A RMA CROSSLINKABLE COMPOSITION WITH IMPROVED ADHESION

Abstract

The invention relates generally to RMA crosslinkable compositions, in particular coating compositions, more in particular pigmented coating compositions (paints) with improved adhesion to substrates. The invention further relates to an adhesion promotor for improving adhesion on a substrate surface of an RMA crosslinkable composition, a method for applying a RMA cross-linked coating layer with improved adhesion and a kit of parts and premixes for use in said method.

Claims

1. A crosslinkable composition which crosslinkable by real Michael addition (RMA) reaction comprising a) a reactive component A with at least two acidic protons CH in activated methylene or methine groups, b) a reactive component B with at least two activated unsaturated CC groups and c) a catalyst C for catalyzing the RMA crosslinking reaction between components A and B, d) an adhesion promotor P being a functional alkoxysilane comprising one or more alkoxysilane groups Si(OR).sub.4m where m is 1, 2 or 3 and R is methyl, ethyl, propyl, isopropyl, butyl or isobutyl, connected to a functional moiety comprising one or more functional groups X or a precursor thereof, which is a functional group reactable with component A or component B wherein said RMA crosslinkable composition is in the form of a kit of parts comprising: at least one part comprising catalyst C but not both A and B and preferably no A or B, and at least one part not comprising catalyst C and comprising other components A, B, wherein one or more of the parts of the kit are an adhesion promotion pre-mix comprising one or more of the adhesion promotors P admixed with one or more of the components A, B, C of the RMA crosslinkable composition, which pre-mix is free of water and pigments.

2. The crosslinkable composition of claim 1 wherein adhesion promotor P is a functional alkoxysilane with the general formula (X(CH.sub.2).sub.n).sub.mSi(OR).sub.4m, where m is 1, 2 or 3; n is 1-20, R is methyl, ethyl, propyl, isopropyl, butyl or isobutyl and X is a functional group reactable with component A or component B or a precursor thereof.

3. The crosslinkable composition of claim 1 or a wherein the adhesion promotion pre-mix further comprises a water scavenger.

4. The crosslinkable composition of claim 1 wherein in the adhesion promotion pre-mix the functional alkoxysilane adhesion promotor P is admixed either with the catalyst C or with an organic solvent T or combinations thereof.

5. The crosslinkable composition of claim 1 wherein the RMA crosslinkable composition comprises a crosslinkable component with component A being predominantly a malonate or an acetoacetate, and a crosslinkable component with component B being an acryloyl and the one or more functional groups X are reactable with malonate or acetoacetate and/or with the acryloyl.

6. The crosslinkable composition of claim 1 wherein the functional group X reactable with component A or component B is a primary or secondary amine, a thiol, isocyanate, epoxy or a RMA reactable component A or B which are same or different from the reactive components A and/or B in the RMA crosslinkable components.

7. The crosslinkable composition of claim 1 wherein one or more functional groups X are a polyfunctional reactive component B reactive with a crosslinkable component with reactive component A, wherein the crosslinkable composition is a reaction product of the functional alkoxysilane adhesion promotor with a reactive component B, said reaction product comprising one or more reactive component B as functional groups X.

8. (canceled)

9. The crosslinkable composition of claim 1 wherein one or more functional groups X are a polyfunctional reactive component A reactive with a crosslinkable component with reactive component B, wherein the crosslinkable composition is a reaction product of the functional alkoxysilane adhesion promotor with a reactive component A, said reaction product comprising one or more reactive component A as functional groups X.

10. (canceled)

11. (canceled)

12. The crosslinkable composition of claim 1 wherein the weight amount of adhesion promotor P, in case of an adduct of an adhesion promotor P with said reactive components A or B not including the weight of reactive components A or B, is between 0.1 and 10 wt % relative to the total weight of the crosslinkable components.

13. The crosslinkable composition according to claim 1 wherein the molar ratio of CC to CC reactive groups, including CH in reactive component A, functional groups X in adhesion promotor P and groups XH in D is between 0.3. and 3.

