WO1992017283A1

WO1992017283A1 - Non-isocyanate ambient temperature curable coating compositions

Info

Publication number: WO1992017283A1
Application number: PCT/US1992/001943
Authority: WO
Inventors: Charles M. Kania; Padmanabhan Sundararaman; Joseph M. Carney; Stephen J. Thomas
Original assignee: Ppg Industries, Inc.
Priority date: 1991-03-27
Filing date: 1992-03-09
Publication date: 1992-10-15
Also published as: MX9201253A; AU1880192A

Abstract

An ambient temperature-curable coating for automotive bodies and parts which is non-toxic and aesthetic in appearance is provided by an isocyanate-free composition comprising an aziridinyl groups-containing acrylic, urethane or urea polymer and an epoxyamide or epoxyester groups-containing acrylic, urethane or urea polymer.

Description

NON-ISOCYANATE AMBIENT TEMPERATURE

CURABLE COATING COMPOSITIONS

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to isocyanate-free coating compositions containing (1) at least one polymer and/or oligomer selected from the group consisting of acrylic, urethane and urea polymers and oligomers and combinations thereof having a molecular weight of at least about 100 and bearing at least two specific aziridine groups and (2) at least one polymer and/or oligomer selected from the group consisting of acrylic, urethane and urea polymers and oligomers and combinations thereof having a molecular weight of at least about 100 and bearing at least two specific epoxy groups capable of forming a durable coating under ambient conditions.

BRIEF_DESCRIPTION OF PRIOR ART

Known compositions which cure at low temperatures, for example, at ambient conditions, for use as highly durable automotive topcoats are usually based on two-package systems. These include, for example, hydroxy functional components cured with either isocyanate or anhydride functional components.

The use of isocyanate functional components requires that specific precautions be taken based on toxicity considerations. Such necessary precautions can be relatively burdensome in areas where said materials are used but controlled conditions do not exist or are difficult to obtain. One such example of a generally non-controlled environment is an automobile body repair shop. The application of isocyanate-containing materials is relatively hazardous to exposed workers without proper protection. However, isocyanate/polyol cured compositions deliver the quality and durability demanded by the user. If the crosslinking composition is an anhydride/polyol system, the general overall appearance of the cured coating, i.e., gloss and D.O.I. (depth of image), is inferior to isocyanate-cured coatings. Accordingly, there is an urgent need for high quality, durable coating compositions which cure under ambient conditions, are relatively non-toxic and have the aesthetic appearance of an isocyanate-cured composition.

The present invention addresses these issues. The coating compositions disclosed and claimed herein are not isocyanate curing, are relatively non-toxic compared to isocyanate, are curable at ambient temperature and are equal, or even better, in performance and appearance to both isocyanate/polyol or anhydride/polyol cured compositions.

In the prior art, there is disclosed the curing of diepoxides with a combination of diaziridines and diphenols. The epoxies used are aromatic based or glycidyl functional bisphenol A materials. Such epoxies are not suitable for application to a substrate where high durability is required, such as in refinishing of automobile surfaces.

British Patent No. 1,190,979 to Strother discloses a coating composition comprising a diepoxide, a diphenol and a diaziridine. The diaziridine compounds used are those in which the aziridinyl groups are tertiary amine groups, preferably defined by the following formula

wherein R is a divalent hydrocarbon radical having 1 to 10 carbon atoms. Diepoxides that are used include diglycidyl ether, the diglycidyl ethers of bisphenols, diglycidyl ether adduct of adipic acid, vinyl cyclohexene dioxide and the diglycidyl ethers of

polyhydric aliphatic alcohols. Diphenols, a necessary component of the system, include bisphenol A, bisphenol F, hydroquinone and resorcinol. The present invention does not require diphenols to obtain curing. Curing of the above mixture requires elevated

temperatures in the range of 100° to 200°C. for a period of 10 minutes to one hour. The epoxides and diphenols used by Strother contribute to poor durability and therefore are not useful for automotive topcoat compositions. In addition, curing at elevated temperatures further render such compositions unattractive for use in the automotive refinishing industry.

