AQUEOUS DISPERSION COMPRISING ALPHA EFFECT BASED NUCLEOPHILE

Abstract

A film-forming thermoset coating composition includes: an aqueous medium; and Option 1 and/or Option 2 as follows: Option 1: a compound, such as an oligomeric or polymeric compound, including a plurality of alpha effect based nucleophile functional groups and/or linkages; and a component reactive with at least one of the alpha effect based nucleophile functional groups and/or linkages; Option 2: a compound, such as an oligomeric or polymeric compound including a plurality of n-methylolated alpha effect based nucleophile functional groups and/or linkages. The plurality of alpha effect based nucleophile functional groups and/or linkages include a semi-carbazide functional group and/or linkage, a carbazate functional group and/or linkage, an oxime functional group, an aminoxy functional group and/or linkage, or combinations thereof.

Claims

1. A film-forming thermoset coating composition, comprising: (a) an aqueous medium; and Option 1 and/or Option 2 as follows: Option 1: (b1) a compound comprising a plurality of alpha effect based nucleophile functional groups and/or linkages; and (c1) a component reactive with at least one of the alpha effect based nucleophile functional groups and/or linkages, wherein the component comprises (i) formaldehyde, (ii) polyformaldehyde, (iii) a compound that generates formaldehyde, (iv) a polyfunctional ketone, or (v) a polyfunctional aldehyde, or combinations thereof; Option 2: (b2) a compound comprising a plurality of n-methylolated alpha effect based nucleophile functional groups and/or linkages, wherein the plurality of alpha effect based nucleophile functional groups and/or linkages of (b1) and/or (b2) comprise a semi-carbazide functional group and/or linkage, a carbazate functional group and/or linkage, an oxime functional group, or an aminoxy functional group and/or linkage, or combinations thereof.

2. The coating composition of claim 1, wherein the compound comprising a plurality of alpha effect based nucleophile functional groups and/or linkages (b1) and/or the compound comprising a plurality of n-methylolated alpha effect based nucleophile functional groups and/or linkages (b2) is monomeric, oligomeric or polymeric.

3. The coating composition of claim 1, wherein the plurality of alpha effect based nucleophile functional groups and/or linkages of (b1) and/or (b2) comprise at least one of the following structures: ##STR00036## wherein R.sup.1 comprises a nitrogen or oxygen containing group, wherein a nitrogen or oxygen atom of the nitrogen or oxygen containing group is bonded directly to the carbonyl carbon bonded to R.sup.1, wherein R.sup.2-R.sup.4 comprise any moiety, wherein for Option 1 at least one of R.sup.2, R.sup.3, and/or R.sup.4 is a hydrogen atom in structure (Ia), and wherein R.sup.2 is a hydrogen atom in structure (Ib) and for Option 2 at least one of R.sup.2, R.sup.3, and/or R comprise a methylol group in structure (Ia), and wherein R.sup.2 comprises a methylol group in structure (Ib).

4. The coating composition of claim 2, wherein the oligomeric or polymeric compound comprises: polyurethane-acrylate core-shell particles comprising a polymeric acrylic core at least partially encapsulated by a polymeric shell comprising urethane linkages, wherein the polymeric shell comprises an acid functional group and the plurality of alpha effect based nucleophile functional groups and/or linkages and/or n-methylolated alpha effect based nucleophile functional groups and/or linkages, wherein the polymeric shell is covalently bonded to at least a portion of the polymeric core.

5. The coating composition of claim 2, wherein the oligomeric or polymeric compound comprises a polyurethane dispersion and/or a polyacrylic dispersion.

6. The coating composition of claim 1, further comprising: a polyester polymer obtained from components comprising polytetrahydrofuran and a carboxylic acid or anhydride thereof.

7. The coating composition of claim 6, wherein the polyester polymer comprises a hydroxyl functional group.

8. The coating composition of claim 1, wherein the coating composition comprises Option 1, wherein the component (c1) comprises a melamine-formaldehyde resin, optionally wherein the melamine-formaldehyde resin contains and/or generates formaldehyde in an amount of 0.1 to 3 weight %, based on the total resin solids of the coating composition.

9. The coating composition of claim 1, wherein the coating composition comprises Option 1, wherein the component (c1) comprises the polyfunctional ketone and/or the polyfunctional aldehyde, wherein the coating composition comprises the polyfunctional ketone and/or the polyfunctional aldehyde in an amount of from 3 to 90 weight %, based on the total resin solids of the coating composition.

10. The coating composition of claim 1, wherein the coating composition is a one-component curing composition.

11. The coating composition of claim 1, wherein the coating composition is curable at a temperature of 100 C. or less.

12. The coating composition of claim 1, wherein the coating composition comprises Option 1, wherein the total amount of formaldehyde present and/or generated in (c1) is in the range of 0.1 to 3 weight %, based on total resin solids of the coating composition.

