KR20010009016A - Two-component water-based polyurethane paint - Google Patents

Abstract

The present invention relates to a two-component aqueous polyurethane coating composition that can be cured at 25 ° C. with a coating that exhibits improved hardness, glossiness, and solvent resistance. The coating composition includes a water-dispersible polymer resin having a hydroxyl group at the end, and a polyisocyanate that can be dispersed in an aqueous polymer resin dispersion and has an average functionality of 2.0 or more.

Description

Two-component water-based polyurethane paint

One-component or two-component solvent-based polyurethane compositions have long been known for producing high quality paints. However, water-based polyurethanes have become very important in recent years because the regulations on the allowable levels of volatile compounds released during the application of paints are becoming more and more stringent.

One-component aqueous polyurethane dispersions are well known and are used in the manufacture of various useful polyurethane products such as paints, adhesives, sealants and the like. Typically, such dispersions are prepared by dispersing a water dispersible polyurethane prepolymer having isocyanates at its ends with an active hydrogen chain extender in an aqueous medium.

In general, the prepolymers used in the preparation of such one component dispersions are substantially linear (ie bifunctional), reactive compounds containing excess diisocyanates containing ionic or nonionic hydrophobic groups or moieties, for example diols. Obtained by reacting with an isocyanate-reactive component comprising a polymeric diol in the presence of.

Although one-component aqueous polyurethane dispersions have reduced amounts of organic solvents compared to comparable solventborne coating compositions, for many uses, the aqueous dispersions, in particular in terms of glossiness, hardness and solvent resistance, It does not exhibit paint performance similar to solvent-based paint compositions. This difference is due to the lack of chemical crosslinking when forming films using one component aqueous systems.

Solvent-based bicomponent polyurethane compositions achieve the desired chemical crosslinking by using polyfunctional polyisocyanates such as those containing isocyanurate groups. Multifunctional polyisocyanates have high viscosity and are hydrophobic. Such polyisocyanates are inadequate for aqueous polyurethane compositions because they cannot be dispersed in aqueous dispersions.

Conventional attempts to carry out crosslinking of bicomponent aqueous polyurethane dispersions using hydrophilic polyisocyanates have been reported, for example, as described in US Pat. Nos. 5,200,489 and 5,252,696. Such patents disclose the preparation of water dispersible polyisocyanates using internal emulsifiers that can be used to prepare bicomponent polyurethane compositions. However, such internal emulsifiers make paints obtained from polyisocyanates susceptible to water. Among these disadvantages of the prior art, bicomponent aqueous based polyurethane coating compositions prepared using water dispersible polyisocyanates have a shorter pot life than desired, a greater amount of isocyanate crosslinking agent, and greater glossiness. Is lower (unless the amount of cosolvent is increased).

The present invention generally relates to bicomponent aqueous polyurethane dispersions having a reduced solvent content. More particularly, the present invention relates to bicomponent aqueous polyurethane dispersions which can be cured at room temperature or, if necessary, at temperatures above room temperature and contain low viscosity polyisocyanates. Paints made from such dispersions have improved hardness, glossiness and solvent resistance over conventional aqueous polyurethane dispersions.

Therefore, in the polyurethane coating industry, a solvent-free, low-solvent, water-based polyurethane coating composition which provides a paint having characteristics of superior physical properties and high glossiness and solvent resistance as compared to a solvent-based polyurethane composition. There is a need.

In one aspect, the present invention relates to a two-component aqueous polyurethane coating composition which can be cured at 25 ° C. (or, if necessary, at a temperature of 25 ° C. or higher), with a coating having improved hardness, glossiness, and solvent resistance. Paint composition

(I) can be cured in an aqueous polymer resin dispersion, has an average functionality of at least 2.0, and

(A) 3,3,5-trimethylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and combinations thereof 25% to 95% by weight of a polyisocyanate adduct selected from the group consisting of cyclodimer or allophanate of

(B) 3,3,5-trimethylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and combinations thereof 5 wt% to 75 wt% of another polyisocyanate adduct selected from the group consisting of cyclotrimer or biuret of

(C) polyisocyanates containing 0% to 30% by weight (preferably 0% to 20% by weight) of an organic solvent inert to isocyanates; And

(II) isocyanate-reactive, water-dispersible polymer resins having a hydroxyl value of 10 to 450 (preferably 28 to 350) and having a hydroxyl group at the terminal;

Including;

Provided that component (B) consists essentially of cyclotrimerized isophorone diisocyanate, component (C) is present in an amount of at least 10% by weight based on the weight of the coating composition.

