Water-soluble polyurethane dispersion composition and base coat composition comprising polyurethane dispersion prepared therefrom

Abstract

The present invention relates to: a water-soluble polyurethane dispersion composition comprising a polycarbonate polyol, an alkylene phosphoric acid polyol, and an isocyanate compound, wherein the alkylene phosphoric acid polyol comprises an acid group and a hydroxyl group; and a base coat composition comprising a polyurethane dispersion prepared from the composition.

Description

Water-soluble polyurethane dispersion composition and base coat composition comprising a polyurethane dispersion prepared therefrom

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0156498, filed November 13, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a water-soluble polyurethane dispersion composition, and a base coat composition comprising a polyurethane dispersion prepared therefrom, wherein the resulting coating film has excellent various physical properties such as appearance characteristics, adhesion, and water resistance.

[0003] Automotive repair is the process of restoring a wide range of damaged areas, from small, localized damage to large, three-panel repairs, to their original condition. Specifically, the automotive repair process for repairing damaged areas is broadly divided into surface conditioning, intermediate coating, and topcoat stages. Specifically, the topcoat stage typically involves masking areas that do not require a topcoat, applying a pigmented base paint to match the color, applying a transparent clear paint to impart gloss and enhance durability, and polishing and evaluation stages to ensure a clean finish to the painted exterior.

[0004] Meanwhile, the transition to aqueous solutions for automotive refinish paints is actively underway worldwide, particularly in the United States and Europe. A common method for aqueous solutions for automotive refinish paints is to aqueousize the resin used in the paint. Methods for aqueous solutions include forcing an organic resin made from petroleum-derived materials to dissolve in water using an emulsifier; creating a resin by incorporating a monomer containing a hydrophilic functional group during the synthesis of the organic resin and then later adding water, such as deionized water; or creating a resin by adding an emulsifier along with a monomer containing a hydrophilic functional group during the synthesis of the organic resin. As described above, when using an emulsifier alone or a monomer containing a hydrophilic functional group alone, the higher the molecular weight of the resin, the more emulsifier or monomer containing a hydrophilic functional group is required. However, excessive amounts of emulsifier or monomer containing a hydrophilic functional group can lead to excessively high hydrophilicity of the resulting resin, which can degrade the physical properties of the coating, such as water resistance and rust prevention.

[0005] Meanwhile, rising consumer demand for acid and scratch resistance is accelerating the development of highly functional yet environmentally friendly base paints. In particular, water-soluble base paints for repair applications are being developed to offer similar film properties to existing solvent-based paints, such as superior appearance, adhesion, and water resistance. Furthermore, the development of water-soluble, environmentally friendly paints is being sought.

[0006] For example, Korean Patent No. 10-1044781 (Patent Document 1) discloses a water-soluble base coat paint composition comprising: i) 60-80 parts by weight of a mixing binder comprising an emulsion resin, a polyurethane dispersion resin, a pH adjuster for the mixing binder, and a first solvent; and ii) 20-40 parts by weight of a color paste composition comprising a polyester resin, a pigment, a pH adjuster for the paste composition, and a second solvent. However, the base coat paint composition of Patent Document 1 had problems of insufficient drying and adhesion.

[0007] Therefore, there is a need for research and development of a base coat composition that has excellent appearance properties, adhesion, water resistance, etc. and is water-soluble and environmentally friendly.

[0008] Accordingly, the present invention provides a base coat composition having excellent appearance properties, adhesion, water resistance, etc., and being water-soluble and thus environmentally friendly.

[0009] The present invention provides a water-soluble polyurethane dispersion composition comprising a polycarbonate polyol, an alkylene phosphate polyol, and an isocyanate compound.

[0010] In addition, the present invention provides a base coat composition for automobile repair, comprising a water-soluble polyurethane dispersion prepared from the above composition, an acrylic resin, and a solvent.

[0011] A base coat composition comprising a polyurethane dispersion prepared from a water-soluble polyurethane dispersion composition according to the present invention exhibits excellent appearance properties, adhesion, and water resistance of the resulting coating film. Furthermore, the base coat composition is water-soluble and therefore environmentally friendly, and its moderate drying speed also provides excellent workability.

[0012] The present invention is described in detail below.

[0013] The “weight average molecular weight” used in this specification is measured by a conventional method known in the art, and can be measured by, for example, a GPC (gel permeation chromatography) method.

[0014] Additionally, the “glass transition temperature” is measured by a conventional method known in the art, and can be measured by, for example, differential scanning calorimetry (DSC).

[0015] Furthermore, functional groups such as “acid value”, “hydroxyl value” and “amine value” can be measured by methods well known in the art, for example, by titration.

[0016] Additionally, “viscosity” is measured by a conventional method well known in the art, and can be measured, for example, using a Brookfield viscometer (rotating spindle viscometer) at room temperature (20°C or 25°C).

[0017] "Average diameter" is measured by a conventional method known in the art, for example, the cumulative distribution of 50% (D) in the particle size distribution measured using a particle size analyzer (PSA). 50 ) can be the diameter.