13. The coating composition of claim 1, further comprising an acid catalyst that is a separate component from the compound (b1) and/or (b2), or is covalently bonded to the compound (b1) and/or (b2).

14. The coating composition of claim 4, wherein the polyurethane-acrylate core-shell particles comprise a polyurethane polymer, an acrylic polymer, a polyester polymer, or a combination thereof.

15. The coating composition of claim 4, wherein the polymeric acrylic core comprises an addition polymer formed from (meth)acrylic monomers, vinyl monomers, or a combination thereof.

16. The coating composition of claim 2, wherein the oligomeric or polymeric compound (b1) and/or (b2) comprise internal alpha effect based nucleophile functional groups and/or linkages on the oligomeric or polymeric compound (b1) and/or (b2).

17. The coating composition of claim 13, wherein the acid catalyst comprises carboxylic acid functional groups formed on the oligomeric or polymeric compound (b1) and/or (b2) and which are obtained from a carboxylic acid or anhydride thereof having a pKa of less than 5.5, such as less than 3.

18. The coating composition of claim 17, wherein the carboxylic acid or anhydride thereof comprises trimellitic anhydride.

19. The coating composition of claim 1, wherein the compound (b1) and/or (b2) further comprises internal maleate functional groups.

20. The coating composition of claim 1, wherein the compound (b1) and/or (b2) comprises aliphatic and/or aromatic rings.

21. The coating composition of claim 1, further comprising a polymer reactive with at least one of (b1), (b2), and (c1), wherein the polymer is obtained from components comprising N-(hydroxymethyl)acrylamide, N-(isobutoxymethyl)acrylamide, or a combination thereof.

22. The coating composition of claim 6, wherein the polyester polymer is obtained from components comprising polytetrahydrofuran and a carboxylic acid or anhydride thereof, wherein the polytetrahydrofuran comprises at least 20 weight % of the components that form the polyester polymer and the carboxylic acid or anhydride thereof comprises at least 5 weight % of the components that form the polyester polymer.

23-28. (canceled)

29. A substrate at least partially coated with a coating formed from the coating composition of claim 1.

30. (canceled)

31. The substrate of claim 29, wherein the substrate comprises a vehicle substrate.

32-104. (canceled)

Description

EXAMPLES

[0215] The following examples are presented to demonstrate the general principles of the invention. The invention should not be considered as limited to the specific examples presented.

Example 1

Preparation of a Resin Having Semi-Carbazide Functionality

Part A: A Polyurethane Dispersion

[0216] A polyurethane was prepared by charging the following components in order into a glass reactor fitted with thermocouple, mechanical stirrer, and condenser under air blanket: 238.3 g of polytetrahydrofuran molecular weight 1000 (Commercially available from BASF (Ludwigshafen, Germany)), 49.5 g of dimethylolpropionic acid, 3.2 g of hydroxyethyl methacrylate, 11.9 g of triethylamine, and 0.5 g of 2,6-di-tert-butyl 4-methyl phenol (commercially available from BASF (Ludwigshafen, Germany)). The mixture was heated to 90 C. and held for 30 minutes. Next, 21.1 g of ethylene glycol dimethacrylate (EGDMA) and 174.2 g of butyl methacrylate (BMA) was charged and temperature was lowered to 50 C. At 50 C., 170.4 g of isophorone diisocyanate was charged into the reactor over 20 minutes. The isocyanate-adding funnel was rinsed with 14.9 g of butyl methacrylate. The temperature of the reaction mixture was held at 80 C. for 2 hours; then the reaction temperature was lowered to 65 C. 90% of the above reaction mixture was charged into a water solution of 829.4 g of deionized water, 24.3 g of hydrazine (35% and commercially available from Sigma Aldrich (Saint Louis, MO)), and 9.7 g of dimethylethanolamine (DMEA), and then mixed and held for 15 minutes to make a polymer dispersion.

