JP7182500B2 - coating - Google Patents

Description

The present disclosure relates to coatings.

Structures manufactured by thermal curing (for example, mortar structures and concrete structures) often have fine cracks on their surfaces. Cracks on the surface of a concrete structure are caused by a temperature difference between the inside and the surface of the structure during heat curing of the concrete, or by sudden temperature changes due to changes in the outside temperature during curing. occur for. Although these cracks are not serious structural defects, they cause deterioration of the aesthetic appearance of concrete structures. In addition, since cracks on the surface of a concrete structure can serve as an infiltration path for deterioration factors such as chloride ions, there is a concern that the long-term durability of the concrete structure will be impaired.

Many concrete structures are exposed to changes in the external environment such as solar radiation, high and low temperatures, dryness and rain, wind and rain, and intrusion of deterioration factors resulting from changes in the external environment. Changes in the external environment as described above may accelerate the deterioration of the surface of concrete structures. Acceleration of such deterioration is conspicuous when cracks are present on the surface of the concrete structure.

Therefore, as a method of suppressing the deterioration of concrete structures caused by cracks, generally, a method of sticking tiles on the surface of concrete structures, and coating agents such as weather-resistant paints and anti-water absorption materials are applied to concrete structures. A method of coating the surface of an object to form a coating layer is known. For example, Patent Literature 1 describes a water absorption preventing material for civil engineering and construction materials that can prevent peeling and whitening of the coated surface while maintaining water absorption preventing performance.

When a glossy coating layer is provided, such as by attaching tiles to the surface of a concrete structure, light reflection may occur depending on the application location, which may have an adverse effect. For example, when it is applied to the wall balustrade of an expressway, car lights may be reflected by the coating layer. For this reason, coated structures with reduced gloss may be desired.

JP 2012-241100 A

However, even if a conventional coating agent is applied to the surface of a concrete structure, uneven coating of the coating agent may occur. In some cases, the aesthetic appearance of the structure is greatly impaired, such as the texture of the structure being spoiled, or color unevenness occurring between the coating layer and the surface of the concrete structure. Moreover, when a structure having a coating layer on its surface (coated structure) is installed outdoors, the coating layer may not be able to perform its original functions due to ultraviolet rays and aging deterioration. In addition, the water absorption preventing material described in Patent Document 1 is expensive as a raw material, and the adhesion to the surface of the concrete structure and the durability of the coating layer are insufficient. is limited to some structures.

An object of the present disclosure is to provide a coating agent capable of forming a coating layer that suppresses the occurrence of coating unevenness and gloss and has excellent weather resistance.

One aspect of the present disclosure is a coating agent containing a synthetic resin emulsion, an inorganic powder, an antifoaming agent, a thickener and a pigment, and used for surface coating of a structure, wherein the inorganic powder is sand, At least one selected from the group consisting of ferronickel slag, ground blast furnace slag, silica fume, calcium carbonate powder and fly ash, the antifoaming agent includes a mineral oil antifoaming agent, and the thickener is a urea urethane resin and wherein the pigment comprises aluminum oxide and titanium oxide to provide a coating.

The coating agent contains a specific synthetic resin emulsion, a specific inorganic powder, a specific antifoaming agent, a specific thickening agent, and a specific pigment, so that the occurrence of coating unevenness and gloss is suppressed, and weather resistance is improved. It is possible to form a coating layer excellent in

The synthetic resin may contain a (meth)acrylic acid-(meth)acrylic acid alkyl ester copolymer having a glass transition temperature of 5 to 10°C, and the emulsion has a viscosity of 100 to 500 mPa s at 23°C. and may have a pH of 7 to 10, a solid content concentration of 20 to 60% by mass, and an average dispersed particle size of 20 to 100 nm.

The content of the inorganic powder is 30 to 200 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion, and the content of the antifoaming agent is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion. 0 parts by mass, the content of the thickener is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion, and the content of the pigment is 100 parts by mass of the synthetic resin emulsion. It may be 1.0 to 20.0 parts by mass.

