Aqueous dispersible polymer composition

Abstract

The present disclosure relates to an aqueous dispersible polymer composition comprising: (a) at least one of: (i) a dendritic polymer in admixture with a hydrophilic functionalizing agent; and (ii) a hydrophilic functionalized dendrimer; and (b) a non-dendritic polymer capable of forming bonds with said dendritic polymer to thereby form a dendrimer-non-dendrimer (DND) polymer hybrid that is dispersible in the aqueous phase, methods of forming the same and uses thereof.

Claims

1. An aqueous dispersible polymer composition comprising: (a) at least one of: (i) a hydroxyl terminated dendritic polymer having a theoretical peripheral functionality of 16 or at least 32 to 64, in admixture with a hydrophilic functionalizing agent which is capable of functionalizing said dendritic polymer to provide a functionalized dendritic polymer wherein at least 5% of its peripheral hydroxyl groups have been functionalized by hydrophilic groups; and (ii) a hydroxyl dendritic polymer having theoretical peripheral functionality of 16 or at least 32 to 64 wherein at least 5% of its peripheral hydroxyl groups have been functionalized by said hydrophilic groups; wherein said hydrophilic functional group is selected from the group consisting of: primary amino groups, secondary amino groups, tertiary amino groups, quaternary ammonium salt groups, carboxyl groups, sulfonic acid groups, and phosphoric acid groups; (b) a non-dendritic polymer capable of forming bonds with said dendritic polymer to thereby form a dendrimer-non-dendrimer (DND) polymer hybrid that is dispersible in the aqueous phase, and said non-dendritic polymer being selected from the group consisting of: polyester, polyacrylate, polyurethane, polyurethane dispersion (PUD), polyester polyol, polyurethane polyol, polyacrylate polyol, polycarbonate, polycarbonate polyol, copolymers and blends thereof, wherein said non-dendritic polymer is present in an amount of from 20% to 95% by weight based on total weight of said DND polymer hybrid; and (c) an aqueous solvent for dispersing said DND polymer hybrid therein.

2. The aqueous dispersible polymer composition of claim 1, wherein the peripheral hydroxyl groups of said dendritic polymer are at least partially substituted by said hydrophilic groups from said functionalizing agent.

3. The aqueous dispersible polymer composition of claim 1, wherein at least 50% of said peripheral hydroxyl groups present on the dendritic polymer are substituted with hydrophilic groups.

4. The aqueous dispersible polymer composition of claim 3, wherein said hydrophilic group is a carboxyl (COOH) group.

5. The aqueous dispersible polymer composition of claim 4, wherein said composition further comprises one or more cross-linkers.

6. The aqueous dispersible polymer composition of claim 5, further comprising nanoparticles dispersed through the bulk of said DND polymer hybrid.

7. The aqueous dispersible polymer composition of claim 6, wherein said nanoparticles are metal oxide nanoparticles.

8. A process for preparing an aqueous dispersible polymer composition of claim 1, said process comprising the steps of: (a) providing at least one of: (i) a hydroxyl terminated dendritic polymer; having 16 or at least 32 to 64 theoretical peripheral hydroxyl groups; or (ii) a hydroxyl functional dendritic polymer having a theoretical peripheral functionality of 16 or at least 32 to 64 wherein at least 5% of its peripheral hydroxyl groups have been functionalized by a hydrophilic group selected from the group consisting of: primary amino groups, secondary amino groups, tertiary amino groups, quaternary ammonium salt groups, carboxyl groups, sulfonic acid groups, and phosphoric acid groups; and either one of steps: (b1) mixing said (i) hydroxyl terminated dendritic polymer with a non-dendritic polymer in the presence of a cross-linker, followed by reaction with a hydrophilic functionalizing agent, wherein said hydrophilic functionalizing agent is selected to functionalize at least 5% of said peripheral hydroxyl groups of said dendritic polymer with said hydrophilic groups; or (b2) mixing said (ii) hydrophilic functionalized dendritic polymer with a non-dendritic polymer, to thereby form a dendrimer-non-dendrimer (DND) polymer hybrid, wherein said nondendritic polymer in (b1) or (b2) is present in an amount of from 20% to 95% by weight based on total weight of said DND polymer hybrid; (c) dispersing said DND polymer hybrid in an aqueous medium, and wherein said non-dendritic polymer is selected from the group consisting of: polyester, polyacrylate, polyurethane, polyester polyol, polyurethane, PUD, polyol, polyacrylate polyol, polycarbonate, polycarbonate polyol, copolymers and blends thereof.

