KR100514965B1 - Mar-Resistant Oligomeric-Based Coatings - Google Patents

Abstract

Cross-linking upon curing to form a three-dimensional network having a chain that is substantially uniform and has a molecular weight controllable crosslinking between the crosslinks and describes a curable coating composition comprising functionalized oligomer components i) and ii), said oligomer i) And the weight average molecular weight of ii) does not exceed about 3,000, the polydispersity of component i) does not exceed about 1.5, and the functional groups that react with each other crosslink the components i) and ii) upon curing, A coating with excellent balance is obtained.

Description

Wear-Resistant Oligomeric-Based Coatings {Mar-Resistant Oligomeric-Based Coatings}

The present invention relates to a curable coating composition which is particularly useful as a top coat in a multilayer system coating system.

Basecoat-clearcoat systems have been found to be widely accepted as automotive finishes for the last decade. Efforts have been made to obtain coating systems for improving the overall appearance, transparency of the top coat, and heat resistance. Further efforts have been made to obtain the development of coating compositions with low volatility organic content (VOC). There is a continuing need for coating compositions that provide significant performance characteristics after application, in particular wear resistance and resistance to environmental corrosion. Previously, wear resistant coatings have been achieved by coating softening which degrades other performance characteristics. The present invention overcomes this problem.

Summary of the Invention

The present invention

i) a binder selected from linear or branched alicyclic moieties containing oligomers or oligomer blends having a weight average molecular weight of no greater than about 3,000 and a polydispersity of no greater than about 1.5 and a functional group of A or A + B; And

ii) any oligomeric crosslinker or crosslinker blend whose weight average molecular weight does not exceed about 3,000 and the functional group is C or C + D.

Wherein components i) and ii) react upon curing to form a three dimensional network having a substantially uniform and adjustable molecular weight chain between crosslinks, wherein the volatile organic content is greater than about 0.4 kg / l. And a curable coating composition of a binder in an organic solvent.

Preferred functional groups in the oligomeric components i) and ii) are as follows:

Component i) Component ii) A = hydroxyl A = hydroxyl A = anhydride A = anhydride A = acid A = acid; B = hydroxyl A = epoxy A = epoxy; B = hydroxyl A = aldimine A = aldimine; B hydroxyl A = ketimine A = ketimine; B = hydroxyl A = silane A = silane; B = hydroxyl A = silane; B = hydroxyl A = silane; B = epoxy C = isocyanate C = melamine C = epoxy C = epoxy; D = hydroxyl C = epoxy C = epoxy; D = melamine C = isocyanate C = isocyanate C = isocyanate C = isocyanate C = isocyanate C = isocyanate C = silane C = melamine C = isocyanate C = acid; D = melamine

Compositions of the invention, including when component i) self-crosslinks, or when component i) + ii) crosslink, are also described herein as acyclic oligomers and / or acrylic polymers, as described in more detail herein below. And / or the dispersed high polymer may contain up to about 30% of the total binder based on the total binder. The invention also relates to a method of coating a substrate and to a substrate coated with the composition comprising applying the composition of the invention to a substrate and curing the composition. As used herein, the term “isocyanate (s)” also includes blocked isocyanate (s).

The composition of the present invention forms a structured polymer network of high hardness and excellent wear resistance. The functional groups of these oligomers are arranged as expected (randomly) for polymers in which the functional groups are randomly distributed so that their polydispersity is typically greater than 2.0. By "polydispersity" is meant the weight average molecular weight divided by the number average molecular weight, both measured by gel permeation chromatography. In the compositions of the present invention, the molecular weight between the crosslinks is controlled to minimize short embrittlement length and long softening length; Minimize the non-functional soluble material in the network; A more uniform network can be formed that maximizes the toughness of the film (energy to breakdown). These systems develop high molecular weight open networks between crosslinks for polymer systems at relatively high glass transition temperatures (T _g ).

The T _g of these systems can be adjusted to provide the best balance of wear, hardness, durability and corrosion. When T _g of a crosslinked film made from a composition of the present invention is measured using dynamic mechanical analysis, the T _g regime is characterized by a steep slope to the gradual slope of the random system based on the polymer. . The reactivity of these systems is that the reaction is complete to minimize hydrophilic groups. These systems are typically baked at 120 to 141 ° C. (250 to 285 ° F.) but can be cured at lower temperatures using more reactive groups and contact reactions.

