CN114450363B - Two-part coating composition and coated article - Google Patents
Two-part coating composition and coated article Download PDFInfo
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- CN114450363B CN114450363B CN202080067946.3A CN202080067946A CN114450363B CN 114450363 B CN114450363 B CN 114450363B CN 202080067946 A CN202080067946 A CN 202080067946A CN 114450363 B CN114450363 B CN 114450363B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/40—Layered products comprising a layer of synthetic resin comprising polyurethanes
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D167/00—Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain; Coating compositions based on derivatives of such polymers
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
- C09D175/04—Polyurethanes
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
- C09D5/02—Emulsion paints including aerosols
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/41—Organic pigments; Organic dyes
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/60—Additives non-macromolecular
- C09D7/61—Additives non-macromolecular inorganic
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Abstract
The present invention provides an aqueous coating composition capable of forming a coating film having excellent lactic acid resistance and oil acid resistance. A main agent containing a polycarbonate polyurethane, a polyester resin and water and a curing agent containing a hydrophilic polyisocyanate compound are blended so that the molar ratio of hydroxyl groups (OH) in the main agent to isocyanate groups (NCO) in the curing agent falls within a specific range.
Description
Technical Field
The present invention relates to a two-part coating composition, and an aqueous coating composition, a coating film and a coated article obtained therefrom.
Background
Plastic molded articles are molded articles of plastic polymer materials used for mobile phones, home electric appliances, office equipment, etc., and may be coated on the surfaces thereof for decoration or function application. Therefore, in addition to the application of the decorative coating, the coating material for coating plastic (coating material for plastic) is sometimes required to impart functions such as abrasion resistance, discoloration and fading resistance, sebum resistance, high gloss, high weather resistance, and electrical insulation to the coating film, depending on the application of the plastic molded product.
In particular, plastic molded articles such as skin and hands of a person in contact with the skin and hands for a long period of time (for example, exterior parts of mobile phones and interior parts of automobiles) are required to have excellent resistance to lactic acid (lactic acid resistance) which is a component of sweat, hand cream, sun oil, etc., and resistance to oleic acid (oil resistance and acidity) which is a component of sebum. In addition, a high gloss or a matt feel is sometimes required for automotive interior parts.
As automotive interior coatings, solvent-based paint coatings and solvent-based two-part curable urethane coatings have been conventionally used. On the other hand, as environmental regulations become more stringent, the coating industry is shifting from solvent-based coatings using organic solvents to aqueous coatings using water. However, the aqueous coating material does not provide a coating film having sufficient lactic acid resistance and oil acid resistance.
Disclosure of Invention
The present invention addresses the problem of providing an aqueous coating composition capable of forming a coating film having excellent lactic acid resistance and oil acid resistance.
It has been found that the above problems can be solved by blending a main agent containing a polycarbonate-based polyurethane, a polyester resin and water with a curing agent containing a hydrophilic polyisocyanate compound so that the molar ratio of hydroxyl groups (OH) in the main agent to isocyanate groups (NCO) in the curing agent falls within a specific range. That is, the present invention relates to the following [ 1 ] to [ 14 ].
A two-part coating composition comprising a main component and a curing agent,
the main agent contains (A) a polycarbonate-based polyurethane having an average particle diameter of 0.01 to 0.1 [ mu ] m, (B) a polyester resin having an average particle diameter of 0.01 [ mu ] m or less,
the curing agent contains (C) a hydrophilic polyisocyanate compound,
the molar ratio NCO/OH of the isocyanate group (NCO) in the hydrophilic polyisocyanate compound (C) to the hydroxyl group (OH) in the polycarbonate-based polyurethane (A) and the polyester resin (B) is 1.6 to 2.0.
The two-part coating composition according to item [ 1 ], wherein the hydroxyl value of the polyester resin (B) is 100 to 200mgKOH/g.
The two-part coating composition according to [ 1 ] or [ 2 ], wherein the hydrophilic polyisocyanate compound (C) has an isocyanate group content of 15 to 25%.