9. The process of claim 8, further comprising a step (d): mixing said DND polymer hybrid with one or more cross-linkers to form said aqueous dispersible polymer composition.

10. The process of claim 8, wherein said mixing step (b2) comprises physical blending.

11. The process of claim 8, wherein said mixing step (b1) comprises chemically reacting said dendritic polymer with said non-dendritic polymer in the presence of a cross-linker.

12. The process of claim 8, further comprising a step (d): at least partially neutralizing said DND polymer hybrid polymer with a base.

13. A method of forming a protective coating over a surface, the method comprising applying the aqueous dispersible polymer composition according to claim 1 over the surface.

14. The method according to claim 13, further comprising a step of curing said protective coating by subjecting said protective coating to temperatures greater than 25 C.

15. The method according to claim 13, further comprising a step of curing said protective coating by exposing said coating to ultra-violet (UV) radiation.

16. An article coated by the aqueous dispersible polymer composition according to claim 1.

17. An aqueous dispersible coating composition comprising: a first component comprising an aqueous dispersible polymer composition according to claim 1; and a second component comprising a cross-linker, wherein the first and second components are mixed together to form the coating composition.

18. The aqueous dispersible polymer composition of claim 1, wherein said non-dendritic polymer is present in an amount of from 50% to 95% by weight based on total weight of said DND polymer hybrid.

19. The process of claim 8, wherein said non-dendritic polymer in (b1) or (b2) is present in an amount of from 50% to 95% by weight based on total weight of said DND polymer hybrid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The accompanying drawings illustrate a disclosed embodiment and serves to explain the principles of the disclosed embodiment. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.

(2) FIG. 1A is a photograph showing the surface appearance of a water-dispersible coating that has been applied onto a tin panel. The water dispersible coating is formed from a functionalized dendritic polymer mixed with cross-linkers.

(3) FIG. 1B is a photograph showing the surface appearance of a water-dispersible coating that has been applied onto a tin panel. The water dispersible coating is formed of a water-dispersible composition in accordance with the present invention.

EXAMPLES

(4) Non-limiting examples of the invention will be further described in greater detail by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.

(5) Materials Used

(6) Below is a list of the raw materials used in the following Examples. The commercial names (in bold) of the following raw chemicals will be used in the Examples for convenience.

(7) 1. Aliphatic polyester diol comprising hydroxyl end groups, with molecular weight 1100 g/mol, hydroxyl (OH) number 110+5 mg KOH/g liquid, (RSP 2163), procured from PCTS Specialty Chemicals Pte Ltd, Singapore.

(8) 2. Polycarbonate diol with hydroxyl end groups, molecular weight 1000 g/mol, OH number 110+10 mg KOH/g wax solid, (Eternacoll UH-100) procured from UBE Chemical Europe.

(9) 3. Polyether diol with hydroxyl end groups, molecular weight 1000 g/mol, OH number 106-118 mg KOH/g liquid, (PPG 1000) procured from Sigma Aldrich, United States of America.

(10) 4. Aqueous hydroxyl-functional polyacrylic dispersion, viscosity of 400-1500 mPa.Math.s, OH equivalent weight around 1145 (Bayhydrol A 145) procured from Bayer MaterialScience AG.

(11) 5. Cycloaliphatic diisocyanate, having a viscosity of approximately 35 mPa.Math.s, NCO content 31.8-32% (Vestanat H12MDI) procured from Evonik Industries, Germany.

(12) 6. Dendritic polymer, with theoretically 64 peripheral hydroxyl groups, having a molecular weight of about 5100 g/mol solid, OH value 470-500, (Boltorn H40) procured from Perstorp Singapore Pte Ltd.

(13) 7. Dendritic polyester polyol, with OH equivalent weight of about 200-300 and solid content of about 70%, (PE-164-70s) procured from Nanovere Technologies, United States of America.

