A coating film with a matte finish.

Abstract

Invention details;

Description

Coating with a matte layer

[0001] The present invention relates to a metallic matte coating film that has a good finished matte design, excellent alkali resistance, and abrasion resistance even when a conventional matting agent (specifically, a conventional matting agent such as silica particles or urethane resin particles) is not used.

[0002] A metallic matte paint finish is often applied to automobile bodies, automobile parts, automobile interior components, home appliances, and the like. Such a metallic matte paint finish is typically achieved by adding a matting agent for adjusting gloss, such as silica, acrylic resin particles, or urethane resin particles, to the paint in addition to the aluminum pigment (see, for example, Patent Documents 1 and 2). However, in conventional techniques, the size of the matting agent (e.g., 2 to 15 μm) is significantly larger than the thickness of the aluminum pigment (e.g., 0.05 to 0.4 μm), disrupting the orientation of the aluminum pigment. When subjected to external impact, the aluminum pigment or matting agent protruding from the finished paint film is scraped off, resulting in a change in the design of the scraped-off aluminum pigment or matting agent, specifically, an increase in gloss. Furthermore, the smoothness of the coating surface of a coating containing a matting agent is inferior to that of a normal metallic coating, and the inclusion of a matting agent disrupts the orientation of the aluminum pigment, resulting in a coating appearance, i.e., a graininess that appears rougher than that of a normal metallic coating. Furthermore, a metallic matte paint finish has been achieved using an aluminum pigment with an average particle size of 20 to 100 μm (see, for example, Patent Document 3). However, when an aluminum pigment with a large average particle size is used, the aluminum pigment may protrude from the finished coating, and upon external impact, it may be scraped off, potentially changing the design. Furthermore, when an aluminum pigment with a large average particle size is used, it may be difficult to achieve a metallic matte coating with excellent smoothness. Not only in the field of paints as described above, but also in the field of inks used in high-quality printing such as gravure printing, offset printing, and screen printing, there is a current demand for the realization of a metallic matte finish with better design, especially by a simple method.

[0003] JP 2005-290314 A JP 2018-76438 A JP 2001-200213 A

[0004] Therefore, in order to solve the problems of the prior art described above, the present invention aims to make it possible to form a coating film that has a good metallic matte design and / or excellent smoothness, even when not using a matting agent that may be scraped off from the coating film by external impact, etc. The present invention also aims to form a coating film that is capable of forming a finished coating film that has a good metallic matte design, in other words, an excellent smoothness that does not suffer from the problem of increased gloss at the parts of the matting agent scraped off by external impact, etc., which is caused by coatings that use conventional matting agents.

[0005] As a result of extensive research aimed at solving the above problems, the present inventors have discovered that by using an aluminum pigment with an average particle size of 5 to 20 μm, which is unlikely to protrude from the finished coating film, and by selectively adhering the resin particles or clumps to the bottom surfaces of the aluminum primary particles when coating the aluminum pigment with a resin, it is possible to provide a good metallic matte coating film and also to form a coating film with excellent adhesion, alkali resistance, and / or abrasion resistance, which has led to the completion of the present invention.

[0006] [1] A coating film having a matte layer containing a resin-adhered aluminum pigment and a binder resin component, wherein the resin-adhered aluminum pigment comprises metallic aluminum powder having an average particle size of 5 to 20 μm and resin particles or clumps adhered to the surface of the metallic aluminum powder, and the surface roughness Ra of the matte layer is 100 nm to 600 nm. [2] The coating film according to [1] above, wherein the surface roughness Ra of the matte layer is 100 nm to 250 nm. [3] The coating film according to [1] or [2] above, wherein the gloss (G60) of the matte layer is 5 to 50 in terms of 60-degree specular reflectance when the angle of incidence and the angle of acceptance are both 60 degrees. [4] The coating film according to any of [1] to [3] above, wherein the average particle size of the resin-adhered aluminum pigment is 5 to 15 μm. [5] The coating film according to any of [1] to [4] above, wherein the circularity of the resin-adhered aluminum pigment is 0.10 to 0.50. [6] The coating film according to any one of [1] to [5] above, wherein the abrasion resistance ΔG60 of the matte layer is 15 or less. [7] The coating film according to any one of [1] to [6] above, wherein the resin-adhered aluminum pigment contained in the matte layer is contained so that the PWC is 5% by mass or more and 35% by mass or less. [8] The coating film according to any one of [1] to [7] above, wherein the matte layer exhibits a flip-flop value of 1.0 or more and less than 1.9. [9] The coating film according to any one of [1] to [8] above, wherein the proportion of resin contained in the solid content of the resin-adhered aluminum pigment is 23.0% or more and 66.0% or less.

[10] The coating film according to any one of [1] to [9] above, wherein the coating film is a one-coat matte layer.

[11] The coating film according to any one of [1] to

[10] above, wherein the resin-adhered aluminum pigment is uncolored.

[12] The coating film according to any one of [1] to

[11] above, wherein the coating film does not contain a glossing agent.

[0007] According to the present invention, even without using a matting agent that may be scraped off from the coating film due to external impact or the like, a coating film can be obtained that has excellent orientation in the coating film and ink layer, and that has a good finished metallic matte design, excellent adhesion, alkali resistance, and / or abrasion resistance. Therefore, by using this coating film, a good metallic matte coating film can be provided even without adding conventional matting agents such as silica, acrylic resin particles, or urethane resin particles as additives. As a result, even when the finished coating film is subjected to external impact or the like, the problem of increased gloss at the scraped-off matting agent portion due to the impact, which is caused by matte coating compositions that use conventional matting agents, can be reduced, and a finished coating film with a good metallic matte design can be provided.

[0008] 1 is an example of an SEM image of the resin-adhered aluminum pigment of Example 1.

[0009] The coating film of the present invention (hereinafter sometimes referred to as "matte coating film") having a matte layer containing an aluminum pigment and a binder resin component without a matting agent will be described in detail below. The following is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be practiced with appropriate modifications within the scope of its gist.

[0010] (Resin-adhered aluminum pigment) The resin-adhered aluminum pigment of the present invention comprises metallic aluminum powder and a resin compound adhered to the surface of the metallic aluminum powder. The resin compound is preferably a polymer of a radically polymerizable monomer and / or oligomer having one or more double bonds in the molecule. Preferably, the proportion of resin contained in the solid content of the resin-adhered aluminum pigment is 23.0% or more and 66.0% or less, and preferably 57.0% or less. The resin-adhered aluminum pigment of the present invention is preferably uncolored.

[0011] (Metallic Aluminum Powder) The metallic aluminum powder contained in the resin-adhered aluminum pigment of the present invention is preferably "flake-shaped aluminum powder," and is suitable for having the surface properties, particle size, and shape required for a metallic pigment, such as surface gloss, whiteness, and brilliance. Hereinafter, metallic aluminum powder will be referred to as "flake-shaped aluminum powder" in this specification. The shape may be granular, plate-shaped, block-shaped, scale-shaped, or other various shapes, but a scale-shaped shape is preferred to impart excellent metallic feel and brightness to the coating film. The average particle size of the flake-shaped aluminum powder is 5 to 30 μm, preferably 5 to 20 μm, more preferably 5 to 15 μm, and even more preferably 5 to 13 μm. Herein, the average particle size can be determined by using a microscope image of the coating film surface and measuring it using image analysis software. Specifically, microscope images of the coating film surface were taken at a magnification of 1000x, randomly selecting 10 fields of view. The area of ​​each particle observed in the microscope image was measured using image analysis software (Image Pro Plus Version 7.0), and the equivalent circle diameter was calculated. The average equivalent circle diameter, i.e., the average particle size, can be determined by calculating the arithmetic mean value of 100 particles. The microscope device is not particularly limited, but an "HRX-01" (Hirox Corporation) or the like can be used. Alternatively, the average particle size of the flaky aluminum powder may be calculated as the particle size at 50% cumulative volume in the cumulative particle size distribution using a laser diffraction particle size distribution analyzer. The laser diffraction particle size distribution analyzer is not particularly limited, but an "SALD-2100" (Shimadzu Corporation) or the like can be used.