The two-part coating composition according to any one of the above [ 1 ] to [ 3 ], wherein the mass ratio of the solid components of the (A) polycarbonate-based polyurethane to the (B) polyester resin is 8:2 to 6:4.
the two-part coating composition according to any one of [ 1 ] to [ 4 ], wherein the main agent further contains a colorant selected from the group consisting of carbon black, metallic pigments and organic pigments.
[ 6 ] an aqueous coating composition comprising the main agent of the two-part coating composition according to any one of the above [ 1 ] to [ 5 ] and the curing agent.
A coating film of the aqueous coating composition of [ 6 ] above.
The coating film according to [ 8 ] above, wherein the crosslinking density is 1.4X10 -3 ～1.7×10 -3 mol/mL。
The coating film according to [ 7 ] or [ 8 ], wherein the surface free energy calculated from the Euler-Wendt (Owens-Wendt) formula is 50mN/m or more.
A coated article comprising a substrate and the coating film according to any one of the above [ 7 ] to [ 9 ] on the surface of the substrate.
The coated article according to [ 11 ] above, wherein the base material is plastic.
[ 12 ] A method for coating a substrate, comprising the steps of:
a step of mixing the main agent of the two-part coating composition according to any one of the above [ 1 ] to [ 5 ] with the curing agent to obtain an aqueous coating composition,
a step of applying the aqueous coating composition to the surface of a substrate,
and a step of drying the applied aqueous coating composition to form a coating film.
The method according to [ 12 ] above, wherein the drying is performed at 70℃to 90℃for 20 to 40 minutes, followed by a normal temperature for 48 hours or more.
The method for coating according to [ 12 ] or [ 13 ], wherein the coating film has a thickness of 25 μm to 45. Mu.m.
According to the present invention, an aqueous coating composition capable of forming a coating film having excellent lactic acid resistance and oil acid resistance can be provided.
Detailed Description
The invention relates to a two-liquid coating composition, which contains a main agent and a curing agent,
the main agent contains (A) a polycarbonate-based polyurethane having an average particle diameter of 0.01 to 0.1 [ mu ] m, (B) a polyester resin having an average particle diameter of 0.01 [ mu ] m or less,
the curing agent contains (C) a hydrophilic polyisocyanate compound,
the molar ratio NCO/OH of the isocyanate group (NCO) in the hydrophilic polyisocyanate compound (C) to the hydroxyl group (OH) in the polycarbonate-based polyurethane (A) and the polyester resin (B) is 1.6 to 2.0.
(A) Polycarbonate-based polyurethane
The main agent of the present invention contains a polycarbonate-based polyurethane. Polyurethane is composed of a hard segment strongly aggregated by a strong hydrogen bond and a soft segment containing a polyester or polyol moiety because it has a urethane bond, a urea bond, or the like in its interior. The polycarbonate-based polyurethane is a polyurethane in which a soft segment-forming polyol is a polycarbonate polyol.
The polycarbonate polyol having a soft segment can be obtained by reacting a diol with a carbonate such as a dialkyl carbonate, and is a polyol having 2 or more carbonate groups and hydroxyl groups in the molecular chain having a molecular weight of 500 to 3000. Examples of the carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, dibutyl carbonate, di-t-butyl carbonate, dipentyl carbonate, dihexyl carbonate, dicyclohexyl carbonate, diheptyl carbonate, dioctyl carbonate, and dicyclohexyl carbonate. Examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 2-ethyl-1, 6-hexanediol, 2-methyl-1, 3-propanediol, neopentyl glycol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, 2' -bis- (4-hydroxycyclohexyl) -propane, p-xylylene glycol, p-tetrachloroxylylene glycol, 1, 4-dimethylolcyclohexane, (3 (4), 8 (9) -bis- (hydroxymethyl) -tricyclodecane dimethylol, bis-hydroxymethyl tetrahydrofuran, bis (2-hydroxyethyl) dimethylhydantoin, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol, and polytetramethylene glycol.
