WO2019225559A1 - 複層塗膜形成方法 - Google Patents
複層塗膜形成方法 Download PDFInfo
- Publication number
- WO2019225559A1 WO2019225559A1 PCT/JP2019/019977 JP2019019977W WO2019225559A1 WO 2019225559 A1 WO2019225559 A1 WO 2019225559A1 JP 2019019977 W JP2019019977 W JP 2019019977W WO 2019225559 A1 WO2019225559 A1 WO 2019225559A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- coating film
- colored
- paint
- parts
- range
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
- B05D7/57—Three layers or more the last layer being a clear coat
- B05D7/572—Three layers or more the last layer being a clear coat all layers being cured or baked together
- B05D7/5723—Three layers or more the last layer being a clear coat all layers being cured or baked together all layers being applied simultaneously
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
- B05D7/57—Three layers or more the last layer being a clear coat
- B05D7/577—Three layers or more the last layer being a clear coat some layers being coated "wet-on-wet", the others not
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
- B05D5/06—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain multicolour or other optical effects
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
- B05D7/142—Auto-deposited coatings, i.e. autophoretic coatings
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2202/00—Metallic substrate
- B05D2202/10—Metallic substrate based on Fe
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2252/00—Sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2350/00—Pretreatment of the substrate
- B05D2350/60—Adding a layer before coating
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2401/00—Form of the coating product, e.g. solution, water dispersion, powders or the like
- B05D2401/20—Aqueous dispersion or solution
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2420/00—Indexing scheme corresponding to the position of each layer within a multilayer coating relative to the substrate
- B05D2420/05—Indexing scheme corresponding to the position of each layer within a multilayer coating relative to the substrate fifth layer from the substrate side
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2451/00—Type of carrier, type of coating (Multilayers)
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2601/00—Inorganic fillers
- B05D2601/20—Inorganic fillers used for non-pigmentation effect
- B05D2601/24—Titanium dioxide, e.g. rutile
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/50—Multilayers
- B05D7/56—Three layers or more
- B05D7/57—Three layers or more the last layer being a clear coat
- B05D7/572—Three layers or more the last layer being a clear coat all layers being cured or baked together
Definitions
- the present invention relates to a method for forming a multilayer coating film, and in particular, it is possible to form a white multilayer coating film with high brightness and excellent brightness, smoothness and weather resistance, and with suppressed white unevenness.
- the present invention relates to a method for forming a multilayer coating film.
- a white composite consisting of an electrodeposition coating, an intermediate coating, a white base coat, a white pearl or silver pearl glitter base coat, and a clear coat is applied to an object such as an automobile outer plate.
- Forming a layer coating film is known (for example, Patent Document 1).
- the white base coat coating film has high brightness.
- a means for forming the white base coat film having high lightness there is a method of reducing the content of color pigments other than the white pigment in the white base coat paint. Since the light transmittance of the film is increased and the hiding power of the base color is lowered, the weather resistance of the formed white multi-layer coating film is sometimes lowered and white unevenness is likely to occur.
- Patent Document 1 high whiteness pearl luster is obtained by using a colored base coat that forms a coating film adjusted in the range of Munsell color charts N7 to N9 with titanium white pigment and aluminum flakes as a white base coat paint. It is described that a multilayer coating film excellent in feeling and color stability can be formed. However, the brightness of the white base coat film formed by this method may be insufficient.
- the coating film is required to have excellent smoothness, but in recent years, water-based coatings have been required from the viewpoint of reducing environmental pollution due to organic solvents.
- the volatilization rate of water, which is a diluting solvent, is slow, and the volatilization rate is greatly affected by the coating environmental conditions such as temperature and humidity. For this reason, the smoothness of the formed coating film may be lowered.
- the present invention sequentially coats an object with an aqueous white base coat paint, an aqueous glitter base coat paint and a clear coat paint, and is excellent in glitter, smoothness and weather resistance, and has white unevenness. It is an object of the present invention to provide a method for forming a multilayer coating film capable of forming a high-brightness white multilayer coating film in which the above is suppressed.
- the present inventors applied a specific first colored paint (P1), second coating material on the cured electrodeposition coating film formed on the steel plate.
- a water-based colored paint (P2), a third water-colored paint (P3), and a clear coat paint (P4) are sequentially applied to form a first colored film, a second colored film,
- P1 first colored paint
- P2 second coating material
- P3 third water-colored paint
- P4 clear coat paint
- the present invention provides the following steps (1) to (6): (1) A process of applying an electrodeposition paint on a steel plate and heat-curing to form a cured electrodeposition coating film, (2) A step of applying a first colored paint (P1) on the cured electrodeposition coating film obtained in step (1) to form a first colored paint film, wherein the first colored paint (P1) Wherein the lightness L * value (L * P1 ) when a cured coating film having a thickness of 30 ⁇ m is formed is in the range of 80 to 89, (3) The binder component (A P2 ) and the titanium dioxide pigment (B) are contained on the first colored coating film obtained in the step (2), and the solid content of the paint is in the range of 21 to 50% by mass.
- the second water-based colored paint (P2) is applied, the cured film thickness (T P2 ) is in the range of 5 to 20 ⁇ m, and the lightness L * value (L * P2 ) at the time of curing is in the range of 85 to 95
- a step of forming a second colored coating film (4)
- the present invention relates to a method for forming a multilayer coating film in which P3 is within a range of 1.1 / 1 to 20/1 .
- the method of the present invention it is possible to form a white multi-layer coating film having high brightness and excellent brightness, smoothness and weather resistance, and with suppressed white unevenness.
- an electrodeposition paint is applied on a steel plate and is cured by heating to form a cured electrodeposition coating (step (1)).
- the electrodeposition paint is applied to the surface of the steel sheet that is the object to be coated, thereby preventing rust and corrosion of the steel sheet and impact resistance of the surface of the article on which the multilayer coating film is formed. It is a paint used for strengthening.
- the steel sheet to be coated for example, a cold-rolled steel sheet, an alloyed hot-dip galvanized steel sheet, an electrogalvanized steel sheet, an electrogalvanized steel double-plated steel sheet, an organic composite plated steel sheet, an Al material, an Mg material, etc. may be used. it can. Moreover, after washing
- the electrodeposition paint used in this step is preferably a thermosetting aqueous paint commonly used in the field, and either a cationic electrodeposition paint or an anionic electrodeposition paint can be used.
- Such an electrodeposition coating is preferably an aqueous coating containing a base resin and a curing agent and an aqueous medium composed of water and / or a hydrophilic organic solvent.
- an epoxy resin for example, an acrylic resin, or a polyester resin
- the base resin it is preferable to use, for example, an epoxy resin, an acrylic resin, or a polyester resin as the base resin.
- a resin having an aromatic ring as at least one kind of the base resin
- an epoxy resin having an aromatic ring it is preferable to use an epoxy resin having an aromatic ring.
- curing agent it is preferable to use a blocked polyisocyanate compound, an amino resin, etc., for example.
- the hydrophilic organic solvent include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, ethylene glycol, and the like.
- an electrodeposition coating method commonly used in the field can be employed as a means for coating the electrodeposition paint on the steel plate.
- a coating film having high rust resistance can be formed over almost the entire surface of an object to be coated that has been subjected to a molding process in advance.
- the electrodeposition coating film formed in this step prevents the occurrence of mixed layers with the first colored coating film formed on the coating film, and improves the coating appearance of the resulting multilayer coating film
- the uncured coating film is baked and cured by heating.
- cured electrodeposition coating film means a coating film obtained by heating and curing an electrodeposition coating film formed on a steel sheet.
- the baking temperature of the uncured electrodeposition coating film is preferably in the range of 110 to 190 ° C., particularly 120 to 180 ° C.
- the baking time is usually preferably 10 to 60 minutes.
- the dry film thickness of the cured electrodeposition coating film after being baked under the above conditions is usually within a range of 5 to 40 ⁇ m, particularly 10 to 30 ⁇ m.
- the rust resistance of the coated steel sheet can be improved by forming the electrodeposition coating film according to the above.
- First colored coating composition (P1) is a paint containing binder component and a coloring pigment, in the case of forming a cured coating film having a thickness of 30 [mu] m, a lightness in the L * a * b * color system L *
- the value (L * P1 ) is in the range of 80-89.
- being excellent in weather resistance specifically means that a decrease in adhesion between the multilayer coating film and the lower electrodeposition coating film does not easily occur after long-term outdoor battering.
- One of the reasons why the coating film formed by the present invention is excellent in weather resistance is that the first colored coating film blocks a relatively large amount of sunlight that causes deterioration of the lower electrodeposition coating film. Can be considered.
- L * a * b * is a color system, is standardized by the International Commission on Illumination (CIE) in 1976, is a color system that has been adopted in JIS Z 8784-1 in Japan, the lightness L *, hue And chromaticity indicating saturation are represented by a * and b * .
- a * indicates the red direction ( ⁇ a * is the green direction)
- b * indicates the yellow direction ( ⁇ b * is the blue direction).
- L * , a *, and b * in the present specification are obtained by using a multi-angle spectrophotometer CM512m3 (trade name, manufactured by Konica Minolta Co., Ltd.) with irradiation light of 45 degrees with respect to the vertical axis of the coating surface. It is defined as a numerical value calculated from the spectral reflectance received at 90 degrees with respect to the coating film surface.
- the first colored paint (P1) has a lightness L * value (L * P1 ) of a coating film obtained by coating so as to be 30 ⁇ m as a cured coating film in the range of 80 to 89.
- the pigment content is adjusted.
- the lightness L * value (L * P1 ) of the first colored coating film is combined with the second colored coating film, which will be described later, and has whiteness that suppresses white unevenness while having sufficient weather resistance.
- a system multilayer coating film can be formed.
- the lightness L * value (L * P1 ) is more preferably in the range of 83 to 89, and still more preferably in the range of 85 to 89.
- the L * P1 is related to the lightness L * value (L * P2 ) at the time of curing of the second colored coating film formed by the second water-based colored paint described later, and the L * P2 is the L * higher than P1, and the difference between the between the L * P2 L * P1 is adjusted to be within the range of 1-10.
- the difference between L * P2 and L * P1 is more preferably in the range of 2 to 9, and still more preferably in the range of 3 to 8.
- the color pigment used in the first color paint (P1) is not particularly limited as long as the L * value (L * P1 ) can be adjusted within the range of 80 to 89, and a conventionally known color pigment can be used. Can be used. Specifically, for example, a titanium oxide pigment (B), a composite metal oxide pigment such as an iron oxide pigment, titanium yellow, etc., an azo pigment, a quinacridone pigment, a diketopyrrolopyrrole pigment, a perylene pigment, and a perinone pigment described later.
