JP6207071B2 - Matte thermal barrier coating composition and coating film forming method using the composition - Google Patents

Description

The present invention relates to a matte thermal barrier coating composition capable of obtaining a matte coating excellent in finish, base concealing property, thermal barrier and heat insulation, and a method for forming a matte thermal barrier coating using the composition The present invention also relates to a coated article on which a thermal barrier coating film is formed by the forming method.

  2. Description of the Related Art Matting coating compositions containing a matting agent such as silica particles, ceramic particles, polymer beads, and hollow resin particles having an average particle size of about several μm to 50 μm are known.

  On the other hand, from the viewpoint of energy saving, there has been an increasing demand for coating films having high heat shielding properties and heat insulation properties. Although the above-mentioned silica particles and polymer beads increase the light reflectance by using many as a matting agent for paints, the contribution to improving the heat shielding property of the coating film is small, and the contribution to improving the heat insulation is not rare.

  Patent Documents 1 and 2 disclose matte paint compositions having high solar reflectance (heat shielding properties) and heat insulation properties using silicon boride ceramic bubble particles. However, the coating film obtained from this coating composition is inferior in the concealability of the base, and if the content of the bubble particles is large, the storage stability of the coating is lowered, or the obtained coating film is liable to deteriorate. There was a problem.

  Patent Document 3 discloses a coating composition to which hollow resin particles that give a high matting effect are added. Although such hollow resin particles can be expected to contribute to the improvement of the heat insulation of the resulting coating film, the coating layer is inferior in the concealment property of the base, and it can be used as a paint containing an organic solvent. When applied, the storage stability of the paint may be inferior.

  The coating composition described in Patent Document 4 containing porous calcium carbonate and titanium white is intended for a coating film that achieves both high light reflectance and low gloss, but to further enhance the matte effect. However, it was necessary to increase the particle diameter of the porous calcium carbonate or increase its concentration. However, when the particle size is increased, the light reflectance and concealing property of the coating film are reduced, and when the concentration is increased, the coating performance such as water resistance may be deteriorated. .

JP 11-323197 A JP 2004-010903 A JP 2010-31161 A JP 2012-92289 A

  An object of the present invention is to provide finish, base concealability, heat shielding and heat insulation, including porous particles (A) having an average particle diameter of 1 to 50 μm containing titanium white and resin (Z), and resin (B). Matte thermal barrier coating composition capable of forming matte coating with excellent properties, method of forming matte thermal barrier coating using the composition, and coating with thermal barrier coating formed by the formation method It is to provide an article.

  As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. That is, the present invention comprises the following items.

Item 1. A matte thermal barrier coating composition comprising a porous particle (A) having an average particle diameter of 1 to 50 μm containing titanium white and a resin (Z) and a resin (B), wherein the porous particle (A) The titanium white content is in the range of 4.0 to 45.0 mass% based on the solid content mass, and contains 5 to 30 mass% of porous particles (A) based on the mass of the resin (B). A matte thermal barrier coating composition.

  Item 2. The porous particles (A) are formed by aggregation of particles having an average particle diameter of 10 to 300 nm, and the apparent density of the porous particles (A) is in the range of 0.5 to 1.3 g / cm 3. Item 2. The matte thermal barrier coating composition according to Item 1, wherein

  Item 3. Item 1 or 2 wherein the resin (Z) is obtained by reacting a resin (a) having an unsaturated group and an acid group, a compound (b) having an amino group, and a radical polymerizable unsaturated monomer (c). The matte thermal barrier coating composition as described.

  Item 4. The matte thermal barrier coating composition according to any one of items 1 to 3, wherein the matte thermal barrier coating composition is applied so that the dry film thickness is in the range of 20 to 70 μm. .

  Item 5. A primer coating composition containing titanium white is applied to form a primer coating, and the matte thermal barrier coating composition according to any one of Items 1 to 3 is applied onto the primer coating. A method for forming a matte thermal barrier coating film, wherein the primer coating has a whiteness (L value) in the range of 80 to 98.

  Item 6. Item 6. A coated article on which a thermal barrier coating film is formed by the method for forming a thermal barrier coating film according to item 4 or 5.