[0018] Water-soluble polyurethane dispersion composition

[0019] The water-soluble polyurethane dispersion composition according to the present invention comprises a polycarbonate polyol, an alkylene phosphate polyol, and an isocyanate compound.

[0020] Typically, resins with an ester structure can be produced by the condensation water being removed when a carboxyl group and a hydroxyl group meet, so conversely, esters tend to hydrolyze in the presence of water, which results in poor water resistance. However, the polycarbonate polyol is produced by the reaction of a hydroxyl-containing bisphenol-based resin with a phosgene structure, releasing hydrochloric acid to produce a carbonic ester. Even in the presence of water, no reverse hydrolysis reaction occurs, so it has the advantage of excellent water resistance.

[0021] In addition, since metal materials such as automobiles have polar properties on their surfaces, coating with a material having polar groups can improve adhesion. Accordingly, the present invention includes an alkylene phosphate polyol that has polar phosphate groups and also contains a polyol group capable of forming urethane, thereby providing the advantages of excellent adhesion of the coating film produced and easy polyurethane production.

[0022] Specifically, the present invention uses polycarbonate polyol and alkylene phosphate polyol containing acid groups and hydroxyl groups as monomers used in the production of polyurethane, thereby improving water resistance due to non-hydrolyzable carbonate groups, and improving adhesion by forming covalent bonds with polar materials through phosphate groups.

[0023] polycarbonate polyol

[0024] Polycarbonate polyol is a resin in which the polyol reacts with an isocyanate compound to form polyurethane.

[0025] The above polycarbonate polyol may be a ring-opening polymer of an alicyclic alkylene carbonate and a polyhydroxy compound.

[0026] At this time, the alicyclic alkylene carbonate may be, for example, an alicyclic alkylene carbonate having 2 to 6 carbon atoms, or an alicyclic alkylene carbonate having 2 to 4 carbon atoms. Specifically, the alicyclic alkylene carbonate may be cycloethylene carbonate.

[0027] The polyhydroxy compound may be, for example, an alkylene diol having 2 to 8 carbon atoms, or an alkylene diol having 4 to 7 carbon atoms. Specifically, the polyhydroxy compound may include at least one selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0028] Specifically, the polycarbonate polyol may be poly(hexamethylene carbonate) diol.

[0029] In addition, the polycarbonate polyol may have a weight average molecular weight (Mw) of 500 to 3,000 g / mol or 1,000 to 2,000 g / mol. When the weight average molecular weight of the polycarbonate polyol is within the above range, the manufactured coating film may have excellent wetting properties and adhesion properties with respect to the substrate. On the other hand, when the weight average molecular weight of the polycarbonate polyol is less than the above range, the viscosity of the polyol may increase, thereby deteriorating the water dispersibility of the manufactured polyurethane, or the glass transition temperature (Tg) of the manufactured polyurethane may increase, thereby deteriorating the wetting properties with respect to the substrate or increasing the hardness of the manufactured coating film, resulting in insufficient adhesion. On the other hand, when the weight average molecular weight of the polycarbonate polyol exceeds the above range, the glass transition temperature (Tg) of the manufactured polyurethane may be excessively low, resulting in insufficient hardness of the manufactured coating film.

[0030] The polycarbonate polyol may have a hydroxyl value (OHv) of 30 to 200 mgKOH / g, 50 to 150 mgKOH / g, or 55 to 120 mgKOH / g. When the hydroxyl value of the polycarbonate polyol is less than the above range, the glass transition temperature (Tg) of the manufactured polyurethane may excessively increase, causing a problem in that the wetting property of the manufactured coating film with the substrate may be reduced or the hardness may increase, resulting in a problem in that the adhesion may be reduced. When the hydroxyl value is less than the above range, the glass transition temperature (Tg) of the manufactured polyurethane may excessively decrease, causing a problem in that the hardness of the manufactured coating film may be reduced.

[0031]

[0032] alkylene phosphate polyol

[0033] Alkylene phosphate polyol reacts with an isocyanate compound to form polyurethane, and serves to improve the adhesion of a composition including the manufactured polyurethane.

[0034] The above alkylene phosphate polyol contains an acid group and a hydroxyl group. Specifically, the above alkylene phosphate polyol may contain a compound represented by the following chemical formula 1.

[0035]

[0036] In chemical formula 1, R 1 is a group containing oxyalkylene or alkylene.

[0037] For example, R 1 may be a polyoxyethylene group.

[0038] Specifically, the alkylene phosphate polyol may include a compound represented by the following chemical formula 2.

[0039]

[0040] In chemical formula 2, R 3 and R 4 are each independently alkylene.

[0041] For example, R 3and R 4 Each may independently be an alkylene having 2 to 5 carbon atoms, or 2 to 3 carbon atoms.

[0042] The above alkylene refers to a branched, straight-chain or cyclic divalent radical derived by removing one hydrogen atom from a carbon atom of an alkyl group.