In another aspect, the present invention relates to a method for producing the coating composition described above, and to a coated substrate containing the coating prepared with the coating composition. The method includes contacting components (I) and (II) of the two-component aqueous polyurethane coating composition to obtain a mixture, and mixing the mixture to obtain a mixed coating composition. The coated substrate is prepared by contacting the mixed paint composition with the substrate.

These and other aspects will become apparent upon reading the following detailed description of the invention.

In accordance with the present invention, it has been surprisingly found that a combination of water dispersible polyisocyanate adducts enables the preparation of solvent-free (or very low solvent) two-component paint compositions characterized by good physical properties. These physical properties can be compared with the physical properties that have been achieved so far only by using a solid solvent bicomponent polyurethane coating composition. In addition, coatings on substrates formed in accordance with the present invention have been found to be "mar-resistant" over a wide range of pencil lead hardness, and the coatings have no scratches in the coating. It may exhibit "self-healing" properties because it tends to disappear when left at room temperature. Thus, "mar" in the coating caused by pencil lead scratching can no longer be observed after a short time. Such surprising damage-resistance and self-healing properties will provide commercial advantages in top coats and transparent coatings, such as automotive paints.

In preparing the coating compositions of the invention, suitable polyisocyanate addition products are shown above. Cyclodimerized polyisocyanates contain ureddione moieties and are usually represented as dimers, while cyclotrimerized polyisocyanates contain isocyanurate moieties and are usually represented as trimers. Allophanates useful in the present invention are suitably made by reacting alcohols with the isocyanates to form carbamate intermediates, followed by further polyisocyanates to form the desired allophanates. Methods for forming allophanate are disclosed, for example, in US Pat. Nos. 5,461,135 and 5,124,427.

Other polyisocyanate addition products are suitably additionally used in the coating compositions of the present invention. Suitable additional polyisocyanate addition products include isopropanols prepared from organic diisocyanates represented by the following general formula R (NCO) ₂ , wherein R represents an organic group having a molecular weight of 24 to 2,100, preferably 56 to 1,000. Cyanurate, allophanate, uretidione or biuret. Preferred diisocyanates according to the present invention are those in which R represents a divalent aliphatic hydrocarbon group having 4 to 25 carbon atoms, a divalent cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms, or a divalent araliphatic hydrocarbon group having 6 to 20 carbon atoms. Examples of organic diisocyanates which are particularly suitable include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 1,10-decane Methylene diisocyanate, 1,12-dodecane methylene diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1-isocyanate-2-isocyanatomethyl cyclopental, isophorone Diisocyanate, bis- (4-isocyanatecyclohexyl) -methane, 1,3- and / or 1,4-bis- (isocyanatomethyl) -cyclohexane, bis- (4-isocyanato-3 -Methyl-cyclohexyl) -methane, α, α, α ', α'-tetramethyl, 1,3- and / or 1,4-xylene diisocyanate, 1-isocyanato-1-1methyl-4 (3) -isocyanatomethyl cyclohexane, 2,4- and / or 2,6-hexahydrotorylene diisocyanate, 4,4'-disclomethylmethane Isocyanate, m- and p-tetramethylxylene diisocyanate, p-xylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-di Phenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, 5-naphthalene diisocyanate. In addition, mixtures of polyisocyanates can be used, and polyisocyanates modified by urethane, allophanate, urea, biuret, carbodiimidine, uretonimine or isocyanurate residues can also be used.

As the organic solvent used randomly in the coating composition of the present invention, a solvent containing no isocyanate-reactive group is suitable. Examples of suitable solvents are acetone, methylamyl ketone, methylisobutyl ketone, n-methylpyrrolidone, dimethylformamide, dimethylacetamide, n-butylacetate, dipropylene glycol dimethyl ether, propylene glycol methylethyl acetate, propylene glycol Methyl ether, and other such water miscible solvents. In addition, mixtures of the above solvents may be used.