The sand is composed of a plurality of particles, and the sand contains 5 parts by mass or less of particles having a particle diameter of 150 μm or more, an activity index of 50 to 80, and a flow value ratio of 80 to 110. may have a density of 1.5 to 3.0 g/cm ³ and a moisture content of 1 or less.

The antifoaming agent may have a specific gravity of 0.80 to 1.0.

The thickening agent may have a density of 1.0-1.3 g/cm ³ .

The pigment further contains 0.5 to 1.0% by weight of a surfactant and 29 to 39% by weight of water, has a pH of 8.0 to 10.0, and a density of 1.9 to 2.3 g. / cm ³ .

The coating material described above may further contain a weather resistance imparting agent, and the weather resistance imparting agent may contain a benzotriazole compound.

The benzotriazole-based compound may have a poly(oxyethylene) group.

The weathering agent is α-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionyl-ω-hydroxypoly(oxyethylene), and α -3-(3-(2H-benzotriazol-2-yl)-5-Tert-butyl-4-hydroxyphenyl)propionyl-ω-3-(3-(2H-benzotriazol-2-yl)-5 -tert-butyl-4-hydroxyphenyl)propionyloxypoly(oxyethylene).

The weather resistance imparting agent may have a solubility of 7.0 to 9.0 mg/L and a density of 1.0 to 1.3 g/cm ³ .

The content of the weather resistance imparting agent may be 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion.

The coating agent described above may further contain a stabilizer, and the stabilizer may contain a compound having a 1,2,2,6,6-pentamethylpiperidyl skeleton.

The stabilizer consists of bis(1,2,2,6,6-pentamethyl-4-piperidyl) decanedioate and methyl (1,2,2,6,6-pentymetal-4-piperidyl) sebacate At least one selected from the group may be included.

The stabilizer may have a viscosity of 100-600 Pa·s and a density of 0.9-1.1 g/cm ³ .

The content of the stabilizer may be 0.1 to 10.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion.

According to the present disclosure, it is possible to provide a coating agent capable of suppressing the occurrence of coating unevenness and gloss and forming a coating layer having excellent weather resistance.

FIG. 1 is a diagram showing the state of a coating layer formed on a mortar structure using the coating agents prepared in Examples 1-4. FIG. 2 shows a mortar structure (Reference Example 1) and a state of a coating layer formed on the mortar structure using the coating agent prepared in Comparative Example 1. FIG. FIG. 3 is a diagram showing the state after weather resistance evaluation of the coating layer formed on the mortar structure using the coating agents prepared in Examples 1-4. FIG. 4 is a diagram showing the state of the mortar structure (Reference Example 1) and the coating layer formed on the mortar structure using the coating agent prepared in Comparative Example 1 after weather resistance evaluation.

Embodiments of the present disclosure will be described below. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents.

The materials exemplified in this specification can be used singly or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the multiple substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. . In this specification, the numerical range indicated by "-" includes each upper limit and lower limit unless otherwise specified.

One embodiment of the coating is a coating containing synthetic resin emulsion, inorganic powder, antifoaming agent, thickening agent and pigment and used for surface coating on structures. The above coating agent is used for surface coating of structures. Structures include buildings, condominiums and houses, as well as bridges, elevated roads, dams, tunnels, and roads. The structure preferably contains concrete, mortar and the like, and more preferably consists of concrete and mortar and the like.

The dispersion medium of the synthetic resin emulsion preferably contains water, alcohol, and the like, and is more preferably water. The emulsion is preferably an aqueous emulsion in which a synthetic resin is dispersed in water. The synthetic resin may be a homopolymer or a copolymer. The copolymer may be a copolymer of three or more components. The copolymers may be alternating copolymers, random copolymers, or block copolymers. A commercially available synthetic resin may be used, or a separately prepared one may be used.