(14) 8. Pure aliphatic polyurethane dispersion (PUD 163P) procured from Nipsea Technologies, Singapore, having solids content: 33.8%; Viscosity: 35.5 cps; pH: 7.87; Mw=39673, and Mn=9747.

(15) 9. Water-dispersible, hexamethylene diisocyanate (HDI), with NCO equivalent weight of about 182 (Bayhydur XP 2547) procured from Bayer MaterialScience AG.

(16) 10. A low viscosity, solvent-free, polyfunctional aliphatic polyisocyanate resin based on hexamethylene diisocyanate (HDI), with NCO equivalent weight of 183, (Desmodur N3600) procured from Bayer MaterialScience AG.

(17) 11. A hexamethoxymethyl-melamine-formaldehyde resin, with 98% solid (Resimene 747) procured from Ineos Melamines, Germany.

(18) 12. A hexamethoxymethyl/n-butyl-melamine formaldehyde resin, with 98% solids (Resimene CE7103) procured from Ineos Melamines, Germany.

(19) Testing Methods

(20) In the following Examples, the following industrially recognized testing methods are used to characterize the water-dispersible coatings: Adhesion (1 mm1 mm): ASTM D3359; Impact (as measured in Inch (in)/pounds (lb) (direct)): ASTM D2794; Pencil Hardness (Break/Scratch): ASTM D3363; Flexibility (): ASTM D522; Stain resistance of household chemicals (50% Ethanol solution, water, 5% NaOH): ASTM D1308; Tensile Strength (Elongation): ASTM D412;

(21) In addition, the following protocol will be adopted for the methyl ethyl ketone (MEK) rub test: (i) Prepare film on a glass panel with 100 m wet film thickness (WFT); (ii) Dry the panel at a predetermined temperature for a predetermined duration (temperature and curing time depend on specific coatings) prior to testing; (iii) Saturate a cotton bud with MEK and hold it at 45 angle to the test surface, rub the test surface with moderate pressure. A complete rub consisting of one forwards rub and one backwards rub motion is considered one double rub. The surface is rubbed continuously until the substrate glass panel is exposed. Record the total number of double rubs.

Comparative Example 1

Preparation of a Carboxy-Terminated Dendritic Polymer

(22) Boltorn H40 and about 50% wt N-Methyl-2-pyrrolidone (NMP) based on Boltorn H40 is mixed in a 100 ml round bottom flask with reflux. Stirring is undertaken at 90 C. for an hour until the mixture turns homogeneous. To the stirred mixture, maleic anhydride is quantitatively added until 5% (Example 1D), 10% (Example 1C), 30% (Example 1B) and 50% (Example 1A) of the hydroxyl functional groups of the Boltorn H40 have been substituted respectively. The temperature is then raised to 100 C. and stirring is continued for another 60 minutes. After that, the mixture is cooled to 65 C., followed by the addition of 22.2 g of triethylamine (TEA) and 180.4 ml of deionised (DI) water. Mixture is stirred for another 15 minutes. The product is cooled to room temperature and filtered with a 25 m filter cloth.

(23) For illustration purposes only, the reaction between the anhydride and the Boltorn dendritic polymer may be represented by a general reaction scheme I shown below, wherein at least m number of OH groups have been substituted by the carboxyl groups (COOH) via reaction with anhydride:

(24) ##STR00001##

(25) Four samples of functionalized dendritic polymer having varying degrees of OH substitution were prepared in accordance with the protocol described in Comparative Example 1 as Comparative Examples 1A-1D respectively. The physical properties of each of the Comparative Examples 1A-1D are tabulated in Table 1 below.

(26) TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Comparative Example 1A Example 1B Example 1C Example 1D H40-50% H40-30% H40-10% H40-5% COOH 50% 30% 10% 5% Percentage Neutralization 100% 100% 100% 100% Dispersion Clear dark Clear dark Hazy Milky light Appearance yellow yellow brownish brownish solution. solution. solution. solution OH Equivalent 800 489 304 279 Weight (g/mol) Solid Content 53.83% 55.39% 52.46% 52.56% % Viscosity 126 158 75.5 86 (cps) PH 7.24 8.34 7.78 6.86

Comparative Example 2

Preparation of Coating Composition Based on Carboxyl-Functionalized Dendritic Polymer

(27) Comparative Example 2 describes the preparation of a coating composition using the carboxyl-functionalized dendritic polymer of Example 1C using a two-component (2K) system. The two components are termed Side A and Side B and their respective compositions are shown below in Table 2.