The isocyanate-reactive aqueous dispersible resin polymer having a hydroxyl group at the terminal used in the coating composition of the present invention preferably has a hydroxyl number of 10 to 450. Preferably, the hydroxy number is 28 to 350. Exemplary such hydroxy-terminated polymers are represented by the general formula:

R ₁ (OH) n

Wherein R ₁ has a molecular weight of 200 to 8,000, preferably 230 to 6,000, wherein (a) polyester, (b) polyether, (c) polyurethane, (d) polyacrylate, (e) Copoly (urethane-acrylate), or a combination thereof. The functionality of the hydroxy-terminated polymer represented by n in the general formula may be 1.8 to 8, preferably 2 to 6.

In addition, the hydroxy-terminated water-dispersible polymer resin according to the present invention has a nonionic or ionic hydrophilic group of 1 to 20% by weight, preferably 2 to 10% by weight. Suitable nonionic groups are polymeric ethylene oxides having 3 to 30 ethylene oxide repeat units. Suitable ionic groups are carboxyl groups, sulfone groups, sulfates and quaternized ammonium groups.

Particular examples of polyesters are the reaction products of one or more carboxylic acids, such as saturated aliphatic carboxylic acids, and / or aromatic carboxylic acids, and one or more polyhydric alcohols. Examples of aliphatic acids are oxalic acid, succinic acid, glutaric acid, adipic acid, pipel acid, suberic acid, sebacic acid, isosebacic acid, and azelaic acid. Examples of aromatic acids are phthalic acid, isophthalic acid, terephthalic acid and their anhydrides. Examples of polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 1,3-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5 -Hexanediol, 3,4-hexanediol, 1,7-heptanediol, 1,6-heptanediol, 1,5-heptanediol, 1,4-heptanediol, 1,3-heptanediol, 2,3- Heptanediol, 2,4-heptanediol, 2,5-heptanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,4-cyclohexanedimethanol, trimethylolpropane, and glycerol. The polyester according to the invention has a molecular weight of 150 to 8,000, preferably 450 to 4,000. Such polyesters have a functionality of 1.5 to 8, preferably 1.8 to 4.

Particular examples of polyethers are polymers obtained by the reaction of starting compounds containing reactive hydrogen atoms with alkylene oxides such as propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin or mixtures thereof. to be. In addition, a specific ratio of ethylene oxide may be included. Suitable starting compounds containing one or more reactive hydrogen atoms are suitable for preparing polyhydroxy polyesters, in addition to the polyols described above, water, methanol, ethanol, 1,2,6-hexanetriol, 1,2, 4-butanetriol, trimethylol ethane, pentaerythritol, mannitol, sorbitol, methyl glycoside, sucrose, phenol, isononyl phenol, resorcinol, hydroquinone and 1,1,1- or 1,1,2- Tris (hydroxyphenyl) ethane. The polyethers according to the invention have a molecular weight of 150 to 8,000, preferably 200 to 6,000. Such polyethers have a functionality of 1.5 to 8, preferably 1.8 to 4.

Particular examples of polyurethanes are the reaction products of diisocyanates with polyols. Suitable diisocyanates for the present invention are organic diisocyanates represented by the following general formula:

R (NCO) ₂

Wherein R represents an organic group having a molecular weight of 24 to 2,100, preferably 56 to 1,000. Preferred isocyanates according to the present invention are those represented by the above general formula wherein R represents a divalent aliphatic hydrocarbon group having 4 to 25 carbon atoms, a divalent cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms, or a divalent araliphatic hydrocarbon group having 6 to 20 carbon atoms. . Examples of organic diisocyanates which are particularly suitable in the present invention include ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene di Isocyanate, 1,10-decane methylene diisocyanate, 1,12-dodecane methylene diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1-isocyanato-2- Isocyanatomethyl cyclopentene, isophorone diisocyanate, bis- (4-isocyanatocyclohexyl) -methane, 1,3- and / or 1,4-bis- (isocyanatomethyl) -cyclo Hexane, bis- (4-isocyanato-3-methyl-cyclohexyl) -methane, α, α, α ', α'-tetramethyl, 1,3- and / or 1,4-xylene diisocyanate, 1-isocyanato-1-methyl-4 (3) -isocyanatomethyl cyclohexane, 2,4- and / or 2,6-hexahydrotoluylene di Socyanate, 4,4'-dicyclohexylmethane diisocyanate, m- and p-tetramethylxylene diisocyanate, p-xylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2 , 6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, 5-naphthalene diisocyanate. Suitable polyols include, in addition to those described above as polyesters and polyethers, hydroxy-terminated polylactones and hydroxy-terminated polycarbonates.