  The matte thermal barrier coating composition of the present invention is capable of forming a matte thermal barrier coating film excellent in finish, base concealing property, thermal barrier and heat insulating properties, and is another invention. The coating method using the coating composition is particularly useful for forming the above-described matte thermal barrier coating film having excellent performance on the outer wall, roof, steel structure and the like of a building.

The matte thermal barrier coating composition of the present invention (hereinafter sometimes referred to as “thermal barrier coating composition”) is a porous particle having an average particle diameter of 1 to 50 μm containing titanium white and a resin (Z) (A ) And resin (B), wherein the titanium white is in the range of 4.0 to 45.0 mass% based on the solid content mass of the porous particles (A). And 5 to 30% by mass of the porous particles (A) based on the mass of the resin (B).

Porous particles (A)
The method for producing the porous particles (A) is not particularly limited, and can be produced by a known method, for example, the methods described in JP-A-50-29691, WO2004 / 029116, etc. Can do.

  The resin (Z) contained in the porous particles (A) is not particularly limited, but is a resin (a) having an unsaturated group and an acid group [denoted as “resin (a)” in the present specification. Yes], and a resin obtained by reacting the compound (b) having an amino group and the radical polymerizable unsaturated monomer (c) is preferable from the viewpoint of easy production of the particles.

  Specifically, the production method of the porous particles (A) includes a resin (a), a compound (b) having an amino group, a radical polymerizable unsaturated monomer (c) and a mixture (M) containing titanium white, By dispersing in an aqueous medium containing the aqueous dispersion resin (d) and adding a radical polymerization initiator (e) to the resulting aqueous dispersion to perform a reaction including a radical polymerization reaction, titanium white and resin (Z ) Containing porous particles (A) as dispersed particles in an aqueous medium. In the above reaction, the compound (b) having an amino group is preferably subjected to an addition reaction with the unsaturated group of the resin (a). The obtained porous particles (A) are dispersed in an aqueous medium or used in the form of powder obtained by removing volatile components, whereby the thermal barrier coating composition of the present invention is used. You can get things.

  The production method of the porous particles (A) is not limited to the above method. For example, the radical polymerizable unsaturated monomer (c) is divided into two, and one monomer (c1) is mixed into the mixture (M). In addition, the mixture (M) is dispersed in an aqueous medium containing the aqueous dispersion resin (d), and the radical polymerization initiator (e1) is added to the obtained aqueous dispersion to perform a polymerization reaction, and then the other monomer ( You may change suitably, such as passing through the process of adding c2) and a radical polymerization initiator (e2), and performing a polymerization reaction.

  The radical polymerization reaction in the production of the porous particles (A) can be performed at a temperature of room temperature to 90 ° C. for about 30 minutes to 12 hours.

  In the present specification, the “aqueous medium” means water or a medium obtained by mixing water and an organic solvent and containing 50% by mass or more of water.

  As the resin (a), a known resin can be used as long as it has an unsaturated group and an acid group. For example, polyester resin, alkyd resin, acrylic resin, polyurethane resin, polyolefin resin, polybutadiene can be used. A resin in which an unsaturated group and an acid group are introduced into a resin such as a series resin by a known method can be used. From the viewpoint of the stability of the porous particles and the ease of production, a polyester resin having an unsaturated group and an acid group can be suitably used as the resin (a). In the present specification, the polyester resin having an unsaturated group and an acid group may be referred to as “polyester resin (a ′)”.

  Examples of the acid group possessed by the resin (a) include a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group. A carboxylic acid group is particularly preferred from the viewpoint of ease of production. The acid value of the resin (a) is preferably in the range of 5 to 50 mgKOH / g.

  The polyester-based resin (a ′) can be produced by a conventionally known method. For example, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetrahydrophthalic acid, tetrahydrophthalic anhydride, methyl Contains one or more unsaturated polybasic acids such as tetrahydrophthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, het anhydride, hymic anhydride, and a reaction product of dicyclopentadiene and maleic anhydride It can be produced by esterifying a polybasic acid and a polyhydric alcohol.

  Other polybasic acids that can be used with the unsaturated polybasic acid in the production of the polyester resin (a ′) include phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid. Acid, hexahydrophthalic acid, hexahydrophthalic anhydride, hexahydroterephthalic acid, hexahydroisophthalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, 2,6-naphthalene Listed are polybasic acids such as dicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic anhydride, 4,4'-biphenyldicarboxylic acid, and dialkyl esters thereof. These can use 1 type (s) or 2 or more types.