- a titanium oxide pigment (B) a composite metal oxide pigment such as an iron oxide pigment, titanium yellow, etc., an azo pigment, a quinacridone pigment, a diketopyrrolopyrrole pigment, a perylene pigment, and a perinone pigment described later.
- Pigment benzimidazolone pigment, isoindoline pigment, isoindolinone pigment, metal chelate azo pigment, phthalocyanine pigment, indanthrone pigment, dioxane pigment, selenium pigment, indigo pigment, carbon black pigment, etc. Any one of these can be used in combination of one or more.
- the color pigment used in the first color paint (P1) it is preferable to use the titanium dioxide pigment (B) as at least one kind from the viewpoint of the weather resistance of the white multi-layer coating film to be formed.
- the content of the titanium dioxide pigment (B) is 100 parts by mass of the total solid content of the binder component in the first colored paint (P1). Is preferably in the range of 60 to 150 parts by mass, preferably 75 to 130 parts by mass, more preferably 90 to 110 parts by mass.
- the color pigment used in the first color paint (P1) it is preferable to use a carbon black pigment as at least one kind from the viewpoint of the weather resistance of the white multi-layer coating film to be formed.
- the content of the carbon black pigment is 0.00 on the basis of 100 parts by mass of the total solid content of the binder component in the first colored paint (P1). It is suitable to be in the range of 01 to 0.50 parts by mass, preferably 0.02 to 0.30 parts by mass, more preferably 0.03 to 0.20 parts by mass.
- a film-forming resin composition usually used for an intermediate coating can be used.
- a resin composition include base resins such as acrylic resins, polyester resins, alkyd resins, and urethane resins having a crosslinkable functional group such as a hydroxyl group, melamine resins, urea resins, and polyisocyanate compounds (block bodies). And the like, which are used in combination with a crosslinking agent such as an organic solvent and / or a solvent such as water.
- the first colored paint (P1) includes, as necessary, a solvent such as water or an organic solvent, a pigment dispersant, a curing catalyst, an antifoaming agent, an antioxidant, an ultraviolet absorber, a light stabilizer, Various additives such as thickeners and surface conditioners, glitter pigments such as aluminum pigments, extender pigments such as barium sulfate, barium carbonate, calcium carbonate, talc, and silica can be appropriately blended.
- the first colored paint (P1) may be an aqueous paint or an organic solvent-type paint, but is preferably an aqueous paint from the viewpoint of VOC reduction.
- the water-based paint is a term contrasted with an organic solvent-type paint, and generally, a binder component, a pigment, and the like are dispersed and / or dissolved in water or a medium mainly containing water (aqueous medium). Means paint.
- the water content in the first colored paint (P1) is preferably about 20 to 80% by mass, more preferably about 30 to 60% by mass.
- the first colored paint (P1) can be prepared by mixing and dispersing the aforementioned components.
- the solid content of the first colored paint (P1) is preferably adjusted in the range of 30 to 60% by mass, more preferably 40 to 50% by mass.
- the first colored paint (P1) is adjusted to a suitable viscosity for coating by adding water, organic solvent, etc., and then applied by a known method such as rotary atomization coating, air spray, airless spray, etc.
- the film thickness is preferably from 15 to 40 ⁇ m, more preferably from 17 to 35 ⁇ m, based on the cured coating film (T P1 ) from the viewpoint of smoothness and finish of the coating film. More preferably, it can be applied so as to be in the range of 20 to 30 ⁇ m.
- the first colored paint (P1) has an average light transmittance (TR P1 ) at a wavelength of 360 to 420 nm of a coating film obtained by coating to a thickness of 30 ⁇ m as a cured coating film of 0.08%. It is preferable from the viewpoint of improving the weather resistance that it is adjusted to be within the following range.
- the average light transmittance (TR P1 ) at a wavelength of 360 to 420 nm is more preferably 0.07% or less, still more preferably 0.06% or less.
- the average light transmittance (TR P1 ) can be set by adjusting the thickness of the cured coating film, the amount of pigment contained in the paint, and the like.
- the average light transmittance (TR P1 ) at a wavelength of 360 to 420 nm of the cured coating film having a thickness of 30 ⁇ m can be measured by the following method.
- the first colored paint (P1) is applied and cured on a polytetrafluoroethylene plate so that the thickness of the coating film when cured is 30 ⁇ m.
- the coating film obtained by curing is peeled off and collected, and an average light transmittance in a wavelength range of 360 to 420 nm is measured using a spectrophotometer.
- a spectrophotometer for example, “SolidSpec-3700” (trade name, manufactured by Shimadzu Corporation) or the like can be used.
- the first colored coating film may be left uncured and used for forming the second colored coating film in the next step (3), or may be cured by heating before coating the second aqueous colored coating material. Also good.
- the first colored coating film is left uncured and used in step (3), the second colored coating film and the third colored coating film formed in steps (3) to (5) in step (6) described later. And can be cured by heating together with the clear coat film, which is advantageous in terms of energy saving.
- the smoothness of the coating film is further improved by polishing the cured first colored coating film surface by means such as water polishing. Can be increased.
- heating means for example, hot air heating, infrared heating, high frequency heating, or the like can be used.
- the heating temperature is preferably 80 to 180 ° C, and more preferably 100 to 160 ° C.
- the heating time is preferably 10 to 60 minutes, more preferably 15 to 40 minutes. If necessary, before performing the heat curing, heating directly or indirectly by preheating, air blowing, etc. at a temperature of about 50 to about 110 ° C., preferably about 60 to about 90 ° C. for about 1 to 60 minutes. May be performed.
- step (3) a second aqueous colored paint (P2), which is an aqueous paint, is applied onto the first colored coating film obtained in step (2), and the cured film thickness ( TP2 ) is 5 to 20 ⁇ m.
- a second colored coating film having a lightness L * value (L * P2 ) in the range of 85 to 95 within the range is formed.
- the lightness L * value (L * P2 ) at the time of curing of the second colored coating film is a state in which both coating films of the first colored coating film and the second colored coating film are cured.
- the brightness obtained by measuring from the surface of the second colored coating film opposite to the side in contact with the first colored coating film.
- the second water-based colored paint (P2) contains a binder component (A P2 ) and a titanium dioxide pigment (B), and has a paint solid content in the range of 21 to 50% by mass.
- the lightness L * P2 is the relationship between the lightness L * value in the case of forming a cured coating film having a thickness of 30 ⁇ m by a first colored coating composition (L * P1), the L * P2 is the L * higher than P1, and the difference between the between the L * P2 L * P1 is adjusted to be within the range of 1-10.
- the second colored coating film using such a second water-based colored paint (P2), the first colored coating film and the third colored coating film formed on the upper and lower sides of the second colored coating film have high brightness.
- a resin composition containing a film-forming resin usually used in paints can be used.
- a thermosetting resin composition can be suitably used.
- a combination of a base resin such as melamine resin, a urea resin, and a crosslinking agent such as a polyisocyanate compound (including a block body) can be used.
- These resin compositions can be used by dissolving or dispersing in an organic solvent and / or a solvent such as water.
- the ratio of the base resin and the cross-linking agent in the resin composition is not particularly limited, but in general, the cross-linking agent is 10 to 100% by mass, preferably 20 to 80% by mass, based on the total solid content of the base resin. Preferably, it can be used within the range of 30 to 60% by mass.
- the titanium dioxide pigment (B) used for the second water-based coloring paint (P2) is a white pigment, and can impart white color to the formed coating film.
- the crystal form of the titanium dioxide pigment (B) may be either a rutile type or an anatase type, but the rutile type is preferred from the viewpoint of excellent concealability and weather resistance of the coating film to be formed.
- the titanium dioxide pigment (B) may be obtained by coating the surface of titanium dioxide with an inorganic oxide such as aluminum oxide, zirconium oxide or silicon dioxide; an organic compound such as amine or alcohol.
- the blending amount of the titanium dioxide pigment (B) is such that the lightness L * value (L * P2 ) at the time of curing of the second colored coating film formed using the second aqueous colored paint (P2) is in the range of 85 to 95.
- the titanium dioxide pigment (B) is preferably in the range of 60 to 150 parts by mass based on 100 parts by mass of the solid content of the binder component (A P2 ), More preferably, it is in the range of 65 to 125 parts by mass, and still more preferably in the range of 70 to 100 parts by mass.
- the lightness L * value (L * P2 ) is more preferably in the range of 87 to 95, and more preferably from the viewpoint of securing high lightness without impairing the weather resistance in combination with the first colored coating film. Is in the range of 89-95.
- the L * P2 is related to the lightness L * value (L * P1 ) when a cured coating film having a thickness of 30 ⁇ m is formed by the first colored paint, and the L * P2 is higher than L * P1, and the difference between the between the L * P2 L * P1 is adjusted to be within the range of 1-10.
- pigment dispersant for the second water-based colored paint (P2), various kinds of pigment dispersant, curing catalyst, antifoaming agent, antioxidant, ultraviolet absorber, light stabilizer, thickener, surface conditioner, etc.
- Additives, glitter pigments such as aluminum pigments, and extender pigments such as barium sulfate, barium carbonate, calcium carbonate, talc, and silica can be appropriately blended.
- the second water-based colored paint (P2) can be applied using a known coating method such as electrostatic coating, air spray, or airless spray.
- the solid content of the second water-based colored paint (P2) is suitably in the range of 21 to 50% by weight, preferably in the range of 22 to 40% by weight, more preferably in the range of 24 to 35% by weight. is there.
- the film thickness of the second colored coating film formed by the second water-based colored paint (P2) is suitably in the range of 5 to 20 ⁇ m, preferably in the range of 6 to 16 ⁇ m, as the cured film thickness (T P2 ). And more preferably within the range of 7 to 14 ⁇ m.
- a multilayer coating film having sufficient smoothness can be formed while suppressing white unevenness.
- the third aqueous colored paint (P3) which is an aqueous paint, is applied onto the uncured second colored coating film obtained in the step (3), and the cured film thickness (T P3 ) is 1.
- a third colored coating film in the range of ⁇ 10 ⁇ m is formed.
- the third water-based colored paint (P3) contains the binder component (A P3 ) and the light interference pigment (C), and has a solid content in the range of 5 to 20% by mass.
- the third colored coating film By forming the third colored coating film using such a third water-based colored paint (P3), it is excellent in glitter, smoothness and weather resistance in combination with the first colored coating film and the second colored coating film. In addition, it is possible to form a white multi-layer coating film with high brightness in which white unevenness is suppressed.
- P3 third water-based colored paint
- the binder component (A P3 ) used in the third aqueous colored paint (P3) is appropriately selected from the base resin and the crosslinking agent listed in the description of the binder component used in the second aqueous colored paint (P2). can do.
