JP2018054522A - Evaluation method of metallic design - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method of metallic design capable of quantifying a metallic touch using a simple parameter.SOLUTION: The evaluation method of metallic design evaluates a metallic design by calculating the ratio between specular glossiness on a design surface 10 which has a metallic design and the brightness at an angle separated away from a regular reflection direction 12 of the design surface 10 and using the ratio.EFFECT: A scale close to an evaluation result of visual observation is obtained by quantifying a metallic touch with a simple parameter by means of combination of a specular glossiness as a colorimetric parameter adjacent to a regular reflection and the brightness at the angle separated away from the regular reflection.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating a metallic design.

  Metallic paints containing various glitter pigments (aluminum flakes, mica flakes, graphite, etc.) are widely used. The color of a coating film obtained by applying a metallic paint (hereinafter referred to as “metallic color”) changes in appearance depending on the observation angle. On the other hand, a paint color whose color appearance does not change depending on the observation angle is called a “solid color”.

In Patent Document 1, as a method for measuring the metallic feeling of a metallic coating film, the reflected light is colorimetrically measured at a plurality of light receiving angles in a plurality of metallic coating films, and the obtained L ^* brightness set is regarded as a variable. In this method, a principal component analysis is performed, and a luminance parameter and a whiteness parameter are expressed by a linear combination formula of L ^* brightness.

JP 2004-286672 A

  In metallic coatings such as silver metallic and super metallic, highlights (observation angle with a small angle from specular reflection light, for example, a light receiving angle of 15 °), high brightness, shade (observation angle with a large angle from specular reflection light, For example, since the discoloration (flip-flop) is large so that the lightness is low at a light receiving angle of 75 °, it is difficult to obtain parameters that are consistent with visual evaluation.

In the method described in Patent Document 1, each coefficient of the linear combination formula is derived by analyzing the visual evaluation result and L ^* brightness with different light receiving angles in association with each other. Since the principal component parameters obtained by Patent Document 1 are determined depending on the visual evaluation results, the metallic feeling cannot be expressed by simple parameters independent of the visual evaluation results.
In addition, according to the study by the present inventors, it is difficult to accurately evaluate the super-metallic coating color in which the brightness of the highlight is high and the brightness is greatly lowered by changing the observation angle slightly with the conventional parameters. It turns out that.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the evaluation method of the metallic design which can quantify a metallic feeling with a simple parameter.

  In order to solve the above problems, the present invention calculates a ratio between the specular gloss of a design surface having a metallic design and the brightness at an angle away from the specular reflection direction of the design surface, and the metallic design is calculated based on the ratio. Provided is a method for evaluating a metallic design characterized by evaluation.

The specular gloss may be measured with an incident angle of 60 ° ± 5 °.
Further, the lightness may be measured by setting an incident angle to 45 ° ± 5 ° and an angle of 45 ° ± 5 ° from the regular reflection direction toward the incident direction as a light receiving angle.

Also, the brightness, the brightness _Y in the XYZ color system, _{X 10 Y} 10 _Z lightness _Y 10 in ₁₀ color ^system, L ^* a * ^{b *} color system or ^L * ^u * ^{v *} lightness L in the color system ^* Either of them may be used.
The lightness is preferably lightness Y in the XYZ color system.
Moreover, the said design surface may have a metallic coating film or a metal layer.

  According to the present invention, the combination of the specular gloss near the specular reflection light and the brightness at an angle away from the specular reflection light, the metallic feeling is quantified with simple parameters, and the visual evaluation result An order close to can be obtained.

It is explanatory drawing of the measurement angle of (a) specular glossiness and (b) brightness.

  Hereinafter, the present invention will be described based on preferred embodiments. FIG. 1 (a) shows an explanatory diagram of the specular gloss measurement angle, and FIG. 1 (b) shows an explanatory diagram of the brightness measurement angle.

  The metallic design evaluation method of the present embodiment includes a step of measuring the specular gloss of the design surface 10 having a metallic design, and a step of measuring the lightness in the light receiving direction 14 at an angle away from the regular reflection direction 12 of the design surface 10. And a step of calculating a ratio of specular gloss: brightness, and the metallic design can be evaluated by the value of this ratio.