Part B: An Acid-SemicarbazideFunctional Latex

[0217] A glass reactor fitted with thermocouple, mechanical stirrer, and condenser under N.sub.2 blanket was charged with 1005.0 g of deionized water, 2.80 g of dimethylethanolamine, 0.33 g of FOAMKILL 649 (commercially available from Crucible Chemical Company (Greenville, SC)), 3.34 g of mercaptopropionic acid (MPA), and 1480.7 g of Part A. Then a mixture of 395.04 g of butyl methacrylate and 80.95 g of EGDMA was charged to the reactor, and then mixed for 10 minutes and heated to 28 C. A mixture of 0.13 grams of t-butylhydroperoxide and 58.32 grams of deionized water was then charged into the flask and mixed for 15 minutes. Next, a mixture of 0.22 grams of ferrous ammonium sulfate, 1.11 grams of sodium metabisulfite, 0.52 g of DMEA and 140.8 grams of deionized water was charged into the flask over 30 minutes. After exothermal, the reaction mixture was cooled to 30 C., then a mixture of 2.31 g of PROXEL GXL commercially available from Arch Biocides (Smyma, GA)) and 2.31 g of deionized water was charged to the reactor. The final dispersion had a Brookfield viscosity (measured according to ASTM D2196 at ambient temperature) of 50.7 centipoise (spindle #2, 60 RPM), a pH (measured herein according to ASTM D4584) of 6.35, and a nonvolatile content of 34.3%. Non-volatile contents (also referred to herein a solids content) were measured by comparing initial sample weights to sample weights after exposure to 110 C. for 1 hour.

Example 2

Preparation of a Resin Having Carbazate Functionality

[0218] A polyurethane was first prepared by charging the following components in order into a four necked round bottom flask fitted with a thermocouple, mechanical stirrer, and condenser under N.sub.2 blanket: 136.6 grams of PROGLYDE DMM (Commercially available for Dow Chemical Company (Midland, MI)), 14.1 grams of dimethylol propionic acid (DMPA), 93.4 grams of isophorone diisocyanate (IPDI) was charged into the flask and heated to 70 C. At 70 C., 0.5 grams of dibutyl tin dilaurate (DBTDL) was charged into the flask. Immediate exotherm was observed. After exotherm subsided, the mixture was heated to 90 C. and held for 60 minutes until the isocyanate equivalent weight measured was 415.7 eq/g by titration (determined using a Metrohm 888 Titrando; titration by dissolving a sample (2.00 g) of the mixture in 30 mL of a solution comprised of 20 mL of dibutylamine and 980 mL of either n-methyl pyrrolidone, followed by titration with 0.2 N HCl solution in isopropanol titration agent). At 90 C., 37.2 grams of Glycerol carbonate (commercially available from InnoSpec (Littleton, CO)) and followed by a rinse with 10.5 grams of PROGLYDE DMM. The mixture was held at 90 C. for 30 minutes. After holding, 15.5 grams of trimethylolpropane (TMP) was added into reaction mixture and the reaction mixture was held at 90 C. until IR spectroscopy showed the absence of the characteristic NCO band. Then, a mixture of dimethylethanolamine (DMEA, 9.4 g) and 35% hydrazine in water (25.3 g) was added into reaction mixture over 30 minutes and followed by a rinse with 17.9 grams of DOWANOL PM (commercially available from Dow Chemical Company (Midland, MI)). The reaction mixture was held at 90 C. until IR spectroscopy showed the absence of the characteristic cyclic carbonate band. Then the reaction temperature was lowered to 70 C. and 314.9 g of DI water (70 C.) was added into reaction mixture over 30 minutes. The final urethane dispersion was held at 70 C. for 30 minutes and then poured out. The final dispersion had a Brookfield viscosity of 118.7 centipoise (spindle #2, 60 RPM), a pH of 7.97, and a nonvolatile content of 26.46%.

Example 3

Solvent Resistance and Humidity Tests

[0219] The cure response of a keto-functional polymer resin with various alpha effect-based nucleophile crosslinker resins was measured by solvent resistance and humidity resistance methods.

[0220] First, the resin was mixed well with either poly-semi-carbazide crosslinker (Example 1) or the polycarbazate crosslinker (Example 2) at a 1:1 keto:nucleophilic group ratio based on resin solids at ambient temperature, keto equivalent weight, and nucleophilic group equivalent weight. The mixture was stirred in a 20 mL glass scintillation vial with a wooden tongue depressor. Once fully blended, the coating composition was allowed to sit under ambient conditions for 1 to 2 hours. The mixture was drawn down over 4 inches by 12 inches steel panels that were pre-coated with an ED 7400 electrocoat (an electrocoat commercially available from PPG Industries Inc. (Pittsburgh, PA)) using a drawdown bar. The panels with wet films were ambient flash for up to 5 minutes before being baked for 30 minutes at 80 C. in an oven. After bake, the panels were taken out of the oven and cooled down to ambient temperature before the Solvent Resistance Test.