  The polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule. For example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, 1,2- or 1,3 A dihydric alcohol such as propanediol, 1,6-hexanediol, 1,4-dimethylolcyclohexane, dipropylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, bis (hydroxymethyl) xylene; glycerin, Examples include trivalent or higher alcohols such as 1,1,1-trimethylolpropane, 1,2,3-butanetriol, pentaerythritol, dipentaerythritol, and the like. Rukoto can.

  The polyester-based resin (a ′) may be produced using a monovalent carboxylic acid compound or an alcohol compound together with the polybasic acid or polyhydric alcohol as necessary.

  The polyester-based resin (a ′) can be produced by a known method. The polybasic acid, the polyhydric alcohol, and other components as necessary are mixed, and in the presence of a solvent or without solvent, a temperature of 120 to 300 ° C. It can manufacture by heating to the temperature of this, and carrying out a condensation reaction normally for 2 hours-24 hours.

  Other production methods for obtaining the polyester-based resin (a ′) include a polyester resin having a functional group such as a carboxyl group and a hydroxyl group, and a function capable of reacting with the functional group to form a chemical bond. Examples thereof include a method of obtaining a polyester resin (a ′) having an unsaturated group by reacting with an unsaturated compound having a group.

  The polyester resin (a ′) is preferably used within a range of 20 to 80% by mass based on the solid content mass of the porous particles (A).

  Examples of the compound (b) having an amino group include monovalent amine compounds such as morpholine, triethylamine, monoethanolamine, diethanolamine and dimethylethanolamine, and polyvalent amine compounds such as ethylenediamine, diethylenetriamine and dipropylenetriamine. it can. The compound (b) having an amino group is preferably used within a range of 0.5 to 10.0% by mass based on the mass of the resin (a).

The titanium white can be used in the range of 4.0 to 45.0 mass%, preferably 4.0 to 40.0 mass%, based on the solid content mass of the porous particles (A). If the amount of titanium white is less than 4.0 % by mass, the resulting coating film may have insufficient concealability and heat shielding properties. Moreover, when there are more titanium whites than 45.0 mass%, manufacture of a porous particle (A) may become difficult.

  The average particle diameter of the titanium white is preferably in the range of 0.1 to 0.4 μm from the viewpoint of the concealability of the coating film. Moreover, it is preferable to select a rutile type from the point of the weather resistance of a coating film.

  As the radically polymerizable unsaturated monomer (c), known ones can be used, for example, styrene; vinyl esters such as vinyl acetate, vinyl butyrate and vinyl laurate; methyl (meth) acrylate, butyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, etc. (Meth) acrylic acid esters: allyl (meth) acrylate, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, neopentyl glycol diacrylate, 1,6-hexanediol di (meth) Acrylate, diallyl terephthalate, a monomer or the like having two or more radical polymerizable unsaturated group such as ethylenebis (meth) acrylamide in a molecule. These monomers may be used alone or in combination of two or more.

  The radically polymerizable unsaturated monomer (c) is preferably used within a range of 5 to 50% by mass based on the solid content mass of the porous particles (A).

  In the present specification, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid. “(Meth) acryloyl” means acryloyl or methacryloyl, and “(meth) acrylamide” means acrylamide or methacrylamide.

  The aqueous dispersion resin (d) is used for stably dispersing the mixture (M) in the form of particles in an aqueous medium. The aqueous dispersion resin (d) is, for example, in water such as polyvinyl alcohol, carboxyalkyl cellulose, polyvinyl pyrrolidone, poly (meth) acrylamide polymer, polyethylene glycol, gelatin, starch, polyalginic acid, poly (meth) acrylic acid polymer. Resins that can be dissolved or dispersed can be mentioned, and these can be used alone or in combination of two or more. The aqueous dispersion resin (d) can be used in combination with a known neutralizing agent, if necessary. The aqueous dispersion resin (d) is preferably used within a range of 0.1 to 20% by mass based on the mass of the mixture (M). In addition, the concentration of the aqueous dispersion resin (d) in the aqueous medium is preferably in the range of 0.1 to 40% by mass from the viewpoint of maintaining a stable dispersion state of the mixture (M).