(28) TABLE-US-00002 TABLE 2 Equivalent Weight Name weight (EW) Amount (g) (%) Side A H40-10% (Example 1C) 303.95 10 29.1 Water 6 17.5 Coalescing Agent 6 17.5 (Coasol) Surfactant (BYK 346) 0.05 0.15 Catalyst (dibutyltin 0.05 0.15 acetate) Side B Bayhydur XP 2547 186 12.24 35.6 total 34.34 100

(29) Side A and Side B are then mixed together to form a water dispersible coating composition. The inventors found that the mixture of Sides A and B (above) resulted in the formation of a very bubbly mixture, which is unsuitable for film formation. The bubbling mixture is further indicative that a significant level of phase separation has occurred. This also suggests that the extent of reaction between the carboxyl-functionalized dendritic polymer and the polyisocyanate cross-linker is low and that an appreciable amount of side-reactions may have occurred between the cross-linkers and the water medium. FIG. 1 shows the appearance of a coating formed by applying the composition of Example 2 to a tin panel surface. As can be observed from FIG. 1A, the surface of the coating is very uneven and experiences severe blistering.

Example 3

Preparation of DND Polymer Hybrid Using Dendritic Polymer and Polyurethane Dispersion (PUD) by Cold Blending

(30) 186.3 g of Boltorn H40 and 93.1 g of NMP are mixed in a 1 L reactor. The mixture is heated up to 90 C. until all the Boltorn H40 are melted and a homogenous solution is obtained. 17.9 g of maleic anhydride is added and the temperature is adjusted to 100 C. and maintained for another 60 minutes. Thereafter, the mixture is cooled to 65 C., and followed by the addition of 22.2 g of TEA and 180.4 g of de-ionized water. The mixture is then stirred for another 15 minutes. The resulting product is cooled to room temperature (approx. 25 C.) and filtered with a 25 m filter cloth. The filtered product is a milky light reddish solution with the solid content of 52.46% and with a viscosity of 75.5 cps, a pH value of 7.78.

(31) 10 g of the filtered product is taken and further blended with 16.56 g of substantially pure PUD 163P at room temperature to give a light milky solution with a solids content of 40%, Ew=803 mg KOH/g and pH=7.35.

Example 4

Preparation of a Coating Composition Based on the Carboxyl-Functionalized DND Polymer Hybrid Obtained from Example 3

(32) Example 4 describes the preparation of a coating composition using the functionalized DND polymer hybrid of Example 3 using a two-component (2K) system. The two components are termed Side A and Side B and their respective compositions are shown below in Table 3. The ratio of peripheral OH groups (DND polymer hybrid) to the NCO groups (cross-linkers) is about 1:2.

(33) TABLE-US-00003 TABLE 3 Wt % Side A DND polymer hybrid (from Example 3) 48.52 Coalescing agent (Coasol) 15.77 Surfactant (BYK 346) 0.73 10% catalyst dibutyltin dilaurate 0.29 (DBTDL) in Coasol Water 12.13 Side B Bayhydur XP2547 22.56 Total 100

(34) Side A is blended with Side B to form the aqueous dispersible polymer composition. Compared to the bubbling mixture obtained in Comparative Example 2, the mixture of the DND polymer hybrid with the cross-linker component (polyisocyanate) results in a completely homogenous solution and no phase separation is observed. Importantly, the resultant mixture can be used to form a film after application onto a panel surface and after curing at 85 C. Compared to the coating of Comparative Example 2, the coating prepared from the DND polymer hybrid displays superior coating performance. In particular, the coating of Example 4 shows higher pencil scratch hardness (increases from HB to 2H); improved water and chemical resistance (MEK rub can increase from less than 10 to 471). The coating performance of Example 4 and a coating prepared from commercial water-borne PUD are tabulated in Table 4 below for comparison.