[0221] The Solvent Resistance Test was performed on each cured coating composition using the following method. Methyl ethyl ketone was used as the solvent for the testing: [0222] 1. Place the test panel on a flat table or other suitable flat firm surface. [0223] 2. Fold a Wypall brand 03086 wipes commercially available at Kimberly-Clark Professional Inc. (Irving, TX) four times (yielding a section with 8 layers of wipe) and secure over the ball end of a 500-g Ball-Peen hammer. The wipe should be snugly held in place with a rubber band in such a fashion that no wrinkles would be formed. [0224] 3. Saturate the cloth with the appropriate solvent for the material being tested, wipe should be re-saturated every 25 double rubs. [0225] 4. Immediately rub the saturated wipe over the test area using a back and forth stroke of 4-6 inches. [0226] 5. Do not exert any downward or upward pressure on the hammer handle. The weight of the hammer controls the downward pressure. [0227] 6. Continue this back and forth action counting one double rub for each forward and backward motion completed until bare substrate is exposed in the center of the strip where the rubs are performed. [0228] 7. Record the test result as the number of double rubs required to expose bare substrate in the center of the rub strip. [0229] 8. The area of wipe should be rotated for the next test set. The wipe used for testing should always be rotated to a fresh spot every time a new area is tested, you can typically get 4 test areas on a single wipe.

[0230] Cross-hatch adhesion according to the ASTM D3359, test method B was additionally performed on the coated and cured test panels. Adhesion results are assessed on a 0 to 5 scale [0-greater than 65% area removed & 5 is 0% area removed]. In certain instances, the test panels were subjected to a 24 hour water soak at ambient temperature with de-ionized water, removed from the water soak, allowed to recover for 5 minutes, and then tested for solvent resistance and cross-hatch adhesion again.

[0231] The coating compositions and results of the testing are shown in Table 1.

TABLE-US-00002 TABLE 1 Resin and Crosslinker Examples Ketone- MEK After Water After Water Functional Example Example double Cross-hatch Soak MEK Soak Cross- Sample Resin.sup.1 1 2 rubs Adhesion double rubs hatch Adhesion CE 20 30 0 7 0 3A 3B 4.46 15.54 88 5 55 1 3C 14.33 5.67 150 5 150 5 .sup.1A latex having keto functional core-shell particles as prepared in US 2020/0290086 A1, Example 3

[0232] From the MEK double rubs and cross-hatch adhesion data before and after water soak in Table 1, addition of alpha effect-based nucleophiles helps cure and adhere the ketone-containing resin.

Example 4

Solvent Resistance

[0233] The cure response of a keto-functional polymer resin with various levels of aminoxy crosslinkers was measured by The Solvent Resistance Test.

[0234] The coating formulations are listed in Table 2. For each sample, the aminoxy crosslinker was first dissolved in water and further neutralized with 50% dimethylethanolamine (DMEA) solution in a 20 mL glass scintillation vial. The resulting solution was thoroughly mixed by hand using a wooden tongue depressor. Additionally, the aminoxy crosslinker was purchased pre-acidified. To show the effect of a similar amount of acid on the keto-functional resin, Sample 4E was composed of the resin with neutralized hydrochloric acid at a similar amount as the sample at 1:1 keto:aminoxy ratio. The Ketone-Functional Resin was then added to the crosslinker solution and mixed thoroughly throughout the addition of the resin. These mixtures were then allowed to sit under ambient conditions for 1 to 2 hours and further drawn down onto 412 steel substrate, which was pre-coated with an ED7400 electrocoat primer (available from PPG Industries) and had been processed and baked according to the manufacturer's recommendations. The test panels containing the wet drawndown coating compositions sat at ambient conditions for up to 5 minutes prior to being baked at 80 C. in an oven for 30 minutes. Each coated test panel was allowed to sit at ambient conditions for 20 to 60 minutes prior to conducting the Solvent Resistance Test.

[0235] The Solvent Resistance Test was performed on each cured coating composition using the method outlined in Example 3. The coating compositions and results of the testing are shown in Table 2. All material amounts are in grams unless otherwise specified in the table.

TABLE-US-00003 TABLE 2 Resin and Crosslinker Example Ketone- Aminoxy MEK Functional Cross- Acid Base double Sample Resin.sup.1 linker.sup.2 Solution.sup.3 Solution.sup.4 rubs CE 4A 20 18 4B 19.17 0.142 0.352 78 4C 18.41 0.273 0.676 150 4D 17.71 0.395 0.975 150 CE 4E 18.953 0.370 0.677 20 .sup.2O,O-1,3-Propanediylbishydroxylamine dihydrochloride available from Sigma Aldrich (Saint Louis, MO), Sigma Aldrich product #689122; CAS # 104845-82-1 .sup.3A 50% solution of dimethylethanolamine (DMEA) .sup.4A 37% solution of hydrochloric acid (HCl)

[0236] From the MEK double rubs data in Table 2, addition of alpha effect-based nucleophiles (aminoxy) helps cure the ketone-containing resin.

[0237] Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.