In U.S. Patent No. 3,763,100, Martin et al relate to coating compositions containing an epoxy-bisphenol adduct, an adduct of an aziridine compound with a polyepoxide and, optionally, a

mono-functional secondary amine that can be air dried or baked at temperatures of from about 25º to about 400ºC. for about five minutes to about 24 hours. Martin et al thus use an aromatic diphenol and, as with Strother, produce a composition not useful for durable automotive refinish topcoats. In fact, Martin et al's coating is used as a metal primer coating to improve adhesion between said primer and a

subsequent topcoat.

Strother et al in U.S. Patent No. 3,346,533 disclose the use of a diphenol for curing a diaziridine compound with cycloaliphatic 1,2-diepoxide. This patent is similar to British Patent No. 1,190,979 to Strother, supra, and for the same reason neither discloses nor teaches the compositions and processes claimed herein.

SUMMARY OF THE INVENTION

The present invention is directed to isocyanate-free coating compositions, capable of forming a durable coating under ambient conditions, containing the following components:

(A) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea, polymers and oligomers having a molecular weight of at least about 100 and bearing at least two aziridinyl groups defined by the following structural formula:

wherein

X represents O, S, NH, NR, wherein R represents alkyl having from one to 12 carbon atoms, or higher, or phenyl,

R₁ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3 and

Ro represents H, CH₃ or combinations thereof and

(B) at least one polymer, oligomer or combinations thereof selected from the groups consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100 and bearing at least two groups selected from epoxy groups defined by one of the following structural formulas:

;

wherein R represents alkyl having from one to 20 carbon atoms and n = 0-20; and

wherein R₃ represents (CH₂)m₂, m₂ being an integer ranging from 1 to 2. DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to isocyanate-free coating compositions, capable of forming a durable coating under ambient conditions, particularly suitable as coating compositions for coating substrates, especially automotive bodies and parts, and which are relatively non-toxic, containing the following components:

(A) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100, preferably from about 100 to about 20,000, and bearing at least two, preferably from two to about 75, aziridinyl groups defined by the following structural formula:

wherein

X represents O, S, NH or NR,

wherein R represents alkyl having from one to 12 carbon atoms, or higher, or phenyl, preferably 0,

R₁ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3, preferably 2, and

R₂ represents H, CH₃ or combinations thereof, preferably H and

(B) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100, preferably from about 100 to about 20,000, and bearing at least two, preferably from two to 75, epoxy groups selected from the epoxy groups defined by one of the following structural formulas:

J

wherein R₁ represents alkyl having from one to 12 carbon atoms and n = 0-20; and

wherein R₃ represents (CH₂)m₂, m₂ being an integer ranging from 1 to 2, preferably 1. Component A can be prepared, for example, from the reaction of isocyanate functional acrylic, urethane or urea polymers and/or oligomers with, for example, hydroxy, amino or mercapto functional alkyl aziridines. Examples of procedures suitable for the preparation of acrylic polymers that can be used herein are disclosed in U.S.

Patent Application No. 07/643,253 of Charles M. Kania, filed on

January 22, 1991, for Aziridine Compounds, Acrylic Polymers Containing Same and Coating Compositions Containing Said Polymers, assigned to the same assignee as the present patent application.

Component B(1) can be obtained, for example, from the reaction of isocyanate functional acrylic, urethane or urea polymers and/or oligomers with glycidol.

Component B(2) is commercially available from MONSANTO

Corporation under the Trade Name LSE-120 Light Stable Epoxy.

Component B(3) can be obtained, for example, from the free radical polymerization of ethylenically-unsaturated monomers, of which one will be selected from glycidyl functional acrylate or

methacrylates, such as glycidyl acrylate or glycidyl methacrylate.

The invention herein is also directed to processes for coating a substrate using such compositions.