Typical functionalized oligomers which can be used as component i) or ii) are as follows:

Acid oligomer: The reaction product of a polyfunctional alcohol such as pentaerythritol, hexanediol, trimethylol propane and the like with a cyclic monomeric anhydride such as hexahydrophthalic anhydride.

Hydroxyl oligomers: The above acid oligomers further reacted with monofunctional epoxides such as butylene oxide, propylene oxide and the like.

Anhydride oligomers: The above acid oligomers further reacted with ketene.

Silane oligomer: The above hydroxyl oligomer further reacted with isocyanato propyl trimethoxy silane.

Epoxy oligomers: cyclohexane dicarboxylic acids such as Araldite O CY-184 (purchased from Ciba Geigy) and alicyclic epoxy such as ERLO-4221 (purchased from Union Carbide). Diglycidyl ester.

Isocyanate oligomers: isocyanurate trimers of DESMODURO 3300 (purchased from Bayer) or tolonate HDTa (purchased from Rhone-Poulenc), hexamethylene diisocyanate, and isocyanurates such as isophorone diisocyanate Trimer.

Aldimine oligomer: reaction product of isobutyraldehyde with diamine such as isophorone diamine and the like.

Ketamine oligomer: The reaction product of methyl isobutyl ketone with diamines such as isophorone diamine.

Melamine oligomer: Commercially available melamine such as CYMELO 1168 (purchased from Cytec Industries).

AB-functionalized oligomers: by further reacting the acid oligomer with a 50% monofunctional epoxy, such as butylene oxide, or a blend of hydroxyl and acid oligomers as described above, or any other blend described above. Acid / hydroxyl functional oligomers prepared.

CD-functionalized crosslinker: an epoxy such as polyglycidyl ether of sorbitol DCE-358O (purchased from Dixie Chemical), or a blend of hydroxyl oligomers with the epoxy crosslinker described above, or any other blend as described above / Hydroxyl functional crosslinker.

The compositions of the present invention may further contain up to 30% by weight of the binder of acyclic oligomers, ie linear or aromatic. Such acyclic oligomers may include, for example, succinic anhydride- or phthalic anhydride derived moieties in “acid oligomers” as described above.

Preferred oligomers (i) have a weight average molecular weight of no greater than about 3,000 and a polydispersity of no greater than about 1.5; More preferred oligomers have a molecular weight of no greater than about 2,500 and a polydispersity of no greater than about 1.4; Most preferred oligomers have a molecular weight of no greater than about 2,200 and a polydispersity of no greater than about 1.25. The composition of the present invention may comprise 100% by weight of component i) when component i) is a self-crosslinking agent. More typically, the composition will comprise from 20 to 80% by weight, preferably from 30 to 70% by weight, more preferably from 40 to 60% by weight, with the remaining amount being component ii).

The coating composition of the present invention may further comprise a functional amount, typically about 0.1 to 5 weight percent catalyst, based on the weight of solids in the composition. A wide variety of catalysts can be used, such as dibutyl tin dilaurate for isocyanate based reactions, tertiary amines such as triethylenediamine or phosphonium based catalysts for epoxy reactions, and sulfonic acids such as dodecylbenzene sulfonic acid for melamine reactions. Can be.

The coating composition of the present invention is formulated into a high solid coating system dissolved in one or more solvents. The solvent is usually organic. Preferred solvents include aromatic hydrocarbons such as petroleum naphtha or xylene; Ketones such as methyl amyl ketone, methyl isobutyl ketone, methyl ethyl ketone or acetone; Esters such as butyl acetate or hexyl acetate; And glycol ether esters such as propylene glycol monomethyl ether acetate.

The coating composition of the present invention is also an acrylic polymer having a weight average molecular weight greater than 3,000, or SCSO-1040 (purchased from Etna Product Inc.) for improved appearance, sag resistance, flowability and leveling resistance. Conventional polyesters such as can contain up to 30% of the total binder. The acrylic polymer may be composed of typical monomers such as acrylate, methacrylate, styrene and the like, and functional monomers such as hydroxy ethyl acrylate, glycidyl methacrylate or gamma methacryl propyl trimethoxy silane and the like.

The coating composition of the present invention may also contain up to 30% of the total binder of dispersed acrylic components, which are polymer particles dispersed in an organic medium, stabilized by what is known as steric stabilization. In the following, the dispersed phase or particles coated by the steric barrier will be referred to as "polymeric polymer" or "core". Stabilizers that form a steric barrier, attached to this core, will be referred to as "macromonomer chains" or "arms."