(Measurement of specular gloss)
Examples of the method for measuring the specular gloss include JIS Z 8741 (specular gloss-measurement method). In this method, the design surface 10 is used as a sample surface, light is incident on the design surface 10 from a predetermined incident direction 11, and the light flux in the regular reflection direction 12 due to specular reflection is measured.
The incident angle θ ₁ is an angle formed by the incident direction 11 and the normal direction 13. The regular reflection angle θ _{2, which} is an angle formed between the regular reflection direction 12 and the normal direction 13, is equal to the incident angle θ ₁ .

A glass surface having a refractive index of a constant value of 1.567 over the entire visible wavelength range is defined as a standard surface, and a specular reflected light beam from the standard surface with respect to an incident angle θ _{1 is} defined as φ _0S . When the specular reflection light flux from the sample surface with respect to the incident angle theta ₁ (design surface) was phi _S, specular gloss G _{S (theta 1)} is obtained by the following expression.

G _S (θ ₁ ) = (φ _S / φ _0S ) × G _OS (θ ₁ )

Here, G _OS (θ ₁ ) is the specular gloss of the standard surface. If the refractive index of the standard surface is 1.567, G _OS (θ ₁ ) = 100% regardless of the incident angle θ _1. It is. Therefore, the specular gloss G _S (θ ₁ ) can also be obtained by the following equation. The unit (%) of the specular gloss can be omitted.

G _S (θ ₁ ) = (φ _S / φ _0S ) × 100 (%)

The incident angle θ ₁ can be selected from, for example, 20 °, 45 °, 60 °, 75 °, 85 °, etc., depending on the degree of reflection on the design surface. The specular gloss at an incident angle of 60 ° (60 ° specular gloss) can be used as a standard, but the incident angle may be determined from the range of 60 ° ± 5 ° (55 to 65 °). Examples of the set angle tolerance include 0.1 ° and 0.2 °.

  The specular gloss measurement device has a light source (not shown) in the incident direction 11 and a light receiver (not shown) in the regular reflection direction 12. The parallel light beam reflected from the design surface can be measured by the light receiver by entering the parallel light beam from the light source to the design surface. An optical system including a lens, an aperture, and the like may be provided between the light source and light receiver and the design surface. The opening angle of the light beam can be regulated by the size of the opening.

(Measurement of brightness)
As the brightness, it may be a parameter that can quantify the amount of reflection (brightness) relative to the color of the silver-based, for example, brightness _{Y, X 10 Y 10 Z 10} Table brightness _{Y 10} in the color system in the XYZ color system, The brightness L ^* in the L ^* a ^* b ^* color system or the L ^* u ^* v ^* color system can be mentioned (for example, refer to old JIS Z 8701, old JIS Z 8729, JIS Z 8781, etc.).
There is generally a relationship of L ^* = 116 (Y / 100) ¹ / 3-16 between the lightness Y and the lightness L ^* , but the L ^* a ^* b ^* color system or the L ^* u ^* v ^* table Since the color system is a color system defined with the intention of a uniform color space and is greatly affected by the psychological quantity, it is preferable to employ the lightness Y rather than the lightness L ^* .

The light source may be annular illumination in which light sources are provided in a circular shape that gives the same incident angle θ ₁ with respect to the normal direction 13, or one-way illumination in which light sources are provided only at one point on the circumference of the incident angle θ _1. Alternatively, annular illumination in which light sources are provided at a number of points on the circumference of the incident angle θ ₁ may be used.
In the case of unidirectional illumination, the regular reflection direction 12 and the light receiving direction 14 are in a plane (incident surface) including the incident direction 11 and the normal direction 13, and the light reception angle θ ₃ is the regular reflection direction 12 and the light receiving direction 14. It is calculated as the angle formed by At this time, positive in the sign of the acceptance angle theta ₃ in the rotation angle of the direction from the specular reflection direction 12 in the incident direction 11 (clockwise in FIG. 1 (a)), a direction away from the incident direction 11 (FIGS. 1 (a) The sign of the light receiving angle θ ₃ is negative at a rotation angle of (counterclockwise). If the acceptance angle theta ₃ is a positive value, it may be omitted positive sign (+). When the light receiving direction 14 coincides with the normal direction 13 (the light receiving angle θ ₃ is equal to the regular reflection angle θ ₂ ), even if the incident direction 11 is shifted around the normal direction 13, the shift in the light receiving direction 14 can be suppressed. preferable.