Suitable hydroxy terminated polylactones are polymeric products of valeratelactone, or ε-caprolactone, having a molecular weight of 400 to 6,000, preferably 650 to 3,000.

Suitable hydroxy terminated polycarbonates are polyhydric alcohols as described above for preparing polyhydroxyl polyesters, diaryl carbonates such as diphenyl carbonate, cyclic carbonates such as ethylene or propylene carbonate, or phosgene There is a reaction product obtained from the reaction. Also suitable are polyester carbonates or polyether carbonates obtained by reaction of the low molecular weight oligomers of the aforementioned polyesters, polylactones or polyethers with phosgene, diaryl carbonates or cyclic carbonates. Suitable hydroxy-terminated polycarbonates for the present invention have a molecular weight of 250 to 8,000, preferably 650 to 3,000.

Specific examples of hydroxy-containing polyacrylates include unsaturated hydroxylacrylic acid monomers (eg, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyacrylate), unsaturated acrylic acid Amide monomers (e.g. acrylamide, N-methylolacrylamide, methacrylamide), unsaturated carboxylic acid monomers (e.g. acrylic acid, methacrylic acid, itaconic acid, crotonic acid), unsaturated acid anhydride monomers (e.g. For example, itaconic anhydride, maleic anhydride, unsaturated glycidyl monomers (eg glycidyl acrylate, glycidyl methacrylate), acrylic ester monomers (eg ethyl acrylate, n-butyl Acrylate, 2-ethylhexyl acrylate), methacrylic acid ester monomers (e.g. methyl methacrylate, n-lauryl methacrylate, isobutyl methacrylate) ), Maleic acid escher monomers (eg dibutyl maleate, diethyl maleate), fumaric acid ester monomers (eg dibutyl fumarate, diethyl fumarate), styrene and derivatives thereof (eg For example, α-methylstyrene, β-chlorostyrene, α-bromostyrene, p-bromostyrene), nitrile (for example, acrylonitrile, methylacrylonitrile, ethylacrylonitrile) and the like There is a polymer obtained by polymerization of the above.

A particular example of copoly (urethane-acrylate) is a copolymer prepared as described above for component (c), except that 2-50% by weight of component (d) was used as the polyol. .

The two-component coating composition according to the invention is prepared by mixing the polyisocyanate of component (I) into a dispersion of an isocyanate-reactive aqueous solution of component (II) and / or a hydroxy terminated polymer. Such mixing of the two components is suitably carried out by simple stirring or vibration without high energy. The amount of the polyisocyanate component is selected to provide an equivalent ratio of NCO / OH of about 1 to 5, preferably about 1.2 to 2.0, based on the isocyanate group of component (I) and the hydroxyl group of component (II). The mixtures prepared according to the invention have a good pot life and spray viscosity of at least 2 hours.

Prior to mixing the polyisocyanate component (I) into the isocyanate reactive component (II), auxiliaries and additives typically used in paint technology can be incorporated into the isocyanate reactive component (II). Such auxiliaries and additives include foaming inhibitors, leveling aids, pigments, dispersion aids for solid pigments, surface active agents and the like.

The two-component paint compositions according to the invention thus obtained are suitable for solvent-containing, or solvent-free, or other water-based paint and substrate coating systems for practically any use in use today. Examples of such applications include painting and coating of metal surfaces, painting and coating of plastic surfaces, painting, coating, or sealing, lime and / or cement-bonding of wood and wood base materials such as plastic boards, fiber boards and papers. Painting, coating, or sealing of surfaces of inorganic materials such as building materials and concrete, and painting and coating of bitumen-containing pavements. Such compositions are also suitable for the combination of various materials in which the materials of the two surfaces may be the same or different.

The aqueous coating composition according to the present invention can be prepared by using any one of a variety of techniques well known in the field of the art such as spraying, roll-on, brush-on, and the like. It can be applied to. Such compositions may also contain pigments, leveling agents, catalysts, and other auxiliaries well known in the art.

The invention is further illustrated in the following examples which are not to be construed as limiting the invention, in which all parts and percentages are given by weight unless otherwise indicated.

