mm/45 min, preferably less than 15 mm/60 min. Further, a dispersion is considered to have acceptable viscosity if the experimentally derived value is less than 200 cp, preferably less than 100 cp. The results of these tests are summarized in Table 2 below:

(38) TABLE-US-00002 TABLE 2 Particle Size/ Foam Viscosity/ m Rating cP Stability Example 1 31 2 43 9 mm/60 min Example 2 35 2 55 2 mm/45 min Example 3 41 2 52 12 mm/45 min Example 4 57 2 36 8 mm/45 mm Example 5 51 2 78 7 mm/45 min Example 6 42 2 30 4 mm/45 min Example 7 73 2 36 8 mm/45 min Example 8 23 2 78 2 mm/45 min Comparative 31 4 40 5 mm/45 min Example 1 Comparative 23 4 250 0 mm/45 min Example 2 Comparative did not disperse Example 3

(39) The above data clearly indicates that epoxy resins of the present invention may be used as dispersing aids in aqueous compositions comprising epoxy resins with acceptable stability and viscosity. Furthermore, it is apparent that aqueous dispersions comprising epoxy resins of the present invention have a reduced tendency to foam in comparison with dispersions comprising epoxy resins which do not possess one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals, i.e. Comparative Examples 1 and 2. Further, the above data indicates that resins comprising one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals having a molecular weight below 400, i.e. Comparative Example 3, were not suitable for use as a dispersing aid for such aqueous compositions.

(40) To further evaluate the effect that compounds of the present invention have upon aqueous dispersions comprising epoxy resins, particle size, Foam Rating, viscosity and stability were experimentally derived as discussed above following the formation of aqueous dispersions by homogenization. For each tested resin, an aqueous composition was prepared containing 5 weight percent of said resin and 45 weight percent DER 331, wherein said weight percentages are based on total weight (including water) of the aqueous composition. Once combined, the aqueous compositions were subjected to homogenization for a period of 5 minutes using a digital homogenizer (ULTRA-TURRAX T25 Digital high-performance disperser by IKA) for a period of 5 minutes, thereby forming an aqueous dispersion. The results of these tests are summarized in Table 3 below:

(41) TABLE-US-00003 TABLE 3 Particle Size/ Viscosity/ m Foam Rating cP Stability Example 2 18 2 98 no separation observed Example 6 19 2 85 no separation observed Example 7 24 2 83 no separation observed Example 8 24 2 87 no separation observed Comparative 23 4 210 no separation Example 2 observed

(42) The above data, in agreement with that provided in Table 2, clearly indicates that epoxy resins of the present invention may be used as dispersing aids in aqueous compositions comprising epoxy resins with acceptable stability and viscosity. Furthermore, it is apparent that aqueous dispersions comprising epoxy resins of the present invention have a reduced tendency to foam in comparison with dispersions comprising epoxy resins which do not possess one or more pendent polyoxyalkylene or polyoxyalkylene alkyl ether radicals, i.e. Comparative Example 2.