[0043] The above alkylene phosphate polyol may have a weight average molecular weight (Mw) of 300 to 800 g / mol, or 500 to 650 g / mol. When the weight average molecular weight of the alkylene phosphate polyol is within the above range, the reaction stability of the manufactured polyurethane dispersion may be excellent and the hardness of the manufactured coating film may be excellent. On the other hand, when the weight average molecular weight of the alkylene phosphate polyol is less than the above range, the low molecular weight may delay the urethane reaction, thereby lowering the stability of the manufactured polyurethane. When it exceeds the above range, the glass transition temperature (Tg) of the manufactured polyurethane may be excessively low, which may cause a problem in that the hardness of the manufactured coating film may be lowered.

[0044] In addition, the alkylene phosphate polyol may have a hydroxyl value (OHv) of 50 to 150 mgKOH / g or 90 to 120 mgKOH / g. When the hydroxyl value of the alkylene phosphate polyol is within the above range, it has the effect of improving the adhesion of the produced coating film by reacting with an isocyanate compound to impart a phosphoric acid group to the polyurethane structure. On the other hand, when the hydroxyl value of the alkylene phosphate polyol is below the above range, the amount of phosphoric acid groups introduced into the structure of the manufactured polyurethane is insufficient, which may result in poor adhesion of the manufactured coating film, or the glass transition temperature (Tg) of the manufactured polyurethane may be excessively low, which may result in a decrease in hardness of the manufactured coating film. When the value exceeds the above range, a large amount of phosphoric acid groups may be provided into the structure of the manufactured polyurethane, which may result in excessive hydrophilization of the polyurethane, which may result in a decrease in water resistance, and a problem may occur in which the reactivity during urethane reaction is reduced, which may result in a decrease in storage stability of the manufactured polyurethane.

[0045] The polycarbonate polyol and the alkylene phosphate polyol may be included in the composition in an equivalent ratio of 0.1:1 to 10:1, or an equivalent ratio of 0.5:1 to 2.5:1. When the weight ratio of the polycarbonate polyol and the alkylene phosphate polyol is within the above range, the adhesion of the manufactured coating film and the water dispersibility stability of the manufactured polyurethane are excellent. On the other hand, when the weight ratio of the polycarbonate polyol and the alkylene phosphate polyol is less than the above range, that is, when a small amount of polycarbonate polyol is included with respect to the weight of the alkylene phosphate polyol, the hydrophilicity of the manufactured polyurethane excessively increases, thereby lowering the water resistance of the manufactured coating film. When the weight ratio exceeds the above range, that is, when an excessive amount of polycarbonate polyol is included with respect to the weight of the alkylene phosphate polyol, the water dispersibility may become poor due to a decrease in the hydrophilicity of the manufactured polyurethane.

[0046]

[0047] isocyanate compounds

[0048] Isocyanate compounds react with polycarbonate polyols and alkylene phosphate polyols to form polyurethanes.

[0049] The above isocyanate compound may include an alicyclic first isocyanate compound and a linear second isocyanate compound. The alicyclic first isocyanate compound has the advantage of improving the hardness of the produced coating film due to its alicyclic structure and improving the water dispersion stability of the produced polyurethane. Meanwhile, the linear second isocyanate compound has the advantage of improving the adhesion of the produced coating film. Accordingly, the dispersion composition contains a combination of an alicyclic isocyanate compound and a linear isocyanate compound, thereby providing the effects of excellent hardness of the produced coating film, excellent water dispersion stability of the produced polyurethane, and improved adhesion of the coating film.

[0050] The first isocyanate compound serves to improve the hardness of the manufactured coating film and to improve the water dispersion stability of the manufactured polyurethane. Specifically, the first isocyanate compound may contain two or more isocyanate groups (NCO groups) in one molecule and may have an alicyclic structure. More specifically, the first isocyanate compound may be a bifunctional compound having an alicyclic structure. For example, the first isocyanate compound may include at least one selected from the group consisting of isophorone diisocyanate and 4,4-dicyclomethane diisocyanate.

[0051] The second isocyanate compound controls the reactivity of the polyurethane composition and controls the glass transition temperature (Tg) of the produced polyurethane. Specifically, the second isocyanate compound may contain two or more isocyanate groups (NCO groups) in one molecule and have a linear structure. More specifically, the second isocyanate compound may be a bifunctional compound having a linear structure. For example, the second isocyanate compound may include at least one selected from the group consisting of hexamethylene diisocyanate and trimethylhexamethylene diisocyanate.

[0052] The first isocyanate compound and the second isocyanate compound may be included in the composition in a weight ratio of 3:1 to 1:1, or a weight ratio of 2:1 to 1:1. When the weight ratio of the first isocyanate compound and the second isocyanate compound is within the above range, there is an effect of improving the water dispersion stability of the manufactured polyurethane and the adhesion of the manufactured coating film. On the other hand, when the weight ratio of the first isocyanate compound and the second isocyanate compound is less than the above range, that is, when a small amount of the first isocyanate compound is included with respect to the weight of the second isocyanate compound, a problem may occur in which the hardness of the manufactured coating film is lowered or the water dispersion stability of the manufactured polyurethane is lowered. On the other hand, when the weight ratio exceeds the above range, that is, when an excessive amount of the first isocyanate compound is included with respect to the weight of the second isocyanate compound, a problem may occur in which the hardness of the manufactured coating film is excessively increased and the adhesion is lowered.