  As the radical polymerization initiator (e), known compounds can be used. For example, azo compounds such as azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile), dibenzoyl peroxide, di- Examples thereof include organic peroxides such as tert-butyl peroxide and cumene hydroperoxide, persulfates such as potassium persulfate, ammonium persulfate and sodium persulfate, and inorganic peroxides such as hydrogen peroxide. Further, the peroxide polymerization initiator may be one or two known reducing agents such as ferrous sulfate, ferrous chloride, Rongalite, thiourea dioxide, erythorbic acid, tartaric acid, and saccharides, if necessary. The above may be added and used as a redox initiator.

  The porous particles (A) preferably have a crosslinked structure inside the particles from the viewpoint of the storage stability of the matte coating composition of the present invention. In order to obtain the crosslinked structure, a polyvalent amine compound having two or more primary or secondary amino groups in one molecule is used as the compound (b) having an amino group in the production of the porous particles (A). Alternatively, a monomer having two or more radically polymerizable unsaturated groups in one molecule may be used as the radically polymerizable unsaturated monomer (c).

  The mixture (M) is a known organic solvent as other components other than the above components; saturated or unsaturated fatty acids such as soybean oil fatty acid, linseed oil fatty acid, coconut oil fatty acid, oleic acid; oils such as soybean oil and linseed oil A petroleum resin, an alkyd resin, etc.

  In preparing the mixture (M), the titanium white may be mixed with the resin (a) and dispersed by a disperser, but a known pigment dispersion resin or pigment dispersant other than the resin (a) may be used. The titanium white may be mixed and dispersed by a disperser to form a paste. The dispersion may be performed by mixing an organic solvent, water, a radical polymerizable unsaturated monomer (c), etc. together with the titanium white.

  The porous particles (A) produced by the production method are formed by agglomeration of particles having an average particle diameter of 10 to 300 nm (an electron micrograph of the inner wall surface of the porous particles in FIG. 1). (Refer to FIG. 2.) Many spherical pores exist inside the porous particles (see the electron micrograph of the cross section of the porous particles in FIG. 2). Due to such a structure, the porous particles (A) are excellent in mechanical strength and chemical stability, and stably maintain voids inside the particles in the thermal barrier coating composition of the present invention. Even inside, it is considered that functions such as hiding power, matting effect, heat shielding and heat insulation can be exhibited.

  In addition, the solid content mass of the porous particles (A) in the present specification is, for example, when the porous particles (A) are produced by the production method and obtained as a dispersion dispersed in an aqueous medium. About 2 grams of the dispersion is weighed and placed in an open container such as a tin plate, and the percentage of non-volatile content (solid content%) when heated and dried at 105 ° C. for 3 hours is determined. It means the converted value.

  The particle diameter of the porous particles (A) and the amount of voids inside the particles can be controlled by the composition of the respective components in the production process of the porous particles (A), the dispersion force in each process, the dispersion time, and the like. Therefore, the above factors can be appropriately adjusted according to the purpose.

  In the present specification, the apparent density of the porous particles (A) is a value measured according to Japan Powder Industry Technical Association Standard SAP 02-82 (1982). The apparent density of the porous particles (A) is the apparent density of the dried porous particles (A) obtained by removing volatile components.

The apparent density of the porous particles (A) is in the range of 0.5 to 1.3 g / cm ³ , preferably 1.1 to 0.6 g / cm ³ , more preferably 0.9 to 0.7 g / cm ³ . Is within. When the apparent density is less than 0.5 g / cm ^3, the mechanical strength of the porous particles (A) may be lowered. When the apparent density is greater than 1.3 g / cm ³ , Thermal insulation may be insufficient.

  The average particle diameter of the porous particles (A) is 1 to 50 μm, preferably 2 to 30 μm. If the average particle size is smaller than 1 μm, the matting effect may be insufficient, and if it is larger than 50 μm, the heat shielding property may be inferior.