The coating composition herein is usually a two-package composition, that is, the aziridine component and the epoxy component are usually mixed, at ambient temperature, just prior to their application to a substrate. The two components can be used such that the range of aziridine (equivalents) to epoxy (equivalents) is from about 3:1 to about 1:3, preferably about 1:1. There is generally associated with two-package component compositions a "pot life", which is defined as the useful time interval between mixing of the

components and the application thereof to the substrate. Generally, such time is about eight hours. The coating composition defined and claimed herein can be applied to the substrate by any conventional technique, such as spraying, brushing, dipping, rolling, etc., with the preferred method before spraying. Additionally, the components can be devolatalized and converted into sprayable powder form. The coating composition can be applied onto many substrates, such as metals, for example, steel and aluminum, wood, glass, plastics, concrete, etc. Additionally, the substrate can be primed or electrocoated prior to applying thereto the coating composition of this invention. The topcoat composition can be pigmented one-coat system or, more preferably, a clear coat over a pigmented base coat.

The coating compositions herein can also contain ingredients, such as inorganic or organic pigments or metal flakes typically used in automobile refinishing operations, plasticizers, inert filters, adhesion promoters, flow additives, thixotropes and additives for sag control and metallic flake orientation (sometimes referred to as microgel) and described in U.S. Patent Nos. 4,025,474, 4,055,607, 4,075,141, 4,115,472, 4,147,688, 4,180,489, 4,242,384, 4,268,547 and 4,290,932, the disclosures of which are hereby incorporated by reference, and other such formulating additives.

The coating compositions herein containing the defined aziridines and epoxies are usually solutions in organic solvents, although other forms can also be used, such as aqueous dispersions, non-aqueous dispersions and powder forms. Common examples of organic solvents that can be used include esters, such as butyl acetate;

ketones, such as methyl isobutyl ketone; aromatic hydrocarbons, such as xylene; and glycol ethers, such as propylene glycol methyl ether acetate. The solvents or carriers can be used in a range of about 20 to about 70 weight percent, based on the final coating composition.

The coating compositions herein are most useful for refinishing automobiles. The curing of the components can,

preferably, be achieved at ambient conditions; or the cure can be promoted at elevated temperatures if desired. DESCRIPTION OF PREFERRED EMBODIMENTS

EXAMPLE 1

50.72 grams of hydroxy ethyl ethyleneimine were added to 200.0 grams of T-1890L, the isocyanurate of isophorone diisocyanate

(obtainable from HULS) over a period of one hour at temperatures ranging from 25° to 47ºC. and then maintained at such temperature for 30 minutes. 42.7 grams of hexyl acetate were then added to the mixture along with 0.2 grams of dibutyl tin dilaurate, and the reaction temperature was raised to 85° to 91°C. and maintained within the latter temperature range for an additional 30 minutes. The resulting product showed no NCO peak in the IR, had a non-volatile content of 66.3 percent (110ºC./one hour), a Gardner viscosity of Z⁸ and a theoretical aziridine equivalent weight of 327 (solid).

A coating composition was prepared by mixing the following materials:

Component Parts by Weight, Grams Aziridine Resin obtained above 81 .2

Polysiloxane solution¹ (flow control) 1 .0

U.V. Absorber² 3 .0

Toluene (solvent) 15 .9

Propylene Glycol Methyl Ether Acetate

(solvent) 26 .4

Butyl Acetate (solvent) 35. 1

Ethyl-3-Ethoxy Propionate (solvent) 10.5

Epoxy Resin³ 86. 2 ¹ Available from DOW Corning Corporation as DC 200, 135 csk dissolved in xylene to give a 0.5 weight percent polysiloxane content.

² Available from Ciba-Geigy Corp. as TINUVIN 328.