- the light interference pigment (C) has a refractive index different from that of a substrate such as titanium dioxide or iron oxide on the surface of a scaly substrate such as mica, artificial mica, glass, silica, iron oxide, aluminum oxide or various metals. It is a glittering pigment coated with a metal oxide. Specific examples include metal oxide-coated mica pigments, metal oxide-coated alumina flake pigments, metal oxide-coated glass flake pigments, metal oxide-coated silica flake pigments described below.
- the metal oxide-coated mica pigment is a pigment obtained by using natural mica or artificial mica as a base material and coating the surface of the base material with a metal oxide.
- Natural mica is a scaly substrate obtained by pulverizing ore mica (mica), and artificial mica is made of industrial raw materials such as SiO 2 , MgO, Al 2 O 3 , K 2 SiF 6 , Na 2 SiF 6, etc. It is synthesized by heating, melting at a high temperature of about 1500 ° C., cooling and crystallizing, and has less impurities and a uniform size and thickness when compared with natural mica.
- fluorine phlogopite mica KMg 3 AlSi 3 O 10 F 2
- potassium tetrasilicon mica KMg 25 AlSi 4 O 10 F 2
- sodium tetrasilicon mica NaMg 25 AlSi 4 O 10 F 2
- Na Teniolite NaMg 2 LiSi 4 O 10 F 2
- LiNa teniolite LiMg 2 LiSi 4 O 10 F 2
- the metal oxide used for coating include titanium oxide and iron oxide. Depending on the coating thickness, an interference color can be developed.
- metal oxide-coated mica pigments Commercially available products can be used as the metal oxide-coated mica pigment.
- metal oxide-coated mica pigments include “TWINCLE PEARL” series manufactured by Nippon Koken Kogyo Co., Ltd., “Lumina” series manufactured by BASF, “Magna Pearl” series, and “IRIODIN” manufactured by MERCK. Series etc. are mentioned.
- the metal oxide-coated alumina flake pigment is a pigment having alumina flake as a base material and the surface of the base material coated with a metal oxide.
- Alumina flake means scaly (flaky) aluminum oxide. It does not need to be a single component of aluminum oxide, and may contain oxides of other metals. Examples of the metal oxide used for coating include titanium oxide and iron oxide. Depending on the coating thickness, an interference color can be developed. A commercial item can be used as said metal oxide coat
- the metal oxide-coated glass flake pigment is obtained by coating a scaly glass substrate with a metal oxide, and since the substrate surface is smooth, strong light reflection occurs and expresses a particle feeling.
- the metal oxide used for the coating is not particularly limited, but titanium oxide and iron oxide are known.
- a commercial item can be used as said metal oxide coating glass flake pigment. Examples of commercially available metal oxide-coated glass flake pigments include “Metashine” series manufactured by Nippon Sheet Glass Co., Ltd.
- the metal oxide-coated silica flake pigment is obtained by coating scaly silica, which is a substrate having a smooth surface and a uniform thickness, with a metal oxide having a refractive index different from that of the substrate.
- a commercially available product can be used as the metal oxide-coated silica flake pigment.
- Examples of commercially available metal oxide-coated silica flake pigments include the “Colorstream” series manufactured by MERCK.
- the light interference pigment (C) may be subjected to a surface treatment for improving dispersibility, water resistance, chemical resistance, weather resistance and the like.
- the size of the light interference pigment (C) it is preferable to use one having an average particle diameter in the range of 5 to 50 ⁇ m from the viewpoint of the finish of the coated film and the expression of interference colors.
- the average particle diameter is preferably in the range of 7 to 35 ⁇ m. It is preferable to use a thickness in the range of 0.05 to 7.0 ⁇ m.
- the average particle diameter here means the median diameter of the volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution measuring device MT3300 (trade name, manufactured by Nikkiso Co., Ltd.).
- the thickness is defined as an average value of 100 or more measured values by observing the cross section of the coating film containing the light interference pigment (C) with a microscope and measuring the thickness using image processing software.
- the content ratio of the binder component (A P3 ) and the light interference pigment (C) is based on the solid content of 100 parts by mass of the binder component (A P3 ).
- the pigment (C) is preferably in the range of 20 to 70 parts by mass from the viewpoint of the glitter of the white multi-layer coating film formed, more preferably in the range of 25 to 60 parts by mass. Is in the range of 28-50 parts by weight.
- the third water-based colored paint (P3) is used for various paints such as a thickener, a curing catalyst, an ultraviolet absorber, a light stabilizer, an antifoaming agent, a plasticizer, a surface conditioner, and an anti-settling agent as necessary. Additives can be included.
- the third water-based colored paint (P3) can be applied using a known coating method such as electrostatic coating, air spray, or airless spray.
- the solid content of the third water-based colored paint (P3) is suitably in the range of 5 to 20% by weight, preferably in the range of 7 to 18% by weight, more preferably in the range of 9 to 15% by weight. is there.
- the film thickness of the third colored coating film formed by the third colored water-based paint (P3) is in the range of 1 to 10 ⁇ m, preferably 1.5 to 7.5 ⁇ m, as the cured film thickness (T P3 ). And more preferably in the range of 2 to 6 ⁇ m.
- the solid content of the third aqueous colored paint (P3) is adjusted to the above range, and the film thickness of the third colored coating film formed by the third colored aqueous paint (P3) is within a specific range and the second colored paint.
- the clear coat paint (P4) is applied on the uncured third colored paint film formed in step (4) to form a clear coat paint film (step (5)).
- the clear coat paint (P4) for example, those known per se that are usually used in the coating of automobile bodies can be used. Specifically, for example, a hydroxyl group, a carboxyl group, an epoxy group, a silanol group, etc.
- a base resin such as an acrylic resin, a polyester resin, an alkyd resin, a urethane resin, an epoxy resin, a fluororesin, a melamine resin, a urea resin, an optionally blocked polyisocyanate compound, and a carboxyl group
- examples thereof include organic solvent-based thermosetting paints, water-based thermosetting paints, thermosetting powder paints and the like that contain a compound or resin, an epoxy group-containing compound or a resin as a vehicle component.
- an organic solvent-based thermosetting paint containing a carboxyl group-containing resin and an epoxy group-containing resin, or a thermosetting paint containing a hydroxyl group-containing acrylic resin and a polyisocyanate compound which may be blocked is preferable.
- the clear coat paint may be a one-component paint or a two-component paint such as a two-component urethane resin paint.
- the clear coat paint (P4) can contain, if necessary, a color pigment, a bright pigment, a dye, a matting agent, etc. to such an extent that the transparency is not impaired.
- a light stabilizer, an antifoaming agent, a thickening agent, a rust preventive agent, a surface conditioner and the like can be appropriately contained.
- the clear coat paint (P4) can be applied by a method known per se, for example, an airless spray, an air spray, a rotary atomizing coating machine, or the like, and electrostatic application may be performed during the coating.
- the clear coat paint (P4) can be applied so that the cured film thickness is usually in the range of 10 to 80 ⁇ m, preferably 15 to 60 ⁇ m, more preferably 20 to 50 ⁇ m.
- an interval of about 1 to 60 minutes at room temperature or about 40 to about 80 ° C. is applied as necessary. Or preheating at a temperature of 1 to 60 minutes.
- the multi-layer coating film including the second colored coating film, the third colored coating film, and the clear coating film formed in the steps (3) to (5) is heated, whereby The layer coating is cured at once.
- the step (2) when the first colored coating film is not heat-cured after the application of the first colored paint (P1), it is formed in the step (2) to (5) in the present step (6).
- the multilayer coating film including these four coating films is cured at once. Can do. In this case, since heat curing can be omitted once, energy saving can be further improved.
- the heating means can be performed by, for example, hot air heating, infrared heating, high frequency heating or the like.
- the heating temperature is preferably from 80 to 160 ° C, more preferably from 100 to 140 ° C.
- the heating time is preferably 10 to 60 minutes, more preferably 15 to 40 minutes. If necessary, before performing the heat curing, heating directly or indirectly by preheating, air blowing, etc. at a temperature of about 50 to about 110 ° C., preferably about 60 to about 90 ° C. for about 1 to 60 minutes. May be performed.
- the multi-layer coating film formed by the above steps is composed of four layers of a first colored coating film, a second colored coating film, a third colored coating film, and a clear coat coating film formed on the cured electrodeposition coating film. It has the laminated structure provided with.
- the specific composition, brightness, film thickness, etc. are determined using the specific first colored paint (P1), the second aqueous colored paint (P2), and the third colored aqueous paint (P3). Since the first colored coating film, the second colored coating film, and the third colored coating film provided are formed, it is excellent in glitter, smoothness and weather resistance, and has a high brightness white multi-layer coating in which white unevenness is suppressed. A film can be formed.
- Production of hydroxyl group-containing acrylic resin 35 parts of propylene glycol monopropyl ether was charged into a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen gas introduction tube and dropping device, and the temperature was raised to 85 ° C. 30 parts of methyl methacrylate, 20 parts of 2-ethylhexyl acrylate, 29 parts of n-butyl acrylate, 15 parts of 2-hydroxyethyl acrylate, 6 parts of acrylic acid, 15 parts of propylene glycol monopropyl ether and 2,2′-azobis (2, A mixture of 2.3 parts of 4-dimethylvaleronitrile) was added dropwise over 4 hours, and aged for 1 hour after completion of the addition.
- Production Example 3 Production of Titanium Dioxide Pigment (B) Dispersion
- PE-1 hydroxyl group-containing polyester resin solution obtained in Production Example 1
- JR-806 90 parts of TEIKA CORPORATION, trade name, rutile type titanium dioxide
- deionized water 5 parts of deionized water were added, and 2- (dimethylamino) ethanol was further added to adjust the pH to 8.0.
- the obtained mixed liquid is put into a wide-mouth glass bottle, glass beads having a diameter of about 1.3 mm ⁇ are added and sealed as a dispersion medium, dispersed for 30 minutes with a paint shaker, and a titanium dioxide pigment (B) dispersion ( X-1) was obtained.
- Production Example 4 Production of Black Pigment Dispersion 18 parts of acrylic resin solution (AC-1) obtained in Production Example 2 (resin solid content 10 parts), “Carbon MA-100” (trade name, manufactured by Mitsubishi Chemical Corporation, carbon black) 10 parts of pigment) and 60 parts of deionized water are mixed, adjusted to pH 8.2 with 2- (dimethylamino) ethanol, and dispersed with a paint shaker for 30 minutes to obtain a black pigment dispersion (X-2). It was.
- the remainder of the monomer emulsion for the core part was dropped into a reaction vessel maintained at the same temperature over 3 hours, and aging was performed for 1 hour after completion of the dropping.