The dispersed polymer contains a high molecular weight core having a weight average molecular weight of about 50,000 to 500,000 at about 10 to 90% by weight, preferably 50 to 80% by weight based on the weight of the dispersed polymer. Preferred average particle sizes are from 0.1 to 0.5 μ. The arm attached to the core constitutes about 10 to 90%, preferably 10 to 59%, by weight of the dispersed polymer, with a weight average molecular weight of about 1,000 to 30,000, preferably 1,000 to 10,000.

The polymer core of the dispersed polymer consists of polymerized acrylic monomer (s) optionally copolymerized with ethylenically unsaturated monomer (s). Suitable monomers include styrene, alkyl acrylates or methacrylates, ethylenically unsaturated monocarboxylic acids and / or silane containing monomers. Monomers such as methyl methacrylate contribute to high T _g (glass transition temperature) dispersed polymers, while "softening" monomers such as butyl acrylate or 2-ethylhexyl acrylate can be applied to low T _g dispersed polymers. Contribute. Other optional monomers are hydroxyalkyl acrylates or methacrylates or acrylonitrile. The polymer core may optionally be crosslinked using diacrylates or dimethacrylates such as allyl methacrylate, or by post-reacting polyfunctional hydroxyl moieties with isocyanates.

The macromonomer arm attached to the core is not only alkyl methacrylate, alkyl acrylate (with 1 to 12 carbon atoms in each alkyl group), but also glycidyl acrylate or glycidyl methacrylate or ethylenically unsaturated monocarboxyl. It may contain polymerized monomers of acids to anchor and / or crosslink. Typically useful hydroxy containing monomers are the aforementioned hydroxy alkyl acrylates or methacrylates.

The coating composition of the present invention may also contain conventional additives such as pigments, stabilizers, rheology modifiers, flow agents, toughening agents and fillers. Such additional additives will of course depend on the desired use of the coating composition. Fillers, pigments and other additives that would adversely affect the transparency of the cured coating will not be included if the composition is desired as a clear coating.

The coating composition is typically applied to the substrate by conventional techniques such as spraying, electrostatic spraying, roller coating, dipping or brushing. The compositions of the present invention are particularly useful as transparent coatings for outdoor products such as automobiles and other vehicle body parts. Typically, substrates are prepared having primers and color coats or other surface preparations prior to coating with the compositions of the present invention.

The composition of the present invention may be cured by application to a substrate by heating to about 120 to 150 ° C. for about 15 to 90 minutes.

The invention is further illustrated by the following procedures and examples, where parts and percentages are by weight unless otherwise indicated. VOC is measured by the procedure of ASTM method D3960.

<Procedure 1>

Tetra hydroxyl functional oligomers

<Production of Acid Oligomer>

To a 12 liter flask with stirrer, condenser, heating mantle, nitrogen inlet, thermocouple and additional port was added 2447.2 g of propylene glycol monomethylether acetate, 792.4 g of pentaerythritol and 1.36 g of triethylamine. The reaction mixture was stirred and heated to 140 ° C. under a blanket of nitrogen, with 3759 g of methyl hexahydrophthalic anhydride added over 6 hours. The reaction mixture was then kept at 140 ° C. until no anhydride band was observed on infrared spectroscopy.

<Production of Diol>

To a 5 liter flask equipped with a stirrer, condenser, heating mantle, nitrogen inlet, thermocouple and additional port was added 2798.4 g of acid oligomer and 2.76 g of triethylamine prepared above. The mixture was stirred and heated to 60 ° C. under nitrogen. Subsequently, 696.9 g of 1,2-epoxy butane was added over 120 minutes, then the temperature was raised to 105 ° C. and maintained at this temperature until the acid value dropped below about 10. The weight percent solids was 71.5, the Gardner viscosity was V, the number average molecular weight was 895, and the weight average molecular weight was 1022 as measured by GPC (polystyrene standard).

<Procedure 2>

Dihydroxyl functional oligomers

<Production of Acid Oligomer>

To a 12 liter flask with stirrer, condenser, heating mantle, nitrogen inlet, thermocouple and additional port was added 2434.5 g of propylene glycol monomethylether acetate, 1222.5 g of hexane diol and 1.37 g of triethylamine. The reaction mixture was stirred and heated to 140 ° C. under a blanket of nitrogen, wherein 3341.6 g of methyl hexahydrophthalic anhydride were added over 6 hours. The reaction mixture was then kept at 140 ° C. until no anhydride band was observed on infrared spectroscopy.

