JP2018053115A - Heat insulation coating composition having aqueous two-liquid curability, heat insulation coating painting method, and heat insulation pavement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a coating composition capable of exhibiting sufficient heat insulation property, surely suppressing increase of road surface temperature, further capable of forming a coated film excellent in weather resistance, water resistance, and stain resistance and having sufficient durability, as an aqueous two-liquid type coating composition for heat insulation to paint an elastic pavement such as a rubber chip urethane pavement; a painting method using the same; and a heat insulation pavement.SOLUTION: There is provided a heat insulation coating composition having aqueous two-liquid curability, and consisting of: a main agent containing hydroxyl group-containing acryl emulsion polyol, hydroxyl group-containing polyurethane dispersion polyol and hydroxyl group-containing acryl dispersion polyol, as a coated film formation binder component dispersed in an aqueous medium, and at least hollow particles as a filler for heat insulation; and a reactive film formation assistant generating a crosslinking reaction with the coated film formation binder component of the main agent so as to cure a coated film, and consisting of a polymer.SELECTED DRAWING: Figure 2

Description

  The present invention is a top coat for road pavements by various elastic pavements such as rubber pavement typified by rubber chip urethane pavement on outdoor poolside, park, kindergarten, nursery school playground equipment facilities, road surface such as jogging course, etc. TECHNICAL FIELD The present invention relates to a heat-shielding coating composition for a water-based protective finish coating applied as a coating material, and particularly to an aqueous two-component room-temperature crosslinking type heat-shielding coating composition, a coating method using the same, and a heat-shielding pavement. .

  In general, rubber chip urethane pave consisting of rubber chip aggregate and urethane binder is often constructed as an elastic pavement on the outdoor pool side, around playground facilities, kindergarten, jogging course, etc. Usually, black rubber chips or colored rubber chips made by crushing waste rubber or the like are used. However, when a black rubber chip or a colored rubber chip is used as it is, a portion that receives direct sunlight in summer becomes extremely hot and often cannot be walked with bare feet. Therefore, it is important to take measures to improve the heat shielding property for rubber chip urethane pavement.

  The heat insulation property of the rubber chip itself is slightly improved by coloring, but it is difficult to reduce the temperature to such an extent that it can be walked, and the colored rubber chip has poor weather resistance, and the choking phenomenon (a phenomenon of whitish discoloration) in about 3 months. There is also a problem that causes.

  Therefore, it is considered effective to improve the heat shielding property by coating the surface of the rubber chip urethane pavement with a heat shielding material.

Conventionally, solvent-based acrylic urethane-based paints are mainly used as heat-shielding improvement technology by general coating, but this type of conventional solvent-based acrylic-urethane-based paints has the effect of reducing the initial temperature. Although there is a problem, the heat shielding effect is limited to a specific hue, there are problems such as poor stain resistance and poor durability of the heat shielding effect, and further, the coating film peels off and the appearance changes over time There is also a problem in durability because it tends to occur. These problems are considered to be caused by an adverse effect (invasion) on the rubber chip by the organic solvent and insufficient adhesion to the rubber chip. Therefore, there have been some problems in using a solvent-based acrylic urethane-based paint as a paint for improving heat-shielding properties against rubber chip urethane pavement.
In particular, the rubber chip is a material that is difficult to adhere to the coating film, and it is difficult to ensure sufficient adhesion of the coating film with a general paint such as a solvent-based acrylic urethane paint.

  Moreover, since the corner | angular part of a small lump-like rubber chip is generally exposed on the surface of urethane rubber chip pavement, rough unevenness exists. Therefore, when coated with a general paint, the paint flows at the uneven edges of the rubber chip urethane pavement surface of the paint base during painting, so that the so-called edge cover is not sufficient and a transparent part of the paint occurs. There are also problems that the uniformity of the coating film is lacking and a stable heat shielding effect cannot be obtained.

  As mentioned above, conventionally, there are few satisfactory paints for improving the heat shielding properties for rubber chip urethane pavement, and particularly, there is no long-term sustainable paint that has excellent heat shielding properties and at the same time excellent durability. Is the actual situation.

By the way, although not used as a paint to improve the heat-shielding properties of rubber chip urethane pavement, acrylic copolymer water dispersion has been conventionally used as an aqueous paint for room temperature drying that is advantageous in terms of environment and safety. Liquid is being used.
Water-based paints composed of this type of acrylic copolymer aqueous dispersion require fusion of emulsion particles in a film forming process at room temperature after coating. Therefore, it is difficult to increase the glass transition temperature (Tg) of the resin in the acrylic copolymer used for the two-component room temperature drying water-based coating because of its film-forming property, and therefore the stain resistance is low. In addition, since the water resistance is fragile, it is not suitable for the painting of rubber chip urethane pavement.

  On the other hand, the market is becoming more and more expensive year by year, and water-based paints are required to have durability, toughness and stain resistance comparable to organic solvent-type urethane paints. Recently, water-based coatings have been required from the viewpoints of environmental sanitation and firefighting law, etc., and it is strongly desired to develop room-temperature drying-type water-based paints having the same coating performance as organic solvent-type urethane paints. It is supposed to be.

As a conventional paint for meeting the above-mentioned demands, a two-part solvent-based paint of an acrylic polyol containing a hydroxyl group and a polyisocyanate has been developed. In this kind of paint, the resin particles can be fused together. In addition, the weathering, water resistance, and the like are improved by causing a urethane reaction that is a crosslinking reaction.
However, when such a solvent-based two-component cross-linking type paint is applied to a rubber chip urethane pavement, there is a problem in adhesion to the rubber chip urethane pavement, which is a coating base, and there is a defect that lacks durability. Further, in this case, a finish suitable for the complicated surface shape of the rubber chip urethane pavement, which is the coating base, cannot be obtained, resulting in poor appearance.

  On the other hand, as an aqueous two-component coating material, recently, a coating material in which an aqueous polyol such as an emulsion is mixed with a water-dispersed isocyanate to undergo a crosslinking reaction to form a coating film has been used. However, when this type of conventional aqueous two-component paint is applied to rubber chip urethane pavement, the finished appearance such as edge cover for the complicated surface shape of rubber chip urethane pavement, which is the coating base, or shielding due to insufficient edge cover. In terms of effects on physical properties such as thermal performance, gloss, weather resistance, outdoor exposure contamination, etc., it must be said that it is inferior to solvent-based two-component paints, and satisfactory quality is obtained. The fact was not.

Japanese Patent Laid-Open No. 2-105879 Japanese Patent Laid-Open No. 1-301761

  Since paved roads such as outdoor poolsides, parks, kindergartens, nursery school playground facilities, and jogging courses frequently come and go, it is difficult to apply drastic improvements to improve heat insulation. Therefore, in addition to changing the material and color of pavement materials such as rubber chip aggregates, it has also been applied conventionally to apply a protective finish with heat insulation, but it has a sufficient effect of improving heat insulation. In fact, no thermal barrier coating composition having excellent durability was found.

  The present invention has been made in the background as described above, and is basically an aqueous two-component type that is coated to improve heat insulation as a top coat material for elastic pavements such as rubber chip urethane pavements. As a coating composition, the coating composition exhibits sufficient heat shielding properties to reliably suppress an increase in road surface temperature, and is excellent in weather resistance, water resistance and stain resistance, and has sufficient durability. It is an object of the present invention to provide a thermal barrier coating composition capable of forming a film, a thermal barrier paint coating method using the same, and a thermal barrier pavement.

  In order to solve the above-mentioned problems, the present inventors have conducted extensive experiments and examinations. As a result, the top coat material for improving the heat shielding property of the road surface of elastic pavement such as rubber chip urethane pavement is not a solvent system. The coating film-forming binder component dispersed in the aqueous medium in the main component of the aqueous two-component coating composition contains a hydroxyl group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, and a hydroxyl group-containing acrylic dispersion polyol. And a composition comprising a reactive film-forming aid made of a polymer, which contains at least hollow particles as a heat-shielding filler, and further causes a crosslinking reaction with the base film-forming binder component to cure the coating film. It has been found that it is effective, and has led to the present invention.

Therefore, the thermal barrier coating composition according to the basic aspect of the present invention (first aspect) is:
As a coating film forming binder component dispersed in an aqueous medium, an acid group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, and a hydroxyl group-containing acrylic dispersion polyol, and at least hollow particles as a heat shielding filler Containing the main agent;
A reactive film-forming aid made of a polymer, which causes a crosslinking reaction with the coating-forming binder component of the main agent to cure the coating;
It is characterized by comprising.

The thermal barrier coating composition according to the second aspect of the present invention is the thermal barrier coating composition according to the first aspect,
The ratio of the hydroxyl group-containing acrylic emulsion polyol to the entire coating film forming binder component is in the range of 70 to 90% by weight, the ratio of the hydroxyl group-containing polyurethane dispersion polyol is in the range of 1 to 20% by weight, and the hydroxyl group-containing acrylic dispersion. It is characterized by having aqueous two-component curability, characterized in that the proportion of polyol is in the range of 5 to 25% by weight.