The light receiving direction 14 can be selected from, for example, 15 °, 25 °, 45 °, 60 °, 75 °, 110 °, etc., with the angle with respect to the regular reflection direction 12 as the light receiving angle θ ₃ . Small light reception angles θ ₃ such as 10 °, 15 °, and 25 ° are highlights, and large light reception angles θ ₃ such as 75 ° and 110 ° are shades, and light reception directions 14 such as 45 ° are such that the light reception direction 14 is close to the normal direction 13. Angle θ ₃ is referred to as the face. For example, the incident angle θ ₁ may be within a range of 45 ° ± 5 ° (40 to 50 °), and the light receiving angle θ ₃ may be within a range of 45 ° ± 5 ° (40 to 50 °). Examples of the set angle tolerance include 0.1 ° and 0.2 °.
The brightness can be measured using a color meter such as a multi-angle spectrophotometer.

(Evaluation of metallic feeling)
When calculating the ratio between the specular gloss and the lightness, a result obtained by performing a certain operation such as addition, subtraction, multiplication, and exponentiation of a constant on the value of the ratio may be used for evaluation. Since the specular gloss is obtained by photometry in the regular reflection direction, the greater the contribution of regular reflection, the greater the value. Further, the brightness at an angle away from the regular reflection direction has a larger value as the contribution of diffuse reflection increases. A flat specular metallic material has strong specular reflection and weak diffuse reflection. Therefore, when the ratio of (specular gloss / brightness) is taken, the larger the value, the more visually a metallic feeling is felt. Since it is easy to evaluate intuitively if it is high, it is preferable.

  The design surface 10 may have a metallic coating film or a metal layer such as a metal foil. As metallic coatings, scaly metal pigments such as aluminum, copper, nickel alloy, stainless steel, scaly metal pigments coated with metal oxide on the surface, scaly metal pigments with colored pigments chemically adsorbed on the surface, Examples thereof include a coating film containing a metal particle pigment such as a scale-like aluminum pigment in which an aluminum oxide layer is formed by causing an oxidation-reduction reaction. Examples of the metal layer include a metal foil, a metal vapor deposition layer, and a metal plating layer.

  A paint (metallic paint) for forming a metallic coating film can be prepared by blending a vehicle, a pigment, a solvent (such as an organic solvent or water), and appropriate additives as necessary, and uniformly dispersing the mixture. it can. Further, the metallic paint may contain a general glitter paint or a colored pigment as a pigment other than the metal particle pigment. The color of the metallic coating film is not limited to silver, and may have a color such as red, blue, yellow, and green.

  As bright pigments, plate-like iron oxide pigments in which aluminum is dissolved, glass flake pigments, glass flake pigments whose surfaces are coated with metal or metal oxides, glass flake pigments in which colored pigments are chemically adsorbed on the surface, and surface Interference mica pigments coated with titanium dioxide, reduced mica pigments obtained by reducing interference mica pigments, colored mica pigments with chemically adsorbed colored pigments on the surface, colored mica pigments coated with iron oxide on the surface, and surfaces coated with titanium dioxide Examples thereof include graphite pigments, silica flakes and alumina flake pigments coated with titanium dioxide on the surface, plate-like iron oxide pigments, hologram pigments, synthetic mica pigments, cholesteric liquid crystal polymer pigments having a helical structure, and bismuth oxychloride pigments.