In the main component, the polycarbonate polyurethane is present in the form of dispersed particles having an average particle diameter of 0.01 to 0.1. Mu.m, preferably 0.015 to 0.07. Mu.m, more preferably 0.02 to 0.05. Mu.m. If the average particle diameter is within the above range, the dispersion state in water is stable. The average particle diameter can be measured by a dynamic light scattering method, a laser diffraction method, or the like.
The polycarbonate-based polyurethane preferably has a hydroxyl value of 100 to 300mgKOH/g, more preferably 150 to 250mgKOH/g, still more preferably 180 to 220 mgKOH/g. The hydroxyl value is a value corresponding to the mass (mg) of KOH required to neutralize 1g of the sample. When the hydroxyl value is within the above range, the resin composition has appropriate reactivity with the hydrophilic polyisocyanate compound (C) in the curing agent, and a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
Examples of commercially available polycarbonate-based polyurethanes include DPU2035ba (manufactured by DAICEL ALLNEX Co., ltd.), NIPPOLAN976 (manufactured by TOSOH Co., ltd.), neoRez R4000 (manufactured by DSM Coating Resins Co., ltd.).
The content of the polycarbonate-based polyurethane in the main agent is, for example, 16 to 32 mass%, preferably 18 to 27 mass%, based on the total mass of the main agent. If the content is within the above range, a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
(B) Polyester resin
The polyester resin is a resin obtained by polycondensing a polycarboxylic acid with a polyol. Examples of the polycarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexanedicarboxylic acid, adipic acid, azelaic acid, sebacic acid, glutaric acid, chlorauric acid, tetrachlorophthalic acid, maleic acid, fumaric acid, itaconic acid, malonic acid, suberic acid, 2-methylsuccinic acid, 3-diethylglutaric acid, 2-dimethylsuccinic acid, octenyl succinic acid, and dodecenylsuccinic acid, and if any, acid anhydrides thereof may be used instead of the carboxylic acids. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycol (for example, polyethylene glycol), 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 2-butylene glycol, 1, 4-butylene glycol, 1, 6-hexanediol, neopentyl glycol hydroxy pyruvate, dimethylolcyclohexane, trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylol benzene, and tris hydroxyethyl isocyanurate. The type of the polyester resin may be appropriately determined according to the type of the polycarbonate-based polyurethane used. By using a polyester resin having good compatibility with polycarbonate polyurethane, a high-gloss coating film can be formed.
In the main agent, the polyester resin has an average particle diameter of 0.01 μm or less, for example, 0.001 to 0.01 μm. If the average particle diameter is within the above range, the polymer is stably dissolved in water. The average particle diameter can be measured by a dynamic light scattering method, a laser diffraction method, or the like.
The polyester resin preferably has a hydroxyl value of 100 to 200mgKOH/g, more preferably 120 to 180 mgKOH/g. If the hydroxyl value is within the above range, a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
The polyester resin is preferably a water-soluble polyester resin neutralized with an amine, from the viewpoint of being capable of forming a coating film excellent in lactic acid resistance and oil acid resistance.
Examples of the commercially available polyester resins include Resydrol AN6617, AN6481, setal 6306, setaqua BE270 (manufactured by DAICEL ALLNEX corporation), and the like.
The content of the polyester resin in the main agent is, for example, 5 to 15 mass%, preferably 6 to 13 mass%, relative to the total mass of the main agent. If the content is within the above range, a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
In the main agent of the present invention, the mass ratio of the solid content of the polycarbonate-based polyurethane (component a) to the solid content of the polyester resin (component B) is preferably 8:2 to 6:4, more preferably 75: 25-65: 35. if (A): (B) When the solid content mass ratio of (b) is within the above range, the crosslinking density and the surface free energy of the coating film formed from the coating composition of the present invention can be within the desired ranges, and a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
The main agent of the present invention contains water. The content of water in the main agent is, for example, 30 to 70 mass%, preferably 40 to 60 mass%, relative to the total mass of the main agent. If the water content is within the above range, an aqueous coating material having less adverse effects on the environment than conventional solvent-based coating materials can be obtained.