[0012] The flaky aluminum powder preferably has a thickness in the range of 0.001 μm to 1 μm and a particle size in the range of 1 μm to 100 μm. The aspect ratio of the flaky aluminum powder is preferably in the range of 10 to 20,000. Here, the aspect ratio is the value obtained by dividing the average particle size of the flaky aluminum powder by the average thickness of the flaky aluminum powder. The purity of the flaky aluminum powder is not particularly limited, but it is preferable that the purity of the flaky aluminum powder used for coatings is 99.5% or higher. The flaky aluminum powder can be obtained by known methods, such as the manufacturing method described in WO 99 / 54074, but commercially available aluminum paste powder can also be used.

[0013] As described above, the resin-adhered aluminum pigment of the present invention contains flaky aluminum powder and a resin compound adhered to the surface of the flaky aluminum powder. The resin compound is preferably a polymer of a radically polymerizable monomer and / or oligomer having one or more double bonds in the molecule. (This "polymer of a radically polymerizable monomer and / or oligomer having one or more double bonds in the molecule" will be described in detail below in the section "(Resin compound that is a polymer of a radically polymerizable monomer and / or oligomer having one or more double bonds in the molecule).") Here, the resin compound adhered to the flaky aluminum powder does not simply mean that the flaky aluminum powder and the resin compound are mixed together, but rather means that there is an interaction between the "flaky aluminum powder" and the "resin compound." Examples of such interactions include chemical bonds, hydrogen bonds, ionic bonds, and van der Waals forces.

[0014] In the resin-adhered aluminum pigment of the present invention, the presence or absence and amount of resin compound attached to the aluminum pigment can be confirmed, for example, by the following method. The resin-adhered aluminum pigment is dispersed in an organic solvent and filtered to remove the resin compound not attached to the aluminum pigment. The solvent is then volatilized to obtain particles in which the resin compound is attached to the aluminum pigment (i.e., the resin-adhered aluminum pigment of this embodiment) (C1). Next, (C1) is treated in an electric furnace to remove the resin compound attached to the surface of the flaky aluminum powder, leaving only the flaky aluminum powder (C2). The presence or absence and amount of resin compound attached can be confirmed by calculating the mass difference between (C1) and (C2). The conditions for removing the resin compound attached to the surface of the flaky aluminum powder in an electric furnace or the like can be appropriately selected depending on the molecular weight and crosslink density of the resin. For example, a method in which treatment is performed for 3 hours at 350°C in a nitrogen atmosphere can be used.

[0015] (Resin Compounds Being Polymers of Radically Polymerizable Monomers and / or Oligomers Having One or More Double Bonds in the Molecule) Radical polymerizable monomers and / or oligomers having one or more double bonds in the molecule include, for example, radical polymerizable monomers and / or oligomers having one double bond, two double bonds, three double bonds, or four or more double bonds in the molecule. The "radical polymerizable monomers and / or oligomers" are not particularly limited, and conventionally known monomers and / or oligomers can be used. Examples of the radical polymerizable monomers and / or oligomers include, but are not limited to, (meth)acrylic acid, (meth)acrylic acid esters, aromatic vinyl compounds, vinyl cyanides, amide group-containing vinyl monomers, hydroxyl group-containing vinyl monomers, epoxy group-containing vinyl monomers, carbonyl group-containing vinyl monomers, anionic vinyl monomers, mono- or diesters of phosphoric or phosphonic acid, and vinyl monomers having a silyl group.

[0016] In this specification, (meth)acrylic is a simple expression for methacrylic or acrylic.

[0017] Examples of the (meth)acrylic acid ester include, but are not limited to, alkyl (meth)acrylate esters having 1 to 50 carbon atoms in the alkyl moiety (polymerizable monomers having one double bond in the molecule), and (poly)oxyethylene di(meth)acrylates having 1 to 100 ethylene oxide groups (polymerizable monomers having two double bonds in the molecule). Examples of the (meth)acrylic acid ester include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclohexyl (meth)acrylate, lauryl (meth)acrylate, and dodecyl (meth)acrylate. Examples of the (poly)oxyethylene di(meth)acrylate include, but are not limited to, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, diethylene glycol methoxy(meth)acrylate, and tetraethylene glycol di(meth)acrylate. Other examples include trimethylolpropane tri(meth)acrylate (a polymerizable monomer having three double bonds in the molecule), tetramethylolpropane tetra(meth)acrylate, di-trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate (all of which are polymerizable monomers having four double bonds in the molecule), di-pentaerythritol hexa(meth)acrylate (a polymerizable monomer having six double bonds in the molecule), di-pentaerythritol penta(meth)acrylate, and di-pentaerythritol penta(meth)acrylate monopropionate (all of which are polymerizable monomers having five double bonds in the molecule). Furthermore, cyclic unsaturated compounds (e.g., cyclohexene) and aromatic unsaturated compounds (e.g., styrene, α-methylstyrene, vinyltoluene, divinylbenzene, cyclohexene vinylvinyl monoxide, divinylbenzene monoxide, vinyl acetate, vinyl propionate, allylbenzene, or diallylbenzene) can also be suitably used.

[0018] Furthermore, examples of the hydroxyl group-containing vinyl monomer include, but are not limited to, hydroxyalkyl esters of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; di-2-hydroxyethyl fumarate; mono-2-hydroxyethyl monobutyl fumarate; allyl alcohol; (poly)oxyethylene mono(meth)acrylate having 1 to 100 ethylene oxide groups; (poly)oxypropylene mono(meth)acrylate having 1 to 100 propylene oxide groups; and further, "Placcel FM, FA Monomer" (trade name of caprolactone addition monomer manufactured by Daicel Chemical Industries, Ltd.) and other hydroxyalkyl esters of α,β-ethylenically unsaturated carboxylic acids.

[0019] Examples of the (poly)oxyethylene mono(meth)acrylate include, but are not limited to, ethylene glycol (meth)acrylate, ethylene glycol methoxy(meth)acrylate, diethylene glycol (meth)acrylate, diethylene glycol methoxy(meth)acrylate, tetraethylene glycol (meth)acrylate, and tetraethylene glycol methoxy(meth)acrylate.

[0020] Furthermore, examples of (poly)oxypropylene mono(meth)acrylates include, but are not limited to, propylene glycol (meth)acrylate, propylene glycol methoxy(meth)acrylate, dipropylene glycol (meth)acrylate, dipropylene glycol methoxy(meth)acrylate, tetrapropylene glycol (meth)acrylate, and tetrapropylene glycol methoxy(meth)acrylate.

[0021] The epoxy group-containing vinyl monomer may be, but is not limited to, glycidyl (meth)acrylate, allyl glycidyl ether, allyl dimethyl glycidyl ether, or the like.