  The average particle size of the titanium white and porous particles (A) is the median size of the volume-based particle size distribution measured by the laser diffraction scattering method using a microtrack particle size distribution measuring device MT3300 (trade name, manufactured by Nikkiso Co., Ltd.). means. Moreover, the value of the average particle diameter of the microparticles within the range where the average particle diameter constituting the porous particles (A) is about 10 to 300 nm is a value obtained by observation with an electron microscope.

Resin (B)
The resin (B) can be used without particular limitation as long as it is a resin having a film-forming ability that can be usually used in the paint field. Representative examples include acrylic resins, alkyd resins, polyester resins, epoxy resins, fluororesins, One or two or more kinds of mixed resins such as a vinyl chloride resin, a polyamide resin, a polyolefin resin, a silicon resin, a petroleum resin; a modified resin obtained by bonding these two or more kinds of resins by a known method can be given. Moreover, resin (B) may have 1 type (s) or 2 or more types of functional groups well-known in the coating-materials field | area.

Matte Thermal Barrier Paint Composition The matte thermal barrier paint composition of the present invention is a matte thermal barrier paint composition containing porous particles (A) and a resin (B), and the mass of the resin (B). The porous particles (A) are contained in a solid content of 5 to 30% by mass based on the above, and, if necessary, known curing agents, pigments, dispersants, additives, solvents and the like used in the coating composition. Can be included.

  When the amount of the porous particles (A) is less than 5% by mass, the matte property and the heat shielding effect of the coating film obtained may be insufficient. When the amount is more than 30% by mass, the matte and the heat shielding effect are saturated. Therefore, the raw material cost of the paint may be high.

  Examples of the solvent include water, an organic solvent, and a mixture of water and an organic solvent, which can be appropriately selected and used.

  As long as the matte thermal barrier coating composition of the present invention contains the porous particles (A) and the resin (B) within the above-mentioned mass range, a water-based coating, a solvent-based coating, a powder coating, and a solvent-free coating The composition may be in any form of paint.

Method for forming matte thermal barrier coating The matte thermal barrier coating composition of the present invention is known for roller coating, brush coating, sink coating, roll coater coating, dip coating, electrodeposition coating, electrostatic coating, spray coating, etc. It can be applied to an object by the method described above. When the thermal barrier coating composition of the present invention is used as a top coating composition, a stable coating quality can be obtained when the obtained coating has a dry film thickness in the range of 20 to 70 μm.

  In general, in roller coating, the film thickness of the obtained coating film tends to vary, and coating film gloss variation (gloss unevenness) due to film thickness difference tends to occur. In addition, the difference in finish is easily noticeable in areas where brush painting and roller coating overlap or in touch-up areas. In the present invention, by coating so that the dry film thickness is in the range of 20 to 70 μm, differences in finish such as gloss unevenness and touch-up site are unlikely to occur. It is possible to form a matte heat-shielding coating film that is excellent at the same time and excellent in finish. When the dry film thickness is less than 20 μm, the matting effect is not significantly affected, but the base concealing property and the heat shielding property may be insufficient. When the dry film thickness is thicker than 70 μm, the cost may be higher than that of a conventional coating film having an equivalent heat insulating property using an inexpensive glass balloon or shirasu balloon.

  In addition, in order to obtain a matte thermal barrier coating film in the above-mentioned dry film thickness range, the thermal barrier coating composition of the present invention may be finished by one-time coating or finished by two or more coatings. Also good.

  Alternatively, a primer coating composition containing titanium white may be applied to form a primer coating, and the matte thermal barrier coating composition of the present invention may be applied onto the primer coating to form a multilayer coating. Good. If the whiteness (L value) of the primer coating film is in the range of 80 to 98, the dry film thickness of the top coating film formed from the matte thermal barrier coating composition of the present invention is in the range of less than 5 to 20 μm. Even in this case, it is possible to obtain a matte multilayer coating film having excellent heat shielding properties and at the same time excellent finish. In addition, when the multilayer coating film requires heat insulation, a heat insulating coating composition containing known porous particles, for example, inexpensive glass balloons, shirasu balloons, hollow glass beads, etc. is applied as the primer coating composition. In addition, by applying the matte thermal barrier coating composition of the present invention as a top coat, it is possible to apply a matte multilayer coating film excellent in finish, thermal barrier and thermal insulation at low cost. .