[0053] The above dispersion composition may contain the isocyanate group of the isocyanate compound in an amount of 1.0 to 1.5 moles (NCO / OH mole ratio) relative to the total moles of hydroxyl groups of the polycarbonate polyol and the alkylene phosphate polyol. Specifically, the dispersion composition may contain the isocyanate group of the isocyanate compound in an amount of 1.1 to 1.4 moles (NCO / OH mole ratio) relative to the total moles of hydroxyl groups of the polycarbonate polyol and the alkylene phosphate polyol. When the NCO / OH mole ratio is within the above range, the appearance and hardness of the produced coating film are excellent. On the other hand, when the NCO / OH mole ratio is less than the above range, the viscosity of the produced polyurethane is high, which causes a problem in that the appearance characteristics of the produced coating film are deteriorated, and when it exceeds the above range, the hardness of the produced coating film may be deteriorated or the adhesion may be insufficient.

[0054] The above dispersion composition may additionally include one or more additives selected from the group consisting of solvents, neutralizing agents, and chain extenders.

[0055] additives

[0056] At this time, each of the above-mentioned additives, such as solvent, neutralizer, and chain extender, can be used without any special restrictions as long as it is one that can be commonly used in the production of polyurethane.

[0057] The content of the above additive can be appropriately adjusted considering various physical properties of the composition, such as fluidity and viscosity.

[0058]

[0059] Base coat composition for automotive repair

[0060] In addition, the base coat composition for automobile repair of the present invention comprises a water-soluble polyurethane dispersion prepared from the water-soluble polyurethane dispersion composition described above, an acrylic resin, and a solvent.

[0061] Water-soluble polyurethane dispersion

[0062] The above water-soluble polyurethane dispersion serves as a main resin of the paint, forms a coating film, and imparts elongation and elasticity properties to the manufactured coating film and imparts rheological properties.

[0063] In addition, the water-soluble polyurethane dispersion is prepared from the composition described above. At this time, the method for preparing the water-soluble polyurethane dispersion is not particularly limited as long as it is a temperature and pressure that can be typically applied when preparing a polyurethane dispersion, and may be performed at, for example, 60 to 100°C or 70 to 90°C.

[0064] The above water-soluble polyurethane dispersion may be a water-dispersed polyurethane resin.

[0065] In addition, the water-soluble polyurethane dispersion may have a viscosity at 25°C of 10 to 500 cP, or 15 to 100 cP. When the viscosity of the polyurethane dispersion at 25°C is within the above range, the workability of a paint composition containing it may be excellent. In addition, when the viscosity of the polyurethane dispersion at 25°C is less than the above range, the viscosity of the urethane resin may be excessively low, which may cause a problem in that the workability of a paint composition containing it may be insufficient, and when the viscosity exceeds the above range, the viscosity of the urethane resin may be excessively high, resulting in poor stability, and poor dispersion stability, which may cause agglomeration over time.

[0066] The above water-soluble polyurethane dispersion may have an acid value (Av) of 10 to 40 mgKOH / g, or 20 to 35 mgKOH / g. When the acid value of the water-soluble polyurethane dispersion is within the above range, the water dispersibility and storage stability of a coating composition containing the same are improved, and the water resistance of the coating film is improved. In addition, when the acid value of the water-soluble polyurethane dispersion is below the above range, the hydrophobicity of the polyurethane dispersion is strengthened, thereby reducing the water dispersibility, and when it exceeds the above range, the hydrophilicity of the polyurethane dispersion is strengthened, thereby increasing the hydrophilic component, and thus the water resistance of the resulting coating film may be poor.

[0067] In addition, the water-soluble polyurethane dispersion may have an amine value of 10 to 40 mmol / g, or 20 to 30 mmol / g. When the amine value of the water-soluble polyurethane dispersion is within the above range, the water resistance, adhesion, and appearance properties of the produced coating film are improved. In addition, when the amine value of the water-soluble polyurethane dispersion is below the above range, the storage stability of the polyurethane dispersion is poor, which may cause a problem in that the coating film formability of the coating composition containing the polyurethane dispersion is insufficient, and when it exceeds the above range, the viscosity of the polyurethane dispersion is high, which may cause a problem in that it cannot be applied to a coating.

[0068] The above water-soluble polyurethane dispersion may have an average diameter of dispersed particles of 50 to 100 nm, or 60 to 80 nm. When the average diameter of the dispersed particles of the polyurethane dispersion is within the above range, the dispersion stability of the polyurethane particles may be improved, thereby improving the appearance of the produced coating film. In addition, when the average diameter of the dispersed particles of the polyurethane dispersion is less than the above range, the viscosity of the dispersion may be excessively high, which may cause a problem in applying the dispersion to paints, and when it exceeds the above range, the viscosity of the dispersion may be excessively low, which may cause a problem in the workability of the paint containing the dispersion. At this time, the average diameter of the dispersed particles may be measured by diluting the dispersion to a concentration of 0.1 mass% in deionized water (DIW) using a particle size analyzer (PSA) or laser light scattering (LLS).

[0069] In addition, the above-mentioned water-soluble polyurethane dispersion can be diluted with a solvent, stored in a separate container, and then thoroughly stirred immediately before use. At this time, the solvent is not particularly limited as long as it is a typical solvent used in paint compositions.