3 A melamme-based epoxy oligomer available from MONSANTO Chemical Co. as LSE-120. The above clearcoat package was then spray applied to 24 gauge cold rolled steel panels (treated with BONDERITE 40, primed with

DP-40/401, a two-component epoxy primer from PPG INDUSTRIES, INC., and basecoated with DELTRON^® Universal Basecoat from PPG INDUSTRIES, INC.). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time:

20 Degree Gloss : 95

D.O.I. : 70

Pencil Hardness : B

Solvent Resistance : Excellent EXAMPLE 2

96.4 grams of hydroxy ethyl ethyleneimine and 20 grams of

1,3-dimethy1-2-imidazolidinone were added to 400 grams of isocyanurate of isophorone diisocyanate (T-1890L) over a period of one hour at temperatures ranging from 23º to 50ºC. Upon completion of the feed 1.2 grams of butanol and 0.4 grams of butyl tin dilaurate were added and the temperature was raised to 70ºC. The reaction was held at this temperature until the NCO disappeared by IR (about one hour). 121 grams of butanol and 10 grams of 1,3-dimethy1-2-imidazolidinone were then added to the reaction mixture. The product showed no NCO in the IR, had a non-volatile content of 61.7 weight percent (110ºC./one hour), a Gardner viscosity of X-Y and a theoretical aziridine

equivalent weight of 327 (solid).

A solution of epoxy functional urethane polymer was then prepared as follows. 4180 grams of dibasic ester (obtainable from Dupont

Corporation), 2950 grams of 1,6-hexanediol, 1800 grams of cyclohexane dimethanol, 3.6 grams of 50 weight percent aqueous hypophosphorous acid solution, 7.1 grams of butane sulfonic acid and 7.1 grams of t-butyl titanate were added to a 12-liter round bottom flask equipped with a stirrer thermometer, nitrogen inlet and distillation receiver and was heated to a maximum temperature of 210ºC. to remove methyl alcohol therefrom, using a nitrogen sparge to facilitate such removal. Over a nine-hour period 1487 grams of methyl alcohol was removed from the reaction mixture, the remainder was cooled to 115ºC. and then 1246.4 grams of methyl isobutyl ketone were added thereto, resulting in a hydroxy functional polymer.

To a three-liter round bottom flask equipped with a nitrogen inlet, stirrer, thermometer and condenser, there was added 390.6 grams of Desmodur N 3390 (a trimer of hexamethylene diisocyanate available from MOBAY), 103.1 grams of the hydroxy functional polymer obtained above, 0.06 grams of dibutyl tin dilaurate and 347.1 grams of methyl isobutyl ketone. The resulting mixture was heated to 80ºC, while watching for an exotherm at 50ºC, and then held at 80ºC, until the isocyanate equivalent weight reached about 600. The reaction mixture was then cooled to 50°C, after which 210.9 grams of glycidol and 30 grams of methyl isobutyl ketone were added thereto. The reaction mixture was held at 50ºC. until the NCO peak disappeared from IR (about three hours) and there were then added 14.5 grams of absolute ethanol and cooled to room temperature. The product obtained was a glycidyl based urethane having no NCO peak in the IR, a non-volatile content of 49.0 weight percent, and a GPC peak molecular weight of 7530.

A coating composition was prepared by mixing the following materials:

Component Parts by Weight, Grams

Aziridine Resin obtained above 76 .5

Polysiloxane solutions¹ 1 .0

Additive² 1 .0

U.V. Absorber³ 3 .0

Toluene 13 .3

Propylene Glycol Methyl Ether Acetate 22 .2

Ethylene Glycol Butyl Ether Acetate 22. 2

Butyl Acetate 29. 4

Ethyl-3-Ethoxy Propionate 8. 9

Epoxy Resin (Glycidyl based

Urethane obtained above) 100.2 ¹ Same as used in Example No. 1.

2 Slip and mar additive available from BYK-MALLINCKRODT as BYK-300.³ Same as used in Example No. 1. The above clearcoat package was then spray applied to 24 gauge cold rolled steel panels (treated with BONDERITE 40, primed with DP-40/401 and basecoated with DELTRON^® Universal Basecoat). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time:

20 Degree Gloss : 86

D.O.I. : 65

Pencil Hardness : 4B

Solvent Resistance : Excellent

EXAMPLE 3

To 2400 grams of refluxing xylene was added a mixture of 750 grams of styrene, 750 grams of methyl methacrylate, 2250 grams of isobornyl methacrylate, 3750 grams of glycidyl methacrylate and an initiator solution containing 250 grams of Lupersol 555 (t-amyl peracetate from Atochem) and 746 grams of xylene. The monomer solution was added over a period of three hours and the initiator solution over a period of 3.5 hours. Upon completion of such additions, 300 grams of xylene were added to the mixture. One hour after the latter addition, there were added 37.5 grams of di-t-butyl peroxide and the reaction mixture was held for an additional two hours. Reflux conditions were maintained throughout the reaction. The product obtained was a glycidyl methacrylate functional acrylic resin having a non-volatile content of 75.2 weight percent (150ºC./two hours), a Gardner Viscosity of Z , a GPC number average molecular weight of 2559, and an epoxy equivalent weight of 375 (solution).

A coating composition was prepared by mixing the following materials:

Component Parts by Weight. Grains

Aziridine Resin used in Example 1 80.3

Polysiloxane solution¹ 1.0

Additive 1.0

U.V. Absorber³ 3.0

Toluene 19.0 Propylene Glycol Methyl Ether Acetate 31.6

Ethylene Glycol Butyl Ether Acetate 31.6

Butyl Acetate 41.9

Ethyl-3-Ethoxy Propionate 12.6

Epoxy Resin (Glycidyl methacrylate

resin obtained above) 63.7 1 Same as used in Examples Nos. 1 and 2.

2 Same as used in Example No. 2.

³ Same as used in Examples Nos. 1 and 2.

The above clearcoat package was then spray applied to 24 gauge cold rolled steel panels (treated with BONDERITE 40, primed with DP 40/401 and basecoated with DELTRON^® Universal Basecoat). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time:

20 Degree Gloss : 92

D.O.I. : 80

Pencil Hardness : 4B

Solvent Resistance: Excellent

EXAMPLE 4

80.17 grams of hydroxy ethyl ethyleneimine and 45.1 grams of butyl acetate were added to 70 percent isocyanate prepolymer solution in butyl acetate based on three moles of m-TMXDI (a diisocyanate available from American Cyanamid) and one mole of trimethylolpropane over a period of one hour at a temperature of 25° to 61ºC. Upon completion of the addition, 3.6 grams of butyl alcohol and 0.34 grams of dibutyl tin dilaurate were added and the temperature raised to 85ºC. The reaction was held for two hours at this temperature until the NCO disappeared by IR. 38.1 grams of butyl acetate were then added. The product showed no isocyanate peak in the IR, had a non-volatile content of 63.2 percent (110º/hour), a Gardner viscosity of Z⁴ and a theoretical aziridine equivalent weight of 348.5 (solid) and a GPC peal molecular weight of 2524.

A coating composition was prepared by mixing the following materials : Component Parts by Weight. Grams

Aziridine Resin obtained above 100 .0

Polysiloxane solution 1 .0

Additive² 1 .0

U.V. Absorber³ 3 .0

Toluene 19 .0

Propylene Glycol Methyl Ether Acetate 31 .6

Ethylene Glycol Butyl Ether Acetate 31 .6

Butyl Acetate 41 .9

Ethyl-3-Ethpxy Propionate 12 .6

Epoxy Resin 44 .0 ¹ Same as used in Example 1.

² Same as used in Example 2.

³ Same as used in Example 1.

4A melamine-based epoxy oligomer available from MONSANTO Chemical Co. as LSE-20.

The above clearcoat package was then spray applied to 24 gauge cold-rolled steel panels (treated with BONDERITE 40, primed with DP-40/401, a two-component epoxy primer from PPG INDUSTRIES, INC., PPG FINISHES, and basecoated with DELTRON^® Universal Basecoat from PPG INDUSTRIES, INC., PPG FINISHES). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time. 20 Degree Gloss : 92

D.O.I. : 80

Pencil Hardness : 4B

Solvent Resistance : Excellent

EXAMPLE 5

In this Example 5, which was used as an isocyanate/polyol control, it can be seen that isocyanate/polyol cured systems, which are toxic, do not result in a coating having all of the desirable properties obtained using the novel compositions defined and claimed herein.