(35) TABLE-US-00004 TABLE 4 Coating prepared based Film Performance on Example 4 PUD 163P 100 Wet Film Thickness (WFT) on tin panel Pencil Hardness, scratch/break 3H/3H HB/4H Impact, In. lb >80 >80 Flexibility, 1/8 pass pass 100 WFT on Glass Pencil Hardness, scratch/break 2H/3H HB/4H MEK Double Rub, cycles 471 <10 Spot test Water resistance (24 hrs) No change blistering 5% NaOH Solution resistance Whitening Whitening and cracking 50% Ethanol resistance 2 hours: No 1 hour: change blistering

(36) From Table 4, it can be seen that a coating prepared from a commercially available water-borne polymer composition, such as PUD, displays comparable hardness and flexibility with the coating of Example 4. However, the disparity in performance becomes clear when both coatings are subject to standard chemical and water resistance tests. For instance, the PUD-based coating could only withstand less than 10 cycles of the MEK double rub whereas the coating of Example 4 is capable of resisting 471 cycles of the MEK double rub. The coating prepared from Example 4 also displayed superior resistance to water, ethanol and alkaline.

Example 5

Preparation of a DND Polymer Hybrid Using Various Non-Dendritic Polymers Via Chemical Bonding

(37) In this Example, the inventors test the use of three different types of copolymers (Examples 5A, 5B and 5C respectively) in a DND polymer hybrid. All three Examples are later used in 1K coating systems.

(38) Example 5A is a DND polymer hybrid comprising PE164-70s (dendrimer) and a commercial polyester RSP2163.

(39) Example 5B is a DND polymer hybrid comprising PE164-70s (dendrimer) and a polycarbonate (UH100)

(40) Example 5C is a DND polymer hybrid comprising PE16470s (dendrimer) and a commercial polyether diol PPG100 polyester RSP2163.

Example 5A

(41) 131.3 g of commercial polyester RSP2163 and 142.4 g of H12MDI are mixed in a 1 L reactor with N.sub.2 plug. The mixture is heated to 90 C. and reacted for 30 minutes. To the heated mixture, there is added 10.1 g of PE164-70s, 22.03 g of dimethylol propionic acid (DMPA) and 97.78 g of NMP. The mixture is kept at 90 C. for further reaction until the NCO % is constant and close to a theoretical value of 4.2% upon complete reaction (this value can be determined by titration). The mixture is then cooled to 45 C. with the addition of 19.6 g TEA, followed by 518.0 g of deionized water to disperse the mixture under high agitation speed of 500 rpm for another 15 minutes. The resultant product is cooled to room temperature and filtered with a 25 m filter cloth.

(42) The final product is a translucent solution with the solid content of 34.37% and with a viscosity of 37 cps, a pH value of 8.01 and an average particle size of 35 nm.

Example 5B

(43) 237.8 g of UH100 and 300.1 g of H12MDI are added to a 2 L reactor with N.sub.2 plug. The mixture is heated up to 90 C. and reacted for 30 minutes, followed by the addition of 42.1 g of DMPA, 20.2 g of PE164-70s and 196.97 g of NMP. The reaction is carried out at 90 C. until the NCO % is constant and close to the theoretical value of 5.4%.

(44) The mixture is cooled to 45 C. with the addition of 38.0 g of TEA, followed by 1056.0 g of deionized water to disperse at high agitation speed of 500 rpm for another 15 minutes. The product is cooled to room temperature and filtered with a 25 m filter cloth. The final product is a translucent solution with the solid content of 32.76% and with a viscosity of 18 cps, a pH value of 7.46 and an average particle size of 37 nm.

Example 5C

(45) 183.1 g of PPG 1000 and 291.3 g of H12MDI were mixed in a 2 L reactor and heated up to 90 C. for reaction. After 30 min, 45.0 g of DMPA, 60.0 g of PE164-70s and 200.2 g of NMP were added into the reaction. The reaction continued at 90 C. until the NCO % is constant and close to the theoretical value. (NCO %=4.2%) The mixture is cooled down to 45 C. with the addition of 40.0 g TEA, followed by 1060.2 g of deionized water to disperse the mixture under high agitation speed of 500 rpm for another 15 minutes. The resultant product is cooled down to room temperature and filtered with a 25 m filter cloth.

(46) The final product is a translucent solution with the solid content of 29.71% and with a viscosity of 180 cps, a pH value of 8.56 and an average particle size of 91 nm.