14. The crosslinkable composition of claim 1 further comprising reactivity moderator component D being an XH group containing component D that is also a Michael addition donor reactable with component B under the action of catalyst C, wherein X is N, P, S or wherein X is C as part of an acidic methyl (CH.sub.3) group, wherein component A is predominantly a malonate or acetoacetate and wherein the XH group of component D has a higher acidity than the CH groups in component A, being characterized in that component D has a pKa (defined in aqueous environment) of at least one unit less than that of the CH groups in component A.

15. The crosslinkable composition of claim 1 comprising latent base catalyst C.

16. (canceled)

17. A method for applying a RMA crosslinked coating with improved adhesion on a substrate surface comprising a) Providing the a kit of parts of the RMA crosslinkable composition according to claim 1 b) Preparing a RMA crosslinkable composition by mixing all parts of the RMA crosslinkable composition, c) applying the RMA crosslinkable composition on the substrate surface, and d) curing the RMA crosslinkable composition.

18. The method of claim 17 wherein the RMA crosslinkable composition is applied by spraying and wherein the adhesion promotion pre-mix comprises functional alkoxysilane adhesion promotor P dissolved in organic solvent and is added to the remaining parts of the RMA crosslinkable composition just before spraying to dilute the composition to a spraying viscosity.

19. The method of claim 17 wherein the substrate is metal.

20. The method of claims 19 for improving adhesion direct to metal, wherein the metal surface may be chemically treated and modified but not coated with a primer layer comprising a polymer binder.

21. An adhesion promotion pre-mix for use in the RMA crosslinkable composition of claim 1 which pre-mix is free of water and pigments and comprises adhesion promotor P being a functional alkoxysilane comprising one or more alkoxysilane groups Si(OR).sub.4m where m is 1, 2 or 3 and R is methyl, ethyl, propyl, isopropyl, butyl or isobutyl, connected to a functional moiety comprising one or more functional groups X, which is a functional group reactable with component A or component B, or a precursor thereof further comprising one or more components of the RMA crosslinkable composition selected from c)-g) c) a reactive component A with at least two acidic protons CH in activated methylene or methine groups, d) a reactive component B with at least two activated unsaturated CC groups and e) a catalyst C for catalyzing the RMA crosslinking reaction between components A and B, but not in combination with both components A and B, f) reactivity moderator D, g) organic solvent T.

22. The adhesion promotion pre-mix of claim 21 comprising adhesion promotor P, substantially no components A and B, base catalyst C and organic solvent T, wherein catalyst C is a carbondioxide blocked strong base catalyst and T is an alcohol.

23. An adhesion promotor for improving adhesion of a RMA crosslinkable composition comprising crosslinkable components comprising reactive component A with at least two acidic protons CH in activated methylene or methine groups (the RMA donor group), and crosslinkable components comprising reactive component B with at least two activated unsaturated groups (the RMA acceptor group), and a catalyst C, capable of activating the RMA reaction between reactive component A and B, said adhesion promotor being a functional alkoxysilane comprising one or more alkoxysilane groups Si(OR).sub.4m where m is 1, 2 or 3 and R is methyl, ethyl, propyl, isopropyl, butyl or isobutyl, connected to a functional moiety comprising one or more functional groups X and X is a reactive component B reactable with component A or a component A reactable with component B wherein reactable component A or B are same or different from the reactive components A and/or B of the RMA crosslinkable components.

24. The adhesion promotor of claim 23 being a reaction product of the functional alkoxysilane wherein functional group X is an amine and a polyfunctional acetoacetate, said reaction product comprising acetoacetate group as functional groups X bonded over an enamine bond to the functional alkoxysilane.

25. (canceled)

26. The adhesion promotor of claim 23 being a reaction product of the functional alkoxysilane wherein functional group X is an amine and a polyfunctional reactive component B, in particular a tri- or tetraacrylate, said reaction product comprising component B as functional groups X bonded by Michael addition to the functional alkoxysilane.