Furthermore, the thermal barrier coating composition according to the third aspect of the present invention is the thermal barrier coating composition according to any one of the first and second aspects,
The hydroxyl group-containing acrylic emulsion polyol has a hydroxyl value of 70 to 90 mgKOH / g and a glass transition temperature (Tg) in the range of 10 to 30 ° C.,
The hydroxyl group-containing polyurethane dispersion polyol has a hydroxyl value of 40 to 60 mg KOH / g and a glass transition temperature (Tg) of -30 to -10 ° C.
The hydroxyl group-containing acrylic dispersion polyol has a hydroxyl value of 40 to 60 mgKOH / g and a glass transition temperature (Tg) in the range of 10 to 30 ° C.

Moreover, the thermal barrier coating composition of the fourth aspect of the present invention is the thermal barrier coating composition of any one of the first to third aspects,
The average particle size of the hydroxyl group-containing acrylic emulsion polyol is 100 to 150 nm, the average particle size of the hydroxyl group-containing urethane dispersion polyol is 40 to 90 nm, and the average particle size of the hydroxyl group-containing acrylic dispersion polyol is 40 to 90 nm. It is a feature.

The thermal barrier coating composition according to the fifth aspect of the present invention is the thermal barrier coating composition according to any one of the first to fourth aspects,
In addition to the hollow particles, the heat shielding filler contains an inorganic heat-shielding colored pigment.

The heat-shielding coating composition of the sixth aspect of the present invention is the heat-shielding coating composition of the fifth aspect,
The inorganic heat-shielding colored pigment has an average particle diameter in the range of 0.5 to 2.0 μm.

Moreover, the thermal barrier coating composition of the seventh aspect of the present invention is the thermal barrier coating composition of any of the fifth and sixth aspects,
The inorganic heat-shielding colored pigment is one or more selected from titanium oxide, iron oxide, and inorganic composite oxide.

The thermal barrier coating composition according to the eighth aspect of the present invention is the thermal barrier coating composition according to any one of the first to seventh aspects,
The hollow particles are made of particles in which hydrocarbons are enclosed in an outer shell made of a polymer.

Moreover, the thermal barrier coating composition of the ninth aspect of the present invention is the thermal barrier coating composition of any one of the first to eighth aspects,
The hollow particles have an average particle diameter of 10 to 30 μm.

The thermal barrier coating composition of the tenth aspect of the present invention is the thermal barrier coating composition of any one of the first to ninth aspects,
The main agent further contains a viscosity control agent.

The heat-shielding coating composition of the eleventh aspect of the present invention is the heat-shielding coating composition of the tenth aspect,
As the viscosity control agent, styrene / methacrylic ester organic ultrafine particles having an average particle size of 50 to 1000 nm and sulfuric acid having an average particle size of 0.1 to 0.5 μm subjected to SiO ₂ —Al ₂ O ₃ surface treatment. Any one or more of barium is used.

The thermal barrier coating composition of the twelfth aspect of the present invention is the thermal barrier coating composition of any of the tenth and eleventh aspects,
The ratio of the viscosity control agent in the main agent is in the range of 2 to 5% by weight.

Moreover, the thermal barrier coating composition of the thirteenth aspect of the present invention is the thermal barrier coating composition of any one of the first to twelfth aspects,
The reactive film-forming aid is characterized by comprising polyisocyanate.

Moreover, the thermal barrier coating composition of the fourteenth aspect of the present invention is the thermal barrier coating composition of the thirteenth aspect,
The blending ratio of the reactive film-forming aid composed of polyisocyanate and the polyol of the coating film forming binder component in the main agent is the isocyanate group (—NCO) of the reactive film-forming aid and the hydroxyl group (—OH) of the main polyol. ) In the range of 0.8 to 1.1.

  Further, in the following fifteenth and sixteenth aspects, as a top coat coating method for a paving surface using the heat-shielding coating composition of each aspect, a heat-shielding paint coating using the heat-shielding coating composition of each aspect described above. The method of construction is prescribed.

That is, the thermal barrier paint coating method of the fifteenth aspect of the present invention is
The main agent and the reactive film-forming aid in the heat-shielding coating composition according to any one of the first to fourteenth aspects are kneaded with an aqueous medium to form an aqueous coating, and the aqueous coating is applied to the surface of the elastic pavement. It is characterized by this.

The heat-shielding paint coating method according to the sixteenth aspect of the present invention is the heat-shielding paint coating method according to the fifteenth aspect,
The elastic pavement is a urethane elastic pavement or an asphalt elastic pavement.

  Further, in the following seventeenth and eighteenth aspects, a heat-shielding pavement in which a top coat is applied to the pavement surface using the heat-shielding coating composition of each of the first to fourteenth aspects is defined. .

That is, the heat-shielding pavement according to the seventeenth aspect of the present invention is
A heat-shielding pavement in which a heat-shielding coating film is formed on the surface of the elastic pavement,
The thermal barrier pavement is
As a coating film forming binder component, a main component containing a hydroxyl group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, and a hydroxyl group-containing acrylic dispersion polyol, and containing at least hollow particles as a heat shielding filler,
It comprises a reactive film-forming aid made of a polymer, which causes a crosslinking reaction with the film-forming binder component of the main agent to cure the coating film,
Each of the polyols and the reactive film-forming aid are cross-linked.

The thermal barrier pavement according to the eighteenth aspect of the present invention is
In the heat-shielding pavement of the seventeenth aspect,
The elastic pavement is a urethane elastic pavement or an asphalt elastic pavement.

  In addition, as a heat-shielding coating film in the heat-shielding pavement according to the seventeenth or eighteenth aspect, the main agent or reactive film-forming aid of the heat-shielding coating composition as described in the first to fourteenth aspects. Of course, any of the agents may be used as it is.

  According to the heat-shielding coating composition of the present invention, it exhibits sufficient heat-shielding properties as an aqueous two-component coating composition that is applied to improve heat-shielding properties as a topcoat material for elastic pavements such as rubber chip urethane pavements. And a paint composition that can reliably suppress an increase in road surface temperature, and that is excellent in weather resistance, water resistance, and stain resistance, and can form a coating film having sufficient durability, Further, it is possible to provide a thermal barrier paint coating method using the same and a thermal barrier pavement.

It is an approximate solution sectional view showing typically an example of a heat-shielding pavement formed using a heat-shielding paint constituent of the present invention. It is a graph which shows the result of the temperature rise test by infrared irradiation about Example 1 and Comparative Example 2 of this invention. It is a graph which shows the result of the temperature rise test by infrared irradiation about Example 2, Example 3, Comparative Example 2, and Comparative Example 3 of this invention. It is a schematic diagram which shows the condition which is performing the said temperature rise test. 6 is a graph showing the spectral emissivity measurement results for Example 2. It is a graph which shows the spectral emissivity measurement result about the comparative example 2. 10 is a graph showing the spectral emissivity measurement results for Comparative Example 3. 10 is a graph showing the spectral emissivity measurement results for Example 3. It is a graph which shows the result of the temperature rise test by infrared irradiation about Examples 5 and 6 and Comparative Examples 6 and 7.

  Hereinafter, the thermal barrier coating composition of the embodiment of the present invention will be described in more detail.

  In the present invention, an aqueous two-component room temperature used as a top coat coating material for covering a pavement surface to add a heat shielding function to an elastic pavement such as rubber pavement and asphalt elastic pavement represented by rubber chip urethane pavement. It defines a crosslinkable thermal barrier coating composition. Here, the two-component crosslinking type heat-shielding coating composition according to the present invention comprises a main agent mainly composed of a coating film-forming binder component and a reactive film-forming aid (curing agent) which is a crosslinking agent.

  The main agent is, as a coating film forming binder component, three kinds of resins (polyols) each having a hydroxyl group, that is, (A) a hydroxyl group-containing acrylic emulsion polyol, (B) a hydroxyl group-containing polyurethane dispersion polyol, and (C) a hydroxyl group-containing In addition, an acrylic dispersion polyol is contained, and as the heat shielding filler, an inorganic heat-shielding colored pigment and hollow particles are contained, and a viscosity control agent (rheology control agent) is preferably contained.

  And to such a main agent, a reactive film-forming aid is mixed (kneaded) together with an aqueous medium such as water as a dispersion medium at the stage immediately before the coating work, and is coated on the rubber chip urethane pavement surface as an aqueous paint. Become.

In addition to the inorganic heat-shielding colored pigment as the heat-shielding filler, yellow iron oxide is used as a green-based colored pigment, for example, to exhibit a colored color tone such as a green-based color tone or a red-based color tone as necessary. Of course, a pigment such as red iron oxide may be blended as a red colored pigment.
In addition, as with general water-based paints, as needed, extender pigments, anti-settling agents, wetting and dispersing agents, viscosity control agents, thickeners, antifoaming agents, leveling agents, antiseptics, antifungal agents, etc. Of course, you may do.

