OA18528A - Acetoacetyl thermosetting resin for zero voc gel coat. - Google Patents

Abstract

Zero VOC thermosetting gel coat and laminating resin compositions, and composites and articles, are produced using a multifunctional Michael acceptor, a multifunctional Michael donor and a base catalyst. The obtained low viscosity resin is useful for producing zero VOC gel coats and laminates having excellent curability at ambient temperatures.

Description

The application of gel coats are widely used in mimerons applications as the external surface layer of composite molded articles. Gel coats are typically found on composite articles that are exposed to the environment requiring moisture résistance, résistance to cracking and similar propertîes, or articles that require a strong, flexible, abrasion and impact résistant surface and/or a smooth glossy finish. Examples of such articles include boat liulls, bath tub enclosures, pools, spas, and body panels on cars and trucks, among others.

Such gel coated articles are typically formed by spraying a gel coat composition from a high pressure spray gun onto the inside surface of an opcn mold, applying the materials and a laminating resin for the composite article onto the gel coat, curing the gel coat and then removing the cured gel coated article from the mold. Gel coated articles can also be fabricated by applying the composite materials into a multi-parl mold. injecting or applying the gel coat composition, closing the mold, curing the gel coat and then removing the cured gel coated article from the mold.

Gel coats for composite articles arc typically formulated from a thermosetting base resin system such as unsaturated polyester, acrylate and urethane type resins with incorporated fillers, pigments and other additives. The gel coat should exhibit low viscosity at high shear to allow for ease of application to the mold, but also resist saggîng or running after it is applied. Another important properly of gel coats is surface tackiness and cure time. A gel coat desirably produces a gel time of 10 to 20 minutes. Many low or zéro VOC gel coats remain tacky after several hours of curing.

Typically, the gel coat resin is mixed with réactivé, polymerizable monomers such as styrene or methyl méthacrylate (MMA), which are also used to reduce resin system viscosity in order to apply the gel coat by spraying. Convcntional gel coat compositions contain 35 to 45 wt% of reactive monomers and other volatile organic compounds (VOCs). The presence of high amounts of styrene and other VOCs results the émission of styrene vapors and other hazardous air

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Hul >;NG pollutants (HAP), which are closely regulated by government régulations. Consequenlly, the composites industry is very interested in providing gel coats that émit lowto zéro VOCs. However, there are difficultîes in attaining gel coats having low to zéro VOCs and acceptable application and performance properties. Several approaches hâve been described for addressing these requirements. One way to reduce VOCs is to reduce the molecular weight of the resin, which leads to a lower viscosity and lower styrene need. However, in application, a gel coat made with a lower molecular weight resin tends to remain tacky for long periods of time. The use of higher molecular weight resins results in higher viscosities that hamper spray applications ofthe gel coat composition, which generally require a viscosity in the range of 50 to 1200 eps under high shear. In order to achieve target viscosity, monomers with high boiling point are used to replace monomers which contribute to VOC. These high boiling point monomers typically hâve higher viscosity and lower reactivity with a resin solid. As a resuit, a higher amount of high’boiling point monomers is required to replace the standard monomers in gel coat formulations and the resulting product is very slow to cure.

There romains a significant need for a resin material that provides good rheology properties for in-mold coating applications, fast curing and a better cured gel coat product having low to zéro VOCs and a high degrcc of crosslinking.

SUMMARY OF TIIE INVENTION

The invention provides methods and gel coat and laminating resin compositions that overcome the above-described deficiencies and provide styrene free and zéro VOC gel coats having a désirable viscosity for application, a fast gel time and set-up, and produce cured gel coats and laminating resins having a high degree of crosslinking with excellent performance properties. In embodiments, the invention provides methods for making styrene free and zéro VOC gel coats. In one embodiment, the method comprises:

reacting a polyhydroxy polyol having at least two, preferably three, hydroxyl groups per molécule with a C1-C5 alkyl acetoacetate in a transestérification process to form a crosslinkable, muItifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups peroligomer; and combining the acetoacetylated polyhydroxy polyol with one or more miiltifunctional acrylate monomers or oligomers, at least one additive component, and a base catalyst, to form a crosslinkable, thermosetling gel coat composition having a viscosity of about 50 to 1200 eps under high shear.

In use, the gel coat composition can be used in making a gel coated article. In embodiments, lhe gel coated article is fabricated by:

applying the thermosctting gel coat composition as an in-mold coating to a surface of a mold;

allowing the gel coat composition to cure at ambient température to form a partially crosslinked, tacky to tacky-frce gel coat;

applying a material to be molded onto the partially crosslinked gel coat;

applying a crosslinkable laminating resin onto said material, the laminating resin comprising an acetoacetylated polyhydroxy polyol having at least two, preferably three, acetoacetyl functional groups per oligomer, one or more multifunctional acrylate monomers or olïgomers and a base catalyst; and allowing the laminating resin and the gel coat to cure at ambient température to a solid, crosslinked, thermoset resin being styrene free with zéro VOCs.

The resulting gel coated article comprises lhe cured thermoset gel coat bonded onto the surface of the article. In embodiments, the cured thermosel gel coat and laminating resin comprise crosslinked acetoacctate functionalized acrylate oligomers, and are preferably at least 50%, preferably 70 to 100%, crosslinked.

The invention also provides methods for making a laminating resin composition. In embodiments, the method comprises:

reacting a polyhydroxy polyol having at least two, preferably three, hydroxyl groups per molécule with a C1-C5 alkyl acetoacetate in a transestérification process to form a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two, preferably three, acetoacetyl functional groups per oligomer; and combining the acetoacetylated polyhydroxy polyol with one or more multifunctional acrylate monomers or oligomers and a base catalyst to form a crosslinkable, thermosetting laminating resin composition having a Brookfield viscosity of about 50 to 1200 cps.

The laminating resin composition can be cured at ambient température to form a solid, crosslinked, thermoset resin comprising crosslinked acetoacetate-functionalizcd acrylate oligomers, with the laminating resin being styrene Iree with zéro VOCs and preferably at least 50%, preferably 70 to 100%, crosslinked.

The invention further provides a crossiinkable, styrene free and zéro VOC gel coat composition, ln an embodiment, the crossiinkable gel coat composition comprises an acetoacetylated polyhydroxy polyol, one or more multifunctional acrylate monomers or oligomers, a base catalyst, and at least one additive component selected from the group consisting of fillers, pigments and thixotropic agents, and has a viscosity of about 50 to 1200 cps under high shear, and is curable under ambient conditions to form a solid lhermoset gel coat comprising crosslinked acetoacetate-functionalized acrylate oligomers, the gel coat being styrene free with zéro VOCs and preferably at least 50%, preferably 70 to 100%, crosslinked.

The invention also provides a crossiinkable, styrene free and zéro VOC laminating resin composition. In an embodiment, the crossiinkable laminating resin composition comprises an acetoacetylated polyhydroxy polyol, one or more multifunctional acrylate monomers or oligomers, and a base catalyst, and has a Brookfield viscosity of about 50 to 1200 cps, and is curable under ambient conditions to form a laminating resin comprising crosslinked acetoacetate-functionalized acrylate oligomers, the laminating resin being styrene free with zéro VOCs and preferably at least 50%, preferably 70 to 100%, crosslinked.

Also provided is a system for forming a gel coal composition. In an embodiment, the system is composed of separate containers packaged together, including:

a container of a curable, thermosetting gel coat composition comprising a crossiinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two, preferably three, acetoacetyl functional groups per oligomer, one or more multifunctional acrylate monomers or oligomers and at least one additive component selected from the group consisting of fillers, pigments and thixotiopic agents for a gel coat;

a container of a base catalyst selected from the group consisting of l,8-diazabicyclo-[5.4.0]undec-7-ene (DBU), l,5-diazabicyclo[4,3,0]non-5-ene (DBN), l,5,7-triazabicyclo[4,4,0|dcc-5-ene (TBD), 7-methyl-l,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethylguanidine (TMG) and l,4-diazabicyclo[2.2.2]octane (DABCO), and N'-butyl-N,N-dicyclohexylguanidine, and mixtures thereof; and directions for combining the contents ofthe containers to form a thermosetting gel coat composition, which. in embodiments, has a viscosity of about 50 to 1200 cps under high shear, is curable at ambient température to form a crosslinked, styrene free and zéro VOC thermosel gel coat comprising crosslinked acetoacetate-functionalized acrylate oligomers, which is preferably at least 50%, preferably 70 to 100%, crosslinked.

A system is also provided for forming a laminating resin composition. In an embodiment, the system is composed of separate containers packaged together, including:

a container of a curable, thermoselting laminating resin composition comprising a crosslinkable, multifunctional acetoacelylated polyhydroxy polyol having at least two, preferably three, acetoacetyl functional groups per oligomer and one or more multifunctional acrylate monomers or oligomers;

a container of a base catalyst selected from the group consisting of l,8-diazabicyclo-[5.4.0]undec-7-ene (DBU), l,5-diazabicyclo[4,3,0]non-5-ene (DBN), l,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD), 7-mclhyl-l,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethylguanidine (TMG) and l,4-diazabicyclo[2.2.2]octane (DABCO), and N’-butyl-N,N-dicyclohexylguanidine, and mixtures thereof; and directions for combining the contents ofthe containers to form a thermoselting laminating resin composition, which, in embodiments, has a Brookfield viscosity of about 50 to 1200 cps, is curable at ambient température to form a crosslinked, styrene free and zéro VOC thermoset laminating resin comprising crosslinked acetoacetate-functionalized acrylate oligomers, which is preferably at least 50%, preferably 70 to 100%, crosslinked.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments ofthe invention relate to methods of making zéro VOC, crosslinkable, thermosetting resins from acetoacetate-functionalized polyhydroxy polyolsand multifunctional acrylate monomers or oligomers for producing laminating resins and gel coat compositions, which are crosslinked using a Michael-type addition reaction with a base catalyst to obtain laminates and gel coated articles. The thermosetting resins hâve excellent curabilïty at ambient or room températures, ln embodiments, the process results in an at least 50%, preferably 70 to 100%, crosslinked thermoset polymer network that is VOC and styrene free with excellent mechanical properties.

The thermosetting resins are crosslinked without styrene or free-radîcals, using a Michael-type addition reaction with a base catalyst at ambient températures to incorporate acrylate lunctionality into a multifunctional acetoacetylated polyhydroxy polyol to produce a lhermoset, crosslinked polymer network in which the acetoacetate-functionalized acrylate oligomers are up to 100% crosslinked.

Unless otherwîse specified herein, the term viscosity refers to the viscosity of a polymer in monomer at 25°C (77°C) measured in centipoise (cps) using a Brookfield R.V model viscometer.

C

D

The viscosity under high shear is measured by a cône and plate (CAP) viscometer at a shear rate of 10,000 1/s. The term NVM refers to non-volatile material dispersed in a volatile substance (e.g., monomer) as measured according to ASTM DI259.

Unless stated otherwise, ail percent and ratios of amounts are by weight.

Acetoacetatc-fiinctioniilixcd polyhydroxy polyol

The acetoacetate-functionalized polyhydroxy polyol has at least two, and in some embodiments preferably at least three acctoacetyl functional groups per oligomer. The functionalized polyol is then blended with a muItifunctional acrylate to form a lherinosetting, crosslinkable resin.

Ir» embodiments ofthe invention, multifunctional acctoacetylated polyols can be prepared by reaction of a polyhydroxy polyol (also termed polyhydric alcohol or polymeric polyol), in a transestérification réaction with an alkyl acetoacetate compound, preferably a C|-C$ alkyl acetoacetate.

Suitable polyhydroxy polyol compounds hâve an average of at least two, preferably at least three (i.e., tripolyol), hydroxyl groups per molécule. Non-limiting examples of polyhydroxy polyols include methyl propanediol (MPD), trimethylolpropanc (TMP), trimethylpentanediol, ditrimethylolpropane (di-TMP), butyl ethyl propanediol (BEPD), neopentyl glycol (NEO), pentaerythritol (Penta), di-pentaerythritol (di-Penta), tris-2-hydroxyethyl isocyanurate (THEIC), 4,4'-isopropylidenedicyclohexanol (hydrogenated bisphenol-A (HBPA), hydroxyl-functionalized acrylic polymers, among others, and mixtures of two or more of such compounds. In embodiments, the polyhydroxy polyol has a hydroxyl number of from 30 up to 1850 mg/KOH/g, and a number average molecular weight of 90 up to 5000 g/mol.

Non-limiting examples of suitable C1-C5 alkyl acetoacelates (esters of acetoacetic acid) include methyl acetoacetate (MAA), ethyl acetoacetate (EAA), n-propyl acetoacetate, isopropyl acetoacetate, 11-butyl acetoacetate, tert-butyl acetoacetate (TBAA), pentyl (amyl) acetoacetate, n-pentyl acetoacetate, isopentyl acetoacetate, tert-pentyl acetoacetate, acetoacetatefunctionalized acrylic polymer based on aceloacetoxyctheyl méthacrylate, including copolymers with different acrylic monomers, among others, and mixtures of two or more of such compounds.

Procedures for preparing crosslinkable, functionalized acctoacetylated polyols by reaction ofa polyol with an alkyl acetoacetate compound in a transestérification reaction are generally known in the art. In embodiments, the polyol and alkyl acetoacetate compounds are reacted in a transestérification reaction at a température of 90 to 200°C for 3 to 15 hours to form the c- O functionalized polyol. In some embodiments, 10 to 90 wt% polyol is combined with 90 to I0 wt% alkyl acetoacetate, based on the total weight ofthe mixture.

In embodiments, at least 70% of the hydroxyI groups ofthe polyhydroxy polyol are converted to acetoacetyl groups, and more preferably 80 to 100% ofthe hydroxyl groups are converted. ln embodiments, the acetoacetylated polyols bave an acetoacetyl content within a range of from 5 to 80 weight %, a hydroxyl number within a range of 0 to 60 mg KOH/g, and acid value of 0 to 5 mg KOH/g, and a number average molecular weight (Mn) within a range of 250 to 6000 g mole' ', preferably 300 to 5000 g mole’¹.

In embodiments, the acetoacetate-functionalized polyol can be prepared in a multi-stage reaction in which the polyhydroxy polyol is initially reacted by the condensation reaction with a dicarboxylic acid/anhydride or polyacîd with a glycol or polyol. Non-limiting examples of suitable carboxylic acids include isophthalic acid, orthophthalic acid, terephtalic acid, succinic acid, adipic acid, maleic acid, fumaric acid, azelaic acid, 1,4-cyclohexane dicarboxylic acid, itaconic acid, sebacic acid, telrahydrophthalic anhydride, trimelitîc anhydride, among others, and mixtures of two or more of such compounds. In embodiments, the dicarboxylic acid and polyhydroxy polyol are reacted in a First stage reaction at 150 to 225°C for about 5 to 20 hours, until an acid value of less than 20 mg KOH/g, preferably less than 10 mg KOH/g, is reached. ln embodiments, the molar ratio of acid functional groups to hydroxyl functional groups is 0.2 to 0.8. ln a second stage reaction, an alkyl acetoacetate compound is mixed with the resulting polyester polyol and the réaction procecds for about 3 to 15 hours to form the acetoacetatefunctionalized polyol. In embodiments, 25 to 90 wt% ofthe polyester polyol is combined with 75 to 10 wt% alkyl acetoacetate, based on the total weight ofthe mixture.

In another embodiment, the acetoacetate-functionalized polyhydroxy polyol can be prepared in a multi-step reaction, in which a C2 to C|₃ alkanolamine is reacted with a cyclic, 5-ring hydroxy-functional carbonate in a first step to form a polyuréthane polyol intermediate. In embodiments, the molar ratio of alkanolamine to the 5-ring carbonate is at or about close to 1 with slightly excess of carbonate. Non-limiting examples of suitable alkanoiamines (also referred to as amino alcohols) include monoethanolamine (MEA), propanolamine, isopropanol amine, and 2-aminobutanol, among others, and mixtures of two or more of such compounds. Non-limiting examples of suitable 5-ring carbonates include glycérine carbonate (GC), ethylene carbonate, propylene carbonate and butylène carbonate, among others, and mixtures of two or more of such compounds.

CD.

In embodiments, lhe alkanolamine and 5-ring hydroxy-functional carbonate are reacted at 20 to 75°C for about 5 lo 8 hours. ln a second stage reaction, lhe resulting polyuréthane polyol is mixed with an alkyl acetoacetate compound and reacted for about 3 to 15 hours to form the functionalized acetoacetylated polyol.

In another embodiment, the acetoacetate-functionalized polyhydroxy polyol can be prepared in a multi-step reaction, în which lhe polyol is formed through free radical copolymerization of vinyl monomers and at least one vinyl monomer containing hydroxyl groups. The resulting polyol contains at least two, preferably three. hydroxyl functional groups in each polymer. Non-limiting examples of suitable vinyl monomers containing hydroxyl groups include hydroxyethyl acrylate, hydroxyethyl méthacrylate, hydroxypropyl acrylate, and hydroxylpropyl méthacrylate, among others, and mixtures of two or more of such compounds. Non-limiting examples of suitable vinyl monomers include aromatic compounds such as styrene, alpha-methyl styrene, vinyl toluene, vinyl phénol and the like, and unsaturated esters such as acrylic and methacrylic ester, vinyl laurate and the like, among others, and mixtures thereof. In a second stage reaction, the resulting polyol is mixed with an alkyl acetoacetate compound and reacted for about 3 to 15 hours to form the functionalized acetoacetylated polyol.

ln another embodiment, the acetoacetate functionalized polyhydroxy polyol is made directly by free radical copolymerization of vinyl monomers and al least one vinyl monomer contains acetoacetate functional group. The resulting copolymer contains at least two, preferably three, acetoacetate functional groups in each polymer. Non-limiting examples of suitable vinyl monomers containing acetoacetate functional group include acetoacetoxyethyl méthacrylate (AAEM), acetoacetoxyethyl acrylate (AAEA), acetoacetoxypropyl méthacrylate, acetoacetoxypropyl acrylate, acetoacetoxybutyl méthacrylate, and acetoacetoxybutyl acrylate, among others, and mixtures thereof.

The resulting acetoacetylate-functionalized polymer is a thermosetting, crosslinkable resin, having at least two, and in some embodiments at least three, acetoacetyl functional groups per polymer, which can be used, for example, in the formulation of laminating resins and gel coat compositions.

Gel Coals

Gel coats (also termed gel coat compositions) arc compositions in a curable (e.g., pre-cured) state, composed ofa blend ofone or more ofthe acetoacetate-functionalized polyhydroxy polyol resin material with one or more multifunctional acrylate monomers and/or oligomers and one or more additives. Gel coats are typically free of fibers. ln embodiments, the acetoacetatefunctionalized polyol is combined with the one or more mullifunctional acrylate monomers or oligomers. Preferably, the molar ratio of the acetoacetate functional group to acrylate functional group is 0.2 to 5.0, and preferably, a molar ratio of 0.3 to 3.0. In embodiments, 15 to 70 wt% of the acetoacetate-functionalized polyol is combined with I5 to 70 wt% ofone or more mtiltifunctional acrylate monomers or oligomers and 2 to 40 wt-% additives, based on the total weight of the mixture.

The gel coat composition can be prepared by high speed dispersion of the filler, pigment and other additives into lhe resin mixture. The viscosity ofthe gel coat composition (without catalyst) can range from 8,000 to 25,000 cps, and preferably 10,000 to 20,000 cps when measured by Brookfield viscometer at 4 rpm.

Multifunctional acrylate monomers. Non-limiting exemples of suitable niultifunctional acrylate monomers include trimethylolpropane triacrylate (TMPTA), di-trimethylolpropane tetraacrylate, tris (2-hydroxy ethyl) isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, polyethylene glycol dîacrylate, ncopentyl glycol diacrylate, pentaerythritol tetraacrylate, 1,2ethylene glycol diacrylate, 1,6-hexanediol diacrylate, 1,12-dodecanol diacrylate, hexanediol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, amine modified polyether acrylates, glycerol propoxylale triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, and the like, as well as mixtures and combinations thereof.

Additives. The gel coat composition includes one or more additive components, for examplc, one or more fillers, pigments, and/or other additives such thixotropic agents, promoters, stabilizers, extenders, wetting agent, leveling agents, air release agents, as practiced in the art to adjnst and enhance the molding properties (e.g., color effect, sprayability, sag résistance, mechanical property consistency, etc.). Gel coats are typically free of fibers.

Examples of fillers for gel coats include inorganic (minerai) fillers, such as clay, magnésium oxide, magnésium hydroxide, aluminum trihydrate (ΑΊΊ I), calcium carbonate, calcium silicate, mica, aluminum hydroxide, barium sulfate, talc, etc., and organic fillers. The amount of filler in the gel coat composition can generally range from 5 up to 30 wt %, based on the total weight of the gel coat composition. Suitable pigments include inorganic pigments, such as titanium dioxide. Thixotropic agents include silica compounds such as fumed silica and precipitated silica, and inorganic clays such as bentonitc clay, vvhicli, if included, can be présent in an amount ranging from 03 up to 6 wt %, based on the total weight of the gel coat composition.

Laminatintî Resin

In embodiments, the acetoacetate-functionalized polyhydroxy polyol resin material can be combined with one or more multifunctional acrylate monomers/olîgomers (as described above) to form a curable laminating resin composition. In embodiments, the laminating resin composition is composed of 10 to 90 wt% of the acetoacetate-functionalized polyol combined with 90 to 10 wt% of multifunctional acrylate monomers/olîgomers, based on the total weight of the mixture. Preferably, the ratio ofthe functionalized polyol to multifunctional acrylate monomer/oligomer is 0.2 to 8.5, and more preferably a ratio of 0.25 to 8.0 (w/w). The viscosity of the laminating resin composition is preferably about 50 to 1200 cps.

In use, the laminating resin composition is combined with a base catalyst, and can be utilized in many applications such as for coatings and in reinforccd composite products by various open and closed molding processes such as spray-up, hand lay-up, resin transfer molding and wet molding.

Applications ln use, the gel coat composition is combined with a base catalyst and applied as an in-mold coating, typically by manual application or using a gel coat spray technique, onto the surface of a mold that is in the shape and form of the desired article (e.g., bathtub, car or aircraft part, bout hull, swimming pool, etc.). The gel coat is allowed to partially cure such that it is tacky to tacky-free.

The amount of base catalyst included in the gel coat composition is typically 0.2 to 2.5 % by weight, based on the total weight of the composition, for optimal processibility, gel time and cure time, the viscosity of the gel coat (with catalyst) can range from 8,000 to 25,000 cps, and preferably 10,000 to 20,000 cps measured by Brooktleld viscometer at 4 rpm. Preferably, the gel time of the gel coat is 5 to 30 minutes at ambient température. The term gel time refers to the time from catalyzation of the gel coat (or laminating resin) to cessation of flow.

Crosslinking of the laminating resin and gel coat occurs by a base-catalyzed Michael-type addition reaction of the acetoacetate-functionalized polyhydroxy polyol and multifunctional acrylate monomers or oligomers al ambient températures (about 20 to 25°C), without heat or U V radiation. The base catalysts are nitrogen containing compounds, which can be represented by the general formula R*R^yR^zN, where R*, R^y, and R^z each individually may represent hydrogen, or a C1-C20 alkyl, aryl, alkylaryl or arylalkyl group, that each optionally may contain one or more

CD hetero-atoms (e.g. oxygen, phosphor, nitrogen or sulfur atoms) and/or substituents, The group may be linear or branched; they also may contain one or more unsaturations or substituents. This general formula R’WlCN also represents nitrogen compounds, wherein the nitrogen atom shown in the formula is part of a cyclic system formed by two of the groups R*, R^y, and R^z, or is présent in the form of an imine group or as a phosphazenc. Non-limiting examples of suitable base catalysts include l,8-diazabicyclo-[5.4.0]undec-7-cne (DBU), l,5-diazabicyclo[4,3,0]non-5-ene (DBN), l,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD), 7-melhyl-l,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethylguanidine (TMG) and l,4-diazabicyclo[2.2.2]octane (DABCO), and N'butyl-N,N-dicyclohexylguanidine, and the like, lu embodiments, the base catalyst can be combined with an organic solvent such as methanol, éthanol, propanol, n-butyl alcohol, acetone. methyl ethyl ketone, among others, and mixtures thereof. In preferred embodiments, the base catalyst is used neat (absence of a solvent).

The article can be a fully or partially cured polymer resin or composite of reinforcing material in a polymer resin matrix, ln embodiments, a rcinforcing material for forming the article is laid into the open mold onto the partially cured gel coat material. Non-limiting examples of reinforcing materials include glass fiber, polyethylene liber, carbon fiber, métal fiber, ceramic fiber, or other material used in the composite plastics industry. In embodiments, dry fibers (e.g., glass fibers, glass fiber malt, etc.) are laid onto the partially cured gel coat within the open mold. The reinforcing material is then wet out by applyîng a laminating resin in a curable (i.e., pre-cured) state that has been combined with a base catalyst. ln embodiments, the laminating resin is composed of 10 to 90 wt% of the acctoacetate-functionalized polyol, 90 lo 10 wt% of multifunctional acrylate monomers or oligoincrs. and 0.2 to 2.5 wt% base catalyst, based on the total weight ofthe mixture.

The laminating resin is allowed to cure to form a hardened fiber-reinforced resin composite in the desired shape within lhe mold. The gel coat becomes an integra! part ofthe finished laminate article by forming a covalent interfacial bond with the laminating resin that is used. The gel coat provides a primary bond at the interface with the composite article, unlike the application ofa resin coating onto the formed article.

Curing of the laminating resin can be conducted at ambient température for about 4 to 40 hours.

The gel coated, composite article can then bc removed from the mold for use. lu some embodiments, the laminate can undergo a post-cure, for example, by heating the mold to an elevated température (i.e., to 65°C) to further increase the degree of cure.

The gel coats of the invention provide a durable and high weather- and wear-resistant coating with good hydrolytîc stability, and/or an aesthetic finished surface to the article being produced to improve surface appearance. The gel coats also provide a résilient, light-stable surface covering and, in embodiments, are sufficiently pigmented to yield a desired color. The base catalyzed Michael addition of acetoacetylated resins to acrylate acceptors produces crosslinked networks with low to no volatile organic compounds (VOCs). ln embodiments, the cured gel coat and/or laminating resin is at least 50% crosslinked, and preferably 70 to 100% crosslinked. Such crosslinking can be assessed, for example, by measuring the residual reaction exotherm by differential scanning calorimetry (DSC).

The invention will be further described by reference to the following detailed example. This example is not meant lo limit the scope of the invention that has been set forth in the foregoing description. Variation within the concepts ofthe invention is apparent to those skilled in the art. The disclosures of the cited references throughout the application are incorporated by reference herein.

EXAMPLES

The following examples are illustrations ofthe présent invention. They are not to be taken as Iimiting the scope ofthe claimed invention. Unless stated otherwise, ail percent and ratios of amounts are by weight.

Materials and Abbreviations.

The following materials were used in the Examples below.

Ingrédient
SR355	Di-trimethylolpropane tetraacrylate (Sartomer Co.)
SR368	Tris (2-hydroxy ethyl) isocyanurate triacrylate (Sartomer Co.)
SR454	Ethoxylated trimethylofpropane triacrylate (Sartomer Co.)
TMPTA	Trimethylolpropane triacrylate
DBU	1,8-Diazabicyclo-[5.4.0]undec-7-ene
DABCO	1,4-Diazabicyclo[2.2.2]octane
TMG	Tetramethylguanidine

Example 1: Préparation of TMP Tris-acetoacctatc

A 3 lîter, 4-neck round-bottom flask fitted with mechanical stirrer, pressure equalizing addition funnel (nitrogen inlet), thcrmocouple connected to a controller and heating mantle, was charged with 604 g (4.50 mol) trimethylolpropane (TMP), 850 g toluene and 303 g ( 1.92 mol) tert-butyI acetoacetate. The mixture was heated to about 1 IO°C. Additional tert-butyI acetoacetate, 1881 g (11.89 mol), was gradually added into flask through additional funnel over about 5 hours. After ail tert.-butyl acetoacetate was added, the mixture température was increased gradually to 135° C and keep at this température for 2 hours. A vacuum (26 Hg) was applied to remove imreacted liquid and a slighl yellow liquid product of 1713 g was obtained.

The reaction is illustrated in Scheme 1 below.

inmrïhylolpropane

terl-Butyl aceioaœiate

Example 2: Préparation of TIIEIC Tris-Acetoacetate

A 2 liter, 4-neck round-bottom flask fitted with mechanical stirrer, pressure equalizing addition Tunnel (nitrogen inlet), thermocouple connected to a controller and heating mantle, was charged with 628 g (2.40 mol) tris (hydroxyl ethyl) isocyanurate (TI IEIC) and 1140 g (7.20 mol) tert-butyl acetoacetate. The mixture was heated gradually to about 150° C in 5 hours and keep at this température for another 2 hours. A vacuum (26 I Ig) was applied to remove unreacted liquid and a yellow liquid product of 1214 g was obtained.

C P

The reaction is illustrated in Scheme 2 below.

lat-Bulyl ncdoacdatc

Examnle 3: Préparation of ÎIBPA Di-Acetoacetate

A I liter, 4-neck round-bottom flask fitted with mechanical stirrer, pressure equalizing addition funnel (nitrogen inlet), lliermocouple connected to a controller and heating mantle, was charged with 4SI g (2.00 mol) 4,4’- isopropyl idencdicyclohexanol (hydrogenated bisphenol-A (IIBPA)) and 163 g (I.03 moi) tert-butyl acetoacetate. Phe mixture was heated to about 110° C.

Additional tert-butyl acetoacetate, 502 g (3.17 mol), was gradually added into flask through additional tunnel over about 3 hours. After all tert-butyl acetoacetate was added, the température was increased gradually to 150° C and keep at this température for 2 hours. A vacuum (26 Hg) was applied to remove unrcactcd liquid and a yellow liquid product of 865 g was obtained.

C-0

The réaction is illustrated in Scheme 3.

4,4'-Isopropylidcnc<licyclohexnnol

Scheme 3

Example 4: Préparation of IPA-TMP Tetra-Acetoacctate

To a three-neck, round-bottom flask equipped with a mechanical stirrer, thermocouple connected to a controller and heating mantle, a Dean-Stark trap, a nitrogen inlet, and a water condenser, was charged 831 g (5.00 mol) isophthalic acid (IPA) and 1342 g (10.00 mol) trimethylolpropane (TMP). The mixture was allowed to react at 215 °C for 8 hours until the acid 10 number was determined to be less than 3.0 mg KOH/g équivalent.

Το 1038 g of the above resulting polyester polyol, 1684 g tert-butyI acetoacetate was gradually added over about 3 hours at 160-170° C. After ail terl-butyI acetoacetate was added, the température was increased gradually to 180 °C and kept at thîs température for another 2 hours. A vacuum (26 I Ig) was applied to remove unreacted liquid and a yellow liquid product 15 of 1846 g was obtained.

The reaction is illustrated in scheme 4.

Examplc 5: Préparation of EA-GC Tris-Acetoacctate

To a three-neck, round-bottom flask equipped with a mechanical stirrer, thermocoupie connected to a controller and heating mantle, a Dean-Stark trap, a nitrogen inlet, and a water condenser, was charged 184 g (3.00 mol) ethanolamine (EA). 358 g (3.00 mol) 4hydroxymethyl-l,3-dioxolan-2-one (glycérine carbonate (GC)) was added into the flask over

0.5 hr at 20-40°C. The mixture was allowed to react at 40-75 °C for 6 hours,

To the resulting urethane tripolyol, 1424 g lert-butyl acetoacetate was added and the température was increased gradua]ly to !40°C and kept at this température for another 3 hours.

A vacuum (26 Hg) was applied to remove unreactcd liquid and a dark yellow liquid product of

1239 g was obtained.

c P

The reaction is illustrated in Scheme 5.

éthanol ami ne

4-liydroxy methyl- l,3-dioxolan-2-one

Urethane tri polyol

Scheme 5

Examplc 6: Préparation of Acetoacetate-functionalized Méthacrylate Copolymer Resin

To a three-neck, round-bottoni flask equipped with a mechanical stirrer, thermocouple connected to a controller and heating mantle, a Dean-Stark trap, a nitrogen inlet, and a water condenser, was charged 500 g of xylene. A monomer solution of 638 g (2.87 mol) isobornyl méthacrylate, 1052 g (4.91 mol) acetoacetoxyethyl méthacrylate, 66 g dicumyl peroxide and 3 g

C Ό

2-mercaptoethanol was added over 4 lir at 140° C. The mixture was allowed to react at !40° C. for another 2 br. A vacuum (26 Hg) was applied to remove xylene and unreacted liquid. The obtained méthacrylate copolymer is solid at room température.

The reaction is illustrated in Scheme 6 below.

Pcroxidv

Scheme 6

Examnle 7: Préparation of Gel Coat Composition

A gel coat composition was prepared by mixing, respectively, 252 g ofthe IPA-TMP Tetra-Acetoacetate from Exainple4, l84gofTMPTA, 120 g of titanium dioxide, 30 g of talc and 4 g of fumed silica under high shear. The gel coat composition had a Brookfield viscosity of 10 20,000 centipoise (cps) at 25°C (77°C) at 4 rpm.

Example 8: Préparation of Laminating Resin Composition

A laminating resin was prepared by mixing, respectively, 263 g of IPA-TMP Tetra (Acetoacetate) from Example 4 and 285 g ofTMPTA. The laminating resin composition had a Brookfield viscosity of 900 centipoise (cps) at 25°C' (77°C).

Example 9: Préparation of DBU Catalyst Solution

A catalyst solution of DBU was prepared by dissolving 20 g DBU in 7 g éthanol. The solution is a clear liquid.

Examplc 1Q: Préparation of DABCO Catalyst Solution

A catalyst solution of DABCO was prepared by dissolving 30 g DABCO in 20 g éthanol. The solution is a clear liquid.

Examplc 11: Gel Coat Laminate Panel Préparation

200 g of the gel coat composition from Example 7 was mixed with 2.7 g DBU catalyst solution from Exampie 9 by hand. The gel coat composition was sprayed on a waxed and buffed fiat tempered glass plate to a thickness of 15-40 mils (I mil=0.001 inch). After 20 minutes at room température (25°C), the gel coat Hlm was tacky free.

200 g of the laminating resin from Exampie 8 was mixed with 2.48 g (1.24 wt-%) DBU catalyst solution from Example 9. A A laminate was formed by applying a 1.5 oz chop-strained mat and the laminating resin/DBU catalyst mixture onto lhe gel coat film. The laminate was allowed tocure for 16-20 hours at ambient température (25°C), then removed from the mold and eut into test parts.

Examplc 12: Gel Coat Formulation

Gel coat formulations were prepared by mixing, respectively, TMPTris (Acetoacetate) (150 g) prepared from Example 1, the acetoacetate-functionalized méthacrylate copolymer resin (68 g) prepared from Example 6, TMPTA (184 g), hepladecafluorodecyl acrylate (9 g, Zonyi TA-N from DuPont), titanium dioxide (120 g), talc (30 g) and fumed silica (4 g). The gel coat composition had a Brookfield viscosity of 16650 centipoise (cps) at 25°C (77°C) at 4 rpm.

Examplc 13: Gel Coat Laminate Panel Préparation

The gel coat composition (200 g) prepared from Example 7 was mixed with the catalyst solution of DBU (1.0 g) and éthanol (0.3 g), and sprayed on a waxed and buffed fiat tempered glass plate to a thickness of 15-40 MILS (1 M1L-0.00I inch). After 20 min., the gel coat film was tacky free and a barrier coat (ARMORGUARD from CCP) was sprayed onto the film to a thickness of 23 MILS. A Ά laminate is made using chopped fiberglass and a polyester resin (STYPOL LSPA-2200, 40% mat/60% resin). Methyl ethyl ketone peroxide (MEKP) co-initiator at 1.2 wt % is used to cure the polyester resin. The laminate is allowed to cure for 16-20 hours al room température, then removed from the mold and cul into test parts.

C U

Example 14: Gel Coat Laminate Panel Préparation

The gel coat composition (200g) prepared from Example 7 was mixed with the catalyst solution of DABCO ( 1.0 g) and éthanol ( 1,0 g), and sprayed on a waxed and buffed fiat tempered glass plate to a thickness of 15-40 MILS (1 MIL-0.001 inch). After 12 hr., the gel coat film was 5 somewhat lacky and a barricr coat (ARMORGUARD from CCP) was sprayed onto the film to a thickness of 23 MILS. A Ά laminate is made using chopped fiberglass and a polyester resin (STYPOL LSPA-2200, 40% mat/60% resin). Methyl ethyl ketone peroxide (MEKP) co-initiator at 1.2 wt % is used to cure the polyester resin. The laminate is allowed to cure for 16-20 hours at room température and 5 hours at 100° C, then removed from the mold and cul into test paris.

Examples 15 to 21: Préparation of Clcar Castines

Clear castings were prepared by mixing the resin, acrylate, and catalyst listed in Table I (below) by hand and pouring the resin mixture into a cavity between two glass plates with 1/8 spacing. The resin was cured at ambient température ovemight and post-cured at 100°C for 5 hours. The cured resins were tested for physical properties according to ASTM D638, D648, and 15 D790. The results are listed in Table I.

C O

Table 1: Physical properties of clear casting of resin

Example	15	16	17	18	19
Resin, weight (g)	Ex 1, 100	Ex 1, 100	Ex 1, 55	Ex 2, 162	Ex 4, 132
Acrylate, weight (g)	TMPTA, 100	SR355, 100	SR368, 48 SR454, 76 TMPTA, 55	TMPTA, 124	TMPTA, 143 g
Catalyst, weight (g)	TMG, 0,7	DBU, 0.7	Ex 10, 3.6	Ex 9, 2.3	Ex 9, 2.3
Viscosity (cp)	95	310	1000	1000	900
Mechanical Properties
Tensile Strength (psi)	7500	6680	10460	10760	6510
Tensile Modulus (ksi)	451	449	514	509	420
Elongation (%)	2.3	1.9	3.2	3.9	1.7
Flex Strength (psi)	13730	12610	17270	18130	16700
Flex Modulus (ksi)	432	438	488	510	477
HDT (<Ό)	62	48	70	77	86

Example	20	21
Resin, weight (g)	Ex 5, 165	Ex 1, 150 Ex 6, 68
Acrylate, weight (g)	TMPTA 113	TMPTA 184
Catalyst, weight (g)	Ex 9. 2.4	Ex 9, 2.3
Viscosity (eps)	-	340
Mechanical Propertîes
Tensile Strength (Psi)	8720	8840
Tensile Modulus (ksi)	456	468
Elongation (%)	4.3	3.6
Flex Strength (psi)	8600	1510
Flex Modulus (ksi)	318	433
HDT (°C)	34	69

The mechanical propertîes of the examples hâve comparable propertîes to typical unsaturated polyester resins,

The invention has been described by reference to detailed examples and méthodologies. These examples arc not meant to limit the scope of tlie invention, it should be understood that variations and modifications may be made while remaining within the spirit and scope of the invention, and the invention is not to be construed as limited to the spécifie embodiments disclosed. The disclosures of référencés cited in tlie application are incorporated by reference herein.

Claims (5)

CLAIMS:

1. A method of making a styrene free and zéro VOC gel coat composition, comprising: reacting a polyhydroxy polyol having at least two hydroxyl groups per molécule with a

C1-C5 alkyl acetoacetate in a transestérification process to form a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per oligomer;

combining the acetoacetylated polyhydroxy polyol with one or more multifunctional acrylate monomers or oligomers, at least one additive component, and a base catalyst, to form a crosslinkable, styrene free, zéro VOC, thermosetting gel coat composition having a viscosity of about 50 to 1200 cps under high shear;

further comprising allowing the gel coat composition to cure at ambient température using Michacl-type addition reaction to form a crosslinked, thermoset gel coat comprising crosslinked acetoacetylate-funclionalized acrylate oligomers.

2 to 40 wt-% additives, based on the total weight of the composition.

8. The method of Claim l, wherein the gel coat is at least 50% crosslinked.

9. The method of Claim 8, wherein the gel coal is 70 to 100% crosslinked.

10. The method of any one of Claims l to 9, wherein the polyhydroxy polyol is selected from the group consisting of methyl propanediol (MPD), trimethylolpropane (TMP), trimethylpentanediol, di-trimethylolpropane (di-TMP), butyl ethyl propanediol (BEPD), neopentyl glycol (NEO), pentaerylhritol (Penta), di-pentaerythritol (di-Penta), tris-2-hydroxyethyl isocyanurate (THEIC), 4,4'-isopropylidenedicyclohexanol (hydrogenated bisphenol-A (HBPA), and hydroxyl-functionalized acrylic polymers, and mixtures thereof.

11. The method of any one of Claims I to 10, wherein the C1-C5 alkyl acetoacetate is selected from the group consisting of methyl acetoacetate (MAA), ethyl acetoacetate (EAA), n-propyl acetoacetate, isopropyl acetoacetate, n-butyl acetoacetate, tert-butyl acetoacetate (TBAA), pentyi (amyl) acetoacetate, n-pentyl acetoacetate, isopentyi acetoacetate, tert-pentyl acetoacetate, and acetoacetate-functionalized acrylic polymer based on acetoacetoxyethyl méthacrylate, and mixtures thereof.

12. The method of any one of Claims I to 11, wherein the additive component is selected from the group consisting of fillers, pigments, thixotropic agents, promoters, inhibitors, stabilizers, extenders, air release agents, leveling agents, and combinations thereof.

13. The method of any one of Claims I to 12, wherein the additive component comprises a filler selected from the group consisting ofclay, magnésium oxide, magnésium hydroxide, aluminum trihydrate (ATH), calcium carbonate, calcium silicate, mica, aluminum hydroxide, barium sulfate and talc, and mixtures thereof.

14. The method of any one of Claims l to 13, wherein the additive component comprises titanium dioxide.

C-o

15. The method of any one of Claims I to 14, wherein the additive component comprises a thixotropic agent selected from the group consisting of fumed silica, precipitated silica, and bentonite clay, and mixtures thereof.

16. The method of any one of Claims l Ιο 15, wherein the base catalyst is selected from the group consisting of l,8-diazabicyclo-[5.4.0]undec-7-ene (DBU), l,5-diazabicyclo[4,3,0]non5-ene (DBN), l,5,7-triazabicyclo|4,4,0]dec-5-ene (TBD), 7-methyl-l,5,7trîazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethylguanidine (TMG) and l,4-diazabicyclo[2.2.2Joctane (DABCO), and N'-butyl-N,N-dicyclohexylguanidine, and mixtures thereof.

17. A method of making a gel coated article, comprising:

reacting a polyhydroxy polyol having at least two hydroxyl groups per molécule with a C1-C5 alkyl acetoacetate in a transestérification process to form a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per oligomer;

combining the acetoacetylated polyhydroxy polyol with one or more multifunctional acrylate monomers or oligomers, at least one additive component, and a base catalyst, to form a crosslinkable thermosetting gel coat composition having a viscosity of about 50 to 1200 cps under high shear; and applying the thermosetting gel coat composition as an in-mold coating to a surface of a mold;

allowing the gel coat composition to cure at ambient temperature to form a partially crosslinked, tacky to tacky-free gel coat;

applying a material to be molded onto the partially crosslinked gel coat;

applying a crosslinkable laminating resin onto said material, the laminating resin comprising an acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per molécule, one or inore multifunctional acrylate monomers or oligomers and a base catalyst; and allowing the laminating resin and lhe gel coal to cure at ambient temperature using a Michael-type addition reaction to a solid, crosslinked, thermoset resin being styrene free with zéro VOCs.

18. The method of Claim 17, wherein the polyhydroxy polyol has at least three hydroxyl groups per molécule.

c o

19. A method of making a laminating resin composition, comprising reacting a polyhydroxy polyol having at least two hydroxyl groups per molécule with a C1-C5 alkyl acetoacetate in a transestérification process to form a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having ai least two acetoacetyl functional groups per oligomer;

combining the acetoacetylated polyhydroxy polyol with one or more multifunctional acrylate monomers or oligomers and a base catalyst to form a crosslinkable thermosetting laminating resin composition having a Brookfield viscosity of about 100 to500 cps;

further comprising allowing the laminating resin to cure at ambient température using a Michael-type addition reaction to form a styrene free, zéro VOC, solid, crosslinked thermoset laminating resin comprising crosslinked acetoacetate-functionalized acrylate oligomers.

20. The method of Claim 19, wherein the multifunctional acetoacetylated polyhydroxy polyol has at least three acetoacetyl functional groups per oligomer.

2321. The method ol'Claim I9 or 20, wherein the thermoset laminating resin is at least 50% crosslinked.

22. A crosslinkable gel coat composition, comprising:

an acetoacetylated polyhydroxy polyol, one or more multifunctional acrylate monomers or oligomers, a base catalyst, and at least one additive component selected from the group consisting of fillers, pigments and thixotropic agents;

the gel coat composition having a viscosity of 50 to 1200 cps under high shear, and being curable under ambient conditions using a Michael-type addition reaction to a styrene free, zéro VOC, solid thermoset gel coat comprising crosslinked acetoacetate-functionalized acrylate oligomers.

23. A crosslinkable laminating resin composition comprising:

an acetoacetylated polyhydroxy polyol, one or more multifunctional acrylate monomers or oligomers, and a base catalyst;

the laminating resin composition having a Brookfield viscosity of 50 to 1200 cps, and being curable under ambient conditions using a Michael-type addition reaction to a styrene free, zéro VOC, solid thermoset laminating resin comprising crosslinked acetoacetate-functionalized acrylate oligomers.

C-&

24. A gel coated article, comprising a cured thermoset gel coat on a surface of the article, the article comprising a resin, and said resin and the thermoset gel coat being crosslinked, solid and styrene free with zéro VOCs, and comprising crosslinked acetoacetate-functionalized acrylate oligomers.

25. A system for forming a gel coat composition, comprising, in separate containers packaged together:

a container of a curable, thermosetting gel coat composition comprising a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per oligomer, one or more multifunctional acrylate monomers or oligomers and at least one additive component selected from lhe group consisting of fillers, pigments and thixotropic agents for a gel coat, the thermosetting gel coat composition having a viscosity of about 50 to 1200 eps under high shear and curable at ambient température to form a crosslinked, thermoset gel coat resin being styrene free with zéro VOCs;

a container of a base catalyst selected from the group consisting of l,8-diazabicyclo[5.4.0]undec-7-cne (DBU), l,5-dîazabicyclo[4,3,0]non-5-ene (DBN), 1,5,7triazabicyclo[4,4,0]dec-5-ene (TBD), 7-methyI-1,5,7-triazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethy (guanidine (TMG) and l,4-diazabîcyclo[2.2.2Joctane (DABCO), and N'-butyl-N,Ndicyclohexylguanidine, and mixtures thereof; and directions for combining the acetoacetylated polyhydroxy polyol and the base catalyst to form a solid, crosslinked, styrene free, zéro VOC gel coat comprising crosslinked acetoacetatefunctionalized acrylate oligomers.

26. The system of Claim 25, wherein the multifunctional acetoacetylated polyhydroxy polyol has at least three acetoacetyl functional groups per oligomer.

27. A system for forming a laminating resin composition, comprising, in separate containers packaged together:

a container of a curable, thermosetting laminating resin composition comprising a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per oligomer and one or more multifunctional acrylate monomers or oligomers;

a container of a base catalyst selected from the group consisting of 1,8-diazabicyclo[5,4.0]undec-7-ene (DBU), l,5-diazabicyclo[4,3,0]non-5-ene (DBN), 1,5,718528 triazabicyclo[4,4,0]dec-5-cne (TBD), 7-methyl- i ,5,7-lriazabicyclo[4,4,0]dec-5-ene (MTBD), tetramethylguanidine (TMG) and l,4-diazabtcyclo[2.2.2]octane (DABCO), and N'-butyl-N,Ndicyclohexylguanidine, and mixtures thereof; and directions for combining the laminating resin and the base catalyst to form a solid, crosslinked, styrene free, zéro VOC laminating resin comprising crosslinked acetoacetatefunctionalized acrylate oligomers.

28. The system of Claim 27, wherein the multifunctional acetoacetylated polyhydroxy polyol has at least three acetoacety! functional groups per oligomer.

29. A method of making a gel coated article, comprising:

making a styrene free and zéro VOC gel coat composition according to the method ofany one of claims I to I6; and applying the gel coat composition as an in-mold coating to a surface of a mold;

allowing the gel coat composition to cure at ambient température to form a partially crosslinked, tacky to tacky-free gel coat;

applying a material to be molded onto the parlially crosslinked gel coat;

applying a crosslinkable laminating resin onto said material, the laminating resin comprising an acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per molécule, one or more multifunctional acrylate monomers or oligomers and a base catalyst; and allowing the laminating resin and the gel coal to cure at ambient température using a Michael-type addition reaction to a solid, crosslinked, thermoset resin being styrene free with zéro VOCs.

30. A system for forming a gel coat composition, comprising, in separate containers packaged together:

a container ofa base catalyst for use in the method ofany one of claims I to 16;

a container containing a composition comprising a crosslinkable, multifunctional acetoacetylated polyhydroxy polyol having at least two acetoacetyl functional groups per oligomer, one or more multifunctional acrylate monomers or oligomers and at least one additive component selected from the group consisting of fillers. pigments and thixotropic agents for a gel coat, for making a styrene free and zéro VOC gel coat composition according to any one of claims I to 16, with the exception ol the base catalyst, the thermosetting gel coat composition

C-o having a viscosity of about 50 to 1200 cps under high shear and beîng curable at ambient température; and directions for combining the composition comprising the acetoacctylated polyhydroxy polyol and the base catalyst to form a solid, crosslinked, styrene free, zéro VOC gel coat

2. The method of Claim l, wherein the polyhydroxy polyol has at least three hydroxyl groups per molécule.

3. The method of Claim l or 2, wherein the acetoacetylated polyhydroxy polyol has at least three acetoacetyl functional groups per oligomer.

4. The method of any one of Claims I to 3, wherein the acetoacetylated polyhydroxy polyol has:

an acetoacetyl content of 5 to 80 weight %.

a hydroxyl number of 0 to 60 mg KOH/g, an acid value ofO to 5 mg KOl l/g, and a number average molecular weight (Mn) of 250 to 6000 g mole'¹.

5. The method ofany one ofClaims I to 4, wherein the molar ratio ofthe acetoacetate functional group of acetoacetylated polyhydroxy polyol to the acrylate functional group of one or more acrylate monomers or oligomers is 0.2 to 5.0.

6. The method of Claim 5, wherein the molar ratio is 0.3 to 3.0.

) xïïiiUcîuaî rRopairy AîtoiîNu’/

OAPiACCrtEdiTGdAqtNT i-Aul jiNG

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7. The method of any one of Claims l to 6, wherein the gel coat composition comprises:

15 to 70 wt% of the acetoacetylated polyhydroxy polyol,

15 to 70 wt% of the one or more multifunctional acrylate monomers or oligomers, and

5 comprising crosslinked acetoacetate-functionalized acrylate oligomers.