Description

EXAMPLES

[0074] The following is a description of certain embodiments of the invention, given by way of example only.

[0075] Abbreviations of adhesion promoters used in the examples are given in Table 1:

TABLE-US-00001 TABLE 1 Abbreviations APTES aminopropyl triethoxysilane (Geniosil GF93 (ex Wacker)) VTMS vinyl trimethoxysilane (Geniosil XL 10 (ex Wacker))

Adhesion Test:

[0076] The results of adhesion stated in the following examples are based on the cross cut adhesion test following the ISO/DIN 2409, ASTM D3359 protocol. The ranking is briefly summarized as follows: [0077] 0: The edges of the cuts are completely smooth; none of the squares of the lattice is detached. [0078] 1: Detachment of small flakes of the coating at the intersection of the cuts. A cross-cut area not significantly greater than 5% is affected. [0079] 2: The coating has flaked along the edges and/or at the intersection of the cuts. A cross-cut area significantly greater than 5%, but not significantly greater than 15% is affected. [0080] 3: The coating has flaked along the edges partly or wholly in large ribbons, and/or it has flaked partly or wholly on different parts of the squares. A cross-cut area significantly greater than 15%, but not significantly greater than 35%, is affected. [0081] 4: The coating has flaked along the edges of the cuts in large ribbons and/or same squares have detached partly or wholly. A cross-cut area significantly greater than 335%, but not significantly greater than 65% is affected. [0082] 5: Any degree of flaking that cannot even be classified by classification 4.
Metal substrate:

[0083] To test the adhesion of given examples and comparative examples films were applied on two types of metal substrates Gardobond 26S 6800 OC and Gardobond C. Gardobond is a trade name of the German producer Chemetall. Other example relate to adhesion on aluminium (Q-panel Al-46).

General Procedure for Mixing Formulations with All Other Adhesion Promoters

[0084] The malonate polyester, DiTMPTA and n-propanol were transferred to a flask and mixed. After obtaining a homogeneous mixture the stated amount of adhesion promoter was added. The solutions were then stirred overnight. Prior to use all mentioned formulations were activated by adding the stated amount of initiator which is a tetrabutylam monium hydroxide TBAH solution reactively blocked with diethylcarbonate, with a base concentration of 0.928 meq/g solution (see procedure for preparation of initiator solutions). The initiator is also referred to herein as catalyst CAT4.

TABLE-US-00002 Catalyst Component CAT4 Aqueous TBAH 100 (55%) Diethylcarbonate 45.1 n-propanol 181

MPE1 Malonated Polyester

[0085] This resin is prepared as follows: into a reactor provided with a distilling column filed with Raschig rings were brought 382 g of neopentyl glycol, 262.8 g of hexahydrophthalic anhydride and 0.2 g of butyl stannoic acid. The mixture was polymerised at 240 C. under nitrogen to an acid value of 0.2 mg KOH/g. The mixture was cooled down to 130 C. and 355 g of diethylmalonate was added. The reaction mixture was heated to 170 C. and ethanol was removed under reduced pressure. Part the resin was modified by addition of succinimide as reactivity moderator; when the viscosity at 100 C. reached 0.5 Pa.s the material was cooled down to 140 and 11.2 grams of solid succinimide were added (MPE1S). This mixture was stirred until all succinimide was dissolved. Both resins were diluted with butyl acetate to 85% solids, to yield a material with OH value 16 mg KOH/g, GPC Mn 1750, and a malonate equivalent weight of 350 (active CH EQW 175)

[0086] We use different layers of tape to create different spacers for the doctor's blade. This results in a variety of cured film thickness, in the examples beneath a range of 50 to 80 microns. Curing is done at 22 C. and a relatively humidity of 45-65%. The adhesion is tested after 24 hours under these conditions.

Series 1: Examples and Comparative Samples with Amino Alkoxy Silanes

[0087] All formulations of next table were prepared by mixing the malonate polyester with DiTMPTA and n-propanol. The comparative samples are then ready to activate and cure.