(C) Hydrophilic polyisocyanate compound
The curing agent of the present invention contains a hydrophilic polyisocyanate compound. The hydrophilic polyisocyanate contains a hydrophilic group having affinity with water and a hydrophobic moiety, and the hydrophobic moiety aggregates in water to obtain a micelle structure, so that the hydrophilic polyisocyanate can be easily and stably dispersed. Therefore, the reaction between isocyanate and water can be suppressed and the crosslinking of the polycarbonate polyurethane and the polyester resin can be promoted. Examples of the hydrophilic group include an alkoxypolyalkylene oxide group (having 2 to 50 carbon atoms, for example), a carboxyl group, a sulfo group, and salts thereof (for example, metal salts, ammonium salts, and amine salts). As the hydrophilic polyisocyanate, a polyisocyanate having a sulfo group forming an ammonium salt or the like can be preferably used. Further, from the viewpoint of forming a coating film excellent in lactic acid resistance and oil acid resistance, an HMDI-based polyisocyanate is preferable.
The isocyanate group content of the hydrophilic polyisocyanate compound is preferably 10 to 30%, more preferably 15 to 25%, and even more preferably 19 to 22%. Wherein the content of isocyanate groups is expressed as mass percent of the amount of isocyanate groups in the polyisocyanate compound, and can be measured based on JIS K1603-1. If the isocyanate group content is within the above range, a coating film excellent in lactic acid resistance and oil acid resistance can be formed by reaction with the main agent.
The acid value of the hydrophilic polyisocyanate compound is preferably 0 to 30mgKOH/g, more preferably 5 to 15mgKOH/g. When the acid value is within the above range, a coating film excellent in lactic acid resistance and oil acid resistance can be formed.
Examples of commercially available hydrophilic polyisocyanates include Bayhydur XP2655, 3100, 302, 304, 305, XP2451/1, XP2487/1, XP2457, 401, XP2759, etc. manufactured by Sumika Covestro Urethane, duranate WB40, WT30, WT20, WL70, WR80, etc. manufactured by Asahi chemical Co., ltd, and Basonat HW1000, HW2000, etc. manufactured by BASF.
The coating composition of the present invention is a two-part coating composition comprising a main agent and a curing agent. In the two-part coating composition of the present invention, the molar ratio of isocyanate groups (NCO) in the (C) hydrophilic polyisocyanate compound in the curing agent to hydroxyl groups (OH) in the (A) polycarbonate-based polyurethane and (B) polyester resin in the main agent is 1.6 to 2.0, preferably 1.7 to 1.9, more preferably 1.8. By setting the NCO/OH ratio within the above range, the crosslinking density of the coating film formed using the coating composition of the present invention can be set within a desired range, and excellent lactic acid resistance and oil acid resistance can be imparted. The above molar ratio NCO/OH can be derived as a molar ratio of an OH amount calculated from the hydroxyl values of the (A) polycarbonate-based polyurethane and the (B) polyester resin to an NCO amount calculated from the isocyanate group content of the (C) hydrophilic polyisocyanate compound.
The coating composition of the present invention may contain pigments. Examples of the pigment include a coloring pigment, an extender pigment, and a metallic pigment, and may be appropriately selected and used according to the coloring or gloss of the coating film, the coating workability, the strength and physical properties of the coating film, and the like. Examples of the coloring pigment include inorganic pigments such as titanium oxide and carbon black, and organic pigments such as phthalocyanine pigments and azo pigments. The extender pigment may be any known pigment, and examples thereof include talc, mica, barium sulfate, clay, and calcium carbonate. Examples of the metallic pigment include a bright pigment and a flake pigment, for example, an aluminum powder pigment, a nickel powder pigment, a gold powder, a silver powder, a bronze powder, a copper powder, a stainless steel powder pigment, a mica (mica) pigment, a graphite pigment, a glass flake pigment, a metal-coated glass powder, a metal-coated mica powder, a metal-coated plastic powder, and a flake iron oxide pigment. The pigment may be blended in any one of the main agent and the curing agent, but is preferably blended in the main agent.