Preparation of Oligomeric Diols

To a 5 liter flask equipped with a stirrer, condenser, heating mantle, nitrogen inlet, thermocouple and additional port was added 2020.4 g of acid oligomer and 2.45 g of triethylamine prepared above. The mixture was stirred and heated to 60 ° C. under nitrogen. Then, 478.3 g of 1,2-epoxy butane was added over 120 minutes, then the temperature was raised to 105 ° C. and maintained at this temperature until the acid value dropped to about 10 or less. The weight percent solids were 69.5, Gardner viscosity was A, number average molecular weight was 679, and weight average molecular weight was 770 as measured by GPC (polystyrene standard).

<Procedure 3>

<Hydroxyl / silane oligomer>

The oligomer obtained from procedure 2 was

Dihydroxyl functional oligomer 250,

Isocyanato propyl trimethoxy silane 60.9, and

1% dibutyl tin dilaurate 0.25 in methylethyl ketone (MEK)

It was further reacted by mixing with.

The mixture was heated at 60 ° C for 3 days. Completion of the reaction was monitored using an infrared spectrometer. The reaction was complete when essentially no isocyanate uptake in the IR.

<Procedure 4>

<Anhydride oligomer>

Anhydride oligomers were prepared from tetrafunctional half acid esters. The following components were charged to a reaction vessel equipped with a heating mantle, reflux condenser, thermocouple, nitrogen inlet and stirrer:

Part I pentaerythritol methyl hexahydrophthalic anhydride triethylamine Weight part 478.02250.00.5 Part II Xylol (135-145 ° C.) 2250.0 gun 4978.5

Part I was charged to the reaction vessel, heated to 180 ° C. under a blanket of nitrogen and held for 30 minutes. After the holding time, the reaction mixture was cooled down and Part II was added.

Linear positioning anhydrides were prepared using the solution prepared above. The solution was charged to a 5 L flask equipped with a stirrer and a gas inlet tube. A gas inlet tube was attached to a ketene generator similar to that described in Williams et al., The Journal of Organic Chemistry 5, 122, 1940. The ketene was bubbled through the solution until all acid groups were converted to anhydride groups. The solvent was then removed in vacuo to yield a linear positioning anhydride having the following characteristics:

Solid weight% 78.0 Anhydride Equivalent Weight 329 ± 4 (solution based) Acid equivalent weight 6176 ± 1323 (Based on solution) Weight average molecular weight 1100

<Example 1>

<Transparent isocyanate>

Part I Tetrahydroxyl Functional Oligomer (Procedure 1) Dihydroxyl Functional Oligomer (Procedure 2) Propylene Glycol Monomethyl Ether Acetate (PM Acetate) Tinuvin O 384 (UV Screener from Ciba Geigy) Tinuvin O 292 (sterically hindered amine light stabilizer from Ciba Geigy) 10% BYK-301O in PM acetate (flow additive from BYK Chemie) 10% dibutyl tin dilaurate butyl acetate in methyl ethyl ketone Weight 217.71149.2426.148.946.721.781.1252.27 II Butolonate O HDT (isocyanurate trimer of hexamethylene diisocyanate purchased from Rhone-Poulenc) 192.23

The coating was sprayed onto a black water soluble basecoat that had already been warmed at 82 ° C. (180 ° F.) for 5 minutes. The coating was cured at 141 ° C. (285 ° F.) for 30 minutes. The coating showed excellent appearance, hardness and wear resistance. This coating has greater hardness and significantly better wear resistance than the reference coating made from a similar final film T _g using routine hydroxyl functional acrylic polymers (polymers having a weight average molecular weight of 6,000 with 32% hydroxyl ethyl acrylate). Indicated. The acrylic resin was replaced with an oligomer based on the corresponding.

characteristic Transparent oligomeric 2K Transparent Polymerizable 2K Glass transition temperature ¹ 42.7 ℃ 48.1 ℃ Hardness ² 141 N / ㎡ 130 N / ㎡ Wet Wear ³ 80% 50.6% Dry Wear ⁴ 94.2% 65.5% Measured with a primary scanning calorimeter. 2 Measured with a Fischerscope O hardness tester in N / mm2. 3 The panel surface is abraded using a 3% slurry of aluminum oxide and felt pads in water and worn using a DaieiO friction tester. The test uses 10 cycles with a weight of 500 g. Grades shown are% unworn surface as measured by image analysis. 4 Wear the panel surface using a Bon AmiO cleanser and felt pad and wear using a DaieiO friction tester. The test uses 15 cycles with a weight of 700 g. Grades shown are% unworn surface as measured by image analysis.