  Next, an Example is given and this invention is demonstrated more concretely. Here, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

Production Example of Porous Particle (A) (Production Example 1) Production of Porous Particle (A1)
Each formulation described in stages 1 to 4 of Table 1 (the numerical values in the table mean parts by mass) were adjusted as follows.
Stage 1. 0.60 part of titanium white was mixed with 10.60 parts of polyester resin having an unsaturated group and an acid group (Note 1) and 10.90 parts of styrene, and dispersed in a container using a disper. . Then, while stirring the contents and 0.21 part of diethylenetriamine was added and the temperature of the contents was controlled at about 30 ° C., stirring was continued for 2 hours to obtain a mixture 1.
Step 2 13.30 parts of a 10% by weight aqueous polyvinyl alcohol solution, 10.50 parts of a 2.5% by weight aqueous hydroxyethyl cellulose solution, 53.40 parts of water, and 0.06 part of diethylenetriamine were mixed with stirring to obtain a mixture 2 Got.

The mixture 1 was added to the mixture 2 with stirring, and the mixture was vigorously stirred until a desired particle size was obtained, whereby a mixture 3 was obtained.
Stage 3 While stirring Mixture 3, 0.01 part ferrous sulfate was added followed by 0.12 part cumene hydroperoxide. Stirring was performed while maintaining the temperature of the contents at about 50 ° C. to obtain a mixture 4.
Stage 4 Slough-off 72N (a preservative manufactured by Nippon Environmental Chemicals Co., Ltd.) 0.35 part was added to the mixture 4 to obtain an aqueous dispersion of porous particles (A1).

The solid content of the aqueous dispersion was 24% by mass, and the apparent density (Note 3) of the dry porous particles (A1) obtained after removing the volatile components of the aqueous dispersion (Note 2) was 0.86 g / cm ³ , and the particle diameter was 5.6 μm.
(Note 1) Production of polyester resin having unsaturated groups and acid groups In a reaction vessel equipped with a stirrer, thermometer, rectifying column and water separator, 35 parts of maleic anhydride, 20 of phthalic anhydride 45 parts of 1,3-propanediol were heated to 230 ° C. in the presence of the esterification catalyst dibutyltin oxide (0.02 parts) and maintained for 1 hour, then xylene was added and the temperature was about 2 hours. While refluxing xylene, water was distilled off to obtain a polyester resin having an unsaturated group and an acid group. The number average molecular weight of this polyester resin was about 2000, and the acid value was 18 mgKOH / g. This polyester resin was used in Production Examples 1-7. In the present specification, the weight average molecular weight or number average molecular weight is a value obtained by converting the weight average molecular weight measured with a gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of polystyrene. is there. The columns are “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel G-2500H × L”, “TSKgel G-2000H × L” (both manufactured by Tosoh Corporation, trade name). These were carried out under the conditions of mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 ml / min, detector: RI.
(Note 2) Removal method of volatile components
The dried porous particles (A1) were obtained by drying under the following conditions using a spray dryer “ADL311S” (manufactured by Yamato Kagaku). Supply speed: 14 ml / min, spray pressure: 0.15 MPa, air volume: 0.3 m ³ / min, inlet temperature: 150 ° C., outlet temperature 60 ° C.
(Note 3) Apparent density measurement method
The apparent density of the dried porous particles obtained under the above conditions (Note 2) was measured according to Japan Powder Industry Technical Association Standard SAP 02-82 (1982). That is, about 150 ml of liquid paraffin is put into a 250 ml graduated cylinder, and the liquid level is measured (x ml). About 20 g of the porous particles weighed (z g) were slowly added, and the whole particle sample was wetted with liquid paraffin by gently shaking the graduated cylinder. As a minute, for example, the liquid level of paraffin at 1 minute, 5 minutes, 15 minutes,... After 60 minutes) is measured. The relationship between the measurement time and the liquid level is plotted in the figure, and the liquid level at time 0 minutes is obtained by extrapolation (y ml), and the calculated density [z / (y−x)] (g / Ml) Apparent density.
(Production Example 2) to (Production Example 7)
In the same manner as in Production Example 1, porous particles (A2) to (A7) were produced according to the formulation of Steps 1 to 4 described in Table 1. Table 1 shows the solid content, the apparent density, and the particle diameter of the obtained aqueous dispersion of particles.