[0088] In example 9 the additional component aminopropyl triethoxy silane was, prior to activation with the blocked TBAH, added to the clear coat composition. In example 10 vinyltrimethoxysilane was added to the clear coat and stirred for one night, to allow water scavenging. Then aminopropyltriethoxysilane was added and the varnish was activated and cured.

[0089] In both examples 9 and 10 only a part of the stock solution was used and the actual amount of initiator was related to the amount of the smaller sample and the total amount initiator needed to complete the lacquer.

TABLE-US-00003 TABLE 4 results of adhesion promotion test with amino alkoxy silanes. comp. example Example 9 10 5 6 type silane APTES APTES + VTMS none none gr. MPE1 47.4 56.9 50.8 46.9 gr. DiTMPTA 26.2 31.4 21.95 25.7 gr APTES 1.3 1.6 0 0 gr VTMS 1.6 gr n-propanol 3.5 6.1 1.5 1.5 gr CAT4 3.1 3.8 3.5 3.26 initial [CC]/ 3.4 3.4 2.8 3.3 gram solids Adhesion ISO/DIN 2409:2003 Gardobond 26S 50-60 0 0 5 5 60-70 0 0 5 5 APTES: Geniosil GF 93 (ex Wacker)

Series 3a: Stability Improvement of Clear Coats Containing Amino Silanes

[0090] The malonate polyester MPE1, DiTMPTA and n-propanol were transferred to a flask and mixed. The vinyl trimethoxysilane is then added and the sample is stirred overnight. Then aminopropyltriethoxysilane was added, and stirred well. In comparative examples the step with vinyl trim ethoxy silane was omitted.

[0091] Of the freshly prepared solutions, a part was isolated, activated and applied on a substrate. The remaining part of the stock solution was sealed and placed in an oven at 60 C. Every week the samples were opened, exposed to air and sealed again. At the given time interval again a part of the stock solution was isolated, activated and applied onto a metal substrate.

[0092] The amount initiator is the amount needed for the total formulation. Since from the stock solution smaller samples were taken, the actual amount initiator was relatively to total amount clear coat and the stated total amount imitator.

TABLE-US-00004 TABLE 5 results of adhesion promotion test with amino alkoxy silanes and aging. Comparative example example 11a 11b 7a 7b Grams MPE1 56.9 47.4 grams DiTMPTA 31.4 26.2 gram n- 6.1 3.5 propanol grams VTMS 1.6 0 Grams APTES 1.6 1.3 CAT4 3.8 3.1 total Adhesion fresh after fresh after (Gardobond aging aging 26S) 76 17 days days 60-70 micron 0 0 0 5 70-80 micron 0 0 0 5 VTMS: Geniosil XL 10 (ex Wacker), APTES: Geniosil GF93 (ex Wacker)

Series 4:

[0093] Thinners were prepared by mixing solvent and aminosilane as described in Table 6 below. Aging experiments were done by keeping the solution at a specified temperature and for a specified time to establish the stability of the solution and its effect on the coating properties.

TABLE-US-00005 TABLE 6 thinners comprising adhesion promotors. Component Thinner 1 Thinner 2 Thinner 3 Butyl acetate 55 55 55 Geniosil GF 93 15 0 0 Geniosil GF 96 0 15 0 Geniosil GF 93 is 3-Aminopropyltriethoxysilane from Wacker Geniosil GF 96 is 3-Aminopropyltrimethoxysilane from Wacker

Paint Preparation

[0094] Paints were prepared by mixing the components as described in Table 7 below.

Paint A

[0095] Paint A is based MPE1 and MPE1S. The succinimide containing resin was mixed with same resin not containing the succinimide and 1,2,4 triazole as adhesion promotor.