- the following monomer emulsion for shell part was added dropwise over 1 hour, and after aging for 1 hour, it was cooled to 30 ° C. while gradually adding 40 parts of 5% 2- (dimethylamino) ethanol aqueous solution to the reaction vessel, The mixture was discharged while being filtered through a 100 mesh nylon cloth to obtain a water-dispersible hydroxyl group-containing acrylic resin (AC-2) aqueous dispersion having an average particle size of 95 nm and a solid content of 30%.
- AC-2 water-dispersible hydroxyl group-containing acrylic resin
- the obtained water-dispersible hydroxyl group-containing acrylic resin had an acid value of 33 mgKOH / g and a hydroxyl value of 25 mgKOH / g.
- Monomer emulsion for core part 40 parts of deionized water, 2.8 parts of “ADEKA rear soap SR-1025”, 2.1 parts of methylenebisacrylamide, 2.8 parts of styrene, 16.1 parts of methyl methacrylate, 28 of ethyl acrylate And 21 parts of n-butyl acrylate were mixed and stirred to obtain a monomer emulsion for the core part.
- Monomer emulsion for shell part 17 parts of deionized water, 1.2 parts of “ADEKA rear soap SR-1025”, 0.03 part of ammonium persulfate, 3 parts of styrene, 5.1 parts of 2-hydroxyethyl acrylate, 5 parts of methacrylic acid .1 part, 6 parts of methyl methacrylate, 1.8 parts of ethyl acrylate and 9 parts of n-butyl acrylate were mixed and stirred to obtain a monomer emulsion for shell part.
- Production Example 12 Production of Hydroxyl-Containing Polyester Resin
- a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen gas inlet tube and water separator 109 parts of trimethylolpropane and 141 parts of 1,6-hexanediol
- 126 parts of 1,2-cyclohexanedicarboxylic acid anhydride and 120 parts of adipic acid were added, the temperature was raised from 160 ° C. to 230 ° C. over 3 hours, and then a condensation reaction was carried out at 230 ° C. for 4 hours.
- the resulting condensation reaction product was added with 38.3 parts of trimellitic anhydride, reacted at 170 ° C. for 30 minutes, and then diluted with 2-ethyl-1-hexanol.
- a hydroxyl group-containing polyester resin solution PE-2 having a solid content of 70% was obtained.
- the obtained hydroxyl group-containing polyester resin had an acid value of 46 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a number average molecular weight of 1,400.
- Production and production example 13 of second water-based colored paint (P2) 10. 100.0 parts of water-dispersible hydroxyl group-containing acrylic resin (AC-2) aqueous dispersion obtained in Production Example 11 (solid content 30 parts), hydroxyl group-containing acrylic resin solution (AC-1) obtained in Production Example 2 0 parts (solid content 11 parts), 6.0 parts of polyester resin solution (PE-2) obtained in Production Example 12 (solid content 4.2 parts), “Cymel 325” (trade name, manufactured by Ornex, melamine resin) 80% solid content) 37.5 parts (solid content 30 parts), titanium dioxide pigment (B) dispersion (X-1) 125.5 parts obtained in Production Example 3, and extender pigment obtained in Production Example 5 The dispersion (X-3) 31.9 parts was mixed uniformly, and further, “Adecanol UH-756VF” (trade name, manufactured by ADEKA, thickener), 2- (dimethylamino) ethanol, and deionized water PH 8.0, paint solid content 32%, 20 ° C. Dokappu No
- Production Examples 14-17 In Production Example 13, the Ford Cup No. at pH 8.0 and 20 ° C. was prepared in the same manner as in Production Example 13, except that the composition and paint solid content were as shown in Table 2 below. Second aqueous colored paints (P2-2) to (P2-5) having a viscosity of 4 according to 40 seconds were obtained.
- Production Example 18 Production of Acrylic Resin Having Hydroxyl Group and Phosphate Group In a reaction vessel equipped with a thermometer, thermostat, stirring device, reflux condenser, nitrogen inlet tube and dropping device, 27.5 parts of methoxypropanol and isobutanol 27.
- the obtained acrylic resin (AC-3) having a hydroxyl group and a phosphate group had an acid value of 83 mgKOH / g, a hydroxyl value of 29 mgKOH / g, and a weight average molecular weight of 10,000.
- Phosphoric group-containing polymerizable monomer Into a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen introducing tube and a dropping device, 57.5 parts of monobutyl phosphoric acid and 41.0 parts of isobutanol were placed, After raising the temperature to 0 ° C., 42.5 parts of glycidyl methacrylate was added dropwise over 2 hours, and the mixture was further aged and stirred for 1 hour. Thereafter, 59.0 parts of isopropanol was added to obtain a phosphate group-containing polymerizable monomer solution having a solid content concentration of 50%. The acid value of the obtained monomer was 285 mgKOH / g.
- Manufacture example 19 of a light interference pigment dispersion In a stirring and mixing vessel, “Xiallic T60-10 SW Crystal Silver” (trade name, manufactured by Merck Co., Ltd., metal oxide-coated alumina flake pigment), 30 parts, 35 parts of 2-ethyl-1-hexanol, and Production Example 18 were obtained. 18 parts of an acrylic resin (AC-3) solution having a hydroxyl group and a phosphate group (9 parts of solid content) was uniformly mixed to obtain a light interference pigment dispersion (X-4).
- AC-3 acrylic resin
- X-4 light interference pigment dispersion
- Production Example 20 In a stirring and mixing vessel, 35 parts of “Magnapearl Expert CFS 1103” (trade name, manufactured by BASF, metal oxide-coated mica pigment), 35 parts of 2-ethyl-1-hexanol, and the hydroxyl group and phosphoric acid obtained in Production Example 18 21 parts (10.5 parts solids) of an acrylic resin (AC-3) solution having a group was uniformly mixed to obtain a light interference pigment dispersion (X-5).
- “Magnapearl Expert CFS 1103” trade name, manufactured by BASF, metal oxide-coated mica pigment
- AC-3 acrylic resin
- X-5 light interference pigment dispersion
- Production and production example 21 of third water-based colored paint (P3) 10. 100.0 parts of water-dispersible hydroxyl group-containing acrylic resin (AC-2) aqueous dispersion obtained in Production Example 11 (solid content 30 parts), hydroxyl group-containing acrylic resin solution (AC-1) obtained in Production Example 2 0 part (11 parts solids), 28.6 parts of the polyester resin solution (PE-2) obtained in Production Example 12 (20 parts solids), “Cymel 325” (trade name, manufactured by Ornex, melamine resin, solid 80%) 37.5 parts (solid content 30 parts) and 83 parts of the light interference pigment dispersion (X-4) obtained in Production Example 19 were mixed uniformly, and “Primal ASE-60” ( The trade name, Dow Chemical Co., polyacrylic acid thickener), 2- (dimethylamino) ethanol, and deionized water were added, pH 8.0, paint solid content 14%, Ford Cup No.
- a third aqueous colored paint (P3-1) having a viscosity of 40 according to 4 was obtained.
- the content of the light interference pigment (C) in the third aqueous colored paint (P3-1) is 30 masses based on 100 parts by mass of the solid content of the binder component in the third aqueous colored paint (P3-1). Was part.
- thermosetting epoxy resin cationic electrodeposition coating composition (trade name “Electron GT-10”, manufactured by Kansai Paint Co., Ltd.) with a film thickness of 20 ⁇ m is applied to a zinc phosphate-treated cold rolled steel sheet. Electrodeposition coating was performed, and the coating was tested by heating at 170 ° C. for 30 minutes to cure.
- Example 1 Apply the first water-based colored paint (P1-1) obtained in Production Example 6 to the above two objects to be coated using a rotary atomizing type electrostatic coating machine so as to have a cured film thickness of 30 ⁇ m. Then, a first colored coating film was formed, allowed to stand for 2 minutes, and then preheated at 80 ° C. for 3 minutes. Next, on the uncured first colored coating film, the second water-based colored paint (P2-1) obtained in Production Example 13 was cured to 12 ⁇ m using a rotary atomizing type electrostatic coating machine. It painted so that the 2nd colored coating film might be formed. Next, one of the two test objects to be coated was taken out, left for 1 minute, and preheated at 80 ° C. for 3 minutes.
- thermosetting acid / epoxy curable acrylic resin organic solvent type clear coat coating (trade name “Magicron KINO-1210TW” is applied onto the uncured third colored coating film. ”Manufactured by Kansai Paint Co., Ltd.) was electrostatically applied to a cured film thickness of 35 ⁇ m using a rotary atomizing type electrostatic coating machine to form a clear coat film. After standing for 7 minutes, heating at 140 ° C. for 30 minutes, the uncured first colored coating film, the uncured second colored coating film, the uncured third colored coating film, and the uncured clear coat film The test coating board B was produced by making it harden
- Example 1 is the same as Example 1 except that the types and cured film thicknesses of the first aqueous colored paint, the second aqueous colored paint, and the third aqueous colored paint are as shown in Tables 4-1 and 4-2 below. Test plate A and test plate B were prepared in the same manner as described above.
- Example 12 Apply the first water-based colored paint (P1-1) obtained in Production Example 6 to the above two objects to be coated using a rotary atomizing type electrostatic coating machine so as to have a cured film thickness of 30 ⁇ m. Then, a first colored coating film was formed, allowed to stand for 2 minutes, and then preheated at 80 ° C. for 3 minutes. Thereafter, the first colored coating film was cured by heating at 140 ° C. for 30 minutes. Next, on the cured first colored coating film, the second water-based colored paint (P2-1) obtained in Production Example 13 has a cured film thickness of 12 ⁇ m using a rotary atomizing electrostatic coater. Thus, the second colored coating film was formed.
- one of the two test objects to be coated was taken out, left for 1 minute, and preheated at 80 ° C. for 3 minutes. Then, it heated at 140 degreeC for 30 minute (s), this uncured 1st colored coating film and an uncured 2nd colored coating film were hardened, and the coating plate A for a test was obtained. Another test object was left for 1 minute after the second water-based colored paint (P2-1) was applied. Thereafter, on the uncured second colored coating film, the third water-based colored paint (P3-1) obtained in Production Example 21 was cured to a thickness of 3 ⁇ m using a rotary atomizing electrostatic coating machine. The third colored coating film was formed by electrostatic coating, and left for 3 minutes. Next, after preheating at 80 ° C.