  In FIG. 1, for example, a rubber chip urethane pavement layer 3 is formed by laying a large number of small rubber aggregates on the surface of a base 1 made of concrete or an asphalt mixture layer. A state in which a heat-shielding coating film 5 is formed by applying an aqueous two-component paint composed of the heat-shielding coating composition of the invention is schematically shown.

  The heat-shielding coating film 5 basically includes three types of resin particles (hydroxyl group-containing acrylic emulsion polyol particles, hydroxyl group-containing polyurethane dispersion polyol particles, and hydroxyl group-containing acrylic dispersion) which are the binder resin components of the main agent as described above. (Polyol particles) 51, two kinds of heat shielding fillers (inorganic heat-shielding colored pigment 52, hollow particles 53), a viscosity control agent 54, and a reactive film-forming auxiliary 55. In addition, in FIG. 1, although it has shown with the particle | grain shape isolate | separated typically about each element which comprises the heat-shielding coating film 5, in the state which the heat-shielding coating film 5 hardened | cured, actually the heat-shielding coating film 5 is shown. Of course, the elements constituting the are integrally coupled.

  Furthermore, the main ingredient component in the heat-insulating coating composition of the present invention will be described in detail.

As a coating film forming binder component in the main agent, a polyol resin having a hydroxyl group is used so that aqueous two-component room temperature crosslinking is possible. As the polyol resin particles, single emulsion particles or dispersion particles are used. Rather than using it, it is important to mix relatively small amounts of two types of dispersion particles with relatively small diameters and different particle characteristics into emulsion particles as the main component, and use a total of three types of polyol resins. It is. That is, in the main component of the heat-shielding coating composition of the present invention, the following three types of aqueous resin particles A to C are dispersed as a coating film-forming binder component in an aqueous medium.
A: Hydroxyl group-containing acrylic emulsion polyol B: Hydroxyl group-containing polyurethane dispersion polyol C: Hydroxyl group-containing acrylic dispersion polyol

  Here, the water-based resin has three forms of a water-soluble type, a dispersion type, and an emulsion type. The general characteristics of each form of resin are as follows.

Appearance of the resin: The water-soluble type is roughly classified into transparent, the dispersion type is roughly translucent to milky white, and the emulsion type is roughly classified into milky white.
Particle size: The water-soluble type is roughly classified into 10 nm or less, the dispersion type is roughly classified into 10 nm to 100 nm, and the emulsion type is classified into 50 nm to 500 nm.
-Molecular weight: The water-soluble type is roughly classified into small (10 ³ to 10 ⁴ ), the dispersion type is medium (10 ³ to 10 ⁶ ), and the emulsion type is large (10 ³ or more).
・ Viscosity: The water-soluble type has a high viscosity and correlates with the molecular weight, the dispersion type has a medium viscosity and has a slight correlation with the molecular weight, and the emulsion type has a low viscosity and does not correlate with the molecular weight.
-Fluidity: Water-soluble type is broadly classified into Newtonian flow, dispersion type is thixotropic, and emulsion type is thixotropic.
・ Film-forming property: Water-soluble type forms a dense coating close to solvent-based resin, Dispersion type has intermediate properties between water-soluble type and emulsion type, and emulsion type forms a coating by particle fusion to make it dense It is roughly divided into lacking.
Water resistance: The water-soluble type is roughly classified into poor or good, the dispersion type is good, and the emulsion type is very good.

  Therefore, the hydroxyl group-containing acrylic emulsion polyol (A) used as a coating film-forming binder component in the main component of the heat-shielding coating composition in the present invention is an emulsion-type aqueous resin and a hydroxyl group-containing polyurethane dispersion polyol (B) and The hydroxyl group-containing acrylic dispersion polyol (C) generally has the above characteristics as a dispersion-type aqueous resin. The above classification is merely conceptual and does not limit the characteristics of each resin used in the present invention.

  The reason why the three types of aqueous resin particles (A), (B) and (C) are blended as the coating film forming binder component is as follows.

  That is, the hydroxyl group-containing acrylic emulsion polyol (A) is known as an aqueous resin that can be cured in two liquids at room temperature. As a main component of the coating film-forming binder component, it imparts appropriate hardness to the coating film, and durability of the coating film. It is a resin necessary to ensure the properties and weather resistance. Therefore, in this embodiment as well, it is used as a main component occupying 70% by weight (90% by weight or less) of the coating film forming binder component. However, when only relatively large-diameter emulsion particles are used as the resin for the coating film forming binder, the gaps between the particles become large and the coating film lacks the denseness, so that sufficient water resistance and adhesion are obtained. In addition, the flexibility of the coating film is reduced and the coating film becomes brittle, and the coating film is liable to be peeled off or damaged. Furthermore, the hydroxyl group-containing acrylic emulsion polyol (A) alone is not sufficient in adhesion to the base (rubber chip urethane pavement).

  Therefore, in the present invention, in combination with the hydroxyl group-containing acrylic emulsion polyol (A), two types of dispersion particles having a relatively small diameter are blended to increase the denseness of the coating film, thereby improving flexibility and eventually durability. To improve water resistance.

  And as two types of dispersion particles, a hydroxyl group having a urethane skeleton different from the hydroxyl group-containing acrylic emulsion polyol (A), which is the main component of the coating film forming binder component, and having a relatively small diameter and different particle form and particle characteristics. Containing urethane dispersion polyol (B) and hydroxyl group-containing urethane dispersion polyol (B) having the same skeleton as the main component, hydroxyl group-containing acrylic emulsion polyol (A), but having a relatively small diameter and different particle form, A hydroxyl group-containing acrylic dispersion polyol (C) having a urethane skeleton different from that of the component hydroxyl group-containing acrylic emulsion polyol (A) and having a relatively small diameter and different particle form and particle characteristics is used. .

Here, the reason why two types of dispersion particles, that is, a hydroxyl group-containing urethane dispersion polyol (B) and a hydroxyl group-containing acrylic dispersion polyol (C) are used as the dispersion particles is as follows.
That is, when only the hydroxyl group-containing urethane dispersion polyol (B) is combined with the hydroxyl group-containing acrylic emulsion polyol (A), there is a problem that weather resistance, stain resistance, and adhesion are inferior. On the other hand, when only the hydroxyl group-containing acrylic dispersion polyol (C) is combined with the hydroxyl group-containing acrylic emulsion polyol (A), there is a problem that the thickness when the coating film is formed becomes non-uniform.
A uniform coating film is formed by combining two types of dispersion particles, a hydroxyl group-containing urethane dispersion polyol (B) and a hydroxyl group-containing acrylic dispersion polyol (C), with the hydroxyl group-containing acrylic emulsion polyol (A). In addition, it is possible to obtain a coating film excellent in weather resistance, stain resistance, and adhesion.

  Here, the hydroxyl group content occupying the entire coating film forming binder component (that is, the total amount of the hydroxyl group-containing acrylic emulsion polyol (A), the hydroxyl group-containing urethane dispersion polyol (B), and the hydroxyl group-containing acrylic dispersion polyol (C)). The blending ratio of the acrylic emulsion polyol (A) is in the range of 70 to 90% by weight, the blending ratio of the hydroxyl group-containing polyurethane dispersion polyol (B) is in the range of 1 to 20% by weight, and the hydroxyl group-containing acrylic dispersion polyol ( The blending ratio of C) is desirably in the range of 5 to 25% by weight.

  In addition, the average particle size of the resin particles of each coating film forming binder component is, in essence, the average particle size of the hydroxyl group-containing urethane dispersion polyol (B) and the hydroxyl group-containing acrylic rather than the average particle size of the hydroxyl group-containing acrylic emulsion polyol (A). The average particle size of the dispersion polyol (C) may be small, but as a specific particle size, the average particle size of the hydroxyl group-containing acrylic emulsion polyol (A) is preferably about 100 to 150 nm, and the hydroxyl group-containing urethane dispersion polyol. The average particle size of (B) is preferably about 40 to 90 nm, and the average particle size of the hydroxyl group-containing acrylic dispersion polyol (C) is preferably about 40 to 90 nm.

  Details of these binder resin components (A), (B), and (C) will be further described.

<Hydroxyl-containing acrylic emulsion polyol (A)>
Hydroxyl group-containing acrylic emulsion polyol is the main component of the coating film forming binder component in the aqueous two-component room temperature crosslinkable thermal barrier coating composition, and imparts hardness to the coating film as an aqueous resin curable at two temperatures Therefore, it is a resin necessary for ensuring weather resistance, water resistance and stain resistance. As this hydroxyl group-containing acrylic emulsion polyol (A), it is desirable to use one having a hydroxyl value of 70 to 90 mg KOH / g and a glass transition temperature (Tg) of 10 to 30 ° C. The mixing ratio of the hydroxyl group-containing acrylic emulsion polyol (A) in the whole is desirably 70 to 90% by weight.