Paint B

[0096] Paint B was prepared from a malonate functional alkyd MA9. MA9 is a malonated alkyd using coconut oil as the oil component, an oil length of 30%, an OH value of 108 mg KOH/g, a GPC Mn of 1800 and an Mw of 4350. The malonate equivalent weight of this material is 360 (active CH equivalent weight 180). This resin was mixed with trimethylol (TMP) reacted with acetoacetate as reactivity moderator and a small amount of Silmer silicone reactive prepolymer.

Paint C

[0097] Paint C was prepared as in Paint A except that Paint C comprises an aminosilane adhesion promotor.

Paint D

[0098] Paint D was prepared from a Malonate functional polyester as described above further comprising malonated TMP but no adhesion improver which was tested on a primer of a ketimine modified epoxy primer paint.

TABLE-US-00006 TABLE 7 paint compositions Component Paint A Paint B Paint C Paint D MPE1 139.4 0 139.4 45.33 MA9 0 44.78 0 Malonate functional TMP 0 0 0 1.89 TMPTAA 0 4.48 0 0 MPE1S 192.2 0 192.2 0 Pigment paste* 565.5 0 565.5 0 Pre-dissolve: 1,2,4-triazole 4.8 0 4.8 0 n-propanol 27.0 0 27.0 0 Subsequently add Miramer M410 0 27.29 Miramer M300 0 0 0 18.17 Acrylate functional IPDI 0 0 0 15.56 trimer Methyl propyl ketone 0 23.37 0 0 Methyl amyl ketone 0 0 0 18.89 Byk 310:315 1:4 2.8 0 2.8 0 Silmer ACR-D2** 0 0.09 0 0.09 Tinuvin 292 4.6 0 4.6 0 Geniosil GF 93 0 0 15 0 *mix 32.0% of Miramer M410 (DiTMPTA component B) with 65.1% of Kronos 2310 and 2.9% of disperbyk 163 and grind until the particle size is smaller than 10 m **Silmer ACR-D2 is reactive silicone comprising multi-functional or linear-difunctional silicone pre-polymers with reactive terminal end groups being acrylates.

Catalyst Preparation Examples:

[0099] Catalyst compositions were prepared by mixing components specified in Table 8. Catalyst 1 and 4 did not comprise an adhesion improver. Catalyst 2 and 3 did comprise an adhesion improver.

TABLE-US-00007 TABLE 8 Catalyst compositions Component Catalyst 1 Catalyst 2 Catalyst 3 Catalyst 4a Aqueous TBAH 100 0 100 0 (55%) Methanolic TBAH 1M 0 51.18 0 51.18 Diethylcarbonate 45.1 0 45.1 Dimethylcarbonate 0 8.6 0 8.6 n-propanol 181 0 181 0 Geniosil GF 93 0 0 5.1 0 Silquest A1120 0 15.92 0 0 TBAH is tetrabutyl ammonium hydroxide Silquest A1120 is N(beta-aminoethyl) gamma-aminopropyltrimethoxy-silane.

Example 12

[0100] Thinner 1 was aged for 1 month at 40 C. 33.25 grams of Catalyst 1 and 70 grams of aged Thinner 1 were subsequently added to 936 grams of Paint A. This mixture was sprayed on a Gardobond 26S/60/OC panel (a Zinc phosphated steel substrate) with a dry layer thickness of 120 m. After 1 day at room temperature and 1 hour at 60 C., adhesion was determined to be very good. The adhesion was tested using the cross-cut adhesion test as described in ASTM D3359.

Example 13.

[0101] The same composition as in Example 12 was sprayed on an electroplated zinc steel panel with a dry layer thickness of 65 m. After 1 day at room temperature, adhesion was determined to be very good.

Example 14.

[0102] Example 13 was repeated except that aged Thinner 2 was used (1 month at 40 C.). Adhesion was determined to be very good.

Example 15.

[0103] Catalyst 2 was aged for 77 days at 25 C. 0.86 grams of aged Catalyst 2 was added to 18 grams of Paint B. This mixture was sprayed onto two Bonderite 1000 treated steel panels with a dry layer thickness of 60 m; one of the panels was baked for 30 minutes at 66 C. and the other was allowed to dry at room temperature. After 1 day at room temperature, adhesion on both panels was determined to be very good, 100% adhesion.