Examples of synthetic resins include (meth)acrylic acid-based resins and vinyl acetate-based resins. Examples of (meth)acrylic acid-based resins include (meth)acrylic acid-(meth)acrylic acid alkyl ester copolymers and (meth)acrylic acid alkyl ester copolymers. The alkyl ester portion of the (meth)acrylic acid alkyl ester may be linear alkyl, branched alkyl or cyclic alkyl, preferably linear alkyl or branched alkyl. The number of carbon atoms in the alkyl ester portion of the (meth)acrylic acid alkyl ester is not particularly limited, but may be, for example, 1-8. By adjusting the number of carbon atoms in the alkyl ester portion of the (meth)acrylic acid alkyl ester, the glass transition temperature of the solid content of the synthetic resin emulsion can be adjusted.

The synthetic resin is preferably (meth)acrylic acid-(meth) from the viewpoint of improving the handling property when preparing the coating agent, improving the workability of the coating agent, and improving the adhesion to the substrate surface. It contains an acrylic acid alkyl ester copolymer, more preferably a methacrylic acid-acrylic acid alkyl ester copolymer.

In the (meth)acrylic acid-(meth)acrylic acid alkyl ester copolymer, even if the ratio of the structural unit derived from (meth)acrylic acid and the structural unit derived from the (meth)acrylic acid alkyl ester is adjusted, good. By adjusting the molar ratio of the structural unit derived from the (meth)acrylic acid alkyl ester to the structural unit derived from (meth)acrylic acid, the glass transition temperature of the solid content of the synthetic resin emulsion can be made appropriate. .

The glass transition temperature (Tg) of the synthetic resin is preferably 5 to 10°C, more preferably 5.5 to 9.5°C, still more preferably 6.0 to 9.0°C. When the glass transition temperature of the synthetic resin is within the above range, the flexibility of the coating layer can be ensured even at low temperatures, and uneven coating of the coated structure can be suppressed.

The "glass transition temperature" of a synthetic resin as used herein means a value obtained by converting a value calculated from the FOX formula represented by the following formula (1) into a Celsius temperature.

1/ _TgP = _W1 / _Tg1 + _W2 / _Tg2 +...+ _Wi / _Tgi +...+ _Wn / _Tgn... Formula (1)

In the above formula (1), Tg _P is the glass transition temperature (unit: K) of the synthetic resin. Tg _i indicates the glass transition temperature of a homopolymer of each monomer. W _i indicates the mass fraction of each monomer, and W ₁ +W ₂ +...+W _i +...W _n =1. For Tg _i (unit: K), a value measured by thermogravimetry (TG) may be used, or a value recorded in "POLYMER HANDBOOK THIRD EDITION" (A WILEY-INTERSCIENCE PUBLICATION) may be used.

The viscosity of the synthetic resin emulsion at 23° C. is preferably 100 to 500 mPa·s, more preferably 200 to 400 mPa·s, still more preferably 250 to 350 mPa·s. When the viscosity of the emulsion is 500 mPa·s or less, the mixing property between the synthetic resin emulsion and the inorganic powder can be improved, and the workability of the coating agent can be improved. Further, when the viscosity of the emulsion is 100 mPa·s or more, sedimentation of the inorganic powder in the coating agent can be further suppressed, and a more uniform coating agent can be obtained.

"Viscosity" as used herein means a value measured according to the description of JIS K 6833-1:2008 "Adhesives - General test methods - Part 1: Determination of basic properties". More specifically, it means a viscosity measured at 23° C. using a BM viscometer (manufactured by Tokyo Keiki Co., Ltd., measurement conditions: rotor No. 1, 12 rpm, 1 minute).

The pH of the synthetic resin emulsion is preferably 7-10, more preferably 7.5-9.5, and still more preferably 8-9. When the pH of the emulsion is within the above range, it is possible to further improve the workability of the coating agent on the surface of the structure, suppress uneven coating of the coated structure, and disperse the inorganic powder and pigment in the coating layer. The ability to maintain the state is improved, and the occurrence of color unevenness can be suppressed. As used herein, "pH" means a value measured according to the description of JIS K 6833-1:2008 "Adhesives-General test methods-Part 1: Determination of basic properties". pH measurements are made at 23°C.

The average dispersed particle size of the synthetic resin emulsion (the average particle size of the synthetic resin dispersed in the dispersion medium) is preferably 20 to 100 nm, more preferably 30 to 90 nm, and even more preferably 40 to 80 nm. When the average dispersed particle size of the emulsion is within the above range, the adhesion of the coating agent to the surface of the structure can be improved. The "average dispersed particle size" used herein means a value measured using a particle size measuring device (manufactured by Otsuka Electronics Co., Ltd., trade name: FPAR-1000).

The solid content concentration (concentration of nonvolatile components) of the emulsion is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and still more preferably 30 to 50% by mass. When the solid content concentration of the emulsion is 60% by mass or less, it is possible to suppress an increase in the viscosity of the emulsion and further improve the workability of the coating agent on the surface of the structure. In addition, when the solid content concentration of the emulsion is 20% by mass or more, it is possible to suppress a decrease in the viscosity of the emulsion and suppress sedimentation of the inorganic powder. "Solid content concentration" as used herein means a value measured according to the description of JIS K 6833-1:2008 "Adhesives-General test methods-Part 1: Determination of basic properties".

The inorganic powder includes, for example, at least one selected from the group consisting of sand, ferronickel slag, ground granulated blast furnace slag, silica fume, calcium carbonate powder and fly ash. The inorganic powder preferably contains at least one of sand and ferronickel slag from the viewpoint of improving workability of the coating agent.

Examples of the sand include mountain sand, river sand, sea sand, crushed stone powder, crushed sand, and silica sand. The sand is composed of a plurality of particles, and the content of particles having a particle diameter of 150 μm or more is preferably 5 parts by mass or less, and 3 parts by mass or less based on the total amount of 100 parts by mass of the sand. is more preferable, and 1 part by mass or less is even more preferable. The content of particles having a particle diameter of 150 μm or more may be 0.01 parts by mass or more based on 100 parts by mass of the total amount of the sand. When the content of particles having a particle diameter of 150 μm or more is 5 parts by mass or less, the surface smoothness of the coating layer obtained by applying the coating agent can be improved, and coating unevenness caused by particle roughness can be reduced. can be further suppressed. The content of particles having a particle diameter of 150 μm or more in the sand can be adjusted by, for example, pulverizing the sand. In the present specification, "content of particles having a particle diameter of 150 µm or more" means "150 µm sieve residue" in JIS A 5041: 2009 "crushed stone for concrete", and JIS A 5041: 2009 "crushed stone for concrete". ” means a value measured according to the method described in .

The activity index of the sand at a material age of 28 days is preferably 50 to 80%, more preferably 55 to 75%, even more preferably 60 to 70%. When the activity index of the sand is 50% or more, the durability of the coating layer obtained by applying the coating agent can be further improved. The term "activity index" used herein means a value measured according to the method described in JIS A 5041:2009 "Crushed stone content for concrete".

The flow value ratio of the sand is preferably 80-110, more preferably 85-110, even more preferably 90-110. When the flow value ratio of the sand is 80 or more, the particles are fine, the increase in the viscosity of the coating agent can be suppressed, and the workability on the surface of the structure can be improved. The “flow value ratio” used herein means a value measured according to the method described in JIS A 5041:2009 “Crushed stone content for concrete”.

The density of the sand is preferably 1.5-3.0 g/cm ³ , more preferably 1.6-2.9 g/cm ³ , and more preferably 1.7-2.8 g/cm ³ . It is even more preferable to have When the density of the sand is 3.0 g/cm ³ or less, sedimentation of sand in the coating agent can be further suppressed. Further, when the density of the sand is 1.5 g/cm ³ or more, the durability of the coating layer obtained by applying the coating agent can be further improved. "Density" as used herein means a value measured according to the method described in JIS A 5041:2009 "Crushed stone content for concrete".

The moisture content of the sand is preferably 1% or less, more preferably 0.75% or less, even more preferably 0.5% or less, even more preferably 0.4% or less. preferable. When the moisture content of the sand is 1% or less, the sand can be easily weighed during production of the coating agent, and the storage stability of the coating agent is excellent. The moisture content of the sand can be adjusted by methods such as drying. "Moisture content" as used herein means a value measured according to the method described in JIS A 5041:2009 "Crushed stone content for concrete".

The ferronickel slag is a residue discharged during the production of ferronickel, which is used as a raw material for stainless steel and the like. Ferronickel slag is a substance mainly composed of silicic acid and calcium oxide, and contains specific constituents such as calcium oxide, silicon dioxide, iron oxide, and magnesium oxide, and has a stable crystal structure. The ferronickel slag is a black powder. Therefore, the color tone of the coating material can be adjusted by adjusting the content of ferronickel slag.

The content of slag having a particle diameter of 150 μm or more in the ferronickel slag is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, based on 100 parts by mass of the total amount of ferronickel slag. is more preferable, and 20 to 30 parts by mass is even more preferable. When the content of slag with a particle diameter of 150 μm or more is 50 parts by mass or less, the surface smoothness of the coating layer obtained by applying the coating agent can be improved, and coating unevenness caused by particle roughness and Color unevenness can be further suppressed. In addition, since the content of slag with a particle size of 150 μm or more is 10 parts by mass or more, it is possible to suppress the viscosity increase of the coating agent due to the fineness of the particle size, and improve the workability of the coating agent. be able to. The content of slag with a particle size of 150 μm or more can be adjusted by, for example, pulverizing ferronickel slag. The "content of slag having a particle size of 150 µm or more" as used herein means a value measured according to the method described in JIS R 5201:2015 "Physical test methods for cement".

The particle size index of the ferronickel slag is preferably 100-300, preferably 130-270, more preferably 160-240. When the particle size index of the ferronickel slag is 300 or less, it is possible to suppress an increase in the viscosity of the coating due to the fineness of the particle size, and improve the workability of the coating. Moreover, since the particle size index of the ferronickel slag is 100 or more, it is possible to further suppress coating unevenness and color unevenness due to the coarseness of the particle size. The term "particle size index" as used herein means an index defined in JIS Z 2601:1993 "Testing methods for foundry sand", and according to the particle size factor (total specific surface area per 1 g of particles of a predetermined size), It means the average surface area over all particle sizes.

The Mohs hardness of the ferronickel slag is preferably 5-10, more preferably 6-9, even more preferably 7-8. When the ferronickel slag has a Mohs hardness of 5 or more, the durability of the coating layer obtained by applying the coating agent can be improved. "Mohs hardness" as used herein means a value measured according to the method described in JIS Z 0312:2004 "Non-metallic abrasive for blasting".

The ground granulated blast furnace slag can be obtained by pulverizing blast furnace slag generally used in the production of mortar and concrete. The Blaine specific surface area of the ground granulated blast furnace slag may be about 2750 to 10000 cm ² /g. Ground blast furnace slag powder includes, for example, blast furnace slag ground powder 3000, blast furnace slag ground powder 4000, blast furnace slag ground powder 6000 and blast furnace slag ground powder 8000 defined in JIS A 6206:2013 "ground blast furnace slag powder for concrete". can be used.

"Blaine specific surface area" as used herein means a value measured according to the method described in JIS R 5201:2015 "Physical test method for cement".

As the silica fume, one mainly composed of amorphous SiO ₂ that dissolves in an alkaline solution can be used. The BET specific surface area of silica fume is preferably 100,000 to 250,000 cm ² /g, more preferably 150,000 to 200,000 cm ² /g, from the viewpoint of obtaining a coating agent with excellent workability and less coating unevenness. "BET specific surface area" as used herein means a value measured according to the method described in JIS Z 8830:2013 "Method for measuring specific surface area of powder (solid) by gas adsorption".

The calcium carbonate powder is powder containing calcium carbonate as a main component. As the calcium carbonate powder, for example, limestone or chemically produced calcium carbonate pulverized and classified can be used. The Blaine specific surface area of the calcium carbonate powder is preferably 1000 to 5000 cm ² /g, more preferably 2000 to 4000 cm ² /g, from the viewpoint of obtaining a coating agent with excellent workability and less coating unevenness.

The fly ash is ash produced when pulverized coal is burned in a coal-fired power plant, and waste collected by an electrostatic precipitator or the like can be used. As fly ash, for example, fly ash type II defined in JIS A 6201:2015 "Fly ash for concrete" can be used.

The content of the inorganic powder is preferably 30 to 200 parts by mass, more preferably 40 to 180 parts by mass, and even more preferably 50 to 170 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion. . When the content of the inorganic powder is 200 parts by mass or less, an increase in the viscosity of the coating agent can be suppressed, and workability to the structure can be improved. In addition, when the content of the inorganic powder is 30 parts by mass or more, it is possible to suppress sedimentation of the inorganic powder in the coating agent.

The antifoaming agent includes a mineral oil antifoaming agent. Mineral oil-based defoamer may be a mixture. Mineral oil antifoams can be, for example, mixtures of mineral oil and surfactants. Surfactants may be, for example, magnesium stearate, nonionic surfactants, and the like.

The pH of the antifoaming agent is preferably 8.0 to 10.0 when it is made into a 2.5% aqueous solution. The specific gravity of the antifoaming agent is preferably 0.80 to 1.0. More preferably, the antifoaming agent has a pH of 8.0 to 10.0 and a density of 0.80 to 1.0 g/cm ³ .

The content of the antifoaming agent is preferably 0.1 to 5.0 parts by mass, more preferably 0.1 to 4.0 parts by mass, with respect to 100 parts by mass of the synthetic resin emulsion. It is more preferably 0.5 to 2.0 parts by mass, and even more preferably 1.0 to 2.0 parts by mass. When the content of the antifoaming agent is 0.1 parts by mass or more, it is possible to suppress the generation of air bubbles during application of the coating agent, and to improve the appearance of the coating layer. When the content of the antifoaming agent is 5.0 parts by mass or less, the cost can be suppressed while maintaining sufficient antifoaming properties.

The thickener includes urea urethane resin. The thickener may be a solution containing a solvent, or may contain a compound such as lithium chloride. Examples of solvents include N-methyl-2-pyrrolidone. The density of the thickener is preferably 1.0-1.3 g/cm ³ .

The content of the thickener is preferably 0.1 to 5.0 parts by mass, more preferably 0.1 to 4.0 parts by mass, with respect to 100 parts by mass of the synthetic resin emulsion. It is more preferably 0.5 to 3.0 parts by mass, and even more preferably 1.0 to 2.0 parts by mass. When the content of the thickener is 0.1 parts by mass or more, sedimentation of the inorganic powder in the coating agent can be suppressed. When the content of the thickener is 5.0 parts by mass or less, the workability of the coating agent can be improved.

The pigments include aluminum oxide and titanium oxide. The pigment may be, for example, a white pigment or the like. Titanium oxide may be titanium dioxide. The content of titanium dioxide in the pigment is preferably 75% by mass or more, more preferably 85% by mass or more, relative to the total amount of the pigment. As the above pigment, a commercially available one may be used, or a separately prepared one may be used. When the pigment is separately prepared, it may be an inorganic compound chemically produced by a chlorine method or a sulfuric acid method using ores such as rutile ore and ilmenite as raw materials.

The above pigment may be prepared in a liquid or paste form by adding a liquid such as water and a surfactant. When a paste is prepared by adding 0.5 to 1.0% by weight of a surfactant and 29 to 39% by weight of water to the pigment, the pH is preferably 8.0 to 10.0. The density of the paste pigment is preferably 1.9 to 2.3 g/cm ³ . More preferably, the paste pigment has a pH of 8.0 to 10.0 and a density of 1.9 to 2.3 g/cm ³ .

The content of the pigment is preferably 1.0 to 20.0 parts by mass, more preferably 1.0 to 15.0 parts by mass, based on 100 parts by mass of the synthetic resin emulsion. It is more preferably 0 to 15.0 parts by mass, and even more preferably 5.0 to 10.0 parts by mass. When the content of the pigment is 1.0 parts by mass or more, the color difference between the coating layer obtained by applying the coating agent and the surface of the structure can be further reduced, and the appearance of the coated structure can be improved. can be excellent. When the content of the pigment is 20.0 parts by mass or less, aggregation of the fine particles of the pigment can be suppressed, and the surface smoothness of the coating layer obtained by applying the coating agent can be improved. Coating unevenness due to roughness can be further suppressed.