(47) Coatings are prepared using 1K systems based on Examples 5A, 5B and 5C. For comparison, respective control coatings 5A, 5B and 5C for each of Examples 5A-5C are also prepared. In particular, each of the control coatings 5A-5C are prepared without the dendrimer PE164-70s in a 1K system.

(48) It has been found that by incorporating the dendritic polymer with another resin such as polyester, polycarbonate or polyether, the performance of the coating film greatly improves as compared to a coating film that has been prepared without a dendritic polymer component.

(49) With respect to Example 5A, the film tensile strength increases by 66.5%, whereas in Example 5C, the incorporation of the dendritic polymer doubled the film tensile strength, while still high elongation ratio. All the above Examples show that with dendritic polymer incorporated, the pencil hardness at least increases 1 grade. Notably, the pencil hardness (scratch) of the 1K polyether PUD coating increased by 5 grades, from 5B to HB after incorporation with the dendritic polymer. The performance of Examples 5A-5C and the control Examples 5A-5C are tabulated in Table 5 below.

(50) TABLE-US-00005 TABLE 5 1K Polyester PUD 1K Polycarbonate PUD 1K Polyether PUD Raw Materials RSP2163 RSP2163/PE164-70s UH100 UH100/PE164-70s PPG PPG/PE164-70s Particle size 29 35 37 37 37 91 (nm) Non-volatile 33.80% 34.37% 33.56% 32.76% 31.28% 29.73% content Viscosity (s) 20 21 17 18 20 51 Viscosity 35.5 37 17 18 18 180 (cps) (S2, 60 rmp) Gravity 1.049 1.048 1.047 1.047 1.047 1.039 (g/cm3) PH 7.87 8.01 7.63 7.46 8.07 8.56 Tensile 26.91 44.80 49.43 50.56 20.45 42.45 Strength (Mpa) Elongation 327 272 336 248 376 265 (%) 60 Gloss 89.2 89.2 89.50 89.70 87.90 84.2 Level In-Can Translucent, Nearly clear Nearly clear Nearly clear Nearly clear High viscosity Appearance flowable solution, much more solution, solution, much solution, solution, liquid, light translucent than much more more translucent much more nearly clear amine smell control translucent than control translucent than control than control Tin Panel Test: Oven 55 C. 14 hours Pencil HB H 2B H 5B HB hardness (Scratch) Pencil 4H 6H 4H 4H 4H 6H hardness (Break) Flexibility passed passed passed passed passed passed Adhesion 0% peel off 0% peel off 0% peel off 0% peel off 0% peel off 0% peel off

Example 6

Preparation of DND Polymer Hybrid Comprising Dendritic Polymer and Commercial Water-Dispersible Polyol Blend

(51) 0.3 g of the H40-5% from Comparative Example 1D and 5.7 g of Bayhydrol A 145 are mixed in a mechanical mixer under agitation speed of 500 rpm. Subsequently, 0.5 g of water was added in to yield a milky solution with solid content of 43.7%, an OH EW of about 1062.

Example 7

Preparation of Coatings Based on the DND Polymer Hybrid of Example 6 and Coatings Based on Commercial Polyacrylic Dispersion

(52) Two coatings are prepared in this Example. Specifically, a first coating (Example 7A) is prepared via a 2K system using a commercially available water-borne polyacrylic dispersion. Also using a 2K system, a second coating (Example 7B) is prepared using the DND polymer hybrid according to Example 6. The various compositions of Examples 7A and 7B are tabulated in Tables 6.1 and 6.2 as shown below.

(53) TABLE-US-00006 TABLE 6.1 WT % Side A Bayhydrol A145 59.6 Water 6 PnB 17.9 Surfynol DF 110C 0.3 BYK 345 0.6 10% DBTDL in PnB 0.3 Side B Desmodur N 3600 15.3 Total 100.00

(54) TABLE-US-00007 TABLE 6.2 WT % Side A DND polymer hybrid 65.6 of Example 6 PnB 15.2 Surfynol DF 110C 0.3 BYK 345 0.5 10% DBTDL in PnB 0.3 Side B Desmodur N 3600 18.0 Total 100.00

(55) The performance of the coatings of Examples 7A and 7B are compared and tabulated in Table 7 below. As can be seen from the comparative results, Example 7B clearly shows improved pencil hardness (scratch) and superior chemical resistance with only 5% dendritic polymer in DND polymer. For example, the MEK rub cycles increased from 36 to 95 when a DND polymer hybrid is used. The film formed from example 7B is glossy and clear (FIG. 1B) when compared to a film formed from Example 2 (FIG. 1A).