  Here, when the hydroxyl value of the hydroxyl-containing acrylic emulsion polyol is less than 70 mgKOH / g, the weather resistance, water resistance and stain resistance are lowered, while when it exceeds 90 mgKOH / g, the brittleness is increased. Further, when the glass transition temperature (Tg) of the hydroxyl group-containing acrylic emulsion polyol used is less than 10 ° C., the weather resistance, water resistance and stain resistance are lowered, while when it exceeds 30 ° C., the brittleness is increased. Furthermore, when the blending ratio of the hydroxyl group-containing acrylic emulsion polyol in the entire coating film forming binder component is less than 70% by weight, the hardness of the coating film becomes insufficient, and the weather resistance, water resistance, and stain resistance are reduced. If the weight percentage is exceeded, brittleness increases.

<Hydroxyl-containing polyurethane dispersion polyol (B)>
A hydroxyl group-containing polyurethane dispersion polyol is a water-based resin that can be cured in two parts at room temperature, and by combining a relatively small amount with the hydroxyl group-containing acrylic emulsion polyol, which is the main component of the aforementioned film-forming binder, Utilizing the characteristics of having the same urethane skeleton as the rubber chip urethane pavement and dispersion particles, it ensures adhesion to the rubber chip urethane pavement, which is the base of the paint, and also gives the coating film flexibility. It is effective for improving the pigment dispersibility. The hydroxyl group-containing polyurethane dispersion polyol used here is preferably one having a hydroxyl value of 40 to 60 mg KOH / g and a glass transition temperature (Tg) in the range of -30 to -10 ° C. The blending ratio in the entire film-forming binder component is preferably in the range of 1 to 20% by weight.

  When the hydroxyl value of the hydroxyl group-containing polyurethane dispersion polyol to be used is less than 40 mgKOH / g, the weather resistance, water resistance and stain resistance are lowered. On the other hand, when it exceeds 60 mgKOH / g, the brittleness is increased. Further, when the glass transition temperature (Tg) of the hydroxyl group-containing polyurethane dispersion polyol used is less than −30 ° C., the weather resistance, water resistance and stain resistance are lowered, while when it exceeds −10 ° C., the brittleness is increased. Furthermore, if the blending ratio of the hydroxyl group-containing acrylic emulsion polyol in the entire coating film forming binder component is less than 1% by weight, the adhesion and flexibility of the coating film are reduced, and if it exceeds 20% by weight, the weather resistance, water resistance, Contamination is reduced.

<Hydroxyl-containing acrylic dispersion polyol (C)>
A hydroxyl group-containing acrylic dispersion polyol is a two-component curable aqueous resin at room temperature, and is combined with a hydroxyl group-containing acrylic emulsion polyol, which is the main component of the above-mentioned coating film-forming binder, in a relatively small amount. Utilizing the properties of John's particles, it mainly improves the adhesion, water resistance, and pigment dispersibility of the coating film. As this hydroxyl group-containing acrylic dispersion polyol, it is desirable to use one having a hydroxyl value of 40 to 60 mg KOH / g and a glass transition temperature (Tg) of 10 to 30 ° C. The blending ratio is desirably 5 to 25% by weight.

  When the hydroxyl value of the hydroxyl group-containing acrylic dispersion polyol to be used is less than 40 mgKOH / g, the weather resistance, water resistance and stain resistance are lowered. On the other hand, when it exceeds 60 mgKOH / g, the brittleness is increased. Further, when the glass transition temperature (Tg) of the hydroxyl group-containing acrylic dispersion polyol used is less than 10 ° C., the weather resistance, water resistance and stain resistance are lowered, while when it exceeds 30 ° C., the brittleness is increased. Furthermore, if the blending ratio of the hydroxyl group-containing acrylic dispersion polyol in the whole coating film forming binder component is less than 5% by weight, the adhesion and flexibility of the coating film are reduced, and if it exceeds 25% by weight, the weather resistance, water resistance, Reduces contamination resistance.

  Furthermore, the heat-shielding coating composition of the embodiment of the present invention includes an inorganic heat-shielding colored pigment and hollow particles as a heat-shielding filler in addition to the coating film-forming binder components (A), (B) and (C). In addition, it is desirable to contain a viscosity control agent (rheology control agent). In this case, about each compounding ratio in a coating composition (ratio with respect to the whole composition in the state which is not disperse | distributed in an aqueous medium), a coating-film formation binder component (said (A), (B), (C ) Is 40 to 50% by weight, and the heat shielding filler is 19 to 40% by weight (however, among the heat shielding fillers, the inorganic heat-shielding colored pigment is 20 to 30% by weight based on the entire composition, hollow particles Is preferably 1 to 10% by weight based on the whole composition), and the viscosity control agent (rheology control agent is preferably 2 to 5% by weight).

  Next, each component other than the above binder resin component in the main agent will be described.

<Inorganic heat-shielding colored pigment as heat-insulating filler>
In the present embodiment, two kinds of heat shielding fillers are blended, that is, inorganic heat shielding colored pigments and hollow particles. Among them, as the inorganic heat shielding colored pigments, titanium oxide having excellent heat shielding properties is blended. In addition to titanium oxide, iron oxide (eg, red iron oxide, yellow iron oxide, etc.) that exhibits heat shielding properties depending on the hue, and other inorganic composite oxide pigments can also be used. As an inorganic heat-shielding colored pigment typified by titanium oxide, the particle diameter is larger than that of a general titanium oxide powder (average of about 0.2 μm), and the effect of reflecting near infrared rays in sunlight is effective. It is preferable to use an inorganic heat-shielding colored pigment having a large large particle diameter inorganic heat-shielding colored pigment, for example, a large particle diameter titanium oxide having an average particle diameter of 0.5 to 2.0 μm. If the average particle size of the inorganic heat-shielding colored pigment such as titanium oxide is less than 0.5 μm, the effect of reflecting the near infrared rays to enhance the heat-shielding property cannot be sufficiently obtained, while if it exceeds 2.0 μm, the weather resistance, Water resistance decreases.

  If the blending amount of the inorganic heat-shielding colored pigment is less than 15% by weight, the effect of improving the heat-shielding property by the inorganic heat-shielding colored pigment is not sufficiently exerted. On the other hand, if it exceeds 25% by weight, weather resistance and water resistance Therefore, the blending ratio of the inorganic heat-shielding colored pigment is preferably in the range of 15 to 25% by weight.

<Hollow particles as heat shielding filler>
As the hollow particles to be blended as the heat shielding filler, it is preferable to use hollow particles having an average particle diameter of 10 to 30 μm in which a hydrocarbon such as isobutane is enclosed in a hollow outer shell made of a polymer. If such hollow particles are blended, the structure in which the hollow particles agglomerated in the coating film are concentrated, the effect of reflecting near-infrared rays is obtained, and the heat insulating effect due to the hollow portion of the particles is also exhibited. In combination, the heat shielding properties of the coating film can be improved. If the average particle size of the hollow particles is less than 10 μm, the hollow particles are likely to aggregate. As a result, the uniform dispersibility of the hollow particles is impaired, resulting in poor appearance. On the other hand, if the particle diameter exceeds 30 μm, the aggregation force of the hollow particles is small. In addition, there is a possibility that the hollow particles are not densely packed in the coating film and a sufficient heat shielding effect cannot be obtained.

  As the outer shell polymer component of the hollow particles, for example, a copolymer of polyvinylidene chloride and acrylonitrile can be used, and the outer shell has a thickness of 0.05 to 0.2 μm (typically about 0.1 μm). Is preferred.

  When the blending amount of the hollow particles is less than 1% by weight, the heat shielding property due to the addition of the hollow particles is not sufficiently exhibited. On the other hand, when the amount exceeds 10% by weight, the hollow particles are formed into a coating film forming binder. In this case, it is difficult to disperse stably and uniformly, resulting in an adverse effect on coating workability and difficulty in coating. Even within this range, the range of 2 to 4% by weight is particularly preferable.

  Furthermore, if the total amount of the heat insulating filler composed of the inorganic heat insulating colored pigment and the hollow particles is less than 14% by weight, the heat insulating property of the coating film is not sufficient, and the coating film rises to a high temperature by irradiation with sunlight. On the other hand, if it exceeds 35% by weight, the weather resistance, water resistance, and adhesion that the binder resin should exhibit cannot be sufficiently obtained. It is desirable to be within the range of ˜35% by weight.

<Viscosity control agent (rheology control agent)
In the present invention, in the rubber chip urethane pavement mainly to be painted, a large number of protrusions due to the corners of a large number of small rubber chip aggregates are exposed on the surface. Therefore, when water-based paint is applied as a top coat on the rubber chip urethane pavement surface, there is a concern that the paint may flow down at the tip (edge part) of the protrusion. Even when forming a coating film on the underlying rubber chip urethane pavement with a heat-shielding water-based paint that cures by a two-component crosslinking reaction at room temperature, the surface of the rubber chip urethane pavement before the paint is cured by the crosslinking reaction. The water-based paint on the protrusions of the film flows down, and the tips of the protrusions are not covered with the heat-shielding coating film, or the heat-shielding coating film becomes extremely thin, and the heat-shielding effect by the coating film is not fully exhibited. Is concerned.