Production Example of Resin (B) (Production Example 8) Production Example of Acrylic Resin (B1) 28.5 parts of deionized water in a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a dropping funnel, “Newcol 707SF” (Nippon Emulsifier Co., Ltd., trade name, anionic emulsifier, solid content 30%) 0.12 part was added and kept at 80 ° C. A pre-emulsion formed by emulsifying the following composition was added dropwise over 4 hours.
36.1 parts deionized water
15 parts of styrene
46 parts of methyl methacrylate
n-Butyl acrylate 18.5 parts
2-Ethylhexyl acrylate 18.5 parts
1.0 part of 2-hydroxyethyl acrylate
Acrylic acid 1.0 part
6.6 parts of 30% Newcol 707SF
0.2 parts of ammonium persulfate
After completion of the dropping, the temperature was further maintained at 80 ° C. for 2.5 hours. Thereafter, the temperature was lowered to 40 ° C. or lower while adding deionized water, and the pH was adjusted to 7 to 8 with aqueous ammonia to obtain an emulsion of an acrylic resin (B1) having a solid content concentration of 50%.

Production of aqueous matte thermal barrier coating composition (Example 1)
In a stirring and mixing container, 14.5 parts of water, a commercially available red rust paste “NS BROWN C522” (manufactured by Sanyo Pigment Co., Ltd., containing 50% by weight of red iron oxide), 18.4 parts, an emulsion of acrylic resin (B1) 200 parts ( 100 parts of solid content), 10.5 parts of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, defoaming agent “SN Deformer A63” (manufactured by San Nopco) 0.8 part, viscosity modifier 0.5 parts of “Primal SCT275” (manufactured by Dow Corning), 20.8 parts (5 parts solids) of an aqueous dispersion of porous particles (A2) having a solid content of 24% by mass obtained in Production Example 2 were added. The mixture was stirred with a disper to obtain an aqueous matte thermal barrier coating composition (P1).
(Examples 2-8 and Comparative Examples 1-3)
Except for changing the porous particles (A2) of Example 1 to the types and amounts of the porous particles shown in Table 2 (the numerical values in the table mean the solid content mass), the same procedure as in Example 1 was performed. Water-based coating compositions (P2) to (P11) were obtained. Comparative Example 3 is a case where particles for gloss adjustment are not included.

(Note 4) Silica powder: hydrous amorphous silicon dioxide powder, average particle size 4 μm, specific gravity 2.15
Manufacture of solvent-type matte thermal barrier coating composition
Example 9
“SD Horus 1000” (one type of synthetic resin blended paint JIS K 5516 manufactured by Kansai Paint Co., Ltd., 100 parts by weight of solid color of Japan Paint Manufacturers Association color chart number 07-40P, with volatile components removed and powdered 10 parts of fine particles (A2) were mixed, and stirred and mixed with a disper to produce a solvent-type matte thermal barrier coating composition (P12), wherein the powdery porous particles (A2) What was obtained by the same method described in (Note 2) was used.
(Comparative Examples 4 and 5)
A solvent-type matte coating composition (P13) was produced in the same manner as in Example 9 except that 10 parts of silica powder (Note 4) was used instead of the porous particles (A2). . The paint in the case where the gloss adjusting agent was not included was described in Comparative Example 5 as (P14).

Evaluation test
Using each of the aqueous coating compositions obtained in Examples 1 to 8 and Comparative Examples 1 and 2, painted plates corresponding to the following tests were prepared and evaluated. The results are shown in Table 2. In Example 9 and Comparative Examples 4 and 5 relating to the solvent-type paint, the evaluation results are shown in Table 3.