Example 16.

[0104] An epoxy amine ecoat from PPG as described below in Example 17 with an excess of epoxy groups (and therefore assumed to have no free reactive amine groups) was applied on a metal panel and subsequently baked for 30 min at 180 C. The composition of Example 12 was sprayed onto said baked primer with a dry layer thickness of 60 m. After 1 day at room temperature, adhesion was determined to be very good.

Example 17.

[0105] An epoxy paint, Aquapon 97-137 was activated with hardener 97-1200 at the volume ratio suggested by the producer (PPG). Then Setalux 10-1440, which is a ketimine functional resin, was added at a level of 5% by volume to the epoxy paint and thoroughly mixed and then applied onto a metal panel and dried for 24 hours. 18 grams of Paint D (having no adhesion improver) was mixed with 0.53 grams of Catalyst 1 and then sprayed onto the day-old primed panels, flashed for 10 minutes at room temperature and then baked for 15 minutes at 66 C. After cooling, adhesion was tested using the cross-cut adhesion test as described in ASTM D3359 and found to be very good.

Example 18.

[0106] An epoxy paint, Aquapon 97-137 was activated with hardener 97-1200 at the volume ratio suggested by the producer (PPG). Then a ketimine prepared from reacting 1 mole of diethylenetriamine with 2 moles of methyl isobutyl ketone, was added at a level of 5% by volume to the epoxy paint and thoroughly mixed and then applied onto a metal panel and dried for 24 hours. 18 grams of Paint D was mixed with 0.53 grams of Catalyst 1 and then sprayed onto the day-old primed panels, flashed for 10 minutes at room temperature and then baked for 15 minutes at 66 C. After cooling, adhesion was tested using the cross-cut adhesion test as described in ASTM D3359 and found to be very good.

Comparative example 8.

[0107] Paint C was aged for 1 month at 40 C. 33.25 grams of Catalyst 1 and 55 grams of Thinner 3 were subsequently added to 951 grams of aged Paint C. This mixture was sprayed on an electroplated zinc steel panel with a dry layer thickness of 65 m. After 1 day at room temperature, adhesion was determined to be very bad. The comparative example shows that the adhesion promotor should preferably not be included in the composition that also comprises the pigments.

Comparative example 9.

[0108] Catalyst 3 was aged for 1 month, after which lumps and crystals of solid material were observed. The comparative example shows that the adhesion promotor should preferably not be included in an aqueous catalyst composition, whereas it is no problem to include it in the non-aqueous catalyst composition.

Comparative example 10.

[0109] 33.25 grams of Catalyst 1, 55 grams of Thinner 3 and 936 grams of Paint A were mixed. This mixture was sprayed on an electroplated zinc steel panel with a dry layer thickness of 65 m. After 1 day at room temperature, adhesion was determined to be very bad. The comparative example shows that the aminosilane adhesion promotor should be included in the composition to get good results.

Comparative example 11.

[0110] An epoxy amine ecoat (available from PPG) with an excess of epoxy groups was applied on a metal panel and subsequently baked for 30 min at 180 C. 33.25 grams of Catalyst 1 and 55 grams Thinner 3 were subsequently added to 936 grams of Paint A. This mixture was sprayed onto said baked primer with a dry layer thickness of 60 m. After 1 day at room temperature, adhesion was determined to be very bad. The comparative example shows that the aminosilane adhesion promotor should be included in the composition to get good results even in combination with this primer.

Comparative example 12.

[0111] 18 grams of Paint B was mixed with 0.68 grams of Catalyst 4a and then sprayed onto two Bonderite 1000 treated steel panels with a dry layer thickness of 60 m; one of the panels was baked for 30 minutes at 66 C. and the other was allowed to dry at room temperature. After 1 day at room temperature, adhesion on both panels was determined to be very bad, 100% adhesion failure.

Comparative example 13.