  Therefore, in this embodiment, the surface tension of the paint at room temperature is such that a viscosity control agent (rheology control agent) is blended with the aqueous paint composition and the tip of the protrusion on the rubber chip urethane pavement surface can be covered during painting. It is desirable to control (generally increase the viscosity at room temperature).

Specific examples of the viscosity control agent include styrene / methacrylic acid ester type (particle size: 50 to 1000 nm) organic ultrafine particles and barium sulfate (particle size: 0.1 to 0.1 nm) subjected to SiO ₂ —Al ₂ O ₃ surface treatment. It is preferable to use one or both of 0.5 μm).
When an aqueous coating composition containing such a viscosity control agent is applied to a rubber chip urethane pavement surface, organic ultrafine particles or barium sulfate particles aggregate with each other, resulting in a large surface tension of the aqueous coating composition. Thus, the tip of the protrusion is also sufficiently covered (covered) with the paint, and a coating film is formed on the tip of the protrusion with a sufficient thickness, so that the heat shielding effect can be surely exhibited. That is, a so-called edge covering effect can be obtained.

  When blending a viscosity control agent (rheology control agent), if the ratio of the viscosity control agent in the main agent is less than 2% by weight, the edge covering effect due to the increase in surface tension cannot be sufficiently obtained, while 5% by weight. If it exceeds 50%, the thixotropy is increased and the adverse effect on the coating workability is increased. Therefore, the ratio of the viscosity control agent is preferably in the range of 2 to 5% by weight.

  The main component in the heat-shielding coating composition of the present invention is dispersed in an aqueous medium such as water, and a reactive film-forming aid is added and mixed immediately before coating on the rubber chip urethane pavement surface as a base.

  The reactive film-forming aid is for enabling two-component curing with the resin particles of the binder component in the main agent dispersed in an aqueous medium as an aqueous paint. As this type of film-forming auxiliary, a high-boiling solvent that assists in the film formation of water-based paint emulsion particles has been generally used. However, when a high-boiling solvent is used, the solvent component is contained in the coating film. In many cases, there are harmful effects. For example, an unnecessary resin film is formed between the underlying rubber chip urethane pavement and the coating film, and the bonding force is lost, or the solvent component remains in the coating film, resulting in cohesive failure of the coating film.

  Therefore, as a reactive film-forming aid in the present invention, the substance itself is also a polymer, and reacts with a binder component, a hydroxyl group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, a hydroxyl group-containing acrylic dispersion polyol, A substance that can be cured (crosslinked) is used. Specifically, a polyisocyanate resin containing an isocyanate group (—NCO) that causes a urethane crosslinking reaction with the hydroxyl group (—OH) of each polyol is used as a reactive auxiliary agent. As a specific polyisocyanate-based resin, it is preferable to use an elastic type resin having a water-dispersible allophanate structure (R is an alkyl group having 1 to 4 carbon atoms) and an isocyanurate ring.

And just before painting on the rubber chip urethane pavement surface as a water-based paint, if the polyisocyanate is added and mixed as a reactive film-forming aid to the main agent, and immediately applied, the isocyanate group (-NCO) is the main agent in the coating film. A urethane bond is generated by cross-linking with the hydroxyl group (—OH) of each polyol of the binder component, and each polyol resin particle is bonded through the reactive film-forming aid, and the coating film is cured (film-forming). Will be.
Since such a polyisocyanate itself is a polymer, an unnecessary resin film is formed between the underlying rubber chip urethane pavement and the coating film, resulting in a loss of bonding force or a solvent component in the coating film. It does not remain and does not cause cohesive failure of the coating film, and is less likely to adversely affect water resistance or the like when the film is formed.

  The molar ratio of the isocyanate group (—NCO) of the polyisocyanate that is a reactive film-forming aid to the hydroxyl group (—OH) of each polyol that is the binder component of the main component is preferably 0.8 to 1.1, and this molar ratio. If it is less than 0.8, the proportion of uncrosslinked polyol increases, and the adhesion and flexibility decrease, and if the molar ratio exceeds 1.1, the weather resistance, water resistance and stain resistance decrease.

  In addition to the inorganic heat-shielding colored pigment as the aforementioned heat-shielding filler, the pigment may be a green-based colored pigment or a red-based colored pigment to exhibit a colored color tone such as a green color tone or a red color tone. The blending ratio of these pigments in the case of adding, for example, is not particularly limited, but is usually 5 to 10% by weight as the blending ratio with respect to the main agent.

  An example of the construction method of the heat-shielding pavement using the coating composition of this invention is as follows. However, the construction method described below is merely an example until it gets tired, and it is needless to say that the construction method is not limited to the following method.

First, the paint composition of the present invention is removed from dirt, sand, oil, etc. adhering to the pavement surface (road surface) of the elastic pavement to be constructed, such as a rubber chip urethane pavement, and cured with a masking tape as necessary. .
Next, the main component of the coating composition of the present invention and the reactive auxiliary agent are prepared in a predetermined weight ratio, water is added as an aqueous medium, and the mixture is sufficiently stirred using a mixing means such as a hand mixer. Use paint. In addition, you may add about 0.1 to 10 weight% (typically 3 weight%) of anti-skid aggregates, such as rubber powder, with respect to the weight of a coating composition as needed.

Then, using a spray gun such as an airless coating apparatus, the first spraying operation of spraying this water-based paint onto the rubber chip urethane pavement surface is performed. Although spraying of the aqueous coating composition is not particularly limited in this case, in the adhesion amount of the coating composition, 0.2~0.5kg / ^{m 2} about, for example, may be set to 0.3 kg / ^{m 2} approximately. Spraying of the aqueous paint spraying unevenness occurs too small is less than 0.2 kg / ^{m 2,} which is uneconomical and too many if it exceeds 0.5 kg / ^{m 2.} After confirming that the sprayed water-based paint has dried, the second spraying operation is performed in the same manner as the first. In place of the spraying operation, painting may be performed using a free broom, a rubber rake, a roller brush or the like.
Then, after removing the masking tape and confirming that the sprayed water-based paint is sufficiently dried (cured), the traffic may be opened. The drying time is usually about 15 minutes to 2 hours at room temperature.

  Examples of the elastic pavement suitable for the heat-shielding pavement of the present invention include urethane-based elastic pavement and asphalt-based elastic pavement in which rubber particles and cork particles are blended, but it is most preferable to use urethane-based elastic pavement.

In addition, the heat-shielding pavement of the present invention is constructed by applying the heat-shielding coating composition of the present invention to the surface of a new or existing elastic pavement. This pavement is poolside, around playground equipment, kindergarten and nursery school grounds, school playgrounds, elderly facilities, disabled facilities, hospitals and other welfare facilities, sidewalks, parks, multipurpose plazas, jogging courses and other outdoor facilities. Applicable to.
And by applying the heat-shielding pavement of this invention to the said outdoor facility, the heat storage of a pavement can be prevented and the temperature rise of a road surface can be suppressed. In addition, the thermal environment of pedestrians is improved, which is effective as a summer heat stroke countermeasure. Furthermore, since it is a water-based paint, there are few adverse effects on people and the environment, and there is almost no odor during construction.

  Examples of the present invention will be described below together with comparative examples. The following examples are for explaining the effects of the present invention, and it goes without saying that the configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

[Example 1]
As a coating film forming binder component, a hydroxyl group value of 80 mg KOH / g, a glass transition temperature (Tg) of 18 ° C., a hydroxyl group-containing acrylic emulsion polyol resin particle having an average particle size of 140 nm, a hydroxyl value of 50 mg KOH / g, and a glass transition temperature Resin particles of a hydroxyl group-containing polyurethane dispersion polyol having a (Tg) of −20 ° C. and an average particle size of 60 nm, a hydroxyl group having a hydroxyl value of 50 mgKOH / g, a glass transition temperature (Tg) of 23 ° C., and an average particle size of 70 nm. Using resin particles of the containing acrylic dispersion polyol, these were blended as follows to obtain a coating film forming binder component. In addition, each compounding quantity (weight%) is a ratio with respect to a total coating-film formation binder component.
・ Hydroxyl group-containing acrylic emulsion polyol: 70% by weight
・ Hydroxyl-containing polyurethane dispersion polyol: 10% by weight
・ Hydroxyl group-containing acrylic dispersion polyol: 20% by weight

Furthermore, as the inorganic heat-shielding colored pigment of the heat-shielding filler, titanium oxide having a large particle diameter of 1 μm in average particle diameter is used. SiO ₂ —Al ₂ O ₃ surface having a particle diameter of 0.3 μm as a viscosity control agent using particles having an average particle diameter of 20 μm in which isobutane is encapsulated (average thickness of the outer shell is 0.1 μm) Using the treated barium sulfate, these were blended as follows to obtain the main agent.
Coating film forming binder component (hydroxyl group-containing acrylic emulsion polyol + hydroxyl group-containing polyurethane dispersion polyol + hydroxyl group-containing acrylic dispersion polyol): 73.0% by weight
-Large particle size titanium oxide: 15.0% by weight
・ Hollow particles: 2.5% by weight
・ Viscosity control agent: 5.0% by weight
In this example, in addition to the above-mentioned components, the main component was added with 3.5% by weight of yellow iron oxide, which is a green pigment, in order to make the color of the coating film green.