<Example 2>

<Anhydride / Transparent Epoxy>

Part I anhydride oligomer (Procedure 4) Tinuvin O 384 (ultraviolet screener from Ciba Geigy) Tinuvin O 292 (sterically hindered amine light stabilizer from Ciba Geigy) 5% BYK-301O (from BYK Chemie) Purchased flow additive) 25% tetra butyl phosphonium chloride butyl acetate in PM acetate Weight part 763.0819.0813.7456.419.8497.0 Diglycidyl ester of II part cyclohexane dicarboxylic acid 358.65

The coating was sprayed onto a black water soluble basecoat that had already been warmed flash at 82 ° C. for 5 minutes. The coating was cured at 141 ° C. for 30 minutes. The coating exhibited excellent appearance, hardness, cure and durability. This coating showed significantly better durability than similar coatings based on standard acrylic anhydride polymers (polymers having a weight average molecular weight of 6,000 containing 27% itaconic anhydride). The acrylic material was replaced with oligomers based on the counterparts. In the accelerated QUV test (using the FS-40 bulb) the coating on the polymerizable anhydride substrate cracked after exposure of 4,000 to 6,000 hours; The coating of the oligomeric substrate did not crack and showed excellent gloss over 10,000 hours of exposure.

<Example 3>

<Transparent melamine>

Part I Parts by weight Tetra hydroxyl functional oligomer (Procedure 1) Dihydroxyl functional oligomer (Procedure 2) CymelO 1168 (melamine purchased from Cytec Ind.) 20% BYK-301O (flow additive purchased from BYK Chemie) catalyst solution ^{* *} catalyst solution CycatO 600 (a sulfonic acid obtained from American Cyanamid) AMP-95O (the amine obtained from Angus Chemical) methanol 16.116.616.10.40.848.010.841.2

The coating was sprayed onto a black water soluble basecoat that had already been warmed flash at 82 ° C. for 5 minutes. The coating was cured at 141 ° C. for 30 minutes. The coating showed good appearance, hardness and wear resistance.

<Example 4>

<Silane (a) / hydroxyl (b) / isocyanate (c)>

Part I Tetra hydroxyl functional oligomer (Procedure 1) Hydroxyl / silane oligomer (Procedure 3) Tinuvin O 384 (ultraviolet screener from Ciba Geigy) Tinuvin O 292 (sterically hindered amine light stabilizer from Ciba Geigy ) 10% BYK-301O in PM acetate (flow additive purchased from BYK Chemie) 10% dibutyl tin dilaurate butyl acetate PM acetate in butyl acetate Weight 243.5175.99.476.973.291.0426.326.3 II Butolonate O HDT (disocyanurate trimer of hexamethylene diisocyanate purchased from Rhone-Poulenc) 157.2

The coating was sprayed onto a black water soluble basecoat that had already been warmed flash at 82 ° C. for 5 minutes. The coating showed excellent appearance, hardness and wear resistance.

Example 5

A) non-aqueous dispersion

The following components were added to a 5 L flask equipped with a stirrer, thermocouple, condenser and additional funnel. The mixture was stirred under nitrogen and heated to reflux (100-104 ° C.). The ingredients are given in parts by weight (in most cases up to the nearest whole number). The dispersed polymer is 63.5 wt% solids in toluene having a weight average molecular weight of 8100. The composition is as follows:

STY / BA / BMA / HEA / MAA / GMA (14.7 / 43.6 / 27.5 / 10.1 / 2.3 / 1.7) Dispersed polymer 206 Isopropanol 12 Spirits 94 Heptane 53 Butanol 3

At reflux tert-butyl peroctoate (0.5 parts) and inorganic spirit (5 parts) were added as a batch. The following components were then added at reflux over 210 minutes:

Styrene 52 Hydroxyethyl acrylate 86 Methyl methacrylate 126 Glycidyl methacrylate 5 Methacrylic acid 14 Methyl acrylate 62 Dispersed polymer 103

These components were then added and the reaction held for 45 minutes:

Butanol 12 Heptane 17 Tertiary Butyl Peroctoate 5 Weapon spirit 31

Butanol (16 parts) and tertiary butyl peroctoate (1.7 parts) were added over 30 minutes and the reaction was held for 60 minutes. Finally, 76 parts of solvent were stripped from the reactor. The particle size was 298 nm as measured by semi-elastic light scattering and the room temperature viscosity was 2000 centipoise at 5 rpm on a Brookfield viscometer and the solid weight was 63.5%.

B) acrylosilane resin

Resin was prepared by this procedure: 400 g of 2 ethyl hexanol and 400 g of N-pentyl propionate were charged to a 5 L flask. Heat to reflux. Premixed and 896 g styrene, 672 g gamma methacryl propyl trimethoxy silane, 336 g 2-ethylhexyl methacrylate, 336 g hydroxypropyl methacrylate, 170.2 g 2.2 (2 methyl butane nitrile ), 40 g 2 ethyl hexanol and 40 g N-pentyl propionate are added to the reflux material over 6 hours. The temperature is maintained for 30 minutes after the addition. Then a premixed blend of 40 g 2 ethyl hexanol, 40 g N-pentyl propionate and 9 g 2.2 (2 methyl butane nitrile) is added over 30 minutes. The temperature is maintained for 30 minutes after addition, then cooled and emptied.

Gardner Holt Viscosity Solid weight Weight average molecular weight X + ½ 73.3% 5686

C) cyclosilane oligomer (i)

Some cyclohexanedimethanol is placed in an oven to melt. Once melted, 294.7 g of cyclohexanedimethanol are taken with 0.11 g of FascatO 420 (tin catalyst from Elf Atochem) and placed in a flask at about 35 ° C. 839 g of isocyanate propyl trimethoxysilane are then added over 75 minutes. Then hold for 2 hours. Cool and empty.

Gardner Hoult Viscosity Solid weight Weight average molecular weight V 90% 1550

D) silanized star polyester (i)

Step I: The following components are added to the reactor and heated to 120-125 ° C. Heat the batch to 145 ° C. If no heat is generated, heat to 145 ° C. It is processed after holding at 145 ° C. for 1 hour.

ingredient weight Pentaerythritol 280.2 4-methyl hexahydrophthalic anhydride 1037.8 Butyl acetate 161.1

Step II: The ingredients are fed at 145 ° C. over 30 minutes. Maintain a temperature of 145 ° C.

ingredient weight Cardura E (monoepoxy purchased from Shell Chemical) 1561.9 Butyl acetate 182.3

Step III: Add to the reactor as a batch. Heat to 175 ° C. The acid value versus time profile is recorded every 30 minutes after reaching 175 ° C until it is stable.

ingredient weight Dibutyltin dilaurate 2.9 Butyl acetate 71.7

Step IV: Once the acid value is stable, cool down to 100 ° C or below. Dilute with butyl acetate.

ingredient weight Butyl acetate 302

Total batch 3600 Weight of solid = 80% Acid value <2

3720 g of star polyester, 1524 g of isocyanate propyl trimethoxysilane and 0.1 g of Fascat 420 catalyst prepared immediately above were placed in the reaction flask. Stir for 90 minutes. Cover with N ₂ throughout time.

Weight of solid = 86.3% Weight average molecular weight = 2200

E) transparent coat composition

Transparent coat composition g Resimine O 6550 (Melamine from Monsanto) Non-aqueous dispersion (A) Acrylosilane resin (B) Cyclosilane oligomer (C) Silaneated star polyester (D) Catalyst solution ^* Dibutyltin dilaurate Resiflow SO (acrylic flow agent from Estron Chemical) TINUVIN 384 (UV screener from CIBA Geigy) TINUVIN 123 (sterically hindered amine light stabilizer from CIBA Geigy) ^* Catalyst solution CycatO 600 ( Sulfonic acid purchased from American Cyanamid) AMP-95O (amine obtained from Angus Chemical) methanol 14.4326.7711.622.2223.173.550.20.42.322.248.010.841.2

The coating was sprayed onto a black water soluble basecoat that had already been warmed flash at 82 ° C. for 5 minutes. The coating was cured at 141 ° C. for 30 minutes. The coating showed good appearance, hardness, corrosiveness and wear resistance.