[0070] The above water-soluble polyurethane dispersion may have a pH of 5 to 9, or 6 to 8. At this time, the pH of the water-soluble polyurethane dispersion may be adjusted using a neutralizing agent as described above in the composition.

[0071] In addition, the water-soluble polyurethane dispersion may be included in the base coat composition in an amount of 10 to 50 parts by weight, 15 to 45 parts by weight, or 25 to 35 parts by weight, based on 100 parts by weight of the base coat composition. When the amount of the polyurethane dispersion is within the above range, there is an effect of improving the water resistance of the manufactured coating film and improving the stability of the coating composition after water dispersion. In addition, when the amount of the polyurethane dispersion is less than the above range, the water resistance of the manufactured coating film and the water dispersion stability of the coating composition are lowered, and when the amount is greater than the above range, the hardness of the manufactured coating film may be lowered.

[0072]

[0073] acrylic resin

[0074] The above acrylic resin is the main resin of the paint, plays a role in forming a coating film, and plays a role in improving the appearance characteristics such as gloss, adhesion, and water resistance of the manufactured coating film.

[0075] The above acrylic resin may be in the form of a water-dispersed acrylic emulsion.

[0076] In addition, the acrylic resin may have a glass transition temperature (Tg) of 10 to 70° C., or 15 to 60° C. When the glass transition temperature of the acrylic resin is within the above range, the film formability and adhesion of the base coat composition containing the acrylic resin and the gloss properties of the film are improved. On the other hand, when the glass transition temperature of the acrylic resin is below the above range, the produced film becomes excessively soft, which causes problems such as insufficient hardness of the film and slow drying of the composition. When the glass transition temperature exceeds the above range, the drying speed of the coat composition containing the acrylic resin becomes fast, which may cause insufficient appearance properties of the produced film.

[0077] The above acrylic resin may have an acid value (Av) of 15 to 35 mgKOH / g, or 20 to 30 mgKOH / g. When the acid value of the acrylic resin is within the above range, the water dispersibility and storage stability of a base coat composition containing the acrylic resin are improved, and the water resistance of the coating film is improved. In addition, when the acid value of the acrylic resin is below the above range, the hydrophobicity of the acrylic resin is strengthened, thereby reducing the water dispersibility, and when it exceeds the above range, the hydrophilicity of the acrylic resin is strengthened, thereby increasing the hydrophilic component, and thus the water resistance of the resulting coating film may be poor.

[0078] In addition, the acrylic resin may have an amine value of 5 to 25 mgKOH / g, or 7 to 15 mgKOH / g. When the amine value of the acrylic resin is within the above range, the water resistance and adhesion of the produced coating film, and the appearance of the coating film are improved. In addition, when the amine value of the acrylic resin is below the above range, the storage stability of the acrylic resin is poor, which may cause a problem in that the coating composition has insufficient film formability, and when it exceeds the above range, the viscosity of the acrylic resin may increase, which may cause a problem in that it cannot be applied to paint.

[0079] The acrylic resin may have a viscosity at 25°C of 10 to 500 cP, or 10 to 300 cP. When the viscosity of the acrylic resin at 25°C is within the above range, the storage stability of the acrylic resin and the storage stability of the paint composition may be improved, and workability may be excellent. On the other hand, when the viscosity of the acrylic resin at 25°C is less than the above range, the viscosity of the acrylic resin may be excessively low, which may cause a problem in that the workability of the paint composition containing the acrylic resin may be insufficient, and when the viscosity exceeds the above range, the viscosity of the acrylic resin may be excessively high, which may result in poor stability during reaction, poor dispersion stability, and agglomeration may occur over time.

[0080] In addition, the average particle diameter of the dispersed particles of the acrylic resin may be 50 to 300 nm, or 100 to 200 nm. When the average particle diameter of the dispersed particles of the water-soluble acrylic resin is within the above range, excellent dispersion stability is achieved when applied to resin and / or paint. On the other hand, when the average particle diameter of the dispersed particles of the acrylic resin is less than the above range, the viscosity of the acrylic resin increases, which may cause a problem of insufficient workability of the paint, and when it exceeds the above range, the dispersed particles of the acrylic resin may be too large, which may cause a problem with the appearance of the manufactured coating film. At this time, the average particle diameter of the dispersed particles may be the result of diluting a sample in water to a concentration of 0.1 mass% and measuring it with LLS (laser light scattering) or PSA (Particle size analyzer).

[0081] In addition, the acrylic resin may be included in the coating composition in an amount of 10 to 50 parts by weight, 15 to 45 parts by weight, or 25 to 35 parts by weight, based on 100 parts by weight of the base coat composition. When the content of the acrylic resin is within the above range, it has the effect of improving the appearance, adhesion, and water resistance of the manufactured coating film. On the other hand, when the content of the acrylic resin is less than the above range, the adhesion, water resistance, and appearance of the manufactured coating film may deteriorate, and when it exceeds the above range, the storage stability of the paint containing it may deteriorate.

[0082]

[0083] solvent

[0084] Solvents play a role in improving workability by controlling the viscosity of the paint composition and as an antifreeze agent.