The main ingredient blended as described above was dispersed and mixed in water at a ratio of 3 parts by weight of water to 100 parts by weight of the main ingredient. Further, as a reactive film-forming aid, an elastic type polyisocyanate having a water-dispersible allophanate structure (R is an alkyl group having 1 to 4 carbon atoms) and an isocyanurate ring is added to 100 parts by weight of a polyisocyanate. An aqueous paint was prepared by adding and mixing at a ratio of 10 parts by weight. In this case, the molar ratio of the isocyanate group (—NCO) in the polyisocyanate which is a film forming aid to the hydroxyl group (—OH) in the binder component of the main component is 0.9. After adding and mixing the polyisocyanate as a film-forming aid to the main agent as described above, it was immediately spray-coated on one side of a black urethane rubber sheet having a thickness of 8 mm according to a conventional method. The coating amount was 300 g / m ² (average film thickness is about 180 μm). The black urethane rubber sheet is obtained by mixing a black urethane rubber chip having a particle diameter of about 1 to 2 mm with a urethane resin, and placing it in a mold and flattening it with a plastering iron to harden it into a sheet shape. .
After coating, it was allowed to stand at room temperature for 72 hours and then subjected to a temperature rise test described later.

[Comparative Example 1]
A water-based paint was prepared in substantially the same manner as in Example 1 except that the hollow particles were not blended in the main agent, and was coated on a black urethane rubber sheet similar to the above. After coating, it was left at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation described later.

[Temperature increase test by infrared irradiation for Example 1 and Comparative Example 1]
The black urethane rubber sheet of Example 1 coated as described above and the black urethane rubber sheet of Comparative Example 1 were subjected to a temperature rise test by infrared irradiation. Specifically, as shown in FIG. 4, the surface of the coating film 5 covered with the black urethane rubber sheet 6 is held so as to be vertical, and a 200 W incandescent infrared lamp 7 is formed from the surface side of the coating film 5. Was irradiated with infrared rays in one direction toward the coating film surface, and the temperature change of the surface (coating film surface) 5A and the back surface (urethane rubber sheet back surface) 6A was examined with a contact thermometer.
The results are shown in Table 1 and FIG. In FIG. 2, the symbol A indicates the test result of Example 1, and the symbol B indicates the test result of Comparative Example 1.

  As is apparent from Table 1 and FIG. 2, in the case of Comparative Example 1 in which no hollow particles were blended, the surface temperature (temperature of the coated surface) after 30 minutes from the start of infrared irradiation was 59 ° C. On the other hand, in the case of Example 1 in which the hollow particles were blended, it rose only to 50 ° C. at the same time point, and it was recognized that there was a temperature reduction effect of 9 ° C. Therefore, it turns out that the temperature rise inhibitory effect of the black urethane rubber sheet by the mixing | blending of a hollow particle is large.

[Example 2]
As a coating film forming binder component, a hydroxyl group value of 80 mg KOH / g, a glass transition temperature (Tg) of 18 ° C., a hydroxyl group-containing acrylic emulsion polyol resin particle having an average particle size of 140 nm, a hydroxyl value of 50 mg KOH / g, and a glass transition temperature Resin particles of a hydroxyl group-containing polyurethane dispersion polyol having a (Tg) of −20 ° C. and an average particle size of 60 nm, a hydroxyl group having a hydroxyl value of 50 mgKOH / g, a glass transition temperature (Tg) of 23 ° C., and an average particle size of 70 nm. Using resin particles of the containing acrylic dispersion polyol, these were blended as follows to obtain a coating film forming binder component. In addition, each compounding quantity (weight%) is a ratio with respect to a total coating-film formation binder component.
・ Hydroxyl group-containing acrylic emulsion polyol: 70% by weight
・ Hydroxyl-containing polyurethane dispersion polyol: 10% by weight
・ Hydroxyl group-containing acrylic dispersion polyol: 20% by weight

Furthermore, as the inorganic heat-shielding colored pigment of the heat-shielding filler, titanium oxide having a large particle diameter of 1 μm in average particle diameter is used. SiO ₂ —Al ₂ O ₃ surface having a particle diameter of 0.3 μm as a viscosity control agent using particles having an average particle diameter of 20 μm in which isobutane is encapsulated (with an average thickness of the outer shell of 0.1 μm) Using the treated barium sulfate, these were blended as follows to obtain the main agent.
Coating film forming binder component (hydroxyl group-containing acrylic emulsion polyol + hydroxyl group-containing polyurethane dispersion polyol + hydroxyl group-containing acrylic dispersion polyol): 73.0% by weight
-Large particle size titanium oxide: 15.0% by weight
・ Hollow particles: 2.5% by weight
・ Viscosity control agent: 5.0% by weight
In this example, in addition to the above-described components, 7.5% by weight of red iron oxide, which is a red pigment, was added to the main agent so that the color of the coating film was red.

The main ingredient blended as described above was dispersed and mixed in water at a ratio of 3 parts by weight of water to 100 parts by weight of the main ingredient. Furthermore, as a reactive film-forming auxiliary, the same polyisocyanate as that used in Example 1 was added and mixed at a ratio of 10 parts by weight of polyisocyanate to 100 parts by weight of the main agent to obtain an aqueous paint. In this case, the molar ratio of the isocyanate group (—NCO) in the polyisocyanate which is a film forming aid to the hydroxyl group (—OH) in the binder component of the main component is 0.9. After the polyisocyanate as a film-forming auxiliary was added and mixed with the main agent as described above, it was immediately spray-coated on one side of the same black urethane rubber sheet having a thickness of 8 mm according to a conventional method. The coating amount was 300 g / m ² (average film thickness is about 180 μm).
After coating, it was left at room temperature for 72 hours, and then subjected to the same temperature increase test as described above.

[Comparative Example 2]
A water-based paint was prepared substantially in the same manner as in Example 2 except that the hollow particles were not blended with the main agent, and was coated on a black urethane rubber sheet material. After coating, it was allowed to stand at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation as described above.

[Comparative Example 3]
Instead of the hollow particles in Example 2, non-hollow zirconia particles having a particle diameter of 15 μm were used, and other than that, an aqueous paint was prepared substantially in the same manner as in Example 1 and applied to a black urethane rubber sheet. . After coating, it was allowed to stand at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation as described above.

[Example 3]
In place of the isobutane-encapsulated hollow particles having an average particle diameter of 20 μm in Example 2, the isobutane-encapsulated hollow particles having a relatively large particle diameter (average particle diameter of 40 μm, outer shell wall thickness of 0.1 μm) were used. Specifically, a water-based paint was prepared in the same manner as in Example 2 and applied to a black urethane rubber sheet material. After coating, it was allowed to stand at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation as described above.

[Results of temperature increase test by infrared irradiation for Examples 2 and 3 and Comparative Examples 1 to 3]
Table 2 and FIG. 3 show the temperature increase test by infrared irradiation for Examples 2 and 3 and Comparative Examples 1 to 3 in which the color tone is common in the red system as described above. In FIG. 3, symbol C indicates the test result of Example 2, D indicates the test result of Comparative Example 2, E indicates the test result of Comparative Example 3, and symbol F indicates the test result of Example 3.

  From the test results of Table 2 and FIG. 3, in Comparative Example 2 in which the hollow particles encapsulating isobutane as a heat shielding filler are not blended, and in Comparative Example 3 in which the hollow zirconia particles having a particle diameter of 15 μm are blended, infrared irradiation starts After 30 minutes, the surface temperature reached 50 ° C., but in Example 2 in which hollow particles with a particle size of 20 μm in which isobutane was encapsulated as a heat shielding filler were blended, the surface temperature reached 46 ° C. 30 minutes after the start of infrared irradiation. It can be seen that the heat shielding effect by the hollow particle blending is large. In addition, although it is a hollow particle encapsulating isobutane, in Example 3 in which hollow particles having a particle size larger than that of Example 2 (particle size of 40 μm) were blended, the temperature increase due to infrared irradiation was higher than in Comparative Example 2 and Comparative Example 3. Although small, it was confirmed that the temperature rise was slightly larger than that of Example 2 having a small particle size. From this result, it is understood that the hollow particles preferably have a relatively small particle size (for example, 10 to 30 μm).

(Reflectance measurement)
A coating amount of 300 g / m ² was applied to each aluminum test piece of the water-based paint composed of each paint composition (main agent + reactive film-forming aid) used in Example 2, Comparative Example 2, Comparative Example 3, and Example 3. (Coating thickness: about 180 μm) The coating film reflectance (sunlight reflectance) and color tone were examined as follows.