(56) TABLE-US-00008 TABLE 7 Example 7A Example 7B Pencil Hardness HB H (Scratch) Pencil Hardness 3H 3H (Break) Adhesion 0% peel off 0% peel off Impact >80 >80 Flexibility passed Passed Gloss (60 on 154 154 glass panel) MEK Rub 36 95 50% Ethanol (1 hr) Blistering, can be easily Less blistering than peeled off Example 7A, but with moderate whitening on the ring edge. Water (24 hrs) Blistering, recovered Less blistering, after 1 hour recovered after 1 hour 5% NaOH (24 hrs) Whitening on the ring Whitening on the ring edge, can be easily edge peeled off

Comparative Example 8

Preparation of Coating Based on Water Dispersible Dendritic Polymer and Surfactant

(57) Comparative Example 8 shows the preparation of an aqueous dispersible coating comprising the functionalized dendritic polymer of Example 1D. To overcome the problem of poor film forming ability, an excess amount of surfactant is added in order to form the coating film. The composition of comparative example 8 is provided in Table 8 below.

(58) TABLE-US-00009 TABLE 8 WT % Side A Dendritic polymer of 35.6 Example 1D Water 9.6 Coasol 9.6 Ecosurf BD-405 5 (surfactant) Rhodasurf LA-9 5 (surfactant) 10% DBTDL in coasol 2.8 Side B Bayhydur XP 2547 32.4 Total 100.00

(59) Next, the coating of Comparative Example 8 is then subjected to the series of standard tests described in the other Examples above. Table 9 below provides the test results of this coating.

(60) TABLE-US-00010 TABLE 9 Comparative Example 8 Drying condition 85 C. for 2 hours Film Appearance Homogenous film, lack of gloss and is hazy looking. Pencil Hardness 2B/2H (Scratch/Break) Adhesion 0% peel off Impact >80 Flexibility Passed MEK Rub >200 50%, Ethanol (1 hr) No changes after 3 hr. 5% NaOH (24 hr) Film whitening and wrinkle, can be easily peel off. Water (24 hr) Low level of blistering, recovered after 30 min.

(61) The above test results show that the use of excess surfactant may help to mitigate the problem of phase separation in 2K coating systems. However, the coating film does not possess a desired glossy appearance and is relatively hazy. Furthermore, even with high dendritic polymer content, the pencil hardness drops to 2B due to the high dosage of surfactant present in the polymer composition which softens the coating. The alkaline resistance is similarly poor. However, the ethanol and water resistance appear to be comparable to coatings prepared from the DND polymer hybrids.

Applications

(62) The disclosed aqueous dispersible polymer composition addresses a number of technical problems known in the art. Firstly, the provision of the disclosed aqueous dispersible coating negates the need for potentially toxic and difficult to dispose organic solvents required by conventional dendritic polymer coatings. The disclosed aqueous dispersible polymer compositions also can be used to prepare coatings having zero or near-zero VOC emission and therefore are well-placed to meet stringent environmental regulations for coating applications.

(63) In addition, the disclosed aqueous dispersible polymer compositions can be formed into films with ease, even without the addition of excess surfactant, thus maintaining their hardness. It has further been demonstrated that the disclosed aqueous dispersible polymer composition affords superior hardness, chemical resistance, alkaline resistance, water resistance and solvent resistance to the formed coatings.

(64) Furthermore, due to their substantially homogeneous nature, the disclosed aqueous dispersible polymer compositions can be easily made into aesthetically-pleasing, glossy films having a substantially smooth, even surface which does not exhibit blistering.

(65) Accordingly, the disclosed aqueous polymer compositions may be used to prepare coatings for numerous applications, including but not limited to, protective coatings for automotives, protective coatings for paints, furniture, air-craft parts, household appliances, and electronic devices.

(66) It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims.