Glycol Ether Amines for Aqueous Two-Component Polyurethane Coatings

Abstract

The present invention provides an aqueous composition comprising: (i) an aqueous acrylic or vinyl polymer dispersion, wherein the polymer contains on average two or more hydroxyl groups or contains a polyol; (ii) one or more pigments, extenders or colorants, or combinations thereof; and (iii) one or more glycol ether amines having the following formula I: 【Chemical 1】 JPEG2025523977000010.jpg23170 [wherein, R 1 is a C1-C6 alkyl group, or preferably a C3-C4 alkyl group, and R 2 and R 3 are independently CH3 or CH2-CH3; and m is from 1 to 6, or preferably from 1 to 2]. The aqueous composition may further comprise a water-dispersible polyisocyanate curing agent, thereby forming a curable aqueous coating composition that forms a polyurethane coating or film.

Description

Technical Field

[0001] The present invention generally relates to an aqueous composition comprising: (i) an aqueous acrylic or vinyl polymer dispersion in which the polymer contains on average two or more hydroxyl groups or contains a polyol; (ii) one or more pigments, extenders or colorants, or combinations thereof; and (iii) one or more glycol ether amines. More specifically, the present invention relates to an aqueous coating composition useful as a pigment dispersion and an isocyanate-curable aqueous coating composition comprising a polyol or hydroxyl group-containing aqueous acrylic or vinyl polymer dispersion, one or more pigments, extenders and / or colorants, and one or more glycol ether amines. The aqueous composition provides enhanced pH stability and pigment dispersion stability and readily forms a polyurethane coating having acceptable appearance and film properties when combined with a water-dispersible polyisocyanate curing agent.

[0002] The polyurethane contains repeating units containing a carbamate group of formula (A). -O-C(=O)-N<(A)

[0003] Polyurethanes have found many applications in the chemical and related industries. Examples of such applications are their use in the preparation of coatings, sealants, and adhesives. Polyurethanes are typically prepared by curing a mixture of two reactants (such as separate components) that react with each other to form the polyurethane. Known aqueous two-component polyurethane coating compositions containing water-dispersible isocyanates and emulsion polymers can significantly reduce the volatile organic compound (VOC) levels of the coatings made from such compositions and have a reasonable cure rate, but have not yet been able to provide the level of composition stability and dry film properties of solvent-based polyurethane compositions. Therefore, there is still a need for a pH neutralizing agent that can improve pigment dispersion and pH stability in aqueous compositions without adversely affecting the dry film properties of the coatings made from the aqueous compositions.

[0004] pH neutralizing agents are typically used at only 0.1 wt% to 1 wt% of the total formulation, but affect the overall performance of aqueous coating compositions. Depending on the formulation, formulators have several options for pH adjustment in the formulation. The most commonly used neutralizing agent is ammonia, which is inappropriate for use in low-odor coatings because of its strong odor. Organic amines such as 2-amino-2-methyl-1-propanol have been accepted in the coating industry because of their multifunctional benefits beyond pH neutralization, such as pH stability, improved pigment dispersion, and low odor. However, there is still a need for an organic amine neutralizing agent that provides the advantages of a low-odor organic amine neutralizing agent and improved pigment or colorant dispersion without adversely affecting the application or final coating, especially in industrial coating applications.

[0005] U.S. Patent No. 5,626,915 to Laura et al. discloses an aqueous coating composition comprising: (i) a polyol; (ii) a surfactant, such as a nonionic surfactant; (iii) a halogenated polyolefin resin material or other similar halogenated resin, such as a PVC resin; (iv) an aliphatic amine, such as an amino-substituted alkanol, such as aminopropanol; and (v) water. The amine can be selected from the group consisting of alkylamines, alkyldiamines, alkanolamines, dialkanolamines, tertiary amines, poly(oxyalkylene) diamines, and mixtures thereof. Laura et al. disclose that the coating has enhanced adhesion to a substrate. However, Laura et al. do not disclose a composition having improved pH stability or dispersion stability.

[0006] The present inventors have sought to solve the problem of providing an aqueous composition that exhibits improved pigment dispersion stability and pH stability and enables the formation of a polyurethane coating without adversely affecting the dry film properties of the polyurethane coating formed using the composition. SUMMARY OF THE INVENTION

[0007] According to the present invention, the aqueous composition comprises (i) an aqueous acrylic or vinyl polymer dispersion, wherein the polymer contains an average of two or more hydroxyl groups, such as a part of the polymer itself, or contains a polyol absorbed in the polymer or adsorbed on the polymer, an aqueous acrylic or vinyl polymer dispersion; and (ii) one or more pigments, extenders or colorants, or combinations thereof; and (iii) one or more glycol ether amines having the following formula I:

[0008]

Chemical formula

[0009] In another aspect according to the present invention, a method of forming a coating includes the steps of mixing the aqueous composition of the present invention with a water-dispersible polyisocyanate curing agent component to form an aqueous coating composition, applying the aqueous coating composition to a substrate or carrier such as a film, and curing to form a coating or film on the substrate or carrier.

Mode for Carrying Out the Invention

[0010] The aqueous composition of the present invention comprises a storage-stable, colored, pigmented or extender-containing aqueous acrylic or vinyl polymer dispersion containing one or more glycol ether amines exhibiting excellent pH stability and low viscosity. The aqueous acrylic or vinyl polymer dispersion comprises a polymer having on average two or more hydroxyl groups per polymer chain or as side chain groups, such as a copolymer of a hydroxyalkyl (meth)acrylate and an alkyl (meth)acrylate, or a polymer in which the polymer acts as a carrier, absorbent or adsorbent and contains at least one polyol in the polymer composition; and the glycol ether amine according to the present invention comprises an alkylamine (oligo)glycol ether having from 1 to 6 ether groups and one hydroxyl group. When the aqueous composition further comprises a water-dispersible polyisocyanate curing agent, the composition readily provides a urethane coating from an aqueous medium. Accordingly, the present composition can produce an emulsion polymer blend capable of forming an aqueous coating composition that provides good dry film properties of appearance, gloss and initial water resistance suitable for industrial or architectural coatings or aqueous wood stains or sealants, enabling easy formulation of an aqueous colored or opaque coating.

[0011] Unless otherwise indicated, the conditions of temperature and pressure are room temperature (23 °C) and standard pressure (101.3 kPa, also referred to as "ambient conditions"). In addition, unless otherwise indicated, all conditions include 50% relative humidity (RH).

[0012] Unless otherwise indicated, any term in parentheses refers alternatively to the entire term as if the parentheses were present, and the term without the parentheses, and combinations of each alternative. Thus, as used herein, terms such as "(meth)acrylate" are intended to include acrylate, methacrylate, and mixtures thereof.

[0013] The singular terms "a", "an", and "the" include their plural referents unless the context clearly dictates otherwise. Unless otherwise specified, the terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0014] All ranges recited herein are inclusive and combinable. For example, the disclosed amount of (iii) one or more glycol ether amines in the range of 0.1 to 2% by weight, or preferably 0.1 to 1.5% by weight, based on the total weight of the aqueous composition, includes amounts in the range of 0.1 to 2% by weight, or 1.5 to 2% by weight, or preferably 0.1 to 1.5% by weight.

[0015] As used herein, the term "addition polymer" means an acrylic or vinyl polymer made by radical addition polymerization, such as radical-initiated polymerization.

[0016] As used herein, the term "aqueous" means that the continuous phase or medium is water and a water-miscible compound in an amount of 0 to 50% by weight based on the weight of the medium. Preferably, "aqueous" means water.

[0017] As used herein, the term "aqueous" means water, or a mixture of water and one or more water-miscible solvents in a small amount (50% by weight or less based on the total weight of water and any solvent), or preferably, a mixture of water and 10% by weight or less based on the total weight of water and any solvent.

[0018] As used herein, the term "ASTM" refers to the publications of ASTM International, Conshohocken, Pa.

[0019] As used herein, the term "component" refers to a composition containing one or more raw materials that, when combined with another component, initiate a reaction, polymerization, or curing. Components are kept separate until combined during use or reaction.

[0020] As used herein, the term "curing" means subjecting to conditions effective for chemical conversion or chemically converting under such conditions.

[0021] As used herein, unless otherwise indicated, the term "calculated Tg" or "calculated glass transition temperature" refers to the Tg of a polymer calculated by using the Fox equation (T.G. Fox, Bull. Am. Physics Soc., Volume 1, Issue No. 3, page 123 (1956)). For reference and use in calculating Tg, a comprehensive compilation of available data describing the glass transition temperatures of homopolymers from suitable monomers is described in Polymer Handbook, Vol. 1, editors Brandrup, J.; Immergut, E.H.; Grulke, E.A., 1999, pages VI / 193 - 277.

[0022] As used herein, the term "dispersed polymer" means a polymer dispersed in a continuous medium. An aqueous dispersed polymer is dispersed in water and includes emulsion polymers that are made as aqueous dispersions and polymers dispersed in water after polymer production.

[0023] As used herein, the term "hydroxyl functionality" refers to the average number of hydroxyls per molecule, and in the case of an addition polymer or oligomer chain, is the number average molecular weight (M n ) of the polymer multiplied by the weight fraction (WF) of all hydroxyl-functional monomers used to make the polymer (where 1 is 100% by weight and 0.1 is 10% by weight), and divided by the hydroxyl equivalent weight (HEW) of the monomer, or in the case of a mixture of two or more monomers, divided by the weighted average hydroxyl equivalent weight. For example, in the case of hydroxyalkyl (meth)acrylate (HEMA), the hydroxyl functionality is 1 and the hydroxyl equivalent weight is the same as its molecular weight; in the case of cyclohexanedimethanol, the hydroxyl functionality is 2 and the hydroxyl equivalent weight is half of its molecular weight. For M of 10,000n has a hydroxyl functionality of (M n × WF / HEW), i.e., (10,000 × 0.1) / 130.1, i.e., 7.69 hydroxyls, in the case of a HEMA-containing polymer containing 10% by weight of HEMA based on the total weight of the monomers used to make the polymer.

[0024] As used herein, the term "hydroxyl equivalent" is calculated based on theoretical calculations in the case of acrylic or vinyl emulsion polymers containing two or more hydroxyl groups, by multiplying the molecular weight of a hydroxyl-functional monomer (e.g., HEMA) or (non-volatile) polyol (e.g., cyclohexanedimethanol) by the hydroxyl functionality of the monomer or polyol, and multiplying by the weight fraction of the hydroxyl-functional monomer or polyol in the aqueous acrylic or vinyl polymer dispersion (1 is 100% by weight, 0.1 is 10% by weight). In the case of commercially available polyols, unless otherwise indicated, the given HEW is that reported by the manufacturer and no further measurements have been carried out.

[0025] As used herein, the term "isocyanate functionality" refers to the average number of isocyanate groups per molecule, and in the case of addition polymers or oligomer chains, is the number average molecular weight of the polymer (M n ) multiplied by the weight fraction (WF) of all isocyanate-functional monomers used to make the vinyl or acrylic polymer (1 is 100% by weight, 0.1 is 10% by weight) and divided by the isocyanate equivalent weight (IEW) of the monomer, or in the case of a mixture of two or more monomers, divided by the weighted average isocyanate equivalent weight. For example, in the case of isocyanatoethyl methacrylate (IEM), the hydroxyl functionality is 1 and the isocyanate equivalent weight is the same as its molecular weight; in the case of hexamethylene diisocyanate, the hydroxyl functionality is 2 and the hydroxyl equivalent weight is half of its molecular weight. For M of 10,000 nFor an IEM-containing polymer having 10 wt% IEM based on the total weight of the monomers used to make the polymer, the isocyanate functionality is, per molecule of polymer, (M n × WF / HEW, i.e., (10,000 × 0.1) / 155.2, i.e., 6.44 isocyanates.

[0026] As used herein, the term "isocyanate equivalent" is the isocyanate equivalent weight (IEW) of a given molecule without further measurement reported by the manufacturer, multiplied by the number of grams of the molecule used, or the number of isocyanate equivalents in a given molecule, multiplied by the number of moles of the molecule used.

[0027] As used herein, the term "ISO" refers to publications of the International Organization for Standardization (Geneva, CH).

[0028] As used herein, unless otherwise indicated, the term "measured glass transition temperature" or "measured Tg" refers to the glass transition temperature of a material determined by differential scanning calorimetry (DSC) scanning from -90 °C to 150 °C while heating at a rate of 10 °C / min. Tg is the inflection point of the heat flow vs. temperature curve, or the maximum value on a plot of its derivative.

[0029] As used herein, the term "(meth)acrylate" means acrylate, methacrylate, and mixtures thereof, and the term "(meth)acrylic" as used herein means acrylic, methacrylic, and mixtures thereof.

[0030] As used herein, unless otherwise indicated, the term "polyol" includes diols, triols, and hydroxyl-functional molecules having four or more hydroxyl groups.

[0031] As used herein, unless otherwise indicated, the term "polyol solid" refers to a diol or polyol, or an acrylic or vinyl dispersion polymer, excluding water and any solvents.

[0032] As used herein, the term "polyester polyol" means a subclass of polyols that are organic molecules having at least two alcohol (-OH) groups (preferably including α and ω-OH) and at least one carboxylic acid ester (CO2-C) functionality. The term "alkyd" means a subclass of polyester polyols that are fatty acid-modified polyester polyols in which at least one carboxylic acid ester functional group is derived from an esterification reaction between the alcohol -OH of a polyol and the carboxyl of a (C8-C 60 ) fatty acid.

[0033] As used herein, unless otherwise indicated, the term "polyisocyanate" refers to any isocyanate-functional molecule having two or more isocyanate groups.

[0034] As used herein, the term "polymer" optionally refers to a polymer made from one or more different monomers such as a copolymer, terpolymer, tetrapolymer, pentapolymer, etc., and may be any of a random, block, graft, continuous, or gradient polymer.

[0035] As used herein, the term "based on the total weight of the monomers used to make the copolymer" refers to the sum of the monomers as solids, excluding chain transfer agents.

[0036] As used herein, the term "substantially free of volatile organic compounds" means that the composition contains an organic solvent, including glycol ether amines, coalescing solvents, and all other organic solvents in a given composition, in a total amount of less than 50 g / L, or preferably less than 25 g / L, based on the total weight of the composition.

[0037] As used herein, the term "total solids" refers to all in a given composition other than water and volatile solvents that evaporate or volatilize at 40°C or below and atmospheric pressure. Thus, coalescing solvents and glycol ether amines are not considered solids. Diols and polyols that react to form a given composition are considered solids.

[0038] As used herein, the phrase "weight %" represents weight percent.

[0039] The aqueous composition according to the present invention comprises (i) an aqueous acrylic or vinyl polymer dispersion, wherein the polymer itself contains on average two or more hydroxyl groups, or each molecule of the polymer in the dispersion contains on average at least one polyol molecule, such as a diol, polyol or oligomer thereof, and the polyol molecule is complexed or reacted (adsorbed) with the polymer that can act as a carrier, or is absorbed (incorporated) into the polymer, an aqueous acrylic or vinyl polymer dispersion. The aqueous acrylic or vinyl dispersed polymer can be a multi-stage polymer that absorbs polyols. The aqueous composition further comprises (ii) one or more pigments, extenders or colorants, or combinations thereof. In addition, the aqueous composition comprises (iii) one or more organic glycol ether amines of the following formula I:

[0040] [Chemical formula] [wherein, R 1 is a C1-C6 alkyl group, preferably a C3-C4 alkyl group; R 2 and R 3 are independently CH3 or CH2-CH3; and m is 1-6, or preferably 1-2] and further comprises. Further, the composition may comprise (iv) one or more coalescing solvents such as alkyl glycol ethers, for example propylene glycol methyl ether.

[0041] (i) The aqueous acrylic or vinyl polymer dispersion contains on average two or more hydroxyl groups, which may be part of the polymer itself, such as in the polymer main chain or as a side chain, or may be post-reacted (absorbed) with the polymer or contained or absorbed in the dispersion by other means, for example, as a polyol incorporated or absorbed into the polymer in the aqueous acrylic or vinyl polymer dispersion.

[0042] Suitable aqueous acrylic or vinyl polymer dispersions may include acrylic, styrene-acrylic, styrene-butadiene, olefin, vinyl chloride, ethylene vinyl acetate, and polyvinyl acetate emulsion polymers, preferably acrylic and styrene-acrylic. The aqueous dispersion polymer composition may have multiple stages, each stage having a separate measured glass transition temperature or Tg (measured Tg), and at least one measured Tg may be -10 to 100 °C, preferably 20 °C to 80 °C. If the measured Tg of the emulsion polymer is too high, a suitable aqueous composition containing the polymer may require excessive solvent for processability. If the measured Tg of the polymer is too low, a coating made from the polymer may suffer from low hardness.

[0043] (i) The aqueous acrylic or vinyl polymer dispersion can be formed by conventional means, such as free radical emulsion polymerization or aqueous addition polymerization in the presence of a free radical initiator (such as a peracid or its salt) in the formation of the aqueous acrylic or vinyl polymer dispersion by addition polymerization. The monomer may be added to the polymerization as a single charge for higher molecular weight products or by stepwise addition polymerization for lower molecular weight or multiphase polymers. It may also be advantageous to perform the monomer addition to the polymer non-uniformly stepwise to form multiphase polymer particles, creating a core-shell, hemispherical, or occluded morphology.

[0044] (i) Monomers suitable for the preparation of aqueous dispersions or emulsion polymers include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, vinyl esters, vinyl ethers, allyl ethers, vinyl arenes such as styrene, and combinations thereof. As used herein, the term "(meth) acrylic acid" refers to methacrylic acid or acrylic acid. To prepare aqueous acrylic or vinyl polymer dispersion polymers, carboxylic acid monomers such as (meth) acrylic acid and itaconic acid, and salts thereof; sulfonic acid monomers such as sodium styrene sulfonate and acrylamide-methyl-propanesulfonate, and salts thereof; and additional monomers including phosphoric acid monomers such as phosphoethyl methacrylate, and salts thereof can be used. Monomers such as styrene, acrylonitrile, and acetoacetoxyethyl methacrylate (AAEM), and monomers capable of imparting co-curable functional groups such as glycidyl (meth) acrylate and hydroxyalkyl (meth) acrylate can also be used in the preparation of aqueous acrylic or vinyl polymer dispersions. When AAEM is used, it may be desirable to post-react the polymer of the (meth) acrylate monomer with a primary amine or ammonia to form a polymer containing the corresponding enamine, acetoacetoxyethyl methacrylate enamine.

[0045] (i) To enable a harder or rubber-like phase in the aqueous acrylic or vinyl polymer dispersion, or to enhance the polyol absorption capacity, it can be advantageous to incorporate a small amount of copolymerized polyethylenically unsaturated monomer groups such as allyl (meth) acrylate, diallyl phthalate, 1,4-butylene glycol di(meth) acrylate, 1,2-ethylene glycol di(meth) acrylate, 1,6-hexanediol di(meth) acrylate, and divinylbenzene into the polymer.

[0046] During polymerization, the molecular weight of (i) an aqueous acrylic or vinyl dispersion polymer may be controlled using a chain transfer agent. Examples of chain transfer agents include dodecyl mercaptan, butyl mercaptopropionate, methyl mercaptopropionate, hydroxy group-containing mercaptans such as hydroxyethyl mercaptan, and mercaptopropionic acid.

[0047] Examples of suitable (i) aqueous acrylic or vinyl dispersion polymers include acrylic and styrene-acrylic polymers, and acrylic and vinyl copolymers from vinyl acetate, preferably acrylic and styrene-acrylic polymers having on average two or more hydroxyl groups.

[0048] Suitable aqueous acrylic or vinyl polymer dispersions having on average two or more hydroxyl groups may include those formed by conventional means. In such polymers, the hydroxyl group functionality may be provided by a hydroxyl-functional vinyl or acrylic monomer, such as hydroxyethyl methacrylate (HEMA), caprolactone (meth)acrylate or allyl alcohol, or by the formation of hydroxyl group-containing side chains in a copolymerized form, via the condensation of a diol or polyol with a carboxyl group-containing monomer, or by post-polymerization, or by absorption or adsorption of a polyol onto the polymer (e.g., onto a multi-stage polymer having a cross-linking step after polymerization).

[0049] In an example of an aqueous acrylic or vinyl polymer dispersion of a polymer containing on average two or more hydroxyl groups according to the present invention, the aqueous dispersion of the acrylic polymer may contain, in polymerized form, a hydroxyl-containing monomer such as hydroxyethyl methacrylate (HEMA) or hydroxypropyl methacrylate. In another example, the acrylic or vinyl polymer may contain, in copolymerized form, a carboxyl-containing monomer such as (meth)acrylic acid, onto which a polyol (i.e., a diol) is adsorbed to form a polyol-containing polymer that can form a polymer, for example, by sequential polymerization with a water-dispersible polyisocyanate. Such an acrylic polymer can be prepared by emulsion polymerization, by suspension addition polymerization followed by dispersion with a surfactant or emulsifier, or by dispersing a preformed polymer in an aqueous medium under shear, for example, in the presence of a surfactant or emulsifier, and then adsorbing the polyol onto the polymer in the presence of shear.

[0050] (i) To incorporate a composition of (chemically reacted) polyol absorbed or adsorbed in an aqueous acrylic or vinyl polymer dispersion composition, the polymer itself can be combined with a diol or polyol composition in neat form (in the case of water-soluble diols or polyols) or in the form of an aqueous dispersion (in the case of low water-soluble diols or polyols). In the aqueous dispersion of the polyol, the diol or polyol is preferably micronized and stabilized with a stabilizing amount of surfactant, preferably at a concentration in the range of about 0.5 to 5% by weight based on the total solids in this aqueous dispersion, and then mixed with the aqueous acrylic or vinyl polymer dispersion. Nonionic surfactants are preferred, including alkylphenol ethoxylate (APEO)-free nonionic wetting agents such as polyalkylene oxide block copolymers, polyoxyethylene glycol alkyl ethers, glucoside alkyl ethers, fatty acid esters, glycerol alkyl esters, sorbitan alkyl esters, and polyoxyethylene glycol alkylphenol ethers, and commercially available wetting agents such as TRITON (trademark) HW-1000 alkyl ethoxylate (Dow Chemical, Midland, Mich.).

[0051] (i) Suitable polyols that can be added, absorbed, or adsorbed into an aqueous acrylic or vinyl polymer dispersion include, for example, anything that provides an acceptable polyurethane. Such polyols include dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4 - butanediol, 1,3 - butanediol, 2,3 - butanediol, 1,2 - butanediol, 3 - methyl - 1,2 - butanediol, 2 - butyl - 2 - ethyl - 1,3 - propanediol, 1,2 - pentanediol, 1,5 - pentanediol, 1,4 - pentanediol, 2,4 - pentanediol, 2,3 - dimethyltrimethylene glycol, tetramethylene glycol, 3 - methyl - 4,3 - pentanediol, 3 - methyl - 1,5 - pentanediol, 2,2,4 - trimethyl - 1,3 - pentanediol, 1,6 - hexanediol, 1,5 - hexanediol, 1,4 - hexanediol, 2,5 - hexanediol, neopentyl glycol, 1,4 - cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, spiroglycol, and dihydroxymethyltricyclodecane; hydroxycarboxylic acids such as 2,2 - dimethylolpropionic acid, 2,2 - dimethylolbutanoic acid, 2,2 - dimethylolpentanoic acid, 2,2 - dimethylolhexanoic acid, and 2,2 - dimethyloctanoic acid; polylactone diols obtained by adding a lactone compound such as ε - caprolactone to such dihydric alcohols; ester diol compounds such as bis(hydroxyethyl) terephthalate; polyether diol compounds such as alkylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polybutylene glycol; polyester diol compounds such as bis(hydroxyethyl) terephthalate, and bis(hydroxyalkyl) poly(alkylene terephthalate) or reaction products of excess polyol and dicarboxylic acid;Polyhydric alcohols having a valency of 3 or more, such as glycerol, trimethylolethane, trimethylolpropane, diglycerol, triglycerol, 1,2,6 - hexanetriol, pentaerythritol, dipentaerythritol, tris(2 - hydroxyethyl) isocyanuric acid, sorbitol, and mannitol; and polylactone polyols obtained by adding lactone compounds such as ε - caprolactone to such polyhydric alcohols having a valency of 3 or more are mentioned.

[0052] Preferably, (i) the polyol contained in the aqueous acrylic or vinyl polymer dispersion has a molecular weight of 100 to 500 and contains any alicyclic diol or polyol having one or more 4 - to 7 - membered aliphatic rings, or is made from an alicyclic diol and / or polyol having a molecular weight of 100 to 500, contains at least 30% by weight of the alicyclic diol and / or polyol, and contains any oligomeric diol or polyol having a weight - average molecular weight of 200 to 3000, preferably 200 to 2000, more preferably 200 to 1000, and realizes a coating composition having substantially no VOC and acceptable film - forming properties. Such polyols include, for example, cyclohexanedimethanol (CHDM), particularly 1,3 CHDM, 1,4 CHDM, mixtures thereof, dianhydro - d - glucitol (having two 5 - membered rings each containing an oxygen atom), 4,8 - bis(hydroxymethyl)tricyclo[5.2.1.0 2,6These oligomers include at least 30% by weight, preferably at least 40% by weight, of a condensation reaction product based on the total weight of the reactants used to produce decane, 2,2,4,4 - tetramethylcyclobutanediol (containing one 4 - membered ring), and an alicyclic diol and / or oligomer of a polyol containing one or more 4 - to 7 - membered aliphatic rings. See, for example, U.S. Patent Application Publication No. 20140170327(A1) to Dombrowski et al. These can include, for example, oligos or polyesters having a desired low molecular weight, short - chain alkyds, oligos or polycarbonates, oligos or polyethers, and oligos or polylactones. Such oligomers can be prepared by conventional means such as bulk polymerization. For example, polyesters can be prepared from, for example, diacids or difunctional anhydrides or their salts, and alicyclic diols or triols having one or more 4 - to 7 - membered aliphatic rings.

[0053] Preferably, in order to improve coating film properties such as hiding, the aqueous acrylic or vinyl polymer dispersion (i) of the present invention contains a first polymer stage formed from monomers that provide pendant pigment - adsorbing functional groups (such as phosphite groups, phosphite ester groups, polyacid side chains, and mixtures thereof), preferably an acorn - type polymer, and in a second polymer stage contains a copolymerization product of a hydroxyl - group - containing monomer such as hydroxyethyl (meth)acrylate or allyl alcohol, and can include the polymers described in U.S. Patent No. 7,179,531(B2). In the multi - stage hydroxyl - functional aqueous acrylic or vinyl polymer dispersion (i), the copolymerizable hydroxyl - group - functional monomer is included in one or more phases of the emulsion polymer particles by step - wise free - radical polymerization to provide advantages such as a faster film - drying rate. For example, this can include placing all of the HEMA within one stage or within the core or shell of a core - shell emulsion polymer, as opposed to distributing all of the HEMA uniformly in both or all phases or stages.

[0054] The preferred amount of (i) an aqueous acrylic or vinyl polymer in the aqueous dispersion composition of the present invention can be in the range of 15 to 50% by weight, or preferably 20 to 45% by weight, as solids based on the total weight of the aqueous composition.

[0055] The aqueous composition of the present invention further comprises (ii) one or more pigments, extenders or colorants, or mixtures thereof. Examples of suitable pigments include, for example, titanium oxide, zinc white, zinc oxide, iron oxide, carbon black, azurite or Egyptian blue, etc., iron ferrocyanide oxide such as Prussian blue pigment, and cobalt blue (oxide) pigment; effect pigments such as aluminum powder, mica powder, and titanium oxide-coated mica powder, etc. can be mentioned. Examples of suitable extenders include talc, clay, kaolin, barite, barium sulfate, barium carbonate, calcium carbonate, silica, and alumina white. Colorants include organic and organometallic compounds that can also be referred to as pigments, such as phthalocyanine azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, indanthrene pigments, and perylene pigments. Colorants can be used in small amounts and are thus combined with extenders or inorganic pigments.

[0056] The preferred total amount of (i) one or more pigments, extenders or colorants, or combinations thereof in the aqueous composition of the present invention can be in the range of 5 to 85% by weight, or 5 to 75% by weight, or 10% by weight or more, or up to 65% by weight, or preferably 20 to 55% by weight based on the total weight of the aqueous composition. The preferred pigment volume concentration (%PVC) in the aqueous composition of the present invention can be 2 to 50%PVC, more preferably 4 to 30%PVC, based on the total volume of the pigments, extenders or colorants, polymers and other total solids contained in the aqueous composition. %PVC is determined by microscopic observation of the cross-section of a dry film made from the aqueous composition. The preferred amount of the colorant can be in the range of 0.01 to 0.5% by weight, or 0.1 to 0.4% by weight based on the total weight of the aqueous composition.

[0057] (iii) One or more glycol ether amines according to the present invention may simply be incorporated into the aqueous composition as part of an aqueous acrylic or vinyl polymer dispersion. The glycol ether amine may be used in an amount sufficient to stabilize the pH of pigments, extenders and / or colorants contained in the aqueous composition. For example, a suitable amount of (iii) one or more glycol ether amines may range from 0.1 to 2% by weight, or preferably from 0.1 to 1.5% by weight, based on the total weight of the aqueous composition.

[0058] The aqueous composition according to the present invention may further comprise (iv) one or more coalescing solvents. Suitable coalescing solvents that assist in film formation during drying include (di)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol n-butyl ether (PnB, including those sold under the trade name DOWANOL™), dipropylene glycol n-butyl ether (DPnB, such as those sold under the trade name DOWANOL™), 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and combinations thereof.

[0059] (iv) A suitable amount of one or more coalescing solvents may range from 0.1 to 1% by weight, or preferably from 0.5 to 1% by weight, based on the total weight of the aqueous composition. Generally, the softer the polymer or the lower the measured Tg, the less coalescing solvent is used to ensure effective film formation.

[0060] The aqueous composition according to the present invention may further contain any one of one or more pigment dispersants, defoamers, wetting agents, anti-settling agents, anti-foaming agents, thickeners or rheology modifiers, ultraviolet absorbers, light stabilizers, surface modifiers, or combinations thereof. The total amount of the additives can be present in an amount of 10% by weight or less or 5% by weight or less based on the total weight of the aqueous composition. The wetting agent may be a VOC, and thus should be used in an amount of 1% by weight or less based on the total weight of the aqueous composition.

[0061] Aqueous coating composition The aqueous coating composition of the present invention comprises an aqueous composition containing (i) an aqueous acrylic or vinyl polymer dispersion, (ii) one or more pigments, extenders or colorants or combinations thereof, and (iii) one or more glycol ether amines combined with a water-dispersible polyisocyanate curing agent. The aqueous coating composition of the present invention contains a stable pigment dispersion that forms a polyurethane layer upon curing in a coating effectively contacting at least a part of a coatable substrate. The curing agent starts curing when mixed. Therefore, the method of using the aqueous coating composition of the present invention includes keeping the curing agent separate until use and combining it with the aqueous composition immediately before applying the composition to the substrate or immediately before forming a film from the composition.

[0062] Suitable polyisocyanates for use as curing agents according to the present invention can include any molecule having two or more isocyanate groups and capable of being dispersed or dissolved in water at room temperature or ambient temperature, and mixtures thereof. Such polyisocyanates can be aliphatic, aromatic, or a mixture of both. The polyisocyanate has an average functionality of >2, but preferably has a higher average functionality of 2.5 to 10.

[0063] Examples of the water-dispersible polyisocyanate include aliphatic diisocyanates and their dimers and trimers, such as C2-C8 alkylene diisocyanates like tetramethylene diisocyanate and hexamethylene diisocyanate (HDI); alicyclic diisocyanates and their dimers and trimers, such as isophorone diisocyanate (IPDI) and dicyclohexyl methane diisocyanate (HMDI); aromatic diisocyanates and their dimers and trimers, such as toluene diisocyanate (TDI) and diphenyl methane diisocyanate (MDI). Examples of the dimers and trimers of the polyisocyanate include biuret adducts, allophanates, uretdiones, uretoimines, isocyanurates, oxadiazinetriones, and polymethylene polyphenyl polyisocyanates. Such polyisocyanates, dimers, and trimers may be used alone or in combination of two or more. Among these polyisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and dimers or trimers of these diisocyanates can improve the flexibility of the resulting coating film.

[0064] Isocyanurate or trimeric polyisocyanate compositions can be prepared by known methods in the art, for example, in the presence of one or more trimerization catalysts such as tertiary amines or phosphines, or heterogeneous catalysts, and optionally in the presence of a solvent and / or adjuvant such as a cocatalyst, preferably at elevated temperature, until the desired NCO content is reached, by trimerizing an alicyclic diisocyanate (e.g., isophorone diisocyanate), and then deactivating the catalyst using an inorganic or organic acid, the corresponding acid halide, and an alkylating agent, preferably by heating. Similarly, an isocyanurate composition containing isocyanurate derived from an aliphatic diisocyanate can be formed by cyclizing an aliphatic diisocyanate in the presence of one or more trimerization catalysts and then deactivating the catalyst. Any of the isocyanurates can be further modified by conventional methods to incorporate urethane, urea, imino-s-triazine, uretonimine, or carbodiimide moieties.

[0065] Other suitable water-dispersible polyisocyanates include, for example, polyether-modified polyisocyanates such as polyalkoxylated isocyanurates having two isocyanate groups, or isocyanate prepolymers such as those obtained from polyethers. One suitable isocyanate prepolymer composition can be formed by the reaction of bis(isocyanatomethyl)cyclohexane and / or another aliphatic diisocyanate with a monol, diol, diamine, or monoamine, and then this can be modified by reaction with additional isocyanate to form an allophanate or biuret-modified prepolymer. Such prepolymers may further contain polyalkoxy or polyether chains. Alternatively, such prepolymers may then be mixed with a trimerization catalyst to obtain an allophanate or biuret-modified polyisocyanate isocyanurate composition. The preparation of such allophanate or biuret prepolymers and subsequent trimerization are known in the art; see, for example, U.S. Pat. Nos. 5,663,272 and 6,028,158. Still further, suitable polyisocyanates may be modified with aminosulfonic acid to make them water-dispersible. It is also possible to use prepolymers formed by reacting a polyisocyanate or its trimer, dimer, or adduct with a compound reactive with the polyisocyanate under conditions such that an excess of isocyanate groups is present. Examples of compounds reactive with polyisocyanates include compounds having active hydrogen groups such as hydroxy or amino, and specific examples thereof include polyhydric alcohols, low molecular weight polyester resins, and amines.

[0066] Still other examples of water-dispersible polyisocyanates include, for example, homopolymers of isocyanate-containing polymerizable unsaturated monomers such as isocyanatoethyl (meth)acrylate, or copolymers of isocyanate-containing polymerizable unsaturated monomers with polymerizable unsaturated monomers other than isocyanate-containing polymerizable unsaturated monomers such as any vinyl or acrylic or styrene monomer.

[0067] Generally, a water-dispersible polyisocyanate composition suitable as a curing agent has a solid content of 20 to 70% by weight, preferably 25 to 65% by weight, or more preferably 30 to 60% by weight.

[0068] The aqueous coating composition of the present invention may have an equivalent ratio of the total number of isocyanate group equivalents to hydroxyl group equivalents in the range of 0.7:1.0 to 2.0:1.0. For example, the ratio of the isocyanate equivalent in the polyisocyanate composition component, which may contain several polyisocyanates, to the total number of hydroxyl group equivalents in the aqueous coating composition may be 0.8:1.0 or more, or 1.8:1.0 or less, or preferably in the range of 0.9:1 to 1.5:1.

[0069] The total solid content of the aqueous coating composition of the present invention may be in the range of 20 to 70% by weight, preferably 25 to 65% by weight, or more preferably 30 to 60% by weight.

[0070] The aqueous coating composition of the present invention can be applied to the surface of a substrate (s) such as a film or a carrier by any suitable method such as brushing, calendaring, rolling, spraying, mopping, trowel coating, or dipping. In one example, in the method of coating the surface of a substrate, the method includes applying a curable aqueous coating composition to at least a part of the surface of the substrate or the carrier to prepare a coated substrate or carrier having a polyurethane coating or film thereon, and curing the curable aqueous coating composition at a curing temperature of 15°C to 80°C including room temperature or ambient temperature.

[0071] Substrates suitable for being coated or sealed independently can include any material to which polyurethane is likely to adhere. Examples of suitable materials are wood, metal, ceramic, plastic, and glass. The surface of the substrate to be coated, adhered, or sealed may be irregular or regular, continuous or discontinuous, porous or non-porous, and may or may not be joined. The substrate to be coated or sealed can be of any shape, such as, for example, a flat or rolled sheet (e.g., a cylinder), a sphere, beads, or finely divided particles.

Examples

[0072] The present invention is illustrated by the following examples. Unless otherwise indicated, all parts and percentages are by weight, all temperatures are in °C, and all preparation and test procedures are carried out under ambient conditions of room temperature (23 °C) and pressure (1 atm). In the following examples and Tables 1, 2, and 3, the following abbreviations were used unless otherwise defined.

[0073] CE: Comparative Example, rpm = revolutions per minute, KU: Krebs unit, 3M: Minnesota Mining and Manufacturing Co., 2-HEMA: 2-hydroxyethyl methacrylate, BA: butyl acrylate, Sty: styrene, MMA: methyl methacrylate, IBOMA: isobornyl methacrylate, MAA: methacrylic acid.

[0074] Materials: All materials used to prepare the aqueous coating composition formulations are listed in Table 1 below. The examples included aqueous coating compositions with four different pH neutralizers. Two comparative examples, CE1 and CE2, contained aminomethylpropanol and trialkanolamine, respectively, and two examples of the present invention, Examples 1 and 2, contained glycol ether amine.

[0075]

Table 1

[0076] The aqueous coating formulations tested in the examples are listed in Table 2 below. The following compounding method was used.

[0077] Pigment grind: In the grinding process, water, dispersant, wetting agent, anti-foaming agent and pH neutralizer were added to a 1 L plastic cylinder in the order shown in Table 2 below. The mixture was then mixed at 400 rpm for 10 minutes by a disperser (also called a dissolver) equipped with a tooth-type dispersion plate (DISPERSER (trademark), type SFJ-400, Shanghai XianDai Environment Engineering Technique Co., Ltd., Shanghai, PRC). Thereafter, the pigment was gradually added stepwise into the cylinder over 30 minutes, and the dispersion speed was gradually increased to 2000 rpm. The dissolver was maintained at 2000 rpm for an additional 30 minutes, and subsequently a rheology modifier and water were added to obtain a pigment dispersion.

[0078] Let-down and coating composition formation: In the let-down process and the part A / part B mixing process, a triple agitator blade was used instead of the dissolver element in the disperser. The materials in the let-down process listed in Table 2 below were added to the pigment dispersion in the same container used to make the pigment dispersion, the mixing speed was gradually decreased to 1000 rpm, maintained at 1000 rpm, and mixed for 15 minutes to obtain an aqueous acrylic or vinyl polymer dispersion. The resulting aqueous dispersion was left standing for 1 day (24 hours) for degassing as part A. Then, part B was added to part A and mixed at 600 rpm for 10 minutes using a disperser.

[0079]

Table 2

[0080] Test method: The following test method was used in the following examples: Dispersion efficiency: In the pigment grinding process, after adding the pigment and before adding the rheology modifier and water, the KU viscosity (in Krebs units) of each paste was measured using a viscometer (BROOKFIELD (trademark) KU-2 viscometer, AMETEK Brookfield, Middleboro, MA) after dispersing for 30 minutes. A viscosity of less than 120 KU is acceptable. A low viscosity means high dispersion efficiency and excellent pigment dispersion performance.

[0081] Viscosity of the aqueous dispersion composition of Part A: After preparing the aqueous acrylic polymer dispersion of Part A, the KU viscosity of the Part A sample was measured immediately using a viscometer (BROOKFIELD (trademark) KU-2 viscometer) (recorded as "initial") and then measured again after 24 hours (recorded as "overnight"). A viscosity of less than 70 KU is acceptable.

[0082] pH stability: An aqueous acrylic or vinyl polymer dispersion of Part A was prepared and allowed to stand for 24 hours. Then, the pH was measured using a pH meter (METTLER TOLEDO (trademark), type S-470 scale Mettler Toledo, Columbus, OH), and the result was recorded as pH0. Next, Part A was sealed in a 250 mL plastic cylinder and placed in an oven at 50 ± 2 °C (model: UF110 MEMMERT GmbH, Schwabach, DE). After 75 days, each sample was taken out of the oven, cooled to room temperature, and the pH was measured using the same pH meter, and the result was recorded as pH1. The pH decrease after 75 days at 50 °C was calculated by the following formula.

[0083]

Equation

[0084] The smaller the change in pH, the better the pH stability. The allowable limit of the change in pH is 5% or less.

[0085] Gloss (60°): The gloss was tested in accordance with GB / T 9754-2007 (Standardization Administration of China, Beijing, PRC). After mixing Part A and Part B to form an aqueous coating composition, the coating film was drawn down onto a glass panel using a bar applicator (150 μm thick). After curing at 60 °C for 45 minutes, the coating film was taken out of the oven and tested using a BYK (trademark) Micro-Tri-Gloss gloss tester (Byk Chemie, Wallingford, CT).

[0086] Initial water resistance: After mixing Part A and Part B to form an aqueous coating composition, the coating film was drawn down onto a tin panel using a bar applicator (150 μm thick). The coating film was cured at room temperature for 15 minutes, then at 60 °C for 45 minutes, and then left at room temperature for 1 hour. Next, the sides of the tin panel were sealed with 3M adhesive tape. Then, the sealed panel was immersed in a deionized water bath. After 48 hours, the appearance of the coating film was visually observed and evaluated in accordance with ASTM D714 (2017). The appearance evaluation in ASTM D714 is shown in Table 3 below. The numbers represent the size of the blisters, and the letters represent the density of the blisters. The performance test results are summarized in Table 4 below.

[0087]

Table 3

[0088]

Table 4

[0089] As shown in Table 4 above, the results were excellent in Examples 1 and 2 of the present invention containing the glycol ether amine corresponding to formula (I). In particular, Examples 1 and 2 of the present invention showed a dramatic improvement in pH stability. Larger R 1The aqueous coating composition of Example 2 of the present invention containing a glycol ether amine having a base also showed excellent dispersion efficiency as compared with CE1, CE2, and CE3. Coatings made from the aqueous coating compositions of Examples 1 and 2 of the present invention both showed very good dry film properties with respect to coating film gloss and initial water resistance.

Claims

1. An aqueous composition comprising: (i) an aqueous acrylic or vinyl polymer dispersion, wherein the polymer contains on average two or more hydroxyl groups or contains a polyol; and (ii) one or more pigments, extenders or colorants, or combinations thereof; and (iii) one or more glycol ether amines having the following formula I: 【Chemical 1】 [wherein, R １ is a C １ -C ６ alkyl group, and R ２ and R ３ are independently CH ３ or CH ２ -CH ３ ; and m is from 1 to 6], and An aqueous composition.

2. The aqueous composition according to claim 1, wherein the acrylic or vinyl polymer containing on average two or more hydroxyl groups is present in an amount of 15 to 50% by weight as solids based on the total weight of the aqueous composition.

3. In formula I, R １ is C ３ to C ４ an alkyl group, and m is 1 to 2. The aqueous composition according to claim 1.

4. The aqueous composition according to claim 1, wherein the amount of the one or more glycol ether amines in (iii) ranges from 0.1 to 2% by weight based on the total weight of the aqueous composition.

5. The aqueous composition according to claim 4, wherein the amount of the one or more glycol ether amines in (iii) ranges from 0.1 to 1.5% by weight based on the total weight of the aqueous composition.

6. The aqueous composition according to claim 1, further comprising (iv) one or more coalescing solvents.

7. The aqueous composition according to claim 1, substantially free of volatile organic compounds, with a total of volatile organic compounds being 50 g / L or less.

8. The aqueous composition according to claim 1, further comprising a water-dispersible polyisocyanate curing agent containing one or more polyisocyanates in an aqueous coating composition.

9. The aqueous composition according to claim 8, wherein the ratio of the isocyanate equivalent in the water-dispersible polyisocyanate curing agent to the total number of hydroxyl group equivalents in the aqueous acrylic or vinyl polymer dispersion ranges from 0.7:1.0 to 2.0:1.

0.

10. A method of forming a coating, comprising: applying the aqueous coating composition according to claim 8 to a substrate or carrier; and curing it to form a coating or film on the substrate or carrier. A method.

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