- thermosetting acid / epoxy curable acrylic resin organic solvent type clear coat coating (trade name “Magicron KINO-1210TW” is applied onto the uncured third colored coating film. ”Manufactured by Kansai Paint Co., Ltd.) was electrostatically applied to a cured film thickness of 35 ⁇ m using a rotary atomizing type electrostatic coating machine to form a clear coat film. After standing for 7 minutes, heating at 140 ° C. for 30 minutes, the uncured first colored coating film, the uncured second colored coating film, the uncured third colored coating film, and the uncured clear coat film The test coating board B was produced by making it harden
- Test method Lightness L * value (L * P2 ) at the time of curing of the second water-based colored paint (P2): The L * value of the test coating plate A was measured. Specifically, using a multi-angle spectrocolorimeter “CM-512m3” (manufactured by Konica Minolta Co., Ltd.), light was irradiated from an angle of 45 ° with respect to an axis perpendicular to the coating surface, and the reflected light The L * value of light in the direction perpendicular to the coating surface was measured.
- CM-512m3 manufactured by Konica Minolta Co., Ltd.
- the L * value (L * 15 value) at a light receiving angle of 15 degrees. was measured.
- An L * 15 value of 115 or higher is an acceptable level.
- the L * value (L * 15 value) at the light receiving angle of 15 degrees is specifically measured light from the angle of 45 ° with respect to the axis perpendicular to the surface to be measured and measured from the regular reflection angle.
- ⁇ 100 galvanic coatings remain, and no small chipping of the coating occurs at the edge of the cutter cut ⁇ : 100 galvanic coatings remain, but the coating is small at the cutting edge of the cutter Fracture occurs: ⁇ : 90 to 99 goby-eyed coatings remain ⁇ : The remaining number of gobang-like coatings is 89 or less.
- White unevenness The test coating plate B was observed with the naked eye, and the degree of occurrence of white unevenness was evaluated according to the following criteria. A: Almost no white unevenness is observed, and the coating film has an extremely excellent appearance. ⁇ : Slight white unevenness is observed, but has an excellent coating film appearance. (Triangle
- the test coated plate B was evaluated using the Wd value measured by “Wave Scan DOI” (trade name, manufactured by BYK Gardner).
- the Wd value is an index of the amplitude of the surface roughness at a wavelength of about 3 to 10 mm, and the smaller the measured value, the higher the smoothness of the coated surface.
- E Wd value was greater than 30.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Laminated Bodies (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
上記高い明度を有する白色系ベースコート塗膜を形成する手段として、該白色系ベースコート塗料中の白色顔料以外の着色顔料の含有量を低減する方法があるが、この場合、形成される白色系ベースコート塗膜の光線透過率が上がり、下地色の隠蔽力が低下するため、形成される白色系複層塗膜の耐候性が低下したり、白色ムラが発生しやすくなったりする場合があった。
(1)鋼板上に電着塗料を塗装し、加熱硬化させて硬化電着塗膜を形成せしめる工程、
(2)工程(1)で得られる硬化電着塗膜上に第1着色塗料(P1)を塗装して、第1着色塗膜を形成せしめる工程であって、前記第1着色塗料(P1)は、厚さ30μmの硬化塗膜を形成した場合の明度L*値(L* P1)が80~89の範囲内である、工程、
(3)工程(2)で得られる第1着色塗膜上に、バインダー成分(AP2)及び二酸化チタン顔料(B)を含有し、かつ塗料固形分が21~50質量%の範囲内である第2水性着色塗料(P2)を塗装して、硬化膜厚(TP2)が5~20μmの範囲内であり、かつ硬化時の明度L*値(L* P2)が85~95の範囲内である第2着色塗膜を形成せしめる工程、
(4)工程(3)で得られる第2着色塗膜上に第3水性着色塗料(P3)を塗装して、硬化膜厚(TP3)が1~10μmの範囲内である第3着色塗膜を形成せしめる工程であって、前記第3水性着色塗料(P3)は、バインダー成分(AP3)及び光干渉性顔料(C)を含有し、かつ塗料固形分が5~20質量%の範囲内である、工程、
(5)工程(4)で得られる第3着色塗膜上に、クリヤーコート塗料(P4)を塗装してクリヤーコート塗膜を形成せしめる工程、並びに
(6)工程(2)~(5)で形成される第1着色塗膜、第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜を含む複層塗膜を加熱することによって、前記複層塗膜を同時に硬化させる工程、
を含む、複層塗膜形成方法であって、
前記L* P2が前記L* P1より高く、かつ前記L* P2と前記L* P1の差が1~10の範囲内であり、かつ前記TP2と前記TP3との比がTP2/TP3=1.1/1~20/1の範囲内である、複層塗膜形成方法に関するものである。
本発明では、まず鋼板上に電着塗料を塗装し、加熱硬化させて硬化電着塗膜を形成する(工程(1))。本明細書において、電着塗料は、被塗装物である鋼板の表面に塗装されることにより、鋼板の錆、腐食を防止するとともに、複層塗膜が形成された物品の表面の耐衝撃性を強化するために使用される塗料である。
工程(1)で得られる硬化電着塗膜上に、第1着色塗料(P1)を塗装して、第1着色塗膜が形成される(工程(2))。第1着色塗料(P1)は、バインダー成分及び着色顔料を含有する塗料であって、厚さ30μmの硬化塗膜を形成した場合の、L*a*b*表色系における明度であるL*値(L* P1)が、80~89の範囲内であるものである。このような第1着色塗料(P1)を用いて第1着色塗膜を形成することにより、耐候性に優れ、かつ白色ムラが抑制された高明度の白色系複層塗膜を形成することができる。このうち、耐候性に優れるとは、具体的には、長期間の屋外バクロ後の、複層塗膜と下層の電着塗膜間との付着力の低下が起こりにくいことをいう。本発明によって形成された塗膜が耐候性に優れる理由の一つとしては、下層の電着塗膜を劣化させる要因となる太陽光線が、上記第1着色塗膜によって比較的多く遮断されることが考えられる。
工程(3)では、工程(2)で得られる第1着色塗膜上に、水性塗料である第2水性着色塗料(P2)を塗装して、硬化膜厚(TP2)が5~20μmの範囲内であり、かつ硬化時の明度L*値(L* P2)が85~95の範囲内である第2着色塗膜を形成させる。ここで、第2着色塗膜の硬化時の明度L*値(L* P2)は、積層状態に形成された第1着色塗膜と第2着色塗膜の両塗膜が硬化された状態において、第2着色塗膜における第1着色塗膜と接する側とは反対側の表面から測定して得られる明度である。また、第2水性着色塗料(P2)は、バインダー成分(AP2)及び二酸化チタン顔料(B)を含有し、かつ塗料固形分が21~50質量%の範囲内のものである。そして、既述のとおり、前記明度L* P2は、第1着色塗料により厚さ30μmの硬化塗膜を形成した場合の明度L*値(L* P1)との関係で、前記L* P2が前記L* P1より高く、かつ前記L* P2と前記L* P1の差が1~10の範囲内であるように調整される。さらに、前記硬化膜厚TP2は、後述する第3着色塗膜の硬化膜厚TP3との関係で、TP2/TP3=1.1/1~20/1の範囲内となるように調整される。このような第2水性着色塗料(P2)を用いて第2着色塗膜を形成することにより、その上下に形成される第1着色塗膜、第3着色塗膜とあいまって、高明度でありながら光輝感及び耐候性に優れ白色ムラが抑制された塗膜を形成することができる。
また、上記明度L*値(L* P2)は、第1着色塗膜とあいまって耐候性を損なうことなく高い明度を確保するとの観点から、より好ましくは87~95の範囲であり、さらに好ましくは89~95の範囲内である。さらに、既述のとおり、前記L* P2は、第1着色塗料により厚さ30μmの硬化塗膜を形成した場合の明度L*値(L* P1)との関係で、前記L* P2が前記L* P1より高く、かつ前記L* P2と前記L* P1の差が1~10の範囲内であるように調整される。
また、第2水性着色塗料(P2)により形成される第2着色塗膜の膜厚は、硬化膜厚(TP2)として5~20μmの範囲内が適切であり、好ましくは6~16μmの範囲内、さらに好ましくは7~14μmの範囲内である。
第2水性着色塗料(P2)の塗料固形分を上述の範囲に調整するとともに、第2水性塗料(P2)により形成される第2着色塗膜の膜厚を一定の範囲に調整することにより、白ムラを抑制しつつ十分な平滑性を備えた複層塗膜を形成することができる。
工程(4)では、工程(3)で得られる未硬化の第2着色塗膜上に、水性塗料である第3水性着色塗料(P3)を塗装して、硬化膜厚(TP3)が1~10μmの範囲内である第3着色塗膜を形成させる。ここで、第3水性着色塗料(P3)は、バインダー成分(AP3)及び光干渉性顔料(C)を含有し、かつ塗料固形分が5~20質量%の範囲内のものである。また、既述のとおり、前記TP3は、第2着色塗膜の硬化膜厚TP2との関係で、TP2/TP3=1.1/1~20/1の範囲内となるように調整される。このような第3水性着色塗料(P3)を用いて第3着色塗膜を形成することにより、第1着色塗膜、第2着色塗膜とあいまって、光輝感、平滑性及び耐候性に優れ、かつ白色ムラが抑制された高明度の白色系複層塗膜を形成することができる。