  Examples of the color pigment include inorganic pigments such as transparent iron oxide pigments and composite oxide pigments such as titanium yellow; azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzs Organic pigments such as imidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, dioxazine pigments, selenium pigments, indigo pigments, carbon black pigments, A titanium oxide pigment etc. are mentioned.

  Examples of the vehicle include a resin component. Specifically, the resin component includes a base resin such as an acrylic resin, a polyester resin, an alkyd resin, and a urethane resin having a crosslinkable functional group such as a hydroxyl group, a melamine resin, a urea resin, a polyisocyanate compound (also a block body). In combination with a cross-linking agent such as

  The method for producing the coating film is not particularly limited as long as it can apply a glittering paint having a uniform film thickness on the substrate, but a spray method such as air spray, airless spray, electrostatic spray or the like is preferable. . When the design surface 10 is formed on the substrate, a coating film made of an undercoat paint or an intermediate paint can be formed in advance before the paint is applied. Moreover, on the coating film of the glitter paint, one or more clear coating films can be formed for the purpose of protecting the coating film.

  When a flake with a high aspect ratio is used as a metal particle pigment, such as a vapor-deposited aluminum pigment having a particle size (major axis) of 10 μm or more and a thickness (minor axis) of 0.1 μm or less (for example, about 0.05 μm). , Can improve the metallic feeling. However, if the orientation of the metal particles is not aligned with the surface direction of the coating film, even if the amount of reflected light emitted from the coating film is high, the regular reflection direction of each flake is less likely to coincide with the regular reflection direction of the design surface. When variation occurs in a direction that looks bright visually, the directivity of reflected light decreases, and the metallic feeling like a flat metal material decreases.

  In recent years, super metal design that is closer to a metal material than a conventional metal design, and a super metal color that can be realized with a coating film have attracted attention. Examples of the design that can be evaluated as having the highest metallic feeling include a mirror-polished metal material, a metal foil, a metal vapor-deposited film, and metal plating. However, metal materials are heavy and tend to be avoided from the viewpoints of improving energy efficiency and light weight in transport devices such as automobiles and portable devices. Metal foil is expensive to process such as sticking and foil stamping. Even when a metal vapor deposition film or metal plating is formed on the surface of the molded part, the cost is high, and depending on the shape, size, etc. of the molded part, it may be difficult to perform vapor deposition or plating.

  For this reason, it is desired to realize a design with a high metallic feeling by painting (coating film), and an objective index of metallic feeling is required. When multiple experienced observers evaluate visually, it is possible to perform advanced evaluation according to human visual perception, but it takes time to train observers and influences such as fatigue and physical condition of observers It is also necessary to consider.

  As a result of studying the reflection characteristics of uniform metal surfaces such as metal materials, metal foils, and metal deposited films, the present inventors have found that the angle dependency of the reflectance is the highest in the reflectance of specularly reflected light and the light receiving angle is It has been found that as the distance from the specular reflection direction increases, the reflectance decreases, and even when the light reception angle is as small as about 15 ° (the light reception direction is close to the regular reflection direction), the brightness is significantly decreased. Although it is conceivable to measure the lightness at a low angle such as 5 to 10 °, a special measuring instrument is required, and the measurement takes time. Therefore, by utilizing the specular glossiness by measuring regular reflection light, it is possible to easily measure the characteristics of a design having a high metallic feeling.

  According to the ratio between the specular gloss and lightness described above, it is possible to reflect a decrease in metallic feeling (increased particle feeling) due to poor orientation of metal particles to a higher degree than conventional parameters, and a design with a high metallic feeling. It is useful for development and evaluation of From a conventional metal design to a super metal design and a metal material, a visual metallic feeling can be evaluated by a unified index. Since a result consistent with the visual evaluation is obtained from simple parameters independent of the visual evaluation, it can be easily applied to on-line inspection of a coating line or the like.

  Hereinafter, the present invention will be specifically described with reference to examples. “Part” means “part by mass”. In addition, this invention is not limited only to these Examples.

(1) Production of hydroxyl group-containing acrylic resin In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and dropping device, 50 parts of ethylene glycol monoethyl ether acetate was stirred, mixed, and heated to 135 ° C. . Then 38 parts methyl methacrylate, 17 parts ethyl acrylate, 17 parts n-butyl acrylate, 7 parts hydroxyethyl methacrylate, 20 parts lauryl methacrylate, 1 part acrylic acid and 2,2'-azobis (2-methylpropionitrile) 2 A monomer / polymerization initiator mixture consisting of parts was dropped into a reaction vessel maintained at the same temperature over 3 hours, and aged for 1 hour after completion of the dropping.
Thereafter, a mixture consisting of 10 parts of ethylene glycol monoethyl ether acetate and 0.6 part of 2,2′-azobis (2-methylpropionitrile) was dropped into the reaction vessel maintained at the same temperature over 1 hour 30 minutes. Aged for another 2 hours.
Next, unreacted ethylene glycol monoethyl ether acetate was distilled off under reduced pressure to obtain a hydroxyl group-containing acrylic resin having a hydroxyl value of 54 mgKOH / g, a number average molecular weight of 20,000, and a resin solid content of 65% by mass. Here, the number average molecular weight means that measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

(2) Manufacture of organic solvent-type paint 1 Consists of 75 parts of a hydroxyl group-containing acrylic resin obtained in (1) and 25 parts of Uban (registered trademark) 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals). 10 parts by weight of aluminum paste GX-180A (trade name, manufactured by Asahi Kasei Aluminum Co., Ltd., 74 mass% solid content, scaly aluminum pigment paste having a primary average particle diameter of 16.9 μm) per 100 parts (solid content) of the resin component The organic solvent-type paint 1 having a solid content of about 25% was prepared by blending, stirring and mixing, and diluting to a viscosity appropriate for coating.

(3) Manufacture of organic solvent-type paint 2 Consists of 75 parts of a hydroxyl group-containing acrylic resin obtained in (1) and 25 parts of Uban (registered trademark) 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals). 30 parts by weight of aluminum paste GX-180A (trade name, manufactured by Asahi Kasei Aluminum Co., Ltd., 74 mass% solid content, scaly aluminum pigment paste having a primary average particle diameter of 16.9 μm) per 100 parts (solid content) of the resin component The organic solvent type paint 2 having a solid content of about 25% was prepared by blending, stirring and mixing, and diluting to a viscosity suitable for coating.

(4) Manufacture of organic solvent-type paint 3 Consists of 75 parts of the hydroxyl group-containing acrylic resin obtained in (1) and 25 parts of Uban (registered trademark) 28-60 (trade name, butyl etherified melamine resin, manufactured by Mitsui Chemicals). For 100 parts of resin component (solid content), METASHEEN (registered trademark) 71-0010 (trade name, manufactured by BASF, solid content of 10% by mass, vapor-deposited aluminum slurry) is mixed with 10 parts of solid content, and mixed by stirring. The organic solvent-type paint 3 having a solid content of about 12% was prepared by diluting to an appropriate viscosity.

(5) Production of vapor-deposited aluminum pigment solution To METASHEEEN (registered trademark) 71-0010 (trade name, manufactured by BASF, solid content of 10% by mass, vapor-deposited aluminum slurry), butyl acetate was added and mixed by stirring. A 5 mass% evaporated aluminum pigment solution was prepared.

(6) Preparation of base material for coated plate Cationic electrodeposition paint “ELECRON (registered trademark) 9400HB” (trade name: Kansai) on a degreased and zinc phosphate-treated steel plate (JIS G 3141, size 400 mm × 300 mm × 0.8 mm) Painted, epoxy resin polyamine-based cationic resin using a block polyisocyanate compound as a curing agent) is electrodeposited to a film thickness of 20 μm based on the cured coating film, and heated at 170 ° C. for 20 minutes. The electrodeposition coating film was obtained by crosslinking and curing.
On the obtained electrodeposition coating surface, an intermediate coating “Lugabake (registered trademark) intermediate coating N-2 gray” (trade name: manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin, organic solvent type) is applied by air spray. Based on the cured coating film, it was coated to a film thickness of 30 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and a coated plate on which an intermediate coating film was formed was used as a substrate.

(7) Preparation of coating plate for evaluation (Sample 1)
The base material obtained in (5) is coated with the organic solvent-type paint 1 obtained in (2) using an air spray so as to have a dry film thickness of 15 μm. After being left for a minute, “Lugabake (registered trademark) clear” (trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used at a booth temperature of 25 using a mini-bell type rotary electrostatic coating machine. The cured coating film was coated at a temperature of 75 ° C. and a humidity of 75% so as to have a film thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample2)
The base material obtained in (5) is coated with the organic solvent-type paint 2 obtained in (3) using an air spray so that the dry film thickness is 5 μm. After being left for a minute, “Lugabake (registered trademark) clear” (trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used at a booth temperature of 25 using a mini-bell type rotary electrostatic coating machine. The cured coating film was coated so as to have a film thickness of 30 μm under the conditions of ° C. and humidity of 75%. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample3)
The base material obtained in (6) is coated with the organic solvent-type paint 3 obtained in (4) so as to have a dry film thickness of 2 μm using an air spray. After being left for a minute, “Lugabake (registered trademark) clear” (trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used at a booth temperature of 25 using a mini-bell type rotary electrostatic coating machine. The cured coating film was coated so as to have a film thickness of 30 μm under the conditions of ° C. and humidity of 75%. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample4)
To the base material obtained in (6), the deposited aluminum pigment liquid obtained in (5) is used with W-101-102P (air spray gun, manufactured by Anest Iwata Co., Ltd.), and the paint adjustment knob is set to 0.00. One stage coating was performed for 5 revolutions, spraying air pressure 0.2 MPa, gun distance 30 cm, gun speed 10 cm / s, and after coating, left at room temperature for 15 minutes, “Lugabake (registered trademark) clear” ( A product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used as a cured coating film at a booth temperature of 25 ° C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine. The coating was applied to a thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample5)
To the base material obtained in (6), the deposited aluminum pigment liquid obtained in (5) is used with W-101-102P (air spray gun, manufactured by Anest Iwata Co., Ltd.), and the paint adjustment knob is set to 0.00. Two stages of coating were performed under the conditions of release for 5 revolutions, spraying air pressure of 0.2 MPa, gun distance of 30 cm, and gun speed of 10 cm / s. After painting and leaving at room temperature for 15 minutes, “Lugabake (registered trademark) clear” ( A product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used as a cured coating film at a booth temperature of 25 ° C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine. The coating was applied to a thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample6)
To the base material obtained in (6), the deposited aluminum pigment liquid obtained in (5) is used with W-101-102P (air spray gun, manufactured by Anest Iwata Co., Ltd.), and the paint adjustment knob is set to 0.00. 5 stages are applied under the conditions of release for 5 revolutions, spraying air pressure 0.2 MPa, gun distance 30 cm, gun speed 10 cm / s, and after coating and leaving at room temperature for 15 minutes, “Lugabake (registered trademark) clear” ( A product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used as a cured coating film at a booth temperature of 25 ° C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine. The coating was applied to a thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample7)
To the base material obtained in (6), the deposited aluminum pigment liquid obtained in (5) is used with W-101-102P (air spray gun, manufactured by Anest Iwata Co., Ltd.), and the paint adjustment knob is set to 0.00. 10 stages were applied under the conditions of release for 5 revolutions, spraying air pressure 0.2 MPa, gun distance 30 cm, gun speed 10 cm / s, and after coating and leaving at room temperature for 15 minutes, “Lugabake (registered trademark) clear” ( A product name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin type, organic solvent type) is used as a cured coating film at a booth temperature of 25 ° C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine. The coating was applied to a thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot-air circulating drying furnace to simultaneously dry and cure the multilayer coating film to prepare a coated plate for measurement.

(Sample8)
After pasting aluminum foil for household use on a smooth tin plate and degreasing the foil surface with a solvent, "Lugabake (registered trademark) clear" (trade name, manufactured by Kansai Paint Co., Ltd., acrylic resin / amino resin, organic solvent The mold was coated as a cured coating film under a condition of a booth temperature of 25 ° C. and a humidity of 75% using a mini-bell type rotary electrostatic coating machine so as to have a film thickness of 30 μm. After coating, it was allowed to stand at room temperature for 15 minutes, and then heated at 140 ° C. for 30 minutes using a hot air circulating drying oven to dry and cure the clear coating film, thereby preparing a coated plate for measurement.

(8) Evaluation of coated plate (measurement of brightness)
Using MA68II (trade name, multi-angle spectrophotometer, manufactured by X-Rite Co., Ltd.), the design surface of the coated plate obtained in (7) is measured, the Y value in the XYZ color system, and L ^* a ^* B ^* L ^* values in the color system were measured. The incident angle is 45 °, and the light receiving angles are 15 ° and 45 °.
Hereinafter, the Y value at a light receiving angle of 15 ° is represented by “Y ₁₅ ”, the Y value at a light receiving angle of 45 ° is represented by “Y ₄₅ ”, and the L ^* value at the light receiving angle of 15 ° is represented by “L ^* ₁₅ ”. The L ^* value at an angle of 45 ° is represented by “L ^* ₄₅ ”.

The flip-flop value “FF” was calculated by the following equation.
FF = 2 × (Y ₁₅ −Y ₄₅ ) / (Y ₁₅ + Y ₄₅ )

(Measurement of specular gloss)
Using micro-tri-gloss (trade name, gloss meter, manufactured by BYK Gardner), the design surface of the coated plate obtained in (7) is irradiated with light from an incident angle of 60 °, and is regularly reflected. Light was received and the specular gloss was measured. The specular gloss at an incident angle of 60 ° is represented by “Gs ₆₀ ”.
Further, the value of “Gs ₆₀ / Y ₄₅ ” and “Gs ₆₀ / L ^* ₄₅ ” was calculated by dividing the value of the specular gloss Gs _{60 by} the value of brightness Y ₄₅ or L ^* ₄₅ .

(Measurement of micro glitter data)
Using the imaging device, image data of the design surface of the coated plate was acquired, and “HG” and “SB”, which are data representing micro glitter, were calculated from the acquired image data by the following formula.

When IPSL ≧ 0.32, HG = 500 · IPSL-142.5
When 0.32> IPSL ≧ 0.15, HG = 102.9 · IPSL-15.4
When 0.15> IPSL, HG = 0

HB = (BV-50) / 2

  Here, IPSL and BV are obtained by the following equations.

IPSL = ∫ ₀ ^N _{０ 0} ^2π P (ν, θ) dνdθ / P (0,0)
BV = PH _av +350 PS _av

Here, P (ν, θ) is a power spectrum obtained by two-dimensional Fourier transform processing of two-dimensional luminance distribution data generated from the acquired image data, ν is a spatial frequency, and θ is an angle. 0 to N are spatial frequency regions corresponding to particle feeling. _{０ 0} ^N dv is the integral in the spatial frequency range _{0 to} ^N , and _{０ 0} ^2π dθ is the integral in the angular range _{0 to} ^2π .

Further, PH _av and PS _av are respectively the average peak height and average peak skirt spread rate of the luminance image, and PH _av = 3 V / A and PS _av = L / PH _av . Here, V and A are the total luminance volume and total luminance area that are equal to or greater than the threshold when binarized with the threshold of “GL + 32”, respectively, and L is the average grain when binarized with the threshold of “GL + 24” Is the diameter. Here, GL is the average gray level of the image data.

The results are shown in Tables 1 and 2. The visual metallic feeling was ranked by visual inspection of a skilled worker, with a general silver coating score of 1 and an aluminum foil score of 5.
Samples 4 to 7, which are the coatings of the vapor-deposited aluminum pigment solution, improved the concealment property as the number of stages increased, and sample 7 did not give the impression of being transparent. The visual scores of samples 4 to 7 were all 4. In Table 1, score 4 is represented by sample 7, and in Table 2, samples 4-7 can be compared.