The coating composition of the present invention may be appropriately blended with additives commonly used in the coating field, for example, solvents, pH adjusters, surface adjusters, wetting agents, dispersants, emulsifiers, tackifiers, anti-settling agents, antiskinning agents, anti-dripping agents, antifoaming agents, color-separating agents, leveling agents, drying agents, plasticizers, mildewcides, antibacterial agents, insecticides, light stabilizers, ultraviolet absorbers, antistatic agents, conductivity imparting agents, and the like, in addition to the above-mentioned components a to C and pigments, depending on the purpose. In particular, by blending silica particles in the coating composition, a coating film having a matt feel can be formed. These optional components may be blended in either one of the main agent and the curing agent, or both of them.
The two-part coating composition of the present invention can be prepared according to conventional methods. For example, the main agent and the curing agent may be prepared separately by uniformly mixing the respective raw materials. The main agent and the curing agent are mixed prior to coating to prepare the aqueous coating composition.
The coating method using the two-part coating composition of the present invention comprises the steps of: a step of mixing a main agent and a curing agent to obtain an aqueous coating composition; a step of applying an aqueous coating composition to the surface of a substrate; and a step of forming a coating film by drying the applied aqueous coating composition.
The mixing of the main agent and the curing agent is not particularly limited, and a conventionally known mixing method can be used. The mixing ratio of the main agent and the curing agent can be appropriately adjusted in such an amount that the above molar ratio NCO/OH in the aqueous coating composition immediately after mixing becomes 1.6 to 2.0. The method of applying the aqueous coating composition is not particularly limited, and known coating methods such as dipping, spin coating, flow coating, roll coating, spray coating, knife coating, and air knife coating can be used. In the application of the aqueous coating composition, water may be used for dilution in order to adjust the viscosity. The coating amount of the aqueous coating composition may vary depending on the type and use of the substrate, and is generally 54 to 81g/m 2 Preferably 64 to 75g/m 2 . The film thickness of the coating film formed on the surface of the substrate depends on the coating amount of the aqueous coating composition, but is preferably 25 to 45 μm, for example, 30 to 40 μm. If the film thickness is within the above range, a coating film having sufficient lactic acid resistance and oil acid resistance can be obtained without requiring excessive curing time.
The drying method is not particularly limited, and for example, it may be dried by heating or naturally dried at ordinary temperature (for example, about 25 ℃). Preferably, both heating and natural drying are combined. For example, it is preferable that the drying is carried out at 70 to 90 ℃, preferably 85 to 95 ℃, for 20 to 40 minutes, preferably 25 to 35 minutes, and then it is further dried at normal temperature for 48 hours or more, preferably 60 to 80 hours. If such drying conditions are employed, it is sufficient to form a coating film having desired properties.
The coating film formed has, for example, 1.4X10 -3 ～1.7×10 -3 mol/mL, preferably having a concentration of 1.5X10 -3 ～1.7×10 -3 Crosslinking density in mol/mL. If the crosslinking density is within the above range, the adhesion to the substrate is excellent in lactic acid resistance and oil acid resistance. The crosslink density can be determined based on the plateau storage modulus and its absolute temperature measured under predetermined conditions using RSA-G2 (manufactured by TA instruments Co., ltd.) and based on the following formula.