That is, for each test piece, the solar reflectance was determined in accordance with “How to determine the solar reflectance of a coating film 7 Measurement of spectral reflectance” and “8 How to determine the solar reflectance” defined in JIS K 5602: 2008. Asked. In addition, in accordance with JIS Z 8722: 2009 “Color measurement method-Reflection and transmission object color 5.3 Measurement method of reflection object 5.3.1 Geometric conditions d [symbol 8 ° (de)] of irradiation and reception” The tristimulus value of the test surface is measured, and D65 according to “Colorimetry—Part 4: CIE1976L * a * b * Color Space 4 Calculation Method 4.1 Basic Coordinates” defined in JIS Z 8781-4: 2013. L * a * b * at the light source was calculated.
The test results are shown in Table 3, and the spectral reflectance is shown in FIGS.

  As shown in Table 3 and FIGS. 5 to 8, Example 2 and Example 3 have a higher reflectance in the near-infrared region than Comparative Example 2 and Comparative Example 3, and in particular, Example 2 is near. It was found to show a high reflectance in the infrared region. From this result, it is clear that the amount of heat applied to the coating film can be suppressed under sunlight by using the coating composition of the present invention.

[Emissivity measurement]
A coating amount of 300 g / m ² was applied to each aluminum test piece of the water-based paint composed of each paint composition (main agent + reactive film-forming aid) used in Example 2, Comparative Example 2, Comparative Example 3, and Example 3. (Coating thickness of about 180 μm), and the thermal emissivity (corrected emissivity) of the coating was examined as follows.

For each test piece, the vertical emissivity is determined in accordance with JIS R 3106: 1998 “Testing method for transmittance, emissivity, and solar heat gain of plate glass 7. Calculation of emissivity of thermal radiation at normal temperature”. In addition, the modified radiation according to “Calculation method of thermal resistance of flat glass and thermal dry distillation rate in buildings 5. Numerical value used in calculation formula 5.2 Emissivity value a)” defined in JIS R 3107: 1998 The rate was determined. However, a gold-deposited glass plate was used for measurement of the background.
-Equipment used: PERKIN ELMER FT-IR Spectrometer SPECTRUM 100
10 ° specular reflection attachment made by PIKE Technologies ・ FFT integration number: 16 times ・ Wavelength range: 5 to 25 μm (2000 ^{−1 to} 400 ⁻¹ )
The test results are shown in Table 4.

    From Table 4, in Example 2 and Example 3, the high thermal emissivity was obtained compared with the comparative example 2 and the comparative example 3, and especially in Example 2, the high thermal emissivity was obtained. From this result, it is clear that heat storage in the coating film can be suppressed by using the coating composition of the present invention.

[Example 4]
As a coating film forming binder component, a hydroxyl group value of 80 mg KOH / g, a glass transition temperature (Tg) of 18 ° C., a hydroxyl group-containing acrylic emulsion polyol resin particle having an average particle size of 140 nm, a hydroxyl value of 50 mg KOH / g, and a glass transition temperature Resin particles of a hydroxyl group-containing polyurethane dispersion polyol having a (Tg) of −20 ° C. and an average particle size of 60 nm, a hydroxyl group having a hydroxyl value of 50 mgKOH / g, a glass transition temperature (Tg) of 23 ° C., and an average particle size of 70 nm. Using resin particles of the containing acrylic dispersion polyol, these were blended as follows to obtain a coating film forming binder component. In addition, each compounding quantity (weight%) is a ratio with respect to a total coating-film formation binder component.
・ Hydroxyl group-containing acrylic emulsion polyol: 70% by weight
・ Hydroxyl-containing polyurethane dispersion polyol: 10% by weight
・ Hydroxyl group-containing acrylic dispersion polyol: 20% by weight

Further, as the inorganic heat-shielding colored pigment of the heat-resistant filler, a large particle size titanium oxide having an average particle diameter of 1 μm is used, and as a hollow particle as the heat-shielding filler, an outer shell made of a copolymer of polyvinylidene chloride and acrylonitrile ( Styrene / methacrylic ester organic ultrafine particles with a particle diameter of 400 nm as a viscosity control agent, using particles with an average particle diameter of 20 μm, encapsulating isobutane in an outer shell thickness of 0.1 μm on average These were blended as follows to make the main agent.
Coating film forming binder component (hydroxyl group-containing acrylic emulsion polyol + hydroxyl group-containing polyurethane dispersion polyol + hydroxyl group-containing acrylic dispersion polyol): 73.0% by weight
-Large particle size titanium oxide: 15.0% by weight
・ Hollow particles: 2.5% by weight
・ Viscosity control agent: 5.0% by weight
In this example, in addition to the above components, 3.5% by weight of yellow iron oxide, which is a green pigment, was added to the main component in order to make the color of the coating film green.

The main ingredient blended as described above was dispersed and mixed in water at a ratio of 3 parts by weight of water to 100 parts by weight of the main ingredient. Furthermore, as a reactive film-forming auxiliary, a polyisocyanate similar to that used in Example 1 was added and mixed at a ratio of 10 parts by weight of polyisocyanate to 100 parts by weight of the main agent to obtain an aqueous paint. In this case, the molar ratio of the isocyanate group (—NCO) in the polyisocyanate which is a film forming aid to the hydroxyl group (—OH) in the binder component of the main component is 0.9. After adding and mixing the polyisocyanate as a film-forming aid to the main agent as described above, it was immediately spray-coated on one side of a black urethane rubber sheet similar to the above having a thickness of 8 mm according to a conventional method. The coating amount was 300 g / m ² (average film thickness is about 180 μm).
The black urethane rubber sheet after coating was subjected to a weather resistance test according to JISK5400 9.8 using a sunshine weather meter (Suga Test Instruments Co., Ltd .: S80), and the weather resistance was evaluated.

[Comparative Example 4]
About the rubber sheet material which solidified the colored urethane rubber chip | tip of a green color tone (thing which does not apply a heat-shielding coating material), the weather resistance test was done by the sunshine weather meter similarly to Example 4, and the weather resistance was evaluated.

[Comparative Example 5]
The same black urethane rubber sheet was coated with a solvent-based paint generally used as a heat-shielding paint at a coating amount of 300 g / m ² . The color tone is white. In the same manner as in Example 4, a weather resistance test was performed using a sunshine weather meter to evaluate the weather resistance. Here, the solvent-based paint generally used as a heat-shielding paint is specifically a paint obtained by blending soda-lime silicate glass hollow particles with acrylic urethane resin white, and the solvent is xylene, acetic acid. Butyl was used.

[Results of weather resistance test]
Table 5 shows the weather resistance test results for the above Example 4, Comparative Example 4, and Comparative Example 5. As evaluation items, observation results of color difference (ΔE), appearance (loss of gloss), appearance (choking deterioration) at 500 hours, 1000 hours, and 2000 hours are shown. In addition, the test was stopped at the time when the problem clearly occurred during the test.

As shown in Table 5, in the case of Comparative Example 4 where the colored rubber sheet material was not coated with the heat-shielding paint, and Comparative Example 5 where the solvent-based heat-shielding paint was painted white on the black urethane rubber sheet, 500 Discoloration, luster and choking phenomenon occurred in ˜1000 hours.
On the other hand, in Example 4 in which the heat-shielding paint of the present invention was applied to the black rubber chip sheet material in a green system, no discoloration, glossiness, or choking phenomenon was observed even after 2000 hours, and long-term weather resistance was obtained. Is clear.

[Example 5]
As a coating film forming binder component, a hydroxyl group value of 80 mg KOH / g, a glass transition temperature (Tg) of 18 ° C., a hydroxyl group-containing acrylic emulsion polyol resin particle having an average particle size of 140 nm, a hydroxyl value of 50 mg KOH / g, and a glass transition temperature Resin particles of a hydroxyl group-containing polyurethane dispersion polyol having a (Tg) of −20 ° C. and an average particle size of 60 nm, a hydroxyl group having a hydroxyl value of 50 mgKOH / g, a glass transition temperature (Tg) of 23 ° C., and an average particle size of 70 nm. Using resin particles of the containing acrylic dispersion polyol, these were blended as follows to obtain a coating film forming binder component. In addition, each compounding quantity (weight%) is a ratio with respect to a total coating-film formation binder component.
・ Hydroxyl group-containing acrylic emulsion polyol: 70% by weight
・ Hydroxyl-containing polyurethane dispersion polyol: 10% by weight
・ Hydroxyl group-containing acrylic dispersion polyol: 20% by weight

Furthermore, as the inorganic heat-shielding colored pigment of the heat-shielding filler, titanium oxide having a large particle diameter of 1 μm in average particle diameter is used. SiO ₂ —Al ₂ O ₃ surface having a particle diameter of 0.3 μm as a viscosity control agent using particles having an average particle diameter of 20 μm in which isobutane is encapsulated (with an average thickness of the outer shell of 0.1 μm) Using the treated barium sulfate, these were blended as follows to obtain the main agent.
Coating film forming binder component (hydroxyl group-containing acrylic emulsion polyol + hydroxyl group-containing polyurethane dispersion polyol + hydroxyl group-containing acrylic dispersion polyol): 73.0% by weight
-Large particle size titanium oxide: 15.0% by weight
・ Hollow particles: 2.5% by weight
・ Viscosity control agent: 5.0% by weight
In this example, in addition to the above components, 3.5% by weight of yellow iron oxide, which is a green pigment, was added to the main component in order to make the color of the coating film green.