Claims (13)

i) a binder selected from linear or branched alicyclic moieties containing oligomers or blends of these oligomers, having a weight average molecular weight of no greater than about 3,000, polydispersity no greater than about 1.5, and having functional groups A or A + B; And ii) a weight average molecular weight does not exceed about 3,000, and comprises any oligomeric crosslinker having functional group C or C + D or a blend of such crosslinkers, The components i) and ii) react on curing to form a three-dimensional network having chains of substantially uniform and adjustable molecular weight between the crosslinks, Wherein A is selected from the group consisting of hydroxyl, acid, epoxy, aldimine, ketimine and silane; B is selected from the group consisting of hydroxyl and epoxy; C is selected from the group consisting of isocyanate, melamine, epoxy, silane and acid; D is selected from the group consisting of hydroxyl and melamine, A curable coating composition of a binder in an organic solvent, wherein the volatile organic content does not exceed 0.4 kg / l. The composition of claim 1 wherein components i) and ii) are present. The composition of claim 1 wherein component i) contains functional groups capable of crosslinking between components i) and component ii) is absent. The composition of claim 1 wherein the oligomer of component i) is an oligomeric ester. The composition of claim 1, wherein the polydispersity of component ii) does not exceed about 1.5. The compound of claim 1, wherein A is hydroxyl and C is isocyanate; A is an acid and C is an epoxy; A is epoxy and C is isocyanate; A is hydroxyl and C is melamine; A is aldimine or ketamine, B is any hydroxyl and C is isocyanate; A is epoxy, B is hydroxyl and C is isocyanate; A is silane, B is hydroxyl and C is melamine; A is acid, B is hydroxyl, C is epoxy and D is melamine; And A is silane, B is epoxy, C is acid and D is melamine. The method of claim 1, (i) 30% by weight or less of the total binder of an acrylic polymer or polyester having a weight average molecular weight greater than 3,000; (ii) up to 30% by weight of the total binder of the acyclic oligomer, having a weight average molecular weight of not more than about 3,000, a polydispersity of not more than about 1.5, and having a functional group A or A + B; or (iii) an acrylic component comprising a core of an acrylic polymer and a plurality of substantially linear stabilizer components grafted thereto, wherein the acrylic component reacts with the acrylic polymer or polyester, the acyclic oligomer, or both At least about 2% ethylenically unsaturated monomer having functional groups, the core being substantially insoluble in the solvent medium, and the stabilizer component being soluble in the solvent medium) up to 30% by weight of the total binder The composition further contains. The composition of claim 1, further comprising up to 200 parts by weight of pigment, based on 100 parts of components i) and ii). A method of coating a substrate comprising applying the composition of claim 1 to the substrate and curing the composition. A substrate coated with the composition of claim 1. The weight average molecular weight does not exceed about 3,000, the polydispersity does not exceed about 1.5, and functional group A or A + B, wherein A is a group consisting of hydroxyl, acid, epoxy, aldimine, ketimine and silane And B is selected from the group consisting of hydroxyl and epoxy), and when cured form a linear or branched alicyclic moiety having a chain of substantially uniform and adjustable molecular weight between the crosslinks. A low volatility organic content (VOC) curable coating composition comprising a binder selected from a containing oligomer or a blend of said oligomers. The compound of claim 11, wherein the weight average molecular weight does not exceed about 3,000, and functional group C or C + D, wherein C is selected from the group consisting of isocyanate, melamine, epoxy, silane and acid, and D is hydroxyl and A low volatility organic content curable coating composition further comprising an oligomeric crosslinker or blend of said crosslinkers). The method according to claim 11 or 12, wherein i) up to 30% by weight of the total binder of an acrylic polymer or polyester having a weight average molecular weight greater than 3,000; ii) a weight average molecular weight of no greater than about 3,000, a polydispersity of no greater than about 1.5 and no more than 30% by weight of the total conjugate of the acyclic oligomer having functional group A or A + B; or (iii) an acrylic component comprising a core of an acrylic polymer and a plurality of substantially linear stabilizer components grafted thereto, wherein the acrylic component reacts with the acrylic polymer or polyester, the acyclic oligomer, or both At least about 2% ethylenically unsaturated monomer having functional groups, the core being substantially insoluble in the solvent medium, and the stabilizer component being soluble in the solvent medium) up to 30% by weight of the total binder A low volatility organic content curable coating composition further containing.