Example 1 Preparation of Paints Containing HDI Dimer and HDI Trimer with Solvent.

Step 1

Preparation of Low Viscosity HDI Dimer / HDI Trimeric Isocyanate Crosslinkers

(a) 100 parts low viscosity hexamethylene diisocyanate (HDI) dimer; (a) 100 parts HDI trimer; And (c) 35.29 parts dipropylene glycol dimethyl ether (product of Dow Chemical Company, commercially available as PROGLYDE DMM) to prepare an HDI dimer / HDI trimer. This material was stirred for 30 minutes at room temperature.

Step 2

Preparation of Aqueous Dispersions of Polyurethane Ionomers and Polyurethane Resins

In a three-neck round bottom flask equipped with a reaction vessel of the appropriate size, ie reactor, temperature controller, condenser and nitrogen purge, the following five components were charged: (1) 110.92 parts of polyester polyol (OH equivalent: 270.75 ); (2) 45.48 parts isophorone diisocyanate (IPDI) monomers; (3) 13.60 parts dimethylol propionic acid (DMPA); (4) 30.00 parts by weight of N-methyl pyrrolidone; And (5) 0.10 part T-12 (dibutyltin dilaurate) catalyst.

This reaction mixture was heated to 80 ° C. and maintained until the NCO peak no longer appeared by IR. 185 parts of the ionomer were metered into an 800 mL disposable beaker and set aside for preparation of the dispersion as follows.

To neutralize the carboxy concentration in the ionomer, 8.78 parts of dimethylethanolamine (DMEA) was added to a 250 mL disposable beaker with tap water in an amount of 199.76 parts. This mixture was manually stirred using a spoon. The ionomer was placed under moderate pressure using a Premier Mill dispersator with a "hi-vis" mix head. In this ionomer, the above water / amine solution was charged and dispersed to obtain a desired aqueous dispersion of ionomer.

Step 3

Preparation and testing of two-component (2K) polyurethane-HDI dimer / HDI trimer paint

Crosslinking of the binary composition was first carried out by adding the following components to an 8 oz glass jar: 18.17 parts of isocyanate crosslinking agent (taken from step 1 of this example); 66.23 parts of ionomer dispersion (taken from step 2 of this example); 0.80 parts of SILWET L-7604 (10% aqueous) from OSi Specialties, Inc .; 0.80 parts of SILWET L-7605 (10% aqueous) from OSi Specialties, Inc .; 12.53 parts of dipropylene glycol dimethyl ether (as PROGLYDE DMM of Dow Coemical Company); And 12.40 parts of water. Standard tests are performed on the resulting paint and the results are presented in Table 1 below.

The coated test panels were cured at room temperature and humidity conditions for two weeks before testing for appearance, mechanical properties, and chemical resistance. Pencil hardness was measured according to ASTM D3363-92a. The conical mandrel bend test was measured according to ASTM D522-92 using an 8/1 inch tester from BYK-Gardner, Inc. Direct and reverse impact values were measured according to ASTM D2794-92 using a variable height impact tester from BYK-Gardner, Inc. Glossiness was measured using a micro-TRZ-gloss, multiangle glossmeter from BYK-Gardner. Cross-hatch adhesion was measured according to ASTM D3359-92a using a cross-hatch cutter from BYK-Gardner. Chemical resistance was measured according to ASTM D1308-87.

Physical properties result chemistry result Thickness (mils) 2.85 Chemical resistance Mandrel deflection (1/4 ") pass 10% in water (1/2 hour test) 20 ^o micro-gloss 84.95 60 ^o micro-gloss 92.30 Acetic acid pass Shock (Direct) +160 Sodium hydroxide pass Shock (inverted) +160 Hydrochloric acid pass Cross-hatch pass Solvent resistance Pencil hardness 〉 9H * (Test 1/2 hour under 2 "water gloss) MEX Rub (100 cycles) pass xylene pass Methyl ethyl ketone pass

* Coating showed damage resistance in 2B-9H pencil hardness test.

Example 2 Preparation of Paint Compositions Containing HDI Dimer and HDI Trimer without Solvent.

Step 1

Preparation of 100% Solid HDI Dimer / HDI Trimeric Isocyanate Crosslinkers

To a suitable reaction vessel, a three necked round bottom flask with stirring and nitrogen purge means, two components were added: (1) 35.00 parts of low viscosity hexamethylene diisocyanate (HDI) dimer; (2) 35.00 parts HDI trimers. These materials were stirred for 30 minutes at room temperature.