Thus, a clearcoat paint commercially available from PPG INDUSTRIES, INC., PPG FINISHES under the trade name DELTRON^® DAU-82, containing an isocyanate and a polyol as component, was spray applied to 24 gauge cold rolled steel panels (treated with BONDERITE 40, primed with DP 40/401, a two-component epoxy primer from PPG INDUSTRIES, INC., PPG FINISHES, and basecoated with DELTRON^® Universal Basecoat from PPG INDUSTRIES, INC., PPG FINISHES). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time:

20 Degree Gloss : 91

D.O.I. : 65

Pencil Hardness : 5B

Solvent Resistance : Fair

EXAMPLE 6

It can be seen in this Example 6 that when compositions are used containing a bisphenol A type epoxy for curing, the coatings obtained are nondurable and much inferior to the coatings resulting from the use of the novel compositions defined and claimed herein. Thus, a clearcoat composition containing the following materials was prepared:

Component Parts by Weight. Grams

Aziridine Resin obtained in Example 4 100 .0

Polysiloxane solution 1 .0

Additive² 1 .0

U.V. Absorber³ 3 .0

Toluene 20 .8

Propylene Glycol Methyl Ether Acetate 33 .4

Ethylene Glycol Butyl Ether Acetate 33 .4

Butyl Acetate 43. 7

Ethyl-3-Ethpxy Propionate 14.4

Epoxy Resin 35 .0 ¹ Same as used in Example 1.

2 Same as used in Example 2.

3 Same as used in Example 3.

4 A bisphenol A type epoxy available from SHELL Chemical Co. as EPON 1001F. The clearcoat package was spray applied to 24 gauge cold rolled steel panels (treated with BONDERITE 40, primed with DP 40/401, a two-component epoxy primer from PPG INDUSTRIES, INC., PPG FINISHES, and basecoated with DELTRON^® Universal Basecoat from PPG INDUSTRIES, INC., PPG FINISHES). The clearcoat film was allowed to cure at ambient conditions. The resulting coating was found to have the following properties after a one-week cure time.

20 Degree Gloss : 96

D.O.I. : 80

Pencil Hardness : 6B

Solvent Resistance : Excellent The data obtained above are summarized below in Table I.

TABLE I

Pencil Solvent³ Q.U.V.⁴ Blushing⁵

Example Epoxy Gloss¹ D.O.I.² Hardness Resistance Percent Gloss Retention Tendency

1 LSE-120 95 70 B Excellent 93 None 2 Glycidyl 86 65 4B Excellent 100 None

Functional

Urethane

3 Glycidyl 92 80 4B Excellent 100 None

Methacrylate

Acrylic

4 LSE-120 92 80 4B Excellent 100 None 5 (Control) 91 65 5B Fair 100 None

Isocyanate

Cured

6 EPON 1001 L 96 80 6B Excellent 14 Severe

1 20 Degree Gloss

2 Depth-of-Image

3 Gasoline Spot Resistance

4 300 Hours Accelerated Weathering

5 Tendency to Blush and Whiten During Q.U.V. Exposure

According to the provisions of the patent statutes, there are described above the invention and what are now considered to be its best embodiments. However, within the scope of the appended claims, it is to be understood that the invention may be practiced otherwise than as specifically described hereinabove.

Claims

WHAT IS CLAIMED IS:

1. Isocyanate-free coating compositions, capable of forming a durable coating under ambient conditions, comprising

(A) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100 and bearing at least two aziridinyl groups defined by the following structural formula:

,

wherein

R₁ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3 and

R₂ represents H, CH₃ or combinations thereof and

(B) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100 and bearing at least two groups selected from epoxy groups defined by one of the following structural formulas:

;

wherein R represents alkyl having from one to 20 carbon atoms and n = 0-20; and ,

wherein R₃ represents (CH₂)m₂, m₂ being an integer ranging from 1 to 2.