[0085] The solvent may include at least one selected from the group consisting of organic solvents and water. For example, the solvent may include a mixture of water and an organic solvent, but may be appropriately selected and used depending on the characteristics or volatilization rate of the resin in the paint.

[0086] The above water may be deionized water, pure water, ultrapure water, distilled water, etc., and serves to reduce the generation of volatile organic compounds (VOCs) in the composition.

[0087] The organic solvent is not particularly limited as long as it is an organic solvent compatible with water, and examples thereof include butyl cellulose, n-butanol, isopropanol, propylene glycol, n-propyl ether, propylene glycol n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol n-butyl ether, propanediol diacetate, propylene glycol, ethylene glycol, and mixtures thereof.

[0088] The above solvent may be included in the base coat composition in an amount of 10 to 50 parts by weight, or 25 to 40 parts by weight, based on 100 parts by weight of the base coat composition. Specifically, the base coat composition may include 10 to 40 parts by weight, or 15 to 35 parts by weight, of water, and 1 to 20 parts by weight, or 4 to 15 parts by weight, of an organic solvent, but is not limited thereto, and the respective contents may be appropriately adjusted in consideration of the viscosity and / or fluidity of the paint.

[0089]

[0090] The above base coat composition may additionally include paint additives that can be typically applied to base paint compositions. Examples of the paint additives include antifoaming agents, leveling agents, dispersants, ultraviolet absorbers, thickeners, weathering additives, antifreeze agents, pigments, and the like. In this case, each component of the paint additives may be applied without particular limitations as long as it can be used in the paint composition.

[0091] The base coat composition according to the present invention as described above has excellent appearance properties such as gloss, adhesion, water resistance, weather resistance, etc. of the produced coating film. In particular, the base coat composition has remarkably excellent adhesion, making it highly suitable as a base coat for automobile repair.

[0092]

[0093] Hereinafter, the present invention will be described in more detail through examples. However, these examples are provided solely to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0094] [Example]

[0095] Manufacturing Example 1. Manufacturing of water-soluble polyurethane dispersion-1

[0096] A water-soluble polyurethane dispersion was prepared by mixing each component in the composition described in Table 1 below.

[0097] Specifically, acetone as a solvent, 3-hydroxy-2-(hydroxymethyl)-2-methylpropanoic acid (DMPA) as an acid compound, triethylamine (TEA) as a neutralizer, poly(hexamethylene carbonate) diol (PCD) as a polycarbonate polyol, and poly(ethylene oxide), α-Hydroxy, ω-phosphonic acid (Poly(ethylene oxide), α-Hydroxy, ω-phosphonic acid) as an alkylene phosphate polyol were added to the reactor and the temperature was raised to 100°C.

[0098] The above polycarbonate polyol may have a weight average molecular weight (Mw) of 2,000 g / mol and a hydroxyl value (OHv) of 56 mgKOH / g, and the above alkylene phosphate polyol may have a weight average molecular weight (Mw) of 600 g / mol and a hydroxyl value (OHv) of 94 mgKOH / g.

[0099] After confirming that DMPA was dissolved, it was cooled to 40℃, and isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HMDI) as isocyanate compounds were added dropwise at 40℃ for 30 minutes. After maintaining at 50℃ for 5 hours, the NCO% was measured by correcting with the amine value, and when it was 2.8 to 3.1 wt%, deionized water (DIW) was added dropwise at 30℃ for 10 minutes, and then an aqueous ethylenediamine (EDA) solution (ethylenediamine concentration: 6.25 wt%) as a chain extender was added dropwise for 5 minutes. After standing at 40℃ for 2 hours, the temperature was raised to 80℃ to recover acetone, and after recovering the acetone, it was cooled to room temperature to manufacture water-soluble polyurethane dispersion-1.

[0100] The manufactured water-soluble polyurethane dispersion-1 had a solid content of 35.2 wt%, an average diameter of dispersed particles of 70 nm, a viscosity at 25°C of 97 cps, an acid value (Av) of 31.5 mgKOH / g, an amine value of 30 mmol / g, and a pH of about 7.

[0101]

[0102] Manufacturing Examples 2 to 8. Manufacturing of water-soluble polyurethane dispersions

[0103] A water-soluble polyurethane dispersion was prepared by mixing each component in the composition as described in Tables 1 and 2 below.

[0104] At this time, the composition of Manufacturing Example 4 could not be manufactured as the resin became gel during the reaction.