Step 2

Preparation of Paint Composition

Crosslinking was carried out according to the procedure as described in Example 1 using the following components to form the desired coating composition having the physical and chemical properties as set forth in Table 2 below: 18.40 parts of isocyanate crosslinker (See step 1 of Example 1); 66.23 parts dispersion (see step 2 of Example 1): 0.80 parts SILWET L-7604 (10% aqueous); 0.80 parts SILWET L-7605 (10% aqueous); 12.53 parts of dipropylene glycol dimethyl ether (as PROGLYDE DMM); And 12.40 parts of water.

Physical properties result chemistry result Thickness (mils) 2.65 Chemical resistance Mandrel deflection (1/4 ") pass 10% in water (1/2 hour test) 20 ^o micro-gloss 85.0 60 ^o micro-gloss 81.5 Acetic acid pass Shock (Direct) +160 Sodium hydroxide pass Shock (inverted) +160 Hydrochloric acid pass Cross-hatch pass Solvent resistance Pencil hardness 〉 9H * (Test 1/2 hour under 2 "water gloss) MEX Rub (100 cycles) pass xylene pass Methyl ethyl ketone pass

* Coating showed damage resistance in 2B-9H pencil hardness test.

Example 3- Preparation of Paint Compositions Containing Allophanate and HDI Trimer without Solvent.

Step 1

Preparation of HDI Trimer / Allophanate Isocyanate Crosslinker

The following trimer / allopanate was prepared using the procedure of Example 2 of Example 1 without solvent:

HDI trimer part 35.00

Allophanate Part 35.00

Step 2

Preparation of Paint Composition

Crosslinking was carried out according to the procedure described in Example 1 using the following components to prepare the desired coating composition: 18.86 parts of isocyanate crosslinking agent (see step 1 of Example 1); 66.23 parts of dispersion (see Step 2 of Example 1); 0.80 parts SILWET L-7604 (10% aqueous); 0.80 parts SILWET L-7605 (10% aqueous); 12.53 parts of dipropylene glycol dimethyl ether (as PROGLYDE DMM); And 12.40 parts of water.

Example 4- Preparation of Paint Containing Allophanate and IPDI Trimer

Step 1

Preparation of IPDI Trimer / Allophanate Isocyanate Crosslinker

The following trimer / allopanate isocyanate was prepared using the procedure of Step 1 of Example 1:

IPDI trimer part 35.00

Allophanate Part 35.00

DMM Part 17.50

Step 2

Preparation of Paint Composition

Crosslinking was carried out according to the procedure described in Example 1 using the following components to prepare the desired coating composition: 22.88 parts of isocyanate crosslinking agent (see step 1 of Example 1); 66.23 parts of dispersion (see Step 2 of Example 1); 0.80 parts SILWET L-7604 (10% aqueous); 0.80 parts SILWET L-7605 (10% aqueous); 12.40 parts of dipropylene glycol dimethyl ether (as PROGLYDE DMM); And 12.40 parts of water.

While the present invention has been described above with reference to particular embodiments, it will be apparent that many variations, modifications, and changes may be made without departing from the spirit of the invention disclosed herein. Accordingly, all such changes, changes and modifications are intended to be included within the spirit and scope of the enclosed claims.

The aqueous polyurethane coating composition of the present invention has excellent physical properties, high gloss and solvent resistance as compared to the solvent-based polyurethane composition, and thus is usefully applied to the polyurethane coating industry requiring a solvent-free and low solvent. Can be.

Claims (17)