[0022] Furthermore, examples of the mono- or diester of phosphoric or phosphonic acid include, but are not limited to, 2-methacryloyloxyethyl phosphate, di-2-methacryloyloxyethyl phosphate, tri-2-methacryloyloxyethyl phosphate, 2-acryloyloxyethyl phosphate, di-2-acryloyloxyethyl phosphate, tri-2-acryloyloxyethyl phosphate, diphenyl-2-acryloyloxyethyl phosphate, dibutyl-2-methacryloyloxyethyl phosphate, dioctyl-2-acryloyloxyethyl phosphate, 2-methacryloyloxypropyl phosphate, bis(2-chloroethyl)vinylphosphonate, diallyl dibutyl phosphonosuccinate, 2-methacryloyloxyethyl phosphate, and 2-acryloyloxyethyl phosphate.

[0023] Furthermore, examples of the vinyl monomer having a silyl group include, but are not limited to, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltri-n-propoxysilane, 3-(meth)acryloyloxypropyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, and 2-trimethoxysilylethyl vinyl ether.

[0024] Other monomers and / or oligomers used to obtain the resin compound include, but are not limited to, olefins such as (meth)acrylamide, ethylene, propylene, and isobutylene; dienes such as butadiene; haloolefins such as vinyl chloride, vinylidene chloride vinyl fluoride, tetrafluoroethylene, and chlorotrifluoroethylene; vinyl carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl benzoate, vinyl p-t-butylbenzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, and vinyl laurate; and isopropenyl carboxylic acid esters such as isopropenyl acetate and isopropenyl propionate. Examples of the resin compound include esters; vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, and cyclohexyl vinyl ether; aromatic vinyl compounds such as styrene and vinyl toluene; allyl esters such as allyl acetate and allyl benzoate; allyl ethers such as allyl ethyl ether and allyl phenyl ether; and further examples include 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, perfluoromethyl(meth)acrylate, perfluoropropyl(meth)acrylate, perfluoropropylmethyl(meth)acrylate, vinylpyrrolidone, and allyl(meth)acrylate. One type of resin compound may be used alone, or two or more types may be used in combination.

[0025] The resin-adhered aluminum pigment of the present invention has resin particles or agglomerates formed from the resin compound adhered to the surface of metallic aluminum powder. The resin particles refer to resin compounds having a size of, for example, 0.05 to 0.2 μm. The resin agglomerates refer to resin compounds having a size of, for example, 0.1 to 0.4 μm, and are formed by aggregating multiple of the above-mentioned resin particles.

[0026] In the resin-adhered aluminum pigment of the present invention, the proportion of resin contained in the solid content is preferably 15.0% or more and 70.0% or less, more preferably 17.0% or more and 66.0% or less, even more preferably 20.0% or more and 60.0% or less, and most preferably 23.0% or more and 57.0% or less, from the viewpoint of metallic matte design (glossiness, flip-flop properties). From the viewpoint of metallic matte design, 20% or more is preferable. If it is 60% or less, the hiding power of the coating film is good.

[0027] (Polymerization Initiator) When producing the resin-adhered aluminum pigment of the present invention, it is preferable to use a polymerization initiator such as a peroxide or azo compound, which does not immobilize the initiator on the surface of the flaky aluminum powder. The method for producing the resin-adhered aluminum pigment of this embodiment will be described later (i.e., see the section "(Method for producing resin-adhered aluminum pigment)"). The polymerization initiator is generally known as a radical generator, and the type is not particularly limited. Examples of polymerization initiators include, but are not limited to, peroxides such as benzoyl peroxide, lauroyl peroxide, and bis-(4-t-butylcyclohexyl)peroxydicarbonate, and azo compounds such as 2,2'-azobis-isobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile. The amount of the polymerization initiator used is not particularly limited as it is adjusted depending on the reaction rate of the radical polymerizable monomer and / or oligomer, but is preferably in the range of 0.1 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the flaky aluminum powder.

[0028] (Other Components) As described below, the resin-adhered aluminum pigment of the present invention may be prepared by dispersing a flake aluminum powder in a predetermined organic solvent, and then adding a chain transfer agent together with the radically polymerizable monomer and / or oligomer described above for the purpose of controlling the molecular weight of the reaction product. Examples of the chain transfer agent include, but are not limited to, alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, and t-dodecyl mercaptan; aromatic mercaptans such as benzyl mercaptan and dodecylbenzyl mercaptan; thiocarboxylic acids such as thiomalic acid or salts thereof, or alkyl esters thereof; polythiols; diisopropyl xanthogen disulfide, di(methylenetrimethylolpropane)xanthogen disulfide, thioglycol; and allyl compounds such as α-methylstyrene dimer. The amount of these chain transfer agents used is preferably in the range of 0.001% by mass to 30% by mass, more preferably 0.05% by mass to 10% by mass, based on the resin.

[0029] (Method for Producing Resin-Adhered Aluminum Pigment) The resin-adhered aluminum metal pigment of the present invention can be produced by dispersing flaky aluminum powder in an organic solvent, heating the mixture, adding a radically polymerizable monomer and / or oligomer, and optionally a polymerization initiator, while stirring, and then reacting the resulting dispersion under vibration (e.g., ultrasonic irradiation using an ultrasonic generator). The organic solvent may be any solvent inert to the flaky aluminum powder, and examples thereof include, but are not limited to, aliphatic hydrocarbons such as hexane, heptane, octane, and mineral spirits; aromatic hydrocarbons such as benzene, toluene, xylene, and solvent naphtha; naphthenic hydrocarbons; isoparaffinic hydrocarbons; ethers such as tetrahydrofuran and diethyl ether; alcohols such as ethanol, 2-propanol, and butanol; esters such as ethyl acetate and butyl acetate; and cellosolves such as ethylene glycol monoethyl ether.

[0030] The mass concentration of the flaky aluminum powder in the organic solvent is preferably 0.1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 35% by mass or less. From the viewpoint of efficiently adhering the resin to the flaky aluminum powder, the mass concentration of the flaky aluminum powder in the organic solvent is preferably 0.1% by mass or more and more preferably 1% by mass or more. Furthermore, from the viewpoint of maintaining a uniform dispersion state of the flaky aluminum powder, the mass concentration of the flaky aluminum powder in the organic solvent is preferably 40% by mass or less and more preferably 35% by mass or less.

[0031] The mass concentration of the radical polymerizable monomer and / or oligomer in the organic solvent is preferably 0.06% by mass or more and 27% by mass or less, more preferably 0.6% by mass or more and 23% by mass or less. From the viewpoint of efficient resin adhesion to the flaky aluminum powder, it is preferably 0.06% by mass or more and more preferably 0.6% by mass or more. From the viewpoint of maintaining uniform resin adhesion to the flaky aluminum powder, it is preferably 27% by mass or less and more preferably 23% by mass or less.

[0032] When producing the resin-adhered aluminum pigment of the present invention, it is preferable to use a combination of shear external action and vibration external action as the external action. The shear external action refers to the action of applying high shear force to promote physical dispersion when dispersing flaky aluminum powder in an organic solvent and when adding a monomer to the dispersion. Examples of methods for this include dispersing the flaky aluminum powder and the monomer using a disperser. The vibration external action refers to the action of using a vibration generator or ultrasonic generator to strongly vibrate the dispersion or the mixed solution during the polymerization reaction to promote physical dispersion. Examples of the application of the vibration external action include intermittent addition during the polymerization reaction, continuous addition during the polymerization reaction, and a combination of intermittent and continuous addition during the polymerization reaction. In addition, methods of applying a vibrational external effect include a method in which vibration and ultrasonic irradiation are applied to the reactor indirectly by applying an external effect from a vibration generator and an ultrasonic vibrator, a method in which the external effect is applied directly to the treated dispersion in the reactor, and a method in which the treated dispersion is circulated in an external circulation container and the vibrational external effect is applied indirectly or directly to the external circulation container. The vibration of the external effect by a vibration generator or the like preferably has a frequency of 10 Hz to 60 kHz. Ultrasonic waves from an external effect by an ultrasonic generator or the like are a type of elastic vibration that propagates through an elastic body, and are usually longitudinal waves that propagate compression and expansion in the direction of wave propagation, but transverse waves may also exist on the reactor wall and its contact surfaces. Note that, in the technical definition, sound waves that are not intended to be heard directly are also included in ultrasound, and all sound waves that propagate through the surface or interior of a liquid or solid are also included in ultrasound. Ultrasound with a frequency of 15 kHz to 10,000 kHz and an output of 5 W or more is preferably used.