(Concealment rate test)
Concealment rate (%) of the coating film is in accordance with JIS K 5600 4-1, Method B (Concealment rate test paper) with a doctor blade so that each test coating composition has a dry film thickness of 25 μm. Painted on test paper with concealment rate and dried at room temperature for 3 days) Randomly select four locations on white (YW) and black (YB), measure tristimulus values at each location, and average tristimulus It is obtained by calculating the values YW and YB. A value obtained by calculating YB / YW obtained by such calculation at a 100-percentage is defined as a concealment rate.
(Gloss measurement)
The 60 ° and 85 ° gloss of the test piece coated on the black ground used in the concealment rate test was measured with a BYK trigloss meter. The higher the 85 ° gloss value is than the 60 ° gloss value, the more glossy the coating film is, and the more likely it is to cause uneven glossiness due to surface irregularities and film thickness variations.
(Heat insulation evaluation)
On the degreased tinplate, the coating compositions (P1) to (P14) were applied with an applicator so that the dry film thickness was 25 to 30 μm, and dried in a room at 23 ° C. and 50% RH for 3 days. A test plate for thermal insulation evaluation was prepared. A 70 mm square hole formed in the upper part of a cardboard box having a side of 40 cm was left in a laboratory at room temperature of about 25 ° C. for 30 minutes. The test plate was cut into a size of 75 mm × 75 mm, and a coated plate in which a thermocouple sensor was fixed to the back tin plate with a cellophane tape was allowed to stand so as to close the hole. From the distance of 40 cm, the surface of the coating film was irradiated with light by HALOGEN LIGHT (LPL1500) (about 800 W / m ² ), and the coating plate back surface temperature after 15 minutes was measured. The measurement results are shown in Tables 2 and 3.
(Example 10) to (Example 12), (Comparative Examples 6 and 7)
“Ale School Primer” (manufactured by Kansai Paint Co., Ltd., weak solvent two-component modified epoxy resin-based primer, containing titanium white) on a tinplate with a 30 μm thick coating on one side [whiteness of coating (L value ) = 92, “CR-200” (trade name, manufactured by Konica Minolta Co., Ltd., color difference meter)] was used to adjust the gloss with a matte thermal barrier coating composition (P2) and silica powder (Note 4). The coating composition (P10) was applied with a medium hair roller so that the predetermined dry film thickness described in Table 4 was obtained. After 16 hours at room temperature, the coating composition was applied to a part of each coated surface with 25 to 25 parts. It was painted (touched up) to 30 μm. After drying in a room at 23 ° C. and 50% RH for 4 days, a coated plate on which a multilayer coating film was formed was obtained.

About the said coating plate, the gloss nonuniformity of the touch-up coating part and the heat-shielding property were evaluated by the method similar to the above. The results are shown in Table 4.
(Evaluation of gloss unevenness)
◎: Cannot be discriminated at all ○ ○: If light is not applied obliquely, it is hardly understood ×: When the light is applied obliquely, gloss unevenness is clearly understood

It is possible to provide a coated article on which a matte coating film excellent in finish, base concealing property, heat shielding property and heat insulating property is formed.

An example of the porous particles in the present invention is an electron micrograph of the inner wall surface of the porous particles (one scale in the photograph = 50 nm). As an example of the porous particle in this invention, it is an electron micrograph of the porous particle cross section (1 scale in a photograph = 1 micrometer).

Claims (6)

A matte thermal barrier coating composition comprising a porous particle (A) having an average particle diameter of 1 to 50 μm containing titanium white and a resin (Z) and a resin (B), wherein the porous particle (A) The titanium white content is in the range of 4.0 to 45.0 mass% based on the solid content mass, and contains 5 to 30 mass% of porous particles (A) based on the mass of the resin (B). A matte thermal barrier coating composition. The porous particles (A) are formed by aggregation of particles having an average particle diameter of 10 to 300 nm, and the apparent density of the porous particles (A) is 0.5 to 1.3 g / cm ³ . The matte thermal barrier coating composition according to claim 1, which is within the range. The resin (Z) is obtained by reacting a resin (a) having an unsaturated group and an acid group, a compound (b) having an amino group, and a radical polymerizable unsaturated monomer (c). The matte thermal barrier coating composition described in 1. The matte thermal barrier coating composition according to any one of claims 1 to 3 is applied so that the dry film thickness is within a range of 20 to 70 µm. Method. A primer coating composition containing titanium white is applied to form a primer coating, and the matte thermal barrier coating composition according to any one of claims 1 to 3 is applied onto the primer coating. A method for forming a matte thermal barrier coating film, wherein the primer coating has a whiteness (L value) in the range of 80 to 98. A coated article on which a thermal barrier coating film is formed by the method for forming a thermal barrier coating film according to claim 4.

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