上記金属酸化物被覆アルミナフレーク顔料としては、市販品を使用することができる。該金属酸化物被覆アルミナフレーク顔料の市販品としては、例えば、MERCK社製の「Xirallic」シリーズ等が挙げられる。
上記金属酸化物被覆ガラスフレーク顔料としては、市販品を使用することができる。該金属酸化物被覆ガラスフレーク顔料の市販品としては、例えば、日本板硝子社製の「メタシャイン」シリーズ等が挙げられる。
上記金属酸化物被覆シリカフレーク顔料としては、市販品を使用することができる。該金属酸化物被覆シリカフレーク顔料の市販品としては、例えば、MERCK社製の「Colorstream」シリーズ等が挙げられる。
また、第3着色水性塗料(P3)により形成される第3着色塗膜の膜厚は、硬化膜厚(TP3)として1~10μmの範囲内であり、好ましくは1.5~7.5μmの範囲内、さらに好ましくは2~6μmの範囲内である。また、既述のとおり、前記TP3は、第2着色塗膜の硬化膜厚TP2との関係で、TP2/TP3=1.1/1~20/1の範囲内となるように調整される。
本発明においては、工程(4)において形成された未硬化の第3着色塗膜上に、クリヤーコート塗料(P4)を塗装して、クリヤーコート塗膜を形成する(工程(5))。
工程(6)においては、工程(3)~(5)で形成される第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜を含む複層塗膜を加熱することによって、前記複層塗膜を一度に硬化させる。
前記工程(2)において、前記第1着色塗料(P1)の塗装後に第1着色塗膜を加熱硬化しない場合は、本工程(6)において、前記工程(2)~(5)で形成される第1着色塗膜、第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜工程(6)を加熱することによって、これら4つの塗膜を含む複層塗膜を一度に硬化させることができる。この場合は、加熱硬化を1回省略できるので、さらに省エネルギー性を向上させることができる。
加熱手段は、例えば、熱風加熱、赤外線加熱、高周波加熱等により行うことができる。加熱温度は、80~160℃が好ましく、100~140℃がより好ましい。また加熱時間は、10~60分間が好ましく、15~40分間がより好ましい。必要に応じて、前記加熱硬化を行う前に、プレヒート、エアブロー等により、約50~約110℃、好ましくは約60~約90℃の温度で1~60分間程度、直接的又は間接的に加熱を行ってもよい。
以上の工程によって形成された複層塗膜は、硬化電着塗膜の上に形成された第1着色塗膜、第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜の4層を備えた積層構造を有する。本発明の方法によれば、特定の第1着色塗料(P1)、第2水性着色塗料(P2)、及び第3着色水性塗料(P3)を用いて、特定の組成、明度、膜厚等を備えた第1着色塗膜、第2着色塗膜、第3着色塗膜を形成するので、光輝感、平滑性及び耐候性に優れ、かつ白色ムラが抑制された高明度の白色系複層塗膜を形成することができる。
製造例1 水酸基含有ポリエステル樹脂の製造
温度計、サーモスタット、攪拌装置、還流冷却器及び水分離器を備えた反応容器に、トリメチロールプロパン174部、ネオペンチルグリコール327部、アジピン酸352部、イソフタル酸109部及び1,2-シクロヘキサンジカルボン酸無水物101部を仕込み、160℃から230℃まで3時間かけて昇温させた後、生成した縮合水を水分離器により留去させながら230℃で保持し、酸価が3mgKOH/g以下となるまで反応させた。この反応生成物に、無水トリメリット酸59部を添加し、170℃で30分間付加反応を行った後、50℃以下に冷却し、2-(ジメチルアミノ)エタノールを酸基に対して当量添加し中和してから、脱イオン水を徐々に添加することにより、固形分濃度45%、pH7.2の水酸基含有ポリエステル樹脂溶液(PE-1)を得た。得られた水酸基含有ポリエステル樹脂は、酸価が35mgKOH/g、水酸基価が128mgKOH/g、重量平均分子量が13000であった。
温度計、サーモスタット、撹拌装置、還流冷却器、窒素ガス導入管及び滴下装置を備えた反応容器にプロピレングリコールモノプロピルエーテル35部を仕込み、85℃に昇温後、メチルメタクリレート30部、2-エチルヘキシルアクリレート20部、n-ブチルアクリレート29部、2-ヒドロキシエチルアクリレート15部、アクリル酸6部、プロピレングリコールモノプロピルエーテル15部及び2,2’-アゾビス(2,4-ジメチルバレロニトリル)2.3部の混合物を4時間かけて滴下し、滴下終了後1時間熟成した。その後さらにプロピレングリコールモノプロピルエーテル10部及び2,2’-アゾビス(2,4-ジメチルバレロニトリル)1部の混合物を1時間かけて滴下し、滴下終了後1時間熟成した。さらにジエタノールアミン7.4部及びプロピレングリコールモノプロピルエーテル13部を加え、固形分55%の水酸基含有アクリル樹脂溶液(AC-1)を得た。得られた水酸基含有アクリル樹脂は酸価が47mgKOH/g、水酸基価が72mgKOH/gであった。
撹拌混合容器に、製造例1で得た水酸基含有ポリエステル樹脂溶液(PE-1)56部(樹脂固形分25部)、「JR-806」(テイカ社製、商品名、ルチル型二酸化チタン)90部及び脱イオン水5部を入れ、更に、2-(ジメチルアミノ)エタノールを添加して、pH8.0に調整した。次いで、得られた混合液を広口ガラスビン中に入れ、分散メジアとして直径約1.3mmφのガラスビーズを加えて密封し、ペイントシェーカーにて30分間分散して、二酸化チタン顔料(B)分散液(X-1)を得た。
製造例2で得たアクリル樹脂溶液(AC-1)18部(樹脂固形分10部)、「カーボンMA-100」(商品名、三菱化学社製、カーボンブラック顔料)10部、及び脱イオン水60部を混合し、2-(ジメチルアミノ)エタノールでpH8.2に調整した後、ペイントシェーカーで30分間分散して黒色顔料分散液(X-2)を得た。
製造例2で得たアクリル樹脂溶液(AC-1)18部(樹脂固形分10部)、「バリファインBF-20」(商品名、堺化学工業社製、硫酸バリウム顔料)25部、「サーフィノール104A」(商品名、エアープロダクツ社製、消泡剤、固形分50%)0.6部(固形分0.3部)、及び脱イオン水36部を混合し、ペイントシェーカーで1時間分散して体質顔料分散液(X-3)を得た。
製造例6
製造例1で得た水酸基含有ポリエステル樹脂溶液(PE-1)7.9部(樹脂固形分5.6部)、製造例2で得た水酸基含有アクリル樹脂溶液(AC-1)23.1部(樹脂固形分12.7部)、「ユーコートUX-8100」(商品名、三洋化成工業社製、ウレタンエマルション、固形分35%)42.9部(樹脂固形分15部)、「サイメル325」(商品名、オルネクス社製、メラミン樹脂、固形分80%)37.5部(樹脂固形分30部)、「バイヒジュールVPLS2310」(商品名、住化バイエルウレタン社製、ブロック化ポリイソシアネート化合物、固形分38%)26.3部(樹脂固形分10部)、製造例3で得た二酸化チタン顔料(B)分散液(X-1)147.2部、製造例4で得た黒色顔料分散液(X-2)0.62部及び製造例5で得た体質顔料分散液(X-3)17.6部を均一に混合した。 次いで、得られた混合物に、「プライマル ASE-60」(商品名、ダウケミカル社製、増粘剤)、2-(ジメチルアミノ)エタノール及び脱イオン水を添加し、pH8.0、塗料固形分48%、20℃におけるフォードカップNo.4による粘度が30秒の、水性第1着色塗料(P1-1)を得た。
製造例6において、配合組成を後記の表1に示すものとする以外は、製造例6と同様にして水性第1着色塗料(P1-2)~(P1-5)を得た。また、各水性第1ベース塗料によって形成される厚さ30μmの硬化塗膜の明度L*値(L* P1)及び波長360~420nmにおける平均光線透過率(TRP1)を表1に併せて示す。
温度計、サーモスタット、撹拌装置、還流冷却器、窒素ガス導入管及び滴下装置を備えた反応容器に、脱イオン水128部、「アデカリアソープSR-1025」(商品名、ADEKA製、乳化剤、有効成分25%)3部を仕込み、窒素気流中で撹拌混合し、80℃に昇温させた。
次いで下記コア部用モノマー乳化物の全量のうちの1%量及び6%過硫酸アンモニウム水溶液5.3部を反応容器内に導入し、80℃で15分間保持した。その後、コア部用モノマー乳化物の残部を3時間かけて、同温度に保持した反応容器内に滴下し、滴下終了後1時間熟成を行なった。次に、下記シェル部用モノマー乳化物を1時間かけて滴下し、1時間熟成した後、5%2-(ジメチルアミノ)エタノール水溶液40部を反応容器に徐々に加えながら30℃まで冷却し、100メッシュのナイロンクロスで濾過しながら排出し、平均粒子径95nm、固形分30%の水分散性水酸基含有アクリル樹脂(AC-2)水分散液を得た。得られた水分散性水酸基含有アクリル樹脂は、酸価が33mgKOH/g、水酸基価が25mgKOH/gであった。
コア部用モノマー乳化物:脱イオン水40部、「アデカリアソープSR-1025」2.8部、メチレンビスアクリルアミド2.1部、スチレン2.8部、メチルメタクリレート16.1部、エチルアクリレート28部及びn-ブチルアクリレート21部を混合攪拌することにより、コア部用モノマー乳化物を得た。
シェル部用モノマー乳化物:脱イオン水17部、「アデカリアソープSR-1025」1.2部、過硫酸アンモニウム0.03部、スチレン3部、2-ヒドロキシエチルアクリレート5.1部、メタクリル酸5.1部、メチルメタクリレート6部、エチルアクリレート1.8部及びn-ブチルアクリレート9部を混合攪拌することにより、シェル部用モノマー乳化物を得た。
温度計、サーモスタット、攪拌装置、還流冷却器、窒素ガス導入管及び水分離器を備えた反応容器に、トリメチロールプロパン109部、1,6-ヘキサンジオール141部、1,2-シクロヘキサンジカルボン酸無水物126部及びアジピン酸120部を仕込み、160℃から230℃まで3時間かけて昇温させた後、230℃で4時間縮合反応させた。次いで、得られた縮合反応生成物に、カルボキシル基を導入するために、無水トリメリット酸38.3部を加えて、170℃で30分間反応させた後、2-エチル-1-ヘキサノールで希釈し、固形分70%の水酸基含有ポリエステル樹脂溶液(PE-2)を得た。得られた水酸基含有ポリエステル樹脂は、酸価が46mgKOH/g、水酸基価が150mgKOH/g、数平均分子量が1,400であった。
製造例13
製造例11で得た水分散性水酸基含有アクリル樹脂(AC-2)水分散液100.0部(固形分30部)、製造例2で得た水酸基含有アクリル樹脂溶液(AC-1)20.0部(固形分11部)、製造例12で得たポリエステル樹脂溶液(PE-2)6.0部(固形分4.2部)、「サイメル325」(商品名、オルネクス社製、メラミン樹脂、固形分80%)37.5部(固形分30部)、製造例3で得た二酸化チタン顔料(B)分散液(X-1)125.5部、及び製造例5で得た体質顔料分散液(X-3)31.9部を均一に混合し、更に、「アデカノールUH-756VF」(商品名、ADEKA社製、増粘剤)、2-(ジメチルアミノ)エタノール、及び脱イオン水を加えて、pH8.0、塗料固形分32%、20℃におけるフォードカップNo.4による粘度40秒の、第2水性着色塗料(P2-1)を得た。
製造例13において、配合組成及び塗料固形分を後記の表2に示すものとする以外は、製造例13と同様にして、pH8.0、20℃におけるフォードカップNo.4による粘度が40秒の、第2水性着色塗料(P2-2)~(P2-5)を得た。
温度計、サーモスタット、撹拌装置、還流冷却器、窒素導入管及び滴下装置を備えた反応容器に、メトキシプロパノール27.5部及びイソブタノール27.5部の混合溶剤を入れ、110℃に加熱し、スチレン25.0部、n-ブチルメタクリレート27.5部、「イソステアリルアクリレート」(商品名、大阪有機化学工業社製、分岐高級アルキルアクリレート)20.0部、4-ヒドロキシブチルアクリレート7.5部、下記リン酸基含有重合性モノマー15.0部、2-メタクリロイルオキシエチルアシッドホスフェート12.5部、イソブタノール10.0部、及びt-ブチルパーオキシオクタノエート4.0部からなる混合物121.5部を4時間かけて上記混合溶剤に加え、さらにt-ブチルパーオキシオクタノエート0.5部とイソプロパノール20.0部とからなる混合物を1時間滴下した。その後、1時間撹拌熟成して固形分50%の水酸基及びリン酸基を有するアクリル樹脂(AC-3)溶液を得た。得られた水酸基及びリン酸基を有するアクリル樹脂(AC-3)は、酸価が83mgKOH/g、水酸基価が29mgKOH/g、重量平均分子量が10,000であった。