n＝E’/3RT
n: cross-link Density (mol/mL) (1/n: molecular weight between Cross-linking points)
R: gas constant (8.31X106 Pa.cc/mol K)
T: absolute temperature of storage modulus of plateau (K)
E': plateau storage modulus (Pa)
The surface free energy of the coating film calculated by the Euro Wenst (Owens-Wendt) formula is preferably 50mN/m or more, for example, 60 to 80mN/m. Euro-Wen Teshi is one of the theoretical formulas of the surface free energy expressed below, and can calculate the unknown surface free energy (gamma) of a solid from the measured values of the contact angles with 2 liquids whose surface free energies are known d S +γ p S )。
γ L (1+cosθ)＝2(γ d S γ d L ) 1/2 +2(γ p S γ p L ) 1/2
γ L : free energy of liquid surface (known)
γ d S : solid surface free energy dispersing component
γ d L : liquid surface free energy dispersing component (known)
γ p S : polar component of free energy on solid surface
γ p L : polar component of free energy on liquid surface (known)
θ: contact angle (measurement value)
In the case of the present invention, the coating film is a solid whose surface free energy is unknown in the formula, and the 2 liquids for measuring the contact angle are liquids whose surface free energies are known in the formula. If the surface free energy is within the above range, sweat or sebum easily wets and spreads on the surface of the coating film, and the damage of sweat/sebum to the coating film can be dispersed.
The substrate to which the aqueous coating composition is applied is not particularly limited, and various kinds and shapes of substrates can be selected according to the use of the substrate. Examples of the base material include olefin polymers such as PPE (polyphenylene ether) resins, polystyrene resins, polypropylene and polyethylene; a polycarbonate resin; acrylic resins such as polymethyl methacrylate and plastic substrates such as ABS resins.
The present invention also relates to a coated article comprising a substrate and a coating film on the surface of the substrate, the coating film being formed by coating the aqueous coating composition of the present invention.
The coating composition of the present invention can be applied to various substrates such as various inorganic substances, metals, wood, plastics, and the like. The coated article of the present invention is particularly suitable for use as a molded plastic article which is excellent in lactic acid resistance and oil acid resistance and is particularly suitable for use as a molded plastic article which is in contact with human skin or hands for a long period of time, specifically, as an interior or exterior part of automobiles or bicycles, as a part for home electric appliances such as audio equipment, video recorders, televisions, and as a part for office equipment such as cellular phones, printers, and computers.
Examples
Coating preparation >
The main ingredients of examples 1 to 3 and comparative examples 1 to 5 were prepared by mixing the raw materials of the main ingredients in accordance with the formulation shown in Table 1 and stirring them for 10 minutes with a dispersing machine. In any of the main agents of examples 1 to 3, the polycarbonate-based polyurethane was present as dispersed particles having an average particle diameter of 30nm, and the polyester resin was dissolved in water. Thereafter, each curing agent was added to the prepared base agent in accordance with the formulation shown in table 1, and the mixture was further stirred with a dispersing machine for 5 minutes, to prepare aqueous coating compositions of examples 1 to 3 and comparative examples 1 to 5, respectively.
1: DAICEL ALLNEX company, dispersion (average particle diameter 30 nm), solid content 37% (moisture content 56%), varnish hydroxyl value 70.3mgKOH/g (solid content conversion 190 mgKOH/g)
2: DAICEL ALLNEX company, 65% solids (moisture content 0%), varnish hydroxyl value 106 (163 mgKOH/g in terms of solids)
3: sumika Covestro Urethane company: 45% of solid content (containing 46% of water), 49.5 of varnish hydroxyl value (110 mgKOH/g in terms of solid content)
4: carbon black manufactured by TOYOCOLOR Co: pigment component 20% (containing 60% of moisture)
And 5: dimethylethanolamine
And 6: BYK Chemie Japan Co
7: BYK Chemie Japan Co
8: dipropylene glycol monomethyl ether
And 9: sumika Covestro Urethane, the solid content was 100%, the isocyanate group content was 21.2%, and the acid value was 10mgKOH/g
10: sumika Covestro Urethane, solid content 100%
< test piece preparation >)
Each of the aqueous coating compositions prepared above was diluted with deionized water to a viscosity suitable for spray coating, and then coated on an ABS-PC resin plate by gas spray coating so that the thickness of the dried coating film became 30±5 μm, and then dried at 80 ℃ for 30 minutes, and further left standing at room temperature for 72 hours to obtain each test piece.
The following evaluation was performed on each of the obtained test pieces. The results are shown in Table 2.