[0105] Classification (by weight) Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Polyurethane Dispersion-1 Polyurethane Dispersion-2 Polyurethane Dispersion-3 Polyurethane Dispersion-4 Polyurethane Dispersion-5 Composition Acetone 10 10 10 10 10 DMPA 0.2 2 3 0.2 0.2 0.2 0.2 TEA 0.3 1 7 0.3 0.3 0.3 0.3 PCD (Mw 2000 g / mol) 18.1 24 1 17.8 -- PCD (Mw 1000 g / mol) ---- 16.9 Poly(ethylene oxide), α-hydroxy, ω-phosphonic Acid 10.9-10.7 29 10.2 IPDI 34.56 34.2 HMDI 2.3 3.4-2.3 3.2 DIW 58 53.4 58.1 58.5 EDA 7.1 10.6 7 7.16.7 Acetone (recovered) -9.9-10-10.1-9.9-10.2 Total 100 100 100 100 100 Physical properties of manufactured polyurethane dispersion Solid content (wt%) 35.2 35.5 35.4-35.6 Viscosity at 25°C (cps) 9 78 999-86 Acid value (mgKOH / g) 31.5 27.6 30.1-30 Average diameter of dispersed particles (nm) 70 6 5 73-79 pH 7.0 7.1 7.1-7.5

[0106] Classification (weight part) Manufacturing Example 6 Manufacturing Example 7 Manufacturing Example 8 Polyurethane dispersion-6 Polyurethane dispersion-7 Polyurethane dispersion-8 Composition Acetone 10 10 10 DMPA 2.3 0.2 0.2 TEA 1.7 0.3 0.3 PCD (Mw 2000 g / mol) 20.3 18.5 18.3 Poly(ethylene oxide), α-hydroxy, ω-phosphonic acid-11.1 11 1,6-Hexane diol 1.2--IPDI 5.9-1.4 HMDI 4.4 4.7 3.6 DIW 5 0.4 57.9 57.9 EDA 13.7 7.3 7.2 Acetone (recovery amount)-10-10-10 Total 99.9 100 99.9 The amount of manufactured polyurethane dispersion Physical properties Solid content (wt%) 35.2 35.1 35.2 Viscosity at 25°C (cps) 978895 Acid value (mgKOH / g) 27.1 32.2 31.9 Average diameter of dispersed particles (nm) 708075 pH 7.0 7.1 7.1

[0107] Experimental Examples 1 to 13. Preparation of Base Coat Composition

[0108] A base coat composition was prepared by mixing each component in the composition as described in Tables 3 and 4 below.

[0109] (Parts by weight)Experimental Example 1Experimental Example 2Experimental Example 3Experimental Example 4Experimental Example 5Experimental Example 6Experimental Example 7Manufacturing Example 131Manufacturing Example 2 31Manufacturing Example 3 31Manufacturing Example 5 31Manufacturing Example 6 31Manufacturing Example 7 31Manufacturing Example 831Acrylic emulsion3030303030303030Deionized water26262626262626Organic solvent88888888Foaming agent0.50.50.50.50.50.50.50.5Thickener0.50.50.50.50.50.50.5Weathering additive11111111Antifreeze agent1.51.51.51.51.51.51.5Leveling agent0.50.50.50.50.50.50.5Metallic Pigment 1111111Total amount 100100100100100100100

[0110] (Part by weight) Experimental example 8 Experimental example 9 Experimental example 10 Experimental example 11 Experimental example 12 Experimental example 13 Manufacturing example 1 (Polyurethane dispersion-1) 154525353131 Acrylic emulsion 303030302535 Deionized water 3815.230.422.829.622 Organic solvent 124.89.67.29.47 Antifoaming agent 0.50.50.50.50.50.50.5 Thickener 0.50.50.50.50.50.5 Weathering additive 111111 Antifreeze agent 1.51.51.51.51.51.5 Leveling agent 0.50.50.50.50.50.5 Metallic Pigment 111111Total amount 100100100100100100

[0111] Below, the manufacturers and product names of each ingredient used in the experimental examples are shown in Table 5.

[0112] Chemical name or physical properties Manufacturer and product name Acrylic emulsion Solid content: 24 wt%, viscosity at 25°C: 100 cP, acid value: 20 mg KOH / g, amine value: 15 mmol / g - Organic solvent n-butanol - Defoaming agent - Manufacturer: Munzing, product name: Agitan 281 Thickener - Manufacturer: Rohm & Haas, product name: RM-8W Weathering additive Hydroxybenzophenone - Antifreeze agent Propylene glycol - Leveling agent - Manufacturer: Air products, product name: Surfynol 104 Metallic pigment - Manufacturer: ECKART GMBH, product name: BG HYDRONLAN 8154

[0113] Test Example: Characteristic Evaluation

[0114] Using a spray gun, the base coat composition of the experimental example was applied to the conductor with a dry film thickness of 21±1㎛, and then cured at 60℃ for 4 hours to prepare a test film. Thereafter, the physical properties of the base coat composition and the test film were measured using the following methods, and the results are shown in Tables 6 and 7.

[0115] (1) Appearance-1 (CF)

[0116] The gloss (LU), image clarity (SH), and smoothness (OP) of the sample coating were measured using an automotive exterior measuring device, Wave Scan DOI (BYK Gardner), and the measured properties were used to calculate the comprehensive appearance evaluation value (CF) using the following mathematical formula 1. At this time, the higher the CF value, the better the appearance of the coating was evaluated.

[0117] [Mathematical Formula 1]

[0118] CF = LUХ0.15 + SHХ0.35 + OPХ0.5

[0119] (2) Appearance-2(FI)

[0120] The appearance characteristics of the sample film were measured using FI (FLOP INDEX) using MA-98 equipment (X-RITE).