リン酸基含有重合性モノマー:温度計、サーモスタット、撹拌装置、還流冷却器、窒素導入管及び滴下装置を備えた反応容器に、モノブチルリン酸57.5部及びイソブタノール41.0部を入れ、90℃まで昇温後、グリシジルメタクリレート42.5部を2時間かけて滴下した後、さらに1時間撹拌熟成した。その後、イソプロパノ-ル59.0部を加えて、固形分濃度50%のリン酸基含有重合性モノマー溶液を得た。得られたモノマーの酸価は285mgKOH/gであった。
製造例19
撹拌混合容器内において、「Xirallic T60-10 SW Crystal Silver」(商品名、メルク社製、金属酸化物被覆アルミナフレーク顔料)30部、2-エチル-1-ヘキサノール35部及び製造例18で得た水酸基及びリン酸基を有するアクリル樹脂(AC-3)溶液18部(固形分9部)を均一に混合して、光干渉性顔料分散液(X-4)を得た。
撹拌混合容器内において、「Magnapearl Exterior CFS 1103」(商品名、BASF社製、金属酸化物被覆マイカ顔料)35部、2-エチル-1-ヘキサノール35部及び製造例18で得た水酸基及びリン酸基を有するアクリル樹脂(AC-3)溶液21部(固形分10.5部)を均一に混合して、光干渉性顔料分散液(X-5)を得た。
製造例21
製造例11で得た水分散性水酸基含有アクリル樹脂(AC-2)水分散液100.0部(固形分30部)、製造例2で得た水酸基含有アクリル樹脂溶液(AC-1)20.0部(固形分11部)、製造例12で得たポリエステル樹脂溶液(PE-2)28.6部(固形分20部)、「サイメル325」(商品名、オルネクス社製、メラミン樹脂、固形分80%)37.5部(固形分30部)、及び製造例19で得た光干渉性顔料分散液(X-4)83部を均一に混合し、更に、「プライマルASE-60」(商品名、ダウケミカル社製、ポリアクリル酸系増粘剤)、2-(ジメチルアミノ)エタノール、及び脱イオン水を加えて、pH8.0、塗料固形分14%、20℃におけるフォードカップNo.4による粘度40秒の、第3水性着色塗料(P3-1)を得た。該第3水性着色塗料(P3-1)における光干渉性顔料(C)の含有量は、該第3水性着色塗料(P3-1)中のバインダー成分の固形分100質量部を基準として30質量部であった。
製造例21において、配合組成及び塗料固形分を後記の表3に示すものとする以外は、製造例21と同様にして、pH8.0、20℃におけるフォードカップNo.4による粘度が40秒の、第3水性着色塗料(P3-2)~(P3-5)を得た。
リン酸亜鉛処理された冷延鋼板に、熱硬化性エポキシ樹脂系カチオン電着塗料組成物(商品名「エレクロンGT-10」、関西ペイント社製)を膜厚20μmになるように電着塗装し、170℃で30分加熱して硬化させて、試験用被塗装物とした。
上記試験用被塗装物2枚に、製造例6で得た第1水性着色塗料(P1-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚30μmとなるように塗装して第1着色塗膜を形成し、2分間放置後、80℃で3分間プレヒートを行なった。次いで、該未硬化の第1着色塗膜上に、製造例13で得た第2水性着色塗料(P2-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚12μmとなるように塗装して第2着色塗膜を形成した。
次いで、該試験用被塗装物2枚のうち1枚を取り出し、1分間放置後、80℃で3分間プレヒートを行なった。その後、140℃で30分間加熱して、該未硬化の第1着色塗膜及び未硬化の第2着色塗膜を硬化させて試験用塗装板Aを得た。
また、もう1枚の試験用被塗装物は、前記第2水性着色塗料(P2-1)の塗装後、1分間放置し、その後、該未硬化の第2着色塗膜上に、製造例21で得た第3水性着色塗料(P3-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚3μmとなるように静電塗装して第3着色塗膜を形成し、3分間放置した。次いで、80℃で3分間プレヒートを行なった後、該未硬化の第3着色塗膜上に熱硬化性の酸・エポキシ硬化型アクリル樹脂系有機溶剤型クリヤーコート塗料(商品名「マジクロンKINO-1210TW」、関西ペイント社製)を、回転霧化型の静電塗装機を用いて、硬化膜厚35μmとなるように静電塗装し、クリヤーコート塗膜を形成した。7分間放置後、140℃で30分間加熱して、上記未硬化の第1着色塗膜、未硬化の第2着色塗膜、未硬化の第3着色塗膜及び未硬化のクリヤーコート塗膜を硬化させることにより、試験用塗装板Bを作製した。
実施例1において、第1水性着色塗料、第2水性着色塗料及び第3水性着色塗料の種類と硬化膜厚を下記表4-1、表4-2に示す通りとする以外は、実施例1と同様にして試験板A及び試験板Bを作製した。
上記試験用被塗装物2枚に、製造例6で得た第1水性着色塗料(P1-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚30μmとなるように塗装して第1着色塗膜を形成し、2分間放置後、80℃で3分間プレヒートを行なった。その後、140℃で30分間加熱して、第1着色塗膜を硬化させた。次いで、該硬化した第1着色塗膜上に、製造例13で得た第2水性着色塗料(P2-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚12μmとなるように塗装して、第2着色塗膜を形成した。
次いで、該試験用被塗装物2枚のうち1枚を取り出し、1分間放置後、80℃で3分間プレヒートを行なった。その後、140℃で30分間加熱して、該未硬化の第1着色塗膜及び未硬化の第2着色塗膜を硬化させて、試験用塗装板Aを得た。
また、もう1枚の試験用被塗装物は、前記第2水性着色塗料(P2-1)の塗装後、1分間放置した。その後、該未硬化の第2着色塗膜上に、製造例21で得た第3水性着色塗料(P3-1)を、回転霧化型の静電塗装機を用いて、硬化膜厚3μmとなるように静電塗装して第3着色塗膜を形成し、3分間放置した。次いで、80℃で3分間プレヒートを行なった後、該未硬化の第3着色塗膜上に熱硬化性の酸・エポキシ硬化型アクリル樹脂系有機溶剤型クリヤーコート塗料(商品名「マジクロンKINO-1210TW」、関西ペイント社製)を、回転霧化型の静電塗装機を用いて、硬化膜厚35μmとなるように静電塗装し、クリヤーコート塗膜を形成した。7分間放置後、140℃で30分間加熱して、上記未硬化の第1着色塗膜、未硬化の第2着色塗膜、未硬化の第3着色塗膜及び未硬化のクリヤーコート塗膜を硬化させることにより、試験用塗装板Bを作製した。
上記実施例1~12及び比較例1~3で得られた各試験用塗装板A及び試験用塗装板Bを使用して、下記の試験方法により評価を行なった。評価結果を下記表4-1、表4-2に示す。
第2水性着色塗料(P2)の硬化時の明度L*値(L* P2):上記試験用塗装板AのL*値を測定した。具体的には、マルチアングル分光測色計「CM-512m3」(コニカミノルタ社製)を用いて、塗膜面に垂直な軸に対し45°の角度から光を照射し、反射した光のうち塗膜面に垂直な方向の光のL*値を測定した。
なお、上記受光角15度のL*値(L*15値)は、具体的には、測定対象面に垂直な軸に対し45°の角度から測定光を照射し、正反射角から測定光の方向に15°の角度で受光した光についてのL*値である。
◎:ゴバン目塗膜が100個残存し、カッターの切り込みの縁において塗膜の小さなフチカケが生じていない
○:ゴバン目塗膜が100個残存するが、カッターの切り込みの縁において塗膜の小さなフチカケが生じている
△:ゴバン目塗膜が90~99個残存する
×:ゴバン目塗膜の残存数が89個以下である。
◎:白色ムラがほとんど認められず、極めて優れた塗膜外観を有する、
○:白色ムラがわずかに認められるが、優れた塗膜外観を有する、
△:白色ムラが認められ、塗膜外観がやや劣る、
×:白色ムラが多く認められ、塗膜外観が劣る。
A:Wd値が5以下であった。
B:Wd値が5より大きく10以下であった。
C:Wd値が10より大きく15以下であった。
D:Wd値が15より大きく30以下であった。
E:Wd値が30より大きかった。
Claims (8)
- 下記の工程(1)~(6):
(1)鋼板上に電着塗料を塗装し、加熱硬化させて硬化電着塗膜を形成せしめる工程、
(2)工程(1)で得られる硬化電着塗膜上に第1着色塗料(P1)を塗装して、第1着色塗膜を形成せしめる工程であって、前記第1着色塗料(P1)は、厚さ30μmの硬化塗膜を形成した場合の明度L*値(L* P1)が80~89の範囲内である、工程、
(3)工程(2)で得られる第1着色塗膜上に、バインダー成分(AP2)及び二酸化チタン顔料(B)を含有し、かつ塗料固形分が21~50質量%の範囲内である第2水性着色塗料(P2)を塗装して、硬化膜厚(TP2)が5~20μmの範囲内であり、かつ硬化時の明度L*値(L* P2)が85~95の範囲内である第2着色塗膜を形成せしめる工程、
(4)工程(3)で得られる第2着色塗膜上に第3水性着色塗料(P3)を塗装して、硬化膜厚(TP3)が1~10μmの範囲内である第3着色塗膜を形成せしめる工程であって、前記第3水性着色塗料(P3)は、バインダー成分(AP3)及び光干渉性顔料(C)を含有し、かつ塗料固形分が5~20質量%の範囲内である、工程、
(5)工程(4)で得られる第3着色塗膜上に、クリヤーコート塗料(P4)を塗装してクリヤーコート塗膜を形成せしめる工程、並びに
(6)工程(3)~(5)で形成される第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜を含む複層塗膜を加熱することによって、前記複層塗膜を同時に硬化させる工程、
を含む、複層塗膜形成方法であって、
前記L* P2が前記L* P1より高く、かつ前記L* P2と前記L* P1の差が1~10の範囲内であり、かつ前記TP2と前記TP3との比がTP2/TP3=1.1/1~20/1の範囲内である、複層塗膜形成方法。 - 前記第1着色塗料(P1)が水性塗料である、請求項1に記載の複層塗膜形成方法。
- 前記第1着色塗膜の硬化膜厚(TP1)が15~40μmの範囲内である、請求項1又は2に記載の複層塗膜形成方法。
- 前記第2水性着色塗料(P2)において、前記バインダー成分(AP2)及び前記二酸化チタン顔料(B)の含有割合が、前記バインダー成分(AP2)の固形分100質量部を基準として、前記二酸化チタン顔料(B)が60~150質量部の範囲内である、請求項1又は2に記載の複層塗膜形成方法。
- 前記第3水性着色塗料(P3)において、前記バインダー成分(AP3)及び前記光干渉性顔料(C)の含有割合が、前記バインダー成分(AP3)の固形分100質量部を基準として、前記光干渉性顔料(C)が20~70質量部の範囲内である、請求項1~4のいずれか1項に記載の複層塗膜形成方法。
- 前記第1着色塗料(P1)を塗装し硬化せしめて得られる厚さ30μmの硬化塗膜の、波長360~420nmにおける平均光線透過率(TRP1)が、0.08%以下の範囲内である、請求項1~5のいずれか1項に記載の複層塗膜形成方法。
- 加熱硬化させた前記第1着色塗膜上に、前記第2水性着色塗料(P2)を塗装する、請求項1~6のいずれか1項に記載の複層塗膜形成方法。
- 未硬化の前記第1着色塗膜上に、前記第2水性着色塗料(P2)を塗装し、前記工程(6)において、前記工程(2)~(5)で形成される第1着色塗膜、第2着色塗膜、第3着色塗膜、及びクリヤーコート塗膜を加熱することによって、これら4つの塗膜を含む複層塗膜を一度に硬化させる、請求項1~6のいずれか1項に記載の複層塗膜形成方法。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17/057,138 US11369991B2 (en) | 2018-05-23 | 2019-05-20 | Method for forming multilayer coating film |
CA3100452A CA3100452C (en) | 2018-05-23 | 2019-05-20 | Method for forming multilayer coating film |