[0112] An epoxy paint, Aquapon 97-137 was activated with hardener 97-1200 at the volume ratio suggested by the producer (PPG). The primer was then applied onto a metal panel and dried for 24 hours. 18 grams of Paint D was mixed with 0.53 grams of Catalyst 1 and then sprayed onto the day-old primed panels, flashed for 10 minutes at room temperature and then baked for 15 minutes at 66 C. After cooling, adhesion was tested using the cross-cut adhesion test as described in ASTM D3359 and found to be very bad. It shows that a paint without adhesion improver on this standard epoxy primer does not show sufficient adhesion, whereas modifying the epoxy primer or adding of an adhesion promotor according to the invention does result in good adhesion.

Catalyst Solution CAT-E: Synthesis of TBA Ethocarbonate in Ethanol

[0113] A solution of tetrabutylammonium hydroxide in methanol is subjected to a solvent switch, by concentrating in a rotating film evaporator at 35 C. under reduced pressure, after adding ethanol. Fresh ethanol is added at various moments while removing methanol. The distillation is finished at a residual methanol content of 4.5 wt % as confirmed by GC analysis. Next, the solution is neutralized by bubbling gaseous CO2 through the liquid via a glass inlet tube at room temperature. The reaction was judged to be finished when a water diluted sample indicates a pH of <8.5; final base content is 1.6 eq/kg solution as determined by potentiometric titration with 0.1 M HCl. This CAT-E was used to prepare the following solutions containing aminosilanes (ex Aldrich):

TABLE-US-00008 solution solution TBAH ethocarbonate/silane CP1 CP2 CAT-E 30.0 39.4 aminopropyl triethoxysilane 23.6 aminopropyl trimethoxysilane 25.1 diethylcarbonate 1.1 dimethylcarbonate 1.6

[0114] Both fresh catalyst solutions were added to a standard clear coat composition, sprayed, cured (20 hours ambient); the cured films were tested on adhesion.

[0115] Both solutions CP1 and CP2 were aged in a closed bottle at 40 C. The aged solution were added to similar clear coat formulations, cured 1 day at RT, and tested on adhesion.

TABLE-US-00009 MPE1 (g) 90.0 75.0 90.0 75.0 DiTMPTA 36.7 30.6 36.7 30.6 n-propanol 4.0 4.0 4.0 4.0 Butylacetate 6.0 5.0 6.0 5.0 CP1 6.6 CP1 aged for 21 days at 40 C. 5.3 CP2 6.6 CP2 aged for 7 days at 40 C. 5.3 Adhesion rating Gardobond 26S 6800 C. 0 0 0 0 Q-panel AL-46 0 0 0 0

[0116] It can be seen that the adhesion performance is stable and remains good upon storage of the aminosilanes in these catalyst formulations, this in contrast to storage in a pack containing reactive components A and B.

Enamine Adduct of Aminopropyltrimethoxysilane and TMP Triacetoacetate TAS1

[0117] Added to a 100 ml round-bottomed flask were 4.5 g of aminopropyl-trimethoxysilane, 7 g of ethylacetate and 19.3 g of TMP triacetoacetate, along with a magnetic stirrer. The flask was then placed in a water bath to help keep the reaction at ambient conditions. The contents were left stirring for 6 hours before adding 3 g of activated 4 A molecular sieves to absorb the water produced as part of the equilibrium reaction. The flask was left overnight and the contents were filtered, and solvent removed in vacuo.

[0118] The enamine adduct prepared (TAS1, 10 g) was formulated with 74 g of MPE1, 30.5 g of DTMPTA, 7 g of butylacetate, 10 g of n-propanol and 5.6 g of CAT4, and subsequently applied to a Gardobond 26S 68000C substrate. Adhesion was tested after 1 day of ambient cure and found to be good (score 0). A similar formulation without TAS1 gave poor adhesion (score 5).

[0119] Thus, the invention has been described by reference to certain embodiments discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art.

[0120] Further modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.