2. Compositions according to claim 1 wherein Component (A) is an acrylic polymer.

3. Compositions according to claim 1 wherein Component (B) is an acrylic polymer.

4. Compositions according to claim 1 wherein each of Components (A) and (B) is an acrylic polymer.

5. Compositions according to claim 1 wherein Component (A) is a urethane polymer.

6. Compositions according to claim 1 wherein Component (B) is a urethane polymer.

7. Compositions according to claim 1 wherein each of Components (A) and (B) are urethane polymers.

8. Compositions according to claim 1 wherein Component (A) is a urea polymer.

9. Compositions according to claim 1 wherein Component (B) is a urea polymer.

10. Compositions according to claim 1 wherein each of Components (A) and (B) are urea polymers.

11. Compositions according to claim 1 wherein the molecular weight of Component (A) is from about 100 to about 20,000.

12. Compositions according to claim 1 wherein the molecular weight of Component (B) is from about 100 to about 20,000.

13. Compositions according to claim 1 wherein the number of aziridinyl groups in Component (A) are from two to about 75.

14. Compositions according to claim 1 wherein the number of epoxy groups in Component (B) are from two to about 75.

15. Compositions according to claim 1 wherein the number of aziridinyl groups in Component (A) are from two to about 75 and the number of epoxy groups in Component (B) are from two to about 75.

16. Compositions according to claim 1 wherein X=0, m₁ is the integer 2, R₂ represents H and m₂ is the integer 1.

17. Compositions according to claim 1 wherein the range of aziridine (equivalents) to epoxy (equivalents) is from about 3:1 to about 1:3.

18. Compositions according to claim 1 wherein the range of aziridine (equivalents) to epoxy (equivalents) is about 1:1.

19. A process for coating a substrate which comprises applying thereto an isocyanate-free coating composition, capable of forming a durable coating under ambient conditions comprising

wherein X represents O, S, NH, NR, wherein R represents an alkyl having from one to 12 carbon atoms, or higher, or phenyl,

R₁ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3 and

R₂ represents H, CH3 or combinations thereof, and

(B) at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane or urea polymers and oligomers having a molecular weight of at least 100 and bearing at least two groups selected from epoxy groups defined by one of the following structural formulas:

wherein R represents alkyl having from one to 20 carbon atoms and n = 0-20; and

(3) , wherein R₃ represents (CH₂)m₂, m₂ being an

integer ranging from 1 to 2.

20. The process of claim 19 wherein Component (A) is an acrylic polymer.

21. The process of claim 19 wherein Component (B) is an acrylic polymer.

22. The process of claim 19 wherein each of Components (A) and (B) is an acrylic polymer.

23. The process of claim 19 wherein Component (A) is a urethane polymer.

24. The process of claim 19 wherein Component (B) is a urethane polymer.

25. The process of claim 19 wherein each of Components (A) and (B) are urethane polymers.

26. The process of claim 19 wherein Component (A) is a urea polymer.

27. The process of claim 19 wherein Component (B) is a urea polymer.

28. The process of claim 19 wherein each of Components (A) and (B) are urea polymers.

29. The process of claim 19 wherein the molecular weight of Component (A) is from about 100 to about 20,000.

30. The process of claim 19 wherein the molecular weight of Component (B) is from about 100 to about 20,000.

31. The process of claim 19 wherein the number of aziridinyl groups in Component (A) are from two to about 75.

32. The process of claim 19 wherein the number of epoxy groups in Component (B) are from two to about 75.

33. The process of claim 19 wherein the number of aziridinyl groups in Component (A) are from two to about 75 and the number of epoxy groups in Component (B) are from two to about 75.

34. The process of claim 19 wherein X=0, m₁ is the integer 2, R₂ represents H and m₂ is the integer 1. 35. The process of claim 19 wherein the range of aziridine

(equivalents) to epoxy (equivalents) is from about 3:1 to about 1:3.

36. The process of claim 19 wherein the range of aziridine

(equivalents) to epoxy (equivalents) is about 1:1.