JP2019547345A JP6625301B1 (ja) | 2018-05-23 | 2019-05-20 | 複層塗膜形成方法 |
CN201980031284.1A CN112135694B (zh) | 2018-05-23 | 2019-05-20 | 多层涂膜形成方法 |
EP19808001.2A EP3797878A4 (en) | 2018-05-23 | 2019-05-20 | MULTI-LAYER COATING FILM FORMING METHOD |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018-099211 | 2018-05-23 | ||
JP2018099211 | 2018-05-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019225559A1 true WO2019225559A1 (ja) | 2019-11-28 |
Family
ID=68616998
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2019/019977 WO2019225559A1 (ja) | 2018-05-23 | 2019-05-20 | 複層塗膜形成方法 |
Country Status (7)
Country | Link |
---|---|
US (1) | US11369991B2 (ja) |
EP (1) | EP3797878A4 (ja) |
JP (1) | JP6625301B1 (ja) |
CN (1) | CN112135694B (ja) |
CA (1) | CA3100452C (ja) |
TW (1) | TWI793326B (ja) |
WO (1) | WO2019225559A1 (ja) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2021014859A1 (ja) * | 2019-07-24 | 2021-01-28 | ||
CN116018215A (zh) * | 2020-07-29 | 2023-04-25 | 关西涂料株式会社 | 多层涂膜形成方法 |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP7213085B2 (ja) * | 2018-12-25 | 2023-01-26 | 日本ペイント・オートモーティブコーティングス株式会社 | 複層塗膜形成方法 |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08164358A (ja) | 1994-12-14 | 1996-06-25 | Honda Motor Co Ltd | 複層塗膜形成法 |
JP2004351391A (ja) * | 2003-05-30 | 2004-12-16 | Honda Motor Co Ltd | 光輝性塗膜形成方法および塗装物 |
WO2011125490A1 (ja) * | 2010-04-08 | 2011-10-13 | 関西ペイント株式会社 | 複層塗膜形成方法 |
JP2012125747A (ja) * | 2010-12-17 | 2012-07-05 | Honda Motor Co Ltd | 複層塗膜形成方法 |
JP2012157827A (ja) * | 2011-02-01 | 2012-08-23 | Kansai Paint Co Ltd | 光輝性複層塗膜の形成方法 |
JP2016221473A (ja) * | 2015-06-02 | 2016-12-28 | 関西ペイント株式会社 | 複層塗膜形成方法 |
JP2017154089A (ja) * | 2016-03-02 | 2017-09-07 | 関西ペイント株式会社 | 複層塗膜形成方法 |
WO2018034278A1 (ja) * | 2016-08-19 | 2018-02-22 | エーエスペイント株式会社 | 複層塗膜形成方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2045022B1 (en) | 2003-05-30 | 2019-10-30 | Honda Motor Co., Ltd. | Method for forming brilliant coating film and coated article showing metallic effect |
JP5053760B2 (ja) * | 2007-08-28 | 2012-10-17 | 日本ペイント株式会社 | 複層塗膜形成方法 |
JP6411343B2 (ja) * | 2013-07-04 | 2018-10-24 | 関西ペイント株式会社 | 塗料組成物及び塗膜形成方法 |
JP6254970B2 (ja) * | 2015-03-31 | 2017-12-27 | 株式会社Subaru | 積層塗膜の形成方法 |
-
2019
- 2019-05-20 CN CN201980031284.1A patent/CN112135694B/zh active Active
- 2019-05-20 WO PCT/JP2019/019977 patent/WO2019225559A1/ja unknown
- 2019-05-20 CA CA3100452A patent/CA3100452C/en active Active
- 2019-05-20 JP JP2019547345A patent/JP6625301B1/ja active Active
- 2019-05-20 US US17/057,138 patent/US11369991B2/en active Active
- 2019-05-20 EP EP19808001.2A patent/EP3797878A4/en active Pending
- 2019-05-22 TW TW108117663A patent/TWI793326B/zh active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08164358A (ja) | 1994-12-14 | 1996-06-25 | Honda Motor Co Ltd | 複層塗膜形成法 |
JP2004351391A (ja) * | 2003-05-30 | 2004-12-16 | Honda Motor Co Ltd | 光輝性塗膜形成方法および塗装物 |
WO2011125490A1 (ja) * | 2010-04-08 | 2011-10-13 | 関西ペイント株式会社 | 複層塗膜形成方法 |
JP2012125747A (ja) * | 2010-12-17 | 2012-07-05 | Honda Motor Co Ltd | 複層塗膜形成方法 |
JP2012157827A (ja) * | 2011-02-01 | 2012-08-23 | Kansai Paint Co Ltd | 光輝性複層塗膜の形成方法 |
JP2016221473A (ja) * | 2015-06-02 | 2016-12-28 | 関西ペイント株式会社 | 複層塗膜形成方法 |
JP2017154089A (ja) * | 2016-03-02 | 2017-09-07 | 関西ペイント株式会社 | 複層塗膜形成方法 |
WO2018034278A1 (ja) * | 2016-08-19 | 2018-02-22 | エーエスペイント株式会社 | 複層塗膜形成方法 |
Non-Patent Citations (1)
Title |
---|
See also references of EP3797878A4 |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2021014859A1 (ja) * | 2019-07-24 | 2021-01-28 | ||
WO2021014859A1 (ja) * | 2019-07-24 | 2021-01-28 | 関西ペイント株式会社 | 複層塗膜形成方法及び複層塗膜 |
JP7097512B2 (ja) | 2019-07-24 | 2022-07-07 | 関西ペイント株式会社 | 複層塗膜形成方法及び複層塗膜 |
CN116018215A (zh) * | 2020-07-29 | 2023-04-25 | 关西涂料株式会社 | 多层涂膜形成方法 |
CN116018215B (zh) * | 2020-07-29 | 2023-09-29 | 关西涂料株式会社 | 多层涂膜形成方法 |
Also Published As
Publication number | Publication date |
---|---|
EP3797878A1 (en) | 2021-03-31 |
JPWO2019225559A1 (ja) | 2020-06-11 |
EP3797878A4 (en) | 2022-03-09 |
CN112135694B (zh) | 2023-06-16 |
TW202003714A (zh) | 2020-01-16 |
CN112135694A (zh) | 2020-12-25 |
US20210121914A1 (en) | 2021-04-29 |
JP6625301B1 (ja) | 2019-12-25 |
CA3100452A1 (en) | 2019-11-28 |
US11369991B2 (en) | 2022-06-28 |
CA3100452C (en) | 2023-03-14 |
TWI793326B (zh) | 2023-02-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6411343B2 (ja) | 塗料組成物及び塗膜形成方法 | |
US10239091B2 (en) | Method for forming multilayer coating film | |
US10441970B2 (en) | Method for forming multilayer coated film | |
JP6625301B1 (ja) | 複層塗膜形成方法 | |
JP2011136317A (ja) | 光輝性複層塗膜の形成方法 | |
WO2020158222A1 (ja) | 複層塗膜及び複層塗膜形成方法 | |
JP2019195791A (ja) | 複層塗膜の形成方法 | |
JP5547526B2 (ja) | 塗料組成物、塗膜形成方法および塗膜構造 | |
JP2006192384A (ja) | 複層塗膜形成方法及び塗膜構造 | |
JP4958090B2 (ja) | 複層塗膜形成方法及び塗装物品 | |
CA3155445C (en) | Method for forming multilayer coating film | |
JP5089518B2 (ja) | 補修塗装方法 | |
JP6473657B2 (ja) | 複層塗膜形成方法 | |
JP2012017364A (ja) | メタリック塗料組成物及び塗膜形成方法 | |
JP2022113338A (ja) | 複層塗膜形成方法 | |
JP4712630B2 (ja) | 多層塗膜の補修方法およびそれから得られた被塗物 | |
JP6355585B2 (ja) | 複層塗膜形成方法 | |
JP2024075086A (ja) | 複層塗膜形成方法 | |
JP2021115856A (ja) | 複層塗膜及び複層塗膜形成方法 | |
WO2021100238A1 (ja) | 複層塗膜形成方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2019547345 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 19808001 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 3100452 Country of ref document: CA |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2019808001 Country of ref document: EP Effective date: 20201223 |