< appearance evaluation >
The presence or absence of coating anomalies such as pitting, cracking, wrinkles, dents, peeling, swelling, etc. was confirmed by visual observation.
< evaluation of adhesion >
The coated film was scored with 10×10 grid scores of a checkerboard square of 2mm based on JIS K5600-5-6 (graining method), a transparent adhesive tape was attached to the checkerboard portion, and after rapid peeling, the number of the checkerboard coating films remaining on the coated surface was evaluated.
O: non-peeling coating film
Delta: a part of the coating film was observed to peel off along the scores
X: peeling of the coating film was observed
< evaluation of lactic acid resistance >)
To the test piece, 0.2ml of a 10% aqueous solution of lactic acid was added dropwise, and the test piece was left at 80.+ -. 2 ℃ for 24 hours, and then rubbed with gauze, and then peeled off with adhesive tape.
O: the coating film has no abnormal color change, stain, swelling, softening, peeling and the like
Delta: the coating film is observed to have a plurality of color changes, swelling, softening and the like
X: significant swelling, softening or peeling of the film was observed
< evaluation of oil resistance and acidity >)
To the test piece, 0.2ml of a 10% petroleum ether solution of oleic acid was added dropwise, and the test piece was left at 80.+ -. 2 ℃ for 24 hours, and then rubbed with gauze, and then peeled off with adhesive tape.
O: the coating film has no abnormal color change, stain, swelling, softening, peeling and the like
Delta: the coating film is observed to have a plurality of color changes, swelling, softening and the like
X: significant swelling, softening or peeling of the film was observed
< crosslink Density >
The plateau storage modulus and the absolute temperature thereof were determined under the following conditions using RSA-G2 (manufactured by TA instruments Co., ltd.) based on the following formula.
Measurement conditions of over-
Frequency: 1Hz
Strain: 0.05%
Temperature range: -50-200 DEG C
Heating rate: 5 ℃/min
Length measurement: 24mm
Width: 8mm of
-calculation type over-head
n＝E’/3RT
n: cross-link Density (mol/mL) (1/n: molecular weight between Cross-linking points)
R: gas constant (8.31X106 Pa.cc/mol K)
T: absolute temperature of storage modulus of plateau (K)
E': plateau storage modulus (Pa)
< surface free energy of coating film >
The free energy of the surface of the coating film was calculated from the values of the contact angle when 1 drop of distilled water was dropped and the contact angle when 1 drop of liquid paraffin was dropped onto the surface of the coated coating film using the formula of Owens-went (Owens-Wendt).
Industrial applicability
The coating composition of the present invention is particularly suitable for use as a coating for interior and exterior parts of automobiles and bicycles, parts for home electric appliances such as audio, video recorders, televisions, and parts for office equipment such as mobile phones, printers, and computers.
Claims (13)
1. A two-component coating composition comprises a main component and a curing agent,
the main agent comprises (A) a polycarbonate-based polyurethane having an average particle diameter of 0.01 to 0.1 [ mu ] m, (B) a polyester resin having an average particle diameter of 0.01 [ mu ] m or less,
the curing agent contains (C) a hydrophilic polyisocyanate compound,
the molar ratio NCO/OH of isocyanate groups NCO in the (C) hydrophilic polyisocyanate compound to OH groups OH in the (A) polycarbonate-based polyurethane and the (B) polyester resin is 1.6 to 2.0,
the mass ratio of the solid components of the (A) polycarbonate polyurethane to the (B) polyester resin is 8:2 to 6:4.
2. the two-part coating composition according to claim 1, wherein the hydroxyl value of the (B) polyester resin is 100 to 200mgKOH/g.
3. The two-part coating composition according to claim 1 or 2, wherein the isocyanate group content of the hydrophilic polyisocyanate compound (C) is 15 to 25%.
4. The two-part coating composition according to claim 1 or 2, wherein the main agent further contains a colorant selected from carbon black, a metallic pigment and an organic pigment.
5. An aqueous coating composition comprising the main component of the two-part coating composition according to any one of claims 1 to 4 and the curing agent.