[0033] When a polymerization initiator is used in the polymerization reaction of the radical polymerizable monomer and / or oligomer, the timing of adding the polymerization initiator is not particularly limited, but it is preferably added simultaneously with and / or after the radical polymerizable monomer and / or oligomer. The temperature when adding the polymerization initiator is not particularly limited as long as the polymerization reaction of the radical polymerizable monomer and / or oligomer occurs, but it is preferably 40° C. or higher and 150° C. or lower. In addition, in order to increase the reaction efficiency, it is preferable to add or react the initiator in an inert gas atmosphere such as nitrogen or helium.

[0034] In addition, during the reaction of the radical polymerizable monomer and / or oligomer, a solvent can be added or replaced as necessary. As the organic solvent, an ester-based solvent is preferred from the viewpoints of environmental load and drying property. In particular, when propyl acetate is used, the amount of residual solvent is small even when the drying temperature is low, and it is preferred from the viewpoints of adhesion and odor.

[0035] (Circularity) The resin-adhered aluminum pigment of the present invention has a smaller circularity than the raw material flaky aluminum powder, because the resin particles or agglomerates adhere not only to the bottom surface portions (e.g., upper and lower surface portions, which are regions with a large area) of the flaky aluminum powder, but also to the edge portions (e.g., peripheral portions, which are regions with a small area). The circularity is calculated from the area S, which is the projected area of ​​the bottom surface portion of the aluminum primary particle, and the perimeter L, which is the length of the edge portion, using the following formula: Circularity = 4πS / L ２The circularity of a typical flaky aluminum powder is preferably 0.65 or more and 0.95 or less, but to obtain a metallic matte design of the resin-adhered aluminum pigment, a circularity of 0.70 or more and 0.90 or less is more preferable. In the resin-adhered aluminum pigment, by preventing too many resin particles or agglomerates from adhering to the edges of the primary particles of the flaky aluminum powder, it may be possible to suppress a decrease in the metallic matte design of the coating film (gloss, flip-flop properties, graininess, coating film smoothness, and orientation) due to particle size enlargement. Furthermore, by preventing too much decrease in the proportion of resin particles or agglomerates at the bottom surface of the resin-adhered aluminum pigment, it may be possible to make the resin particles or agglomerates at the bottom surface less likely to be scraped off by external impact, etc., which may ultimately result in increased gloss, changes in design, and sufficient abrasion resistance. The circularity of the resin-adhered aluminum pigment is preferably 0.10 or more from the viewpoint of abrasion resistance, and preferably 0.60 or less from the viewpoint of glossy design. From these viewpoints, the circularity of the resin-adhered aluminum pigment is more preferably 0.12 to 0.50, even more preferably 0.15 to 0.45, and most preferably 0.2 to 0.35. The temperature at which the polymerization initiator is added is not particularly limited as long as it is a temperature at which the polymerization reaction of the radically polymerizable monomer and / or oligomer occurs, but is preferably 50°C to 100°C, more preferably 60°C to 85°C. To improve reaction efficiency, it is preferable to add the polymerization initiator and allow the reaction to occur under an inert gas atmosphere such as nitrogen or helium, and it is preferable to use a combination of a shear external action and a vibration external action as the external action. The vibration of the external action, such as that generated by a vibration generator, preferably has a frequency of 10 Hz to 60 kHz.

[0036] (Matte Paint Composition) The coating film of the present invention is formed using a matte paint composition containing the resin-adhered aluminum pigment (a) and binder resin component (b). As the binder resin component (b), any conventionally known binder resin component can be used without any particular limitation. Examples of the binder resin component (b) include emulsion resins such as acrylic resins, acrylic-silicone resins, and fluororesins, alkyd resins, oil-free alkyd resins, vinyl chloride resins, urethane resins, melamine resins, unsaturated polyester resins, urea resins, cellulose-based resins, epoxy resins, and fluororesins. A method for producing the matte paint composition of the present invention involves, for example, mixing the resin-adhered aluminum pigment (a) and the binder resin component (b) so that the ratio of (a) to the total of 100 parts by weight (solids weight) of (a) + (b) (hereinafter, this ratio will be referred to as PWC (pigment weight concentration)) falls within a specific range. The PWC is preferably mixed in an amount of 5% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less, and even more preferably 8% by mass or more and 30% by mass or less. The PWC also has a significant effect on the properties of the coating film. From the viewpoint of the metallic matte design (gloss, flip-flop properties), a content of 5% by mass or more is preferred. From the viewpoint of suppressing the increase in the appearance of the coating film, i.e., the increase in the graininess, a content of 30% by mass or less is preferred. The matte coating composition of the present invention may optionally contain other additives such as inorganic fillers in addition to extender pigments, coloring pigments, luster pigments, silica, etc.; film-forming aids such as hydrophobic film-forming aids and hydrophilic film-forming aids; colorants for coloring organic pigments and inorganic pigments; antifoaming agents; dispersants; UV absorbers; and light stabilizers. (a) and (b) are dissolved in a solvent at the aforementioned specific PWC ratio. The matte coating composition of the present invention may contain an organic solvent, water, or a mixture thereof as the solvent. Usable solvents include organic solvents typically used in paints, such as aliphatic hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents.

[0037] The above-described matte coating composition can be used for any of solvent-based (oil-based), water-based, and powder-based coatings. When the matte coating composition is a solvent-based coating or ink composition, the binder resin for the coating or ink composition can be a coating or ink resin used in conventional metallic coatings and metallic inks. Known coating methods can be used with the coating or ink containing the resin-adhered aluminum pigment of this embodiment. Examples include spraying, flow coating, roll coating, brush coating, dip coating, spin coating, screen printing, casting, gravure printing, and flexographic printing. Furthermore, after coating, heat treatment, preferably at 20°C to 500°C, more preferably at 40°C to 250°C, or ultraviolet irradiation, can also be performed as desired. The coating can also be applied to a substrate heated to 40°C to 250°C.

[0038] (Coating Film) The coating film of the present invention is formed by applying the above-described matte coating composition to a substrate using a predetermined coating method to a coating film thickness of 6 to 70 μm, preferably 10 to 30 μm. The coating film of the present invention may be distributed on the substrate or may be distributed separately from the substrate as a standalone coating film. While any commonly used coating method can be selected, preferred methods include air spraying and flow coating. After application, the substrate is maintained at 50 to 90°C for 30 minutes to 1 hour to form a luxurious, matte coating film with excellent adhesion to the substrate surface. The substrate is not particularly limited, but examples include various metal plates, inorganic plates such as glass, various plastic plates, and paperboard. These substrates may have undergone surface treatments such as phosphate treatment, chromate treatment, plating treatment, composite oxide treatment, electrodeposition coating treatment, primer treatment, and degreasing treatment.

[0039] (Matte Layer) The coating film of the present invention is not particularly limited as long as it can achieve a matte design. It has a single-coat matte layer obtained by a single coating process containing the resin-adhered aluminum pigment and a binder resin component. In addition to the matte layer, the coating film of the present invention may also have a layer that is not intended to achieve a matte finish, such as a clear layer. Although the coating film of the present invention exhibits a sufficient metallic matte design due to the matte layer without the use of a matting agent, it may also have a layer containing a matting agent. For example, the coating film of the present invention may have a multilayer structure with a layer containing a matting agent or a layer such as a clear layer that is not intended to achieve a matte finish, above and / or below the matte layer. Furthermore, the matte layer of the present invention may contain, in addition to the resin-adhered aluminum pigment and binder resin described above, a conventionally used aluminum pigment, as long as the matte design is not impaired.

[0040] (Surface Roughness Ra) The surface roughness Ra of the matte layer of the present invention can be measured using an atomic force microscope (AFM) (e.g., Dimension Icon (manufactured by Bruker)) to evaluate the smoothness of the coating surface. By setting the surface roughness Ra of the matte layer to 650 nm or less, it is possible to prevent the resin-adhered aluminum pigment protruding from the coating film from being scraped off due to external impact, etc., and thereby prevent an increase in gloss and changes in design. The upper limit of the surface roughness Ra of the matte layer is preferably 600 nm or less, more preferably 550 nm or less, and most preferably 500 nm or less. The lower limit of the surface roughness Ra of the matte layer is not particularly limited as long as it provides a matte design, but can be, for example, 100 nm or more. The surface roughness Ra of the matte layer is preferably 100 nm or more and 500 nm or less, more preferably 100 nm or more and 250 nm or less.

[0041] (Glossiness) The degree of gloss of the matte layer of the present invention can be expressed by glossiness (G60). The glossiness (G60) can be expressed as the 60-degree specular reflectance when the reflectance is measured at an incident angle and a receiving angle of 60 degrees according to the 60-degree specular glossiness. The glossiness (G60) is preferably 5 or more and 50 or less. From the viewpoint of metallic matte design and because scratches become more noticeable at low glossiness (G60 of 10 or less), the glossiness (G60) is more preferably 10 or more and 40 or less, even more preferably 10 or more and 35 or less, even more preferably 15 or more and 35 or less, and most preferably 15 or more and 25 or less.

[0042] (Abrasion resistance ΔG60) The abrasion resistance of the matte layer of the present invention can be evaluated by polishing the surface of the matte layer coating film using a compound and measuring the difference in gloss G60 (ΔG60) between before and after polishing. From the viewpoint of the external impact resistance of the coating film, the lower limit of the abrasion resistance ΔG60 is 0 or more, and the upper limit is preferably 20 or less, more preferably 15 or less, even more preferably 10 or less, and most preferably 5 or less.

[0043] (Flip-flop property) Furthermore, the flip-flop property (F / F) of the matte layer of the present invention refers to the F / F value calculated from the slope of the logarithm of the reflected light intensity (L value) at 60 degrees and 10 degrees toward the light source, with the angle of specular reflection of light from a light source at an incident angle of 45 degrees as the base point. The L value at 60 degrees is L(60°) and the L value at 10 degrees is L(10°), and the F / F value is calculated from the following formula. F / F={Log(L(10°)−Log(L(60°)} / (60−10)×100 The F / F value is a parameter proportional to the degree of orientation of the metallic pigment, and represents the magnitude of the flip-flop effect of the pigment. The F / F value preferably exhibits a metallic matte design property of 0.91 or more and less than 2.0. It is more preferable that the metallic matte design property is 1.00 or more and 1.90 or less, even more preferable that the metallic matte design property is 1.10 or more and 1.85 or less, and most preferably that the metallic matte design property is 1.20 or more and 1.80 or less.

[0044] In the matte layer of the present invention, the aluminum pigment is preferably oriented in the vicinity of the surface thereof. More preferably, in the matte layer of the present invention, the distance from the surface of the matte layer to the resin-adhered aluminum pigment oriented closest to the surface is 2 μm or less.

[0045] When the coating film of the present invention is immersed in a 2.5N sodium hydroxide solution at 55°C for 4 hours and the alkali resistance is evaluated based on the color difference ΔE between the immersed and unimmersed areas, it preferably exhibits alkali resistance such that ΔE is less than 1.0 (ΔE = 1.0). An alkali resistance of less than ΔE = 1.0 is preferable in that it allows for the provision of a one-coat coating film with excellent workability for fields requiring extremely high alkali resistance, but a ΔE of 0.5 or less is more preferable, and a ΔE of 0.3 or less is even more preferable. The color difference ΔE can be measured using a colorimeter. Specifically, it can be measured by the method described below (i.e., see the section titled "Evaluation of Alkali Resistance" in the Examples).

[0046] The matte coating film of the present invention described above contains the resin-adhered aluminum pigment described above, and therefore can form a coating film having a good finished metallic matte design and excellent alkali resistance, without the need for a matting agent that may be scraped off from the coating film due to external impact, etc. Furthermore, because it contains the resin-adhered aluminum pigment described above, a matte ink composition can be obtained that enables the production of printed matter having a good finished metallic matte design and excellent alkali resistance, without the need for a matting agent.

[0047] The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples.

[0048] In the examples and comparative examples, various physical properties were measured by the following methods.

[0049] [Example 1] <Production of Resin-Adhered Aluminum Pigment> 89.12 g of aluminum paste FD-5060 (manufactured by Asahi Kasei Corporation, average particle size 6 μm, nonvolatile content 72%) was placed in an ultrasonic dissolution and dispersion device GSC50AG (manufactured by Sonic Technology Corporation), 494.22 g of mineral spirits was added, and the mixture was stirred while introducing nitrogen gas. The temperature in the system was raised to 70 ° C., and the first step / dispersion step was carried out for 1 hour. Next, 3.21 g of acrylic acid, 12.51 g of trimethylolpropane trimethacrylate, 29.20 g of di-trimethylolpropane tetraacrylate, and 105 g of mineral spirits were added all at once, and immediately 0.63 g of 2,2'-azobis-2,4-dimethylvaleronitrile and 45 g of mineral spirits were also added all at once, and the second step / polymerization step was initiated. In the second step / polymerization step, polymerization was carried out for 6 hours while maintaining the temperature in the system at 70 ° C. From the second step / treatment step to the end of the second step / polymerization step, the reaction slurry solution in the ultrasonic dissolution and dispersion device GSC50AG was continuously irradiated with ultrasonic waves at a frequency of 36 kHz and an output of 5 W or more. After the polymerization was completed, the unreacted amount of trimethylolpropane trimethacrylate in the filtrate was sampled and analyzed by gas chromatography, revealing that more than 99% of the added amount had reacted. After the polymerization was completed, the mixture was naturally cooled and the slurry was filtered to obtain a paste-like resin-adhered aluminum pigment. The nonvolatile content (according to JIS-K-5910) of this paste was 31.2% by mass. A portion of this paste was pretreated in a thermogravimetric / differential thermal TG-DTA (TG-DTASTA2500 Regulus, manufactured by NETZSCH) by holding it at 150°C for 30 minutes under argon flow to volatilize the solvent contained in the paste, and then the temperature was raised from 150 to 500°C (heating rate: 20°C / min). The percentage of resin in the resin-adhered aluminum pigment was calculated from the weight at 150°C before the start of the temperature increase and the weight at 500°C after the temperature increase using the following formula: Resin percentage (%) = (Weight at 150°C - Weight at 500°C) / Weight at 150°C x 100 The percentage of resin in the resin-adhered aluminum pigment was 40.2%.

[0050] The resin-adhered aluminum pigment was ultrasonically cleaned with excess n-hexane for 10 minutes, the solution was filtered, and then ultrasonically cleaned again with n-hexane, filtered, and air-dried to obtain a measurement sample of the resin-adhered aluminum pigment. The measurement sample was then dispersed in n-hexane and dropped onto a silicon wafer. After air-drying, it was dried in a 50°C dryer for 30 minutes, and gold was vapor-deposited. Ten fields of view were photographed at 1000x magnification using a scanning electron microscope (SEM, S-2600H, manufactured by Hitachi Corporation), with the images randomly selected so that no overlap occurred. A representative example is shown in Figure 1. The SEM images obtained by the above SEM measurement were analyzed using image analysis software (Image Pro Plus Version 7.0) to measure the perimeter and area of ​​each observed particle. Using the measurement results obtained using the image analysis software, the circularity was calculated using the following formula based on the area S, which is the projected area of ​​the base of the aluminum primary particle, and the perimeter L, which is the length of the edge portion. Circularity = 4πS / L ２ The circularity was 0.26. The results are summarized in Table 1.

[0051] <Evaluation of the Design Properties of Metallic Matte Coating Films> The resin-adhered aluminum pigment obtained above was used to prepare a matte coating composition having the following composition. The amount of resin-adhered aluminum pigment in the coating was changed so that the proportion of resin-adhered aluminum pigment in the matte coating film (PWC) was 14.9%. Resin-adhered aluminum pigment = 1.1 g (solid mass) Thinner (a mixture of 30 parts butyl acetate, 45 parts toluene, 20 parts isopropyl alcohol, and 5 parts ethyl cellosolve): (D) g The total amount of the resin-adhered aluminum pigment and (D) was adjusted to 33 g. Clear (a mixture of 29 parts of Acrydic A-166 (manufactured by DIC), 3 parts of nitrocellulose (industrial nitrocellulose 1 / 2 AS, manufactured by Companhia Nitro Qumica Brasileira), and 68 parts of the above thinner) (binder resin component): 42 g The obtained matte coating composition was spray-coated onto an ABS resin plate to a film thickness of 15 μm. This was then dried at 55° C. for 30 minutes to prepare a coated plate for evaluation, and evaluations of design and alkali resistance were carried out. The results are shown in Table 1.

[0052] The surface roughness Ra (nm) of the coating film was measured using an atomic force microscope (AFM) (Dimension Icon (manufactured by Bruker)). Measurement was performed over five fields of view under the conditions of a 30 μm measurement field, 512 × 256 pixels, and a scanning speed (μm / sec) of 30 μm × 0.3 to 0.7 Hz. A primary plane fit was performed on each measurement image to calculate Ra, and the calculated average value is shown in Table 1.

[0053] <Gloss G60 Evaluation> The gloss G60 of the coating film was measured at 60 degrees (both the incident angle and the reflection angle were 60 degrees) using a gloss meter (Digital Variable Gloss Meter UGV-5D, manufactured by Suga Test Instruments Co., Ltd.) and expressed as a percentage, with the gloss of the reference surface for specular gloss being taken as 100. The results are shown in Table 1.

[0054] <Flip-flop property evaluation F / F> The flip-flop property F / F of the coating film was evaluated using a goniochromatic colorimeter (manufactured by Suga Test Instruments Co., Ltd.). The F / F value was calculated from the slope of the logarithm of the reflected light intensity (L value) at 60 degrees and 10 degrees toward the light source, starting from the specular reflection of light at an incident angle of 45 degrees from a light source. The F / F value is a parameter proportional to the degree of orientation of the metal pigment and represents the degree of flip-flop effect of the pigment. The results are shown in Table 1.

[0055] <Abrasion Resistance Evaluation> The coated plate prepared above was applied with 0.17 g of compound (#9800, Soft 99) on a sponge, and a load of 100 g was applied, and the coated plate was rubbed back and forth 25 times. The gloss G60 of the coated plate before and after the application was measured, and the difference ΔG60 was calculated. The results are shown in Table 1.

[0056] <Evaluation of Alkali Resistance> The lower half of the coated plate prepared above was immersed in a beaker containing 2.5N NaOH aqueous solution and left to stand at 55°C for 4 hours. After the test, the coated plate was washed with water and dried, and then the immersed and unimmersed parts were colorimetrically measured according to JIS-Z-8722 (8-d method), and the color difference ΔE was determined according to JIS-Z-8730. The color difference ΔE was evaluated as follows. The smaller the value, the more excellent the alkali resistance of the coating film formed on the coated plate. Taking practicality into consideration, ○ was evaluated as passing, and × was evaluated as failing. Alkali Resistance Evaluation ○: ΔE less than 1.0 ×: ΔE 1.0 or more

[0057] [Example 2] A resin-adhered aluminum pigment was obtained in the same manner as in Example 1, except that the aluminum paste in Example 1 was changed to GX-4100 (manufactured by Asahi Kasei Corporation, average particle size 10 μm, non-volatile content 74%), and the amounts of acrylic acid, trimethylolpropane trimethacrylate, and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 2.64 g, 9.89 g, and 23.08 g, respectively. The non-volatile content of this paste (according to JIS-K-5910) was 34.7 mass%. The proportion of resin in the resin-adhered aluminum pigment was 34.3%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0058] Example 3 A resin-adhered aluminum pigment was obtained in the same manner as in Example 1, except that the aluminum paste in Example 1 was changed to GX-4130 (manufactured by Asahi Kasei Corporation, average particle size 13 μm, non-volatile content 74%), and the amounts of acrylic acid, trimethylolpropane trimethacrylate, and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 2.31 g, 7.91 g, and 18.47 g, respectively. The non-volatile content of this paste (according to JIS-K-5910) was 37.3 mass%. The proportion of resin in the resin-adhered aluminum pigment was 29.6%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0059] [Example 4] A resin-adhered aluminum pigment was obtained in the same manner as in Example 1, except that the aluminum paste in Example 1 was changed to SB-10 (manufactured by Asahi Kasei Corporation, average particle size 10 μm, non-volatile content 66%), and the amounts of acrylic acid, trimethylolpropane trimethacrylate, and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 5.00 g, 21.17 g, and 49.41 g, respectively. The non-volatile content of this paste (according to JIS-K-5910) was 24.6 mass%. The proportion of resin in the resin-adhered aluminum pigment was 56.2%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0060] Example 5 A resin-adhered aluminum pigment was obtained in the same manner as in Example 1, except that the aluminum paste in Example 1 was changed to GX-40A (manufactured by Asahi Kasei Corporation, average particle size 19 μm, non-volatile content 74%), and the amounts of acrylic acid, trimethylolpropane trimethacrylate, and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 0.99 g, 5.94 g, and 13.85 g, respectively. The non-volatile content of this paste (according to JIS-K-5910) was 44.7 mass%. The proportion of resin in the resin-adhered aluminum pigment was 23.2%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0061] Example 6 The resin-adhered aluminum pigment obtained in Example 1 and resin-coated aluminum paste PV-K5060 (manufactured by Asahi Kasei Corporation, average particle size 6 μm, non-volatile content 50%) were mixed in weight ratios of 7:3, 1:1, and 3:7 in terms of solid content, and the design properties were evaluated in the same manner as in Example 1. The results are summarized in Table 1.

[0062] Example 7 81 g of aluminum paste 0-2100 (Asahi Kasei Corporation, average particle size 10 μm, nonvolatile content 74%) was placed in a 2 L four-neck flask, 567 g of mineral spirits was added, and the mixture was stirred while introducing nitrogen gas. The temperature in the system was raised to 50°C and stirring was continued for 60 minutes. Next, 1.80 g of acrylic acid was added and stirring was continued at 50°C for 60 minutes. Next, a solution consisting of 10.70 g of divinylbenzene, 17.98 g of trimethylolpropane trimethacrylate, 7.19 g of di-trimethylolpropane tetraacrylate, 0.30 g of 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and 100 g of mineral spirits was prepared and added all at once. The polymerization process was carried out for a total of 12 hours while maintaining the temperature in the system at 50°C. During the polymerization process, an ultrasonic cleaner (B5510J-DTH, manufactured by Emerson Japan Co., Ltd.) was used to indirectly irradiate the mixture in the 2-L four-neck flask with ultrasonic waves at a frequency of 42 kHz and an output of 180 W. The method for applying ultrasonic vibrational external action during polymerization was as follows: Continuous ultrasonic irradiation was performed from the start of polymerization until the first hour of polymerization. Intermittent ultrasonic irradiation (5 minutes of ultrasonic irradiation every 15 minutes of polymerization) was performed from the first hour of polymerization to the 12th hour of polymerization. Next, at the end of the 12-hour polymerization process, a solution consisting of 0.30 g of bis-(4-t-butylcyclohexyl) peroxydicarbonate and 10 g of mineral spirits was prepared and added all at once. The polymerization process was continued for 1 hour while maintaining the temperature in the system at 50°C. After the polymerization was completed, a sample was taken of the filtrate, and the amount of unreacted trimethylolpropane trimethacrylate in the filtrate was analyzed by gas chromatography. This indicated that more than 99% of the added amount had reacted. After the polymerization was completed, the mixture was allowed to cool naturally, and the slurry was filtered to obtain a paste-like resin-adhered aluminum pigment. The nonvolatile content of this paste (according to JIS-K-5910) was 35.2% by mass. The proportion of resin in the resin-adhered aluminum pigment was 37.5%. The design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0063] Example 8: 83 g of aluminum paste FD-5060 (manufactured by Asahi Kasei Corporation, average particle size 6 μm, nonvolatile content 74%) was placed in a 2 L four-neck flask, 457 g of mineral spirits was added, and the mixture was stirred while introducing nitrogen gas. The temperature in the system was raised to 70 ° C. and stirring was continued for 60 minutes. Next, 1.80 g of acrylic acid was added and stirring was continued at 70 ° C. for 60 minutes. Next, a solution consisting of 6.20 g of trimethylolpropane trimethacrylate, 2.60 g of di-trimethylolpropane tetraacrylate, 0.30 g of 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and 124 g of mineral spirits was prepared, and the entire solution was added dropwise over 4.5 hours at a rate of approximately 0.5 g / min. After the completion of the dropwise addition, the temperature in the system was lowered to 50 ° C., and stirring was continued for 1.5 hours after reaching 50 ° C., completing the first polymerization step of 6.0 hours. During the 6.0-hour first polymerization step, ultrasonic waves were indirectly irradiated onto the mixture in the 2-L four-neck flask using an ultrasonic cleaner (manufactured by Emerson Japan Co., Ltd.; CPX5800H-J, oscillation frequency 40 kHz, maximum ultrasonic output 160 W, heater capacity 200 W, maximum power capacity 410 W). The method for applying an external vibrational effect using ultrasonic waves during polymerization was as follows. Intermittent ultrasonic irradiation (2 minutes of ultrasonic irradiation every 15 minutes after polymerization) was applied from the start of dropwise addition of the solution until 4.5 hours into polymerization. Note that ultrasonic irradiation was not applied during the temperature-lowering step to 50°C after 4.5 hours and during the 1.5 hours of continuous stirring. After the completion of the 6.0-hour first polymerization step, a solution consisting of 9.00 g of divinylbenzene, 14.90 g of trimethylolpropane trimethacrylate, 6.00 g of di-trimethylolpropane tetraacrylate, 0.30 g of 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and 83 g of mineral spirits was prepared and added all at once. The second polymerization step was carried out for a total of 12 hours while maintaining the temperature in the system at 50°C. The method for applying external ultrasonic vibration during the 12-hour second polymerization step after the all-at-once addition of the solution was as follows: Continuous ultrasonic irradiation was applied from the all-at-once addition of the solution until the first hour of polymerization. Intermittent ultrasonic irradiation (5 minutes of ultrasonic irradiation every 15 minutes of polymerization) was applied from the first hour to the 12th hour of polymerization.Next, at the end of the 12-hour polymerization process, a solution consisting of 0.30 g of bis-(4-t-butylcyclohexyl) peroxydicarbonate and 10 g of mineral spirits was prepared and added all at once. The third polymerization process was continued for 1 hour while maintaining the temperature in the system at 50°C. After the polymerization was completed, the amount of unreacted trimethylolpropane trimethacrylate in the filtrate was sampled and analyzed by gas chromatography. It was found that more than 99% of the added amount had reacted. After the polymerization was completed, the mixture was allowed to cool naturally, and the slurry was filtered to obtain a paste-like resin compound-adhered aluminum pigment. The nonvolatile content (according to JIS-K-5910) of this paste was 35.0% by mass. The resin content of the resin-adhered aluminum pigment was 39.0%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 2.

[0064] [Example 9] A resin-adhered aluminum pigment was obtained in the same manner as in Example 4, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 31.76 g and 74.11 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 20.3 mass%. The proportion of resin in the resin-adhered aluminum pigment was 65.3%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0065] [Example 10] A resin-adhered aluminum pigment was obtained in the same manner as in Example 2, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 6.59 g and 15.39 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 39.5 mass%. The proportion of resin in the resin-adhered aluminum pigment was 27.2%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0066] [Example 11] A resin-adhered aluminum pigment was obtained in the same manner as in Example 3, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 5.28 g and 12.31 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 42.4 mass%. The proportion of resin in the resin-adhered aluminum pigment was 23.2%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0067] [Example 12] A resin-adhered aluminum pigment was obtained in the same manner as in Example 5, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 8.32 g and 19.39 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 40.2 mass%. The proportion of resin in the resin-adhered aluminum pigment was 30.3%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 1.

[0068] <Evaluation of Design Properties of Metallic Matte Coating Film> Using the resin-adhered aluminum pigment obtained in Example 2, a matte coating composition having the following composition was prepared. The amount of resin-adhered aluminum pigment in the coating was changed so that the proportion of resin-adhered aluminum pigment (PWC) in the matte coating film was 8, 20.3, or 25.9%, and these compositions were designated Examples 13, 14, and 15, respectively. Resin-adhered aluminum pigment = 0.55, 1.6, or 2.2 g (solids mass); Thinner (a mixture of 30 parts butyl acetate, 45 parts toluene, 20 parts isopropyl alcohol, and 5 parts ethyl cellosolve): (D) g. The total amount of the resin-adhered aluminum pigment and (D) was adjusted to 33 g. Clear (a mixture of 29 parts of Acrydic A-166 (manufactured by DIC), 3 parts of nitrocellulose (industrial nitrocellulose 1 / 2 AS, manufactured by Companhia Nitro Qumica Brasileira), and 68 parts of the above thinner) (binder resin component): 42 g The obtained matte coating composition was spray-coated onto an ABS resin plate to a film thickness of 15 μm. This was then dried at 55° C. for 30 minutes to prepare a coated plate for evaluation, and evaluations of design and alkali resistance were carried out. The results are shown in Table 1.