The main ingredient blended as described above was dispersed and mixed in water at a ratio of 3 parts by weight of water to 100 parts by weight of the main ingredient. Furthermore, as a reactive film-forming auxiliary, a polyisocyanate similar to that used in Example 1 was added and mixed at a ratio of 10 parts by weight of polyisocyanate to 100 parts by weight of the main agent to obtain an aqueous paint. In this case, the molar ratio of the isocyanate group (—NCO) in the polyisocyanate which is a film forming aid to the hydroxyl group (—OH) in the binder component of the main component is 0.9. After adding and mixing the polyisocyanate as a film-forming aid to the main agent as described above, it was immediately spray-coated on one side of a black urethane rubber sheet similar to the above having a thickness of 8 mm according to a conventional method. The coating amount was 300 g / m ² (average film thickness is about 180 μm).
After the coating, it was left at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation similar to the case of Example 1 described above.

[Comparative Example 6]
The black urethane rubber sheet not coated with the heat-shielding paint was subjected to a temperature increase test by infrared irradiation similar to the case of Example 1 described above.

[Comparative Example 7]
The colored urethane rubber sheet obtained by solidifying a urethane rubber chip having a red color tone (not coated with a heat-shielding paint) was subjected to a temperature increase test by infrared irradiation similar to the case of Example 1 described above.

[Example 6]
A water-based paint was prepared in substantially the same manner as in Example 5 except that the green pigment in Example 5 was not blended, and was applied to a black urethane rubber sheet material. After coating, it was allowed to stand at room temperature for 72 hours, and then subjected to a temperature rise test by infrared irradiation as described above.

[Temperature increase test results of Examples 5 and 6 and Comparative Examples 6 and 7]
The temperature rise test results of Examples 5 and 6 and Comparative Examples 6 and 7 are shown in Table 6 and FIG. In FIG. 9, symbol G indicates the test result of Example 5, symbol H indicates the test result of Comparative Example 6, symbol I indicates the test result of Comparative Example 7, and symbol J indicates the test result of Example 6. .

  From the test results of Table 6 and FIG. 9, in the case of the black urethane rubber sheet (Comparative Example 6) and the red colored urethane rubber sheet (Comparative Example 7), the surface temperature after 30 minutes by infrared irradiation is Rise to 62 ° C and 52 ° C, respectively. On the other hand, in the case of Example 5 and Example 6 in which the black urethane rubber sheet was coated with the heat-shielding paint according to the present invention, the surface temperature was 45 ° C. or less even after 30 minutes, and the temperature of the black urethane rubber sheet It can be seen that the rise inhibition curing is large.

DESCRIPTION OF SYMBOLS 1 ... Base part 3 ... Rubber chip urethane pavement layer 5 ... Thermal barrier coating 51 ... Hydroxyl group-containing acrylic emulsion polyol particle, Hydroxyl group-containing polyurethane dispersion polyol particle, and Hydroxyl group-containing acrylic dispersion polyol particle 52 ..Inorganic heat-shielding colored pigments 53 ... Hollow particles 54 ... Viscosity control agents 55 ... Reactive film-forming aids

Claims (18)

The coating film-forming binder component dispersed in the aqueous medium contains a hydroxyl group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, and a hydroxyl group-containing acrylic dispersion polyol, and at least hollow particles as a heat shielding filler With the main agent;
A reactive film-forming aid made of a polymer, which causes a crosslinking reaction with the coating-forming binder component of the main agent to cure the coating;
A thermal barrier coating composition having aqueous two-component curability, comprising: In the heat-shielding coating composition having aqueous two-component curability according to claim 1,
The ratio of the hydroxyl group-containing acrylic emulsion polyol to the entire coating film forming binder component is in the range of 70 to 90% by weight, the ratio of the hydroxyl group-containing polyurethane dispersion polyol is in the range of 1 to 20% by weight, and the hydroxyl group-containing acrylic dispersion. A thermal barrier coating composition having aqueous two-component curability, wherein the proportion of polyol is in the range of 5 to 25% by weight. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 and 2,
The hydroxyl group-containing acrylic emulsion polyol has a hydroxyl value of 70 to 90 mgKOH / g and a glass transition temperature (Tg) in the range of 10 to 30 ° C.,
The hydroxyl group-containing polyurethane dispersion polyol has a hydroxyl value of 40 to 60 mg KOH / g and a glass transition temperature (Tg) of -30 to -10 ° C.
The hydroxyl group-containing acrylic dispersion polyol has a hydroxyl value of 40 to 60 mg KOH / g and a glass transition temperature (Tg) in the range of 10 to 30 ° C.
A heat-shielding coating composition having aqueous two-component curability. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 3,
The average particle size of the hydroxyl group-containing acrylic emulsion polyol is 100 to 150 nm, the average particle size of the hydroxyl group-containing polyurethane dispersion polyol is 40 to 90 nm, and the average particle size of the hydroxyl group-containing acrylic dispersion polyol is 40 to 90 nm. A heat-shielding coating composition having aqueous two-component curability. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 4,
In addition to the hollow particles, the heat-insulating filler contains an inorganic heat-shielding colored pigment, and a heat-shielding coating composition having aqueous two-component curability. In the heat-shielding coating composition having aqueous two-component curability according to claim 5,
An average particle size of the inorganic heat-shielding colored pigment is in a range of 0.5 to 2.0 μm, and a heat-shielding coating composition having aqueous two-component curability. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 5 and 6,
A thermal barrier coating composition having aqueous two-component curability, wherein the inorganic thermal barrier color pigment is at least one selected from titanium oxide, iron oxide, and inorganic composite oxide pigments. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 7,
A thermal barrier coating composition having aqueous two-component curability, wherein the hollow particles are particles in which a hydrocarbon is encapsulated in a polymer outer shell. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 8,
A heat-shielding coating composition having aqueous two-component curability, wherein the hollow particles have an average particle size of 10 to 30 μm. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 9,
A heat-shielding coating composition having aqueous two-component curability, wherein the main agent further contains a viscosity control agent. In the heat-shielding coating composition having aqueous two-component curability according to claim 10,
As the viscosity control agent, styrene / methacrylic ester organic ultrafine particles having an average particle size of 50 to 1000 nm and sulfuric acid having an average particle size of 0.1 to 0.5 μm subjected to SiO ₂ —Al ₂ O ₃ surface treatment. A thermal barrier coating composition having aqueous two-component curability, characterized in that any one or more of barium is used. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 10 and 11,
A thermal barrier coating composition having aqueous two-component curability, wherein the ratio of the viscosity control agent in the main agent is in the range of 2 to 5% by weight. In the heat-shielding coating composition having aqueous two-component curability according to any one of claims 1 to 12,
A thermal barrier coating composition having aqueous two-component curability, wherein the reactive film-forming aid is made of polyisocyanate. In the heat-shielding coating composition having aqueous two-component curability according to claim 13,
The blending ratio of the reactive film-forming aid composed of polyisocyanate and the polyol of the coating film forming binder component in the main agent is the isocyanate group (—NCO) of the reactive film-forming aid and the hydroxyl group (—OH) of the main polyol. ) In the range of 0.8 to 1.1, a thermal barrier coating composition having aqueous two-component curability.   The main agent and the reactive film-forming aid in the heat-shielding coating composition according to any one of claims 1 to 14 are kneaded with an aqueous medium to form an aqueous coating, and the aqueous coating is applied to the surface of the elastic pavement. A heat-shielding paint coating method characterized by painting. In the heat-shielding paint coating method according to claim 15,
The heat-shielding paint coating method, wherein the elastic pavement is urethane-based elastic pavement or asphalt-based elastic pavement. A heat-shielding pavement in which a heat-shielding coating film is formed on the surface of the elastic pavement,
The thermal barrier pavement is
A main agent containing a hydroxyl group-containing acrylic emulsion polyol, a hydroxyl group-containing polyurethane dispersion polyol, and a hydroxyl group-containing acrylic dispersion polyol as a coating film forming binder component, and containing at least hollow particles as a heat shielding filler;
A reactive film-forming aid made of a polymer, which causes a crosslinking reaction with the coating-forming binder component of the main agent to cure the coating;
Consists of
A heat-shielding pavement, wherein each polyol and a reactive film-forming aid are cross-linked. The heat-shielding pavement according to claim 17,
The heat-shielding pavement, wherein the elastic pavement is a urethane-type elastic pavement or an asphalt-type elastic pavement.

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