[0121] (3) Appearance-3 (OP)

[0122] The smoothness (OP) of the sample coating was measured using an automotive exterior measuring device, Wave Scan DOI (BYK Gardner).

[0123] (4) Adhesion

[0124] According to the ASTM D3359 tape adhesion test method, 100 squares measuring 2 mm x 2 mm (width x height) were formed on the surface of the specimen film using a cutter knife, and then the squares were removed four times using tape, and the adhesion was measured by counting the number of squares remaining.

[0125] (5) Water resistance

[0126] Water resistance was measured according to ASTM D714, and the frequency and size of blister occurrence were checked after leaving the specimen film at 40℃ for 10 days.

[0127] Specifically, bluster size was rated from 0 to 10, with 10 indicating no bluster, 8 indicating the presence of small blusters visible to the naked eye, and 6, 4 and 2 indicating the presence of progressively larger blusters.

[0128] Additionally, the frequency of occurrence of bluster was evaluated as D (Dense) if frequent, MD (Medium dense) if relatively less frequent, M (Medium) if average, and F (Few) if rare.

[0129] (6) Color difference after saving

[0130] After the base coat composition was left to stand (stored) at 50°C for 10 days, it was painted as described above to prepare a test film. Thereafter, L*, a*, and b* at 45° of the test film prepared with the composition before storage and the test film prepared with the composition after storage were measured using a colorimeter, and the △E value was calculated.

[0131] (7) Dryness

[0132] The drying property was evaluated by measuring the drying time when the sample film was air-blown at a distance of 70 cm.

[0133] Specifically, the time required for touch drying at 25℃ was measured using the method described in ASTM D1640. The time for hardening was measured as the time when the coating film did not leave a mark when pressed firmly by hand and twisted from side to side.

[0134] Experimental Example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Experimental Example 5 Experimental Example 6 Appearance (CF) 757273737272 Appearance (FI) 42.53.53.52.52.5 Appearance (OP) 8584.271.58484.284.2 Drying Time 2 minutes 18 seconds 7 minutes 2 seconds 2 minutes 50 seconds 2 minutes 30 seconds 7 minutes 2 seconds 6 minutes 45 seconds Adhesion 100 / 100 50 / 100 70 / 100 100 / 100 50 / 100 100 / 100 Water Resistance No blister No blister Blister size 2 (Medium) No blister No blister No blister Color difference after storage (△E*) 0.5 1 1.0 2 0.8 9 0.5 5 1.2 0.6 1

[0135] Experimental Example 7 Experimental Example 8 Experimental Example 9 Experimental Example 10 Experimental Example 11 Experimental Example 12 Experimental Example 13 Appearance (CF) 737474.574.5747474.5 Appearance (FI) 3.53.93.73.83.83.73.9 Appearance (OP) 71.583.582.784.682.683.884.1 Drying 5 min 10 sec 2 min 30 sec 2 min 20 sec 2 min 25 sec 2 min 27 sec 2 min 28 sec 2 min 25 sec Adhesion 80 / 100100 / 100100 / 100100 / 100100 / 100100 / 100100 / 100100 / 100 Water Resistance Blister size 6 (Medium) No blister No blister No blister No blister No blister No blister After storage Color difference (△E*)0.750.540.530.550.540.530.55

[0136] As seen in Tables 6 and 7, Experimental Examples 1, 4, and 8 to 13 were excellent in all properties.

[0137] On the other hand, experimental example 2, which did not include alkylene phosphate polyol in the synthesis of polyurethane dispersion, had poor adhesion and drying properties, and experimental example 3, which did not include linear isocyanate, had poor water resistance and adhesion.

[0138] In addition, experimental example 5, which included hexanediol instead of alkylene phosphate polyol during polyurethane dispersion synthesis, had poor adhesion and drying properties, experimental example 6, which did not include alicyclic isocyanate, had poor drying properties, and experimental example 7, in which the weight ratios of alicyclic isocyanate and linear isocyanate were different, had poor drying properties, adhesion, and water resistance.

Claims

1. Containing polycarbonate polyol, alkylene phosphate polyol and isocyanate compound, A water-soluble polyurethane dispersion composition, wherein the alkylene phosphate polyol contains an acid group and a hydroxyl group.

2. In claim 1, A water-soluble polyurethane dispersion composition, wherein the alkylene phosphate polyol comprises a compound represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, R 1 is a group containing oxyalkylene or alkylene.

3. In claim 1, A water-soluble polyurethane dispersion composition comprising a first isocyanate compound having an alicyclic structure and a second isocyanate compound having a linear structure.

4. A base coat composition for automobile repair, comprising a water-soluble polyurethane dispersion prepared from the composition of any one of claims 1 to 3, an acrylic resin and a solvent.

5. In claim 4, A base coat composition for automobile repair, wherein the water-soluble polyurethane dispersion has a viscosity of 10 to 500 cP at 25°C, an acid value of 10 to 40 mgKOH / g, an amine value of 10 to 40 mmol / g, and an average diameter of dispersed particles of 50 to 100 nm.

6. In claim 4, A base coat composition for automotive repair comprising 10 to 50 parts by weight of a water-soluble polyurethane dispersion and 10 to 50 parts by weight of an acrylic resin.

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