[0069] Comparative Example 1 Resin-attached aluminum paste FD-5060 (manufactured by Asahi Kasei Corporation, average particle size 6 μm, non-volatile content 72%) was combined with a matting agent used to impart a matte effect (manufactured by Asahipen Co., Ltd., silica particles 2 to 5 μm, non-volatile content 15%) to achieve the same gloss as in Example 1 (the amount of pigment solid content in the paint was the same as in Example 1, with 25% of the solid content replaced by the matting agent), and a design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0070] Comparative Example 2 A resin-attached aluminum paste GX-4100 (manufactured by Asahi Kasei Corporation, average particle size 10 μm, non-volatile content 74%) was combined with a matting agent used to impart a matte effect (manufactured by Asahipen Co., Ltd., silica particles 2-5 μm, non-volatile content 15%) to achieve the same gloss as in Example 2 (the amount of pigment solids in the paint was the same as in Example 1, with 23% of the solids replaced by the matting agent), and a design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0071] [Comparative Example 3] Aluminum paste GX-4130 (manufactured by Asahi Kasei Corporation, average particle size 13 μm, non-volatile content 74%) was combined with a matting agent used to impart a matte effect (manufactured by Asahipen Co., Ltd., silica particles 2-5 μm, non-volatile content 15%) to achieve a gloss level equivalent to that of Example 3 (the amount of pigment solid content in the paint was the same as in Example 1, with 20% of the solid content replaced by the matting agent), and a design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0072] Comparative Example 4 Aluminum paste SB-10 (manufactured by Asahi Kasei Corporation, average particle size 10 μm, non-volatile content 66%) and a matting agent used for the purpose of imparting a matte effect (manufactured by Asahipen Co., Ltd., silica particles 2 to 5 μm, non-volatile content 15%) were combined to achieve the same gloss as in Example 4 (the amount of pigment solid content in the paint was the same as in Example 1, with 35% of the solid content replaced with the matting agent), and a design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0073] Comparative Example 5 Aluminum paste GX-40A (manufactured by Asahi Kasei Corporation, average particle size 19 μm, non-volatile content 74%) and a matting agent used to impart a matte effect (manufactured by Asahipen Co., Ltd., silica particles 2 to 5 μm, non-volatile content 15%) were combined to achieve the same gloss as in Example 5 (the amount of pigment solid content in the paint was the same as in Example 1, with 15% of the solid content replaced by the matting agent), and a design evaluation was carried out in the same manner as in Example 1, and the results are summarized in Table 2.

[0074] [Comparative Example 6] A resin-adhered aluminum pigment was obtained in the same manner as in Example 5, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 10.69 g and 24.93 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 36.2 mass%. The proportion of resin in the resin-adhered aluminum pigment was 35.7%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 2.

[0075] Comparative Example 7 A resin-adhered aluminum pigment was obtained in the same manner as in Example 1, except that the amounts of trimethylolpropane trimethacrylate and di-trimethylolpropane tetraacrylate used in the second step / polymerization step were changed to 6.26 g and 14.60 g, respectively. The nonvolatile content of this paste (according to JIS-K-5910) was 38.6 mass%. The proportion of resin in the resin-adhered aluminum pigment was 27.3%. A design evaluation similar to that in Example 1 was conducted, and the results are summarized in Table 2.

[0076] The resin-adhered aluminum pigment obtained in Example 2 was used to prepare matte paint compositions having the following formulations. The amount of resin-adhered aluminum pigment in the paint was changed so that the proportion of resin-adhered aluminum pigment (PWC) in the matte paint film was 4.0 and 36.0%, respectively, and these were designated Comparative Examples 8 and 9. Resin-adhered aluminum pigment = 0.26 and 3.55 g (solids mass); Thinner (a mixture of 30 parts butyl acetate, 45 parts toluene, 20 parts isopropyl alcohol, and 5 parts ethyl cellosolve): (D) g. The total amount of the resin-adhered aluminum pigment and (D) was adjusted to 33 g. Clear (a mixture of 29 parts of Acrydic A-166 (manufactured by DIC), 3 parts of nitrocellulose (industrial nitrocellulose 1 / 2 AS, manufactured by Companhia Nitro Qumica Brasileira), and 68 parts of the above thinner) (binder resin component): 42 g The obtained matte coating composition was spray-coated onto an ABS resin plate to a film thickness of 15 μm. This was then dried at 55° C. for 30 minutes to prepare a coated plate for evaluation, which was then evaluated for design and alkali resistance. The results are shown in Table 2.

[0077]

[0078]

[0079] The results of Examples 1 to 15 and Comparative Examples 1 to 9 confirmed that the matte coating film of the present invention, which contains a resin-adhered aluminum pigment and a binder resin component, has excellent metallic matte design, coating film smoothness, alkali resistance, and / or abrasion resistance, even when it does not use a matting agent that may be scraped off from the coating film by external impact, etc. Furthermore, the comparison results of Examples 1 to 15 and Comparative Examples 1 to 9 also showed that the coating composition of the present invention can achieve metallic matte design, coating film smoothness, and abrasion resistance that are equal to or better than conventional aluminum-containing coating compositions that use matting agents, without using a matting agent, and can more consistently provide excellent metallic matte design.

[0080] The matte coating film of the present invention has industrial applicability in the automotive industry (including motorcycles), aircraft industry, home appliance industry, etc., for example, various parts for automobiles and aircraft, and various parts for information appliances such as general home appliances and mobile phones.

Claims

DEPCT6918 / 05 / 25691. Coating film composed of: a matte layer containing resin-bonded aluminum pigment and a resin binder component, in which the resin-bonded aluminum pigment contains aluminum metal powder with an average particle diameter of 5 to 20 micrometers and granules or nodules of resin bonded to the surface of the aluminum metal powder, and the matte layer has a surface roughness of Ra100 nm or more and 600 nm or less.

2. Coating film according to claim 1, in which the matte layer has a surface roughness of Ra100 nm or more. 250 nm or less.

3. Coating film according to claim 1 or 2, where the matte layer has a gloss (G60) of 5 or more and 50 or less, which is a specular reflectance at an angle of 60 degrees at the angle of incidence and 60 degrees at the angle of reception.

4. Coating film according to claim 1 or 2, where the resin-bound aluminum pigment has an average particle diameter of 5 to 15 µm.

5. Coating film according to claim 1 or 2, where the resin-bound aluminum pigment has a roundness of 0.10 or more and 0.50 or less; 6. Coating film according to claim 1 or 2, where the matte layer has a Delta G6015 or less abrasion resistance; 7. Coating film according to claim 1 or 2, where the resin-bonded aluminum pigment present in the matte layer is present in such a way that the PWC is 5% by mass or more and 35% by mass or less; 8. Coating film according to claim 1 or 2, where the matte layer has a flip-flop value of 1.0 or more and less. 1.

99. Coating film according to claim 1 or 2, where the proportion of resin contained in the solid volume of the resin-bonded aluminum pigment is 23.0% or more and 66.0% or less; 10. Coating film according to claim 1 or 2, where the coating film is a single-layer matte finish; 11. Coating film according to claim 1 or 2, where the resin-bonded aluminum pigment is colorless; 12. Coating film according to claim 1 or 2, where the coating film contains no matte coating agent.

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