When the L ^* ₁₅ value is compared with the visual rating, there is no correlation, and the L ^* ₁₅ value of the aluminum foil is lower than the general silver coating color. Similarly, the FF value is different from the visual score.
Regarding the Gs ₆₀ value, which is the measurement result of specular reflection light, the value of the aluminum foil was the maximum among the eight types of samples. Therefore, by taking a ratio of Gs ₆₀ / L ^* ₄₅ , a result consistent with the visual metallic feeling was obtained. Further, according to the ratio of Gs ₆₀ / Y ₄₅ , the numerical value of the aluminum foil was close to 100, and the order of metallic feeling could be quantified more easily. Therefore, parameters such as Gs ₆₀ / L ^* ₄₅ and Gs ₆₀ / Y ₄₅ were obtained by taking a ratio between the specular gloss and the lightness so that the metallic feeling can be quantified by a simple measuring method.

For samples 4 to 7 (the number of coating stages is 1, 2, 5, and 10 respectively), as shown in Table 2, there was no clear difference between the FF values as the conventional parameters, but Gs ₆₀ / L ^* _45. According to the ratio of Gs ₆₀ / Y _45, the smaller the number of coating stages, the larger the ratio value and the higher the metal feeling. As for the brightness of highlights (for example, the light receiving angle is 15 °), the larger the number of painting stages, the larger the value of L ^* _{15 and} the whiter the appearance. However, the larger the number of coating stages, the more the orientation of the aluminum flakes used as the deposited aluminum pigment in the coating film is disturbed, so the value of the specular gloss Gs ₆₀ becomes smaller.

As for the brightness of the face (for example, the light receiving angle is 45 ° ± 5 °), the L ^* ₄₅ value increased and the brightness increased as the concealability by the coating film increased with the increase in the number of coating stages. The brightness of the shade (for example, the light receiving angle is 75 ° to 110 °) is not particularly measured, but is considered to show the same tendency.

The apparent metallic feeling is more highly evaluated by simultaneously observing the brightness of the highlight and the blackness of the face or shade. Since not only the highlight is bright (white) but also the face or shade is dark (black), the metal feeling is considered to be high. Therefore, among samples 4 to 7, sample 4 has the highest metal feeling and sample 7 has the highest. It can also be evaluated that the metal feeling is low. That is, according to the results in Table 2, samples 4 to 7 have a small difference in visual metal feeling by taking the ratio between the specular gloss and the brightness, such as Gs ₆₀ / L ^* ₄₅ and Gs ₆₀ / Y _45. In the meantime, we were able to obtain and evaluate a numerical value close to the sense of metal feeling.

DESCRIPTION OF SYMBOLS 10 ... Design surface, 11 ... Incident direction, 12 ... Regular reflection direction, 13 ... Normal direction, 14 ... Light receiving direction.

Claims (6)

  Evaluation of a metallic design characterized by calculating a ratio between the specular gloss of a design surface having a metallic design and the brightness at an angle away from the specular reflection direction of the design surface, and evaluating the metallic design based on the ratio Method.   The method for evaluating a metallic design according to claim 1, wherein the specular gloss is measured at an incident angle of 60 ° ± 5 °.   The lightness is measured by using an incident angle of 45 ° ± 5 ° and an angle of 45 ° ± 5 ° from the regular reflection direction toward the incident direction as a light receiving angle. Evaluation method of metallic design. The brightness, the brightness _Y in the XYZ color system, _{X 10 Y} 10 brightness _Y 10 in _{Z 10} color ^system, L ^* a * ^{b *} color system or ^L * ^u * ^{v *} in the lightness ^{L *} color system It is either, The evaluation method of the metallic design of any one of Claims 1-3 characterized by the above-mentioned.   The method for evaluating a metallic design according to claim 4, wherein the lightness is lightness Y in an XYZ color system.   The said design surface has a metallic coating film or a metal layer, The evaluation method of the metallic design of any one of Claims 1-5 characterized by the above-mentioned.

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