6. A coating film formed by applying the aqueous coating composition according to claim 5.
7. The coating film according to claim 6, wherein the crosslink density is 1.4X10 -3 ～1.7×10 -3 mol/mL。
8. The coating film according to claim 6 or 7, wherein the surface free energy calculated by Euro-Wen Teshi is 50mN/m or more.
9. A coated article comprising a substrate and the coating film according to any one of claims 6 to 8 on the surface of the substrate.
10. The coated article according to claim 9, wherein the substrate is plastic.
11. A method for coating a substrate, comprising the steps of:
the step of mixing the main component of the two-part coating composition according to any one of claims 1 to 4 with the curing agent to obtain an aqueous coating composition,
a step of applying the aqueous coating composition to the surface of a substrate,
and a step of drying the applied aqueous coating composition to form a coating film.
12. The method according to claim 11, wherein the drying is performed at 70 to 90 ℃ for 20 to 40 minutes, followed by a period of 48 hours or more at normal temperature.
13. The coating method according to claim 11 or 12, wherein the coating film has a thickness of 25 μm to 45 μm.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2019-179026 | 2019-09-30 | ||
| JP2019179026 | 2019-09-30 | ||
| PCT/JP2020/037276 WO2021066055A1 (en) | 2019-09-30 | 2020-09-30 | Two-part coating material composition and coated article |
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| CN114450363A CN114450363A (en) | 2022-05-06 |
| CN114450363B true CN114450363B (en) | 2023-05-12 |
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| JP (1) | JP7075545B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE10251797A1 (en) | 2002-11-07 | 2004-05-19 | Bayer Ag | Polyurethane resin with a high carbonate group content |
| CN102046686B (en) | 2008-05-29 | 2013-08-28 | 宇部兴产株式会社 | Aqueous polyurethane resin dispersion, manufacturing method thereof, and paint composition containing the same |
| WO2011010539A1 (en) * | 2009-07-24 | 2011-01-27 | 関西ペイント株式会社 | Water-based coating composition and method for forming multilayer coating film |
| CN102597040B (en) * | 2009-11-10 | 2014-05-28 | 宇部兴产株式会社 | Aqueous polyurethane resin dispersion, process for production thereof, and use thereof |
| CN102002166B (en) * | 2010-10-11 | 2012-07-04 | 中国海洋石油总公司 | Hydroxylated polyurethane water dispersoid for waterborne soft-feel coating and preparation method thereof |
| JP6208120B2 (en) | 2012-03-22 | 2017-10-04 | 日本ペイント・オートモーティブコーティングス株式会社 | Multi-layer coating formation method |
| CN105073921B (en) * | 2013-04-01 | 2018-04-06 | Dic株式会社 | Aqueous surface-treating agent and the article for having used the aqueous surface-treating agent |
| JP6565309B2 (en) * | 2015-05-07 | 2019-08-28 | 東ソー株式会社 | UV-absorbing polyurethane composition, coating material using the composition, and coating film |
| KR102056513B1 (en) | 2016-08-17 | 2019-12-16 | 주식회사 엘지화학 | Optical film having a good adhesive and a good durability, and polarizing plate comprising the same |
| CN107841210A (en) * | 2017-09-30 | 2018-03-27 | 东来涂料技术（上海）有限公司 | A kind of high resistance to chemicals moral character interior trim high-gloss black colored paint and preparation method thereof |
| JP7074984B2 (en) * | 2017-11-29 | 2022-05-25 | 関西ペイント株式会社 | Aqueous 2-component 1-coat paint composition |
| CN108192490B (en) * | 2017-12-19 | 2020-09-08 | 万华化学（宁波）有限公司 | Water-based composite resin composition, water-based plastic paint and preparation method thereof |
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| WO2021066055A1 (en) | 2021-04-08 |
| JPWO2021066055A1 (en) | 2021-04-08 |
| JP7075545B2 (en) | 2022-05-25 |
| WO2021066055A8 (en) | 2021-10-07 |
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