A two-component aqueous polyurethane coating composition that can be cured into a paint having improved hardness, gloss and solvent resistance, wherein the coating composition is (I) can be cured in an aqueous polymer resin dispersion, has an average functionality of at least 2.0, and (A) 3,3,5-trimethylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and combinations thereof 25% to 95% by weight of a polyisocyanate adduct selected from the group consisting of cyclodimer or allophanate of (B) 3,3,5-trimethylhexamethylene diisocyanate, 2-methylhexamethylene diisocyanate, isophorone diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and combinations thereof 5 wt% to 75 wt% of another polyisocyanate adduct selected from the group consisting of cyclotrimer or biuret of (C) polyisocyanates containing 0-30% by weight of an organic solvent inert to isocyanates; And (II) isocyanate-reactive, water-dispersible polymer resins having a hydroxyl value of 10 to 450 (preferably 28 to 350) and having a hydroxyl group at the terminal; Including; Provided that component (B) consists essentially of cyclotrimerized isophorone diisocyanate, wherein component (C) is present in an amount of at least 10% by weight based on the weight of the coating composition Aqueous polyurethane composition. A two-component aqueous polyurethane coating composition that can be cured into a paint having improved hardness, gloss and solvent resistance, wherein the coating composition is (I) can be cured in an aqueous polymer resin dispersion, has an average functionality of at least 2.0, and (A) cyclodimerized 1,4-tetramethylene diisocyanate, cyclodimerized 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate allophanate, 1,6-hexamethylene diisocyanate allo 25% to 95% by weight of a polyisocyanate adduct selected from the group consisting of panates, and combinations thereof, (B) 5 weights of a polyisocyanate product selected from the group consisting of cyclotrimerized hexamethylene diisocyanate, hexamethylene diisocyanate biuret, cyclotrimerized isophorone diisocyanate, isophorone diisocyanate biuret, and combinations thereof % To 75% by weight, (C) polyisocyanates containing 0-30% by weight of an organic solvent inert to isocyanates; And (II) Isocyanate-reactive, water-dispersible polymer resins having a hydroxyl value of 10 to 450 and having a hydroxyl group at the terminal Including; Provided that component (B) consists essentially of cyclotrimerized isophorone diisocyanate, wherein component (C) is present in an amount of at least 10% by weight based on the weight of the coating composition Aqueous polyurethane composition. A composition according to claim 1, wherein the polyisocyanate adduct of component (A) is uretdione or allophanate, or a combination thereof, prepared from hexamethylene diisocyanate. 4. The composition of claim 3 wherein the aliphatic diisocyanate is tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, and combinations thereof. 4. A composition according to claim 3, wherein the adduct has an average isocyanate content of 16 to 25, preferably 18 to 23. The composition of claim 1, wherein said polyisocyanate further contains isocyanurate, allophanate, uretidione or biuret, prepared from organic isocyanates represented by the general formula: R (NCO) ₂ In the formula, R represents a divalent aliphatic hydrocarbon group having 4 to 25 carbon atoms, a divalent cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms, or a divalent araliphatic hydrocarbon group having 6 to 20 carbon atoms. 6. The diisocyanate of claim 5, wherein the diisocyanate is 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 4,4'-diisocyanatodicyclohexylmethane, 3,3,5-trimethylhexamethylene di Isocyanate, 2-methylhexamethylene diisocyanate, isophorone diisocyanate, and combinations thereof. A coated article made by contacting a substrate with the coating composition of claim 1. The method of claim 1, wherein the organic solvent is acetone, methyl amyl ketone, methyl ethyl ketone, methyl isobutyl ketone, n-methylpyrrolidone, dimethylformamide, dimethylacetamide, n-butyl acetate, dipropylene glycol dimethyl ether , Propylene glycol methylethyl acetate, propylene glycol methyl ether, xylene, and combinations thereof. The composition of claim 1, wherein the hydroxy-terminated water dispersible polymer resin is selected from the group of resins represented by the following general formula: R ₁ (OH) n Wherein R ₁ is selected from the group consisting of polyesters, polyethers, polyurethanes, polyacrylates, copoly (urethaneacrylates), and combinations thereof. 10. The composition of claim 9, wherein the hydroxy-terminated water dispersible polymer resin has a molecular weight of 150 to 8,000. The composition of claim 10, wherein the hydroxy-terminated water dispersible polymer resin has a molecular weight of 650 to 5,000. 11. The composition of claim 10 wherein the functionality of the hydroxy-terminated water dispersible polymer resin is from 1.8 to 8. 11. The composition of claim 10, wherein the functionality of the hydroxy-terminated water dispersible polymer resin is 2 to 6. The composition of claim 10, wherein R ₁ is polyurethane. The composition of claim 10, wherein R ₁ is copoly (urethane-acrylate). A method for producing a coating composition, characterized by contacting component (I) and component (II) of the two-component aqueous polyurethane coating composition of claim 1 to provide a mixture, and mixing the mixture.