AMENDED CLAIMS

[received by the International Bureau on 18 September 1992 (18.09.92); original claims 1 and 19 amended; other claims unchanged ( 7 pages )]

,

wherein

R₁ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3 and

R₂ represents H, CH₃ or combinations thereof; and a member selected from the group consisting of (B) and (C) wherein

(B) is at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane and urea polymers and oligomers having a molecular weight of at least about 100 and bearing at least two groups selected from epoxy groups defined by one of the following structural formulas:

; and

wherein R3 represents (CH₂)m₂, m₂ being an integer ranging from 1 to 2; and

(C) is a polymer or oligomer represented by the following structural formula:

wherein R represents alkyl having from one to 20 carbon atoms and n = 0-20.

17. Compositions according to claim 1 wherein the range of aziridine (equivalents) to epoxy (equivalents) is from about 3:1 to about 1:3. 18. Compositions according to claim 1 wherein the range of aziridine (equivalents) to epoxy (equivalents) is about 1:1.

wherein X represents O, S, NH, NR. wherein R represents an alkyl having from one to 12 carbon atoms, or higher, or phenyl,

R^ represents (CH₂)m₁, m₁ being an integer ranging from 1 to 3 and

R₂ represents H, CH₃ or combinations thereof; and a member selected from the group consisting of (B) and (C) wherein (B) is at least one polymer, oligomer or combinations thereof selected from the group consisting of acrylic, urethane or urea polymers and oligomers having a molecular weight of at least 100 and bearing at least two groups selected from epoxy groups defined by one of the following structural formulas:

: and

wherein R₃ represents (CH₂)m₂, m₂ being an integer ranging from

1 to 2; and (C) is a polymer or oligomer represented by the following structural formula:

wherein R represents alkyl having from one to 20 carbon atoms and n = 0-20.

20. The process of claim 19 wherein Component (A) is an acrylic polymer.

21. The process of claim 19 wherein Component (B) is an acrylic polymer.

23. The process of claim 19 wherein Component (A) is a urethane polymer.

24. The process of claim 19 wherein Component (B) is a urethane polymer. 25. The process of claim 19 wherein each of Components (A) and (B) are urethane polymers.

26. The process of claim 19 wherein Component (A) is a urea polymer.

27. The process of claim 19 wherein Component (B) is a urea polymer.

29. The process of claim 19 wherein the molecular weight of Component (A) is from about 100 to about 20,000. 30. The process of claim 19 wherein the molecular weight of Component (B) is from about 100 to about 20,000.

33. The process of claim 19 wherein the number of aziridinyl groups in Component (A) are from two to about 75 and the number of epoxy groups in Component (B) are from two to about 75. 34. The process of claim 19 wherein X=0, m₁ is the integer 2, R₂ represents H and m₂ is the integer 1.

35. The process of claim 19 wherein the range of aziridine (equivalents) to epoxy (equivalents) is from about 3:1 to about 1:3.

36. The process of claim 19 wherein the range of aziridine (equivalents) to epoxy (equivalents) is about 1:1.

STATEMENT UNDER ARTICLE 19

Claims 1 and 19 have been amended to correct language and

typographical errors in the way the claims are written and in the structural formula, respectively. The amended claim specifies that the material that was originally referred to as B(2), now referred to as (C), is itself a polymer or oligomer represented by the given structural formula rather than a group. This is not new matter but is supported by the specification on page.8, lines 22-23 as well as Examples 1 and 4. The structural formula read within the context of the disclosure and Examples makes clear that the melamine based epoxy oligomer is itself an oligomer and not a group pendant to another polymer. Also, the bonds in the

structural formula for the melamine based epoxy oligomer have been corrected. The methylene group of the upper diglycidyl melamine radical is now bonded to the nitrogen of the lower diglycidyl melamine radical rather than to the alkoxymethylene group which is already tetravalent. This amendment simply corrects a

typographical error and does not constitute new matter. Also, a missing bond between the nitrogen and one of the groups has been added. The amendment to the Summary of the Invention and Abstract are simply to make them consistent with the amended claims.