The coating agents described above may contain other ingredients in addition to the synthetic resin emulsion, inorganic powder, defoamer, thickener and pigment. Other components include, for example, weather resistance imparting agents, stabilizers and dispersants.

The weatherability-imparting agent may contain, for example, an ultraviolet absorber. The weather resistance-imparting agent may contain a benzotriazole-based compound. The benzotriazole-based compound may have a poly(oxyethylene) group.

The weathering agent is α-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionyl-ω-hydroxypoly(oxyethylene), and α -3-(3-(2H-benzotriazol-2-yl)-5-Tert-butyl-4-hydroxyphenyl)propionyl-ω-3-(3-(2H-benzotriazol-2-yl)-5 -tert-butyl-4-hydroxyphenyl)propionyloxypoly(oxyethylene).

The solubility of the weathering agent is preferably 7.0 to 9.0 mg/L. The density of the weather resistance imparting agent is preferably 1.0 to 1.3 g/cm ³ . More preferably, the weatherability imparting agent has a solubility of 7.0 to 9.0 mg/L and a density of 1.0 to 1.3 g/cm ³ . As used herein, "solubility" means solubility in water, and indicates the amount of a substance that can be dissolved in 1 L of water. "Density" as used herein means a value measured according to the method described in JIS K 0061:2001 "Determination of Density and Specific Gravity of Chemical Products".

The content of the weather resistance imparting agent is preferably 0.1 to 10.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, based on 100 parts by mass of the synthetic resin emulsion. More preferably 0.5 to 1.5 parts by mass. When the content of the weather resistance-imparting agent is 0.1 parts by mass or more, deterioration of the coating layer obtained by application of the coating agent due to ultraviolet rays can be suppressed. When the content of the weather resistance imparting agent is 10.0 parts by mass or less, the cost can be suppressed.

Stabilizers can be used, for example, sterically hindered amine light stabilizers. The stabilizer contains a compound having at least one skeleton selected from the group consisting of a 1,2,2,6,6-pentamethylpiperidine skeleton and a 2,2,6,6-tetramethylpiperidine skeleton. is preferred, and it is more preferred to contain a compound having a 1,2,2,6,6-pentamethylpiperidine skeleton.

The stabilizer consists of bis(1,2,2,6,6-pentamethyl-4-piperidyl) decanedioate and methyl (1,2,2,6,6-pentymetal-4-piperidyl) sebacate At least one selected from the group may be included.

It is preferable that the stabilizer has a viscosity of 100 to 600 Pa·s. The density of the stabilizer is preferably 0.9-1.1 g/cm ³ . More preferably, the stabilizer has a viscosity of 100 to 600 Pa·s and a density of 0.9 to 1.1 g/cm ³ .

The content of the stabilizer is preferably 0.1 to 10.0 parts by mass, more preferably 0.3 to 5.0 parts by mass, more preferably 0.5 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion. It is more preferable to contain up to 1.5 parts by mass. When the content of the stabilizer is 0.1 parts by mass or more, deterioration of the coating layer obtained by application of the coating agent due to ultraviolet rays can be suppressed. Cost can be held down because content of a stabilizer is 10.0 mass parts or less.

Examples of the dispersant include metal salts of fatty acids, fatty acid esters, and low melting point resins. By including a dispersing agent in the coating agent, sedimentation of inorganic powder and the like can be further suppressed.

The viscosity of the above-described coating agent at 23° C. can be, for example, 4000 MPa·sec or less, 3000 MPa·sec or less, or 2000 MPa·sec or less. The viscosity of the coating agent described above at 23° C. may be, for example, 500 MPa·sec or more. When the viscosity of the coating agent at 23°C is within the above range, the applicability to the surface of the structure can be further improved, and the coating layer obtained by the coating agent can be excellent in appearance. be able to. "Viscosity" as used herein can be measured by the method described in Examples.

The coating agent described above can be prepared, for example, by the following manufacturing method. One embodiment of the method of making the coating comprises mixing a synthetic resin emulsion, inorganic powder, defoamer, thickener and pigment.

One embodiment of the coating application method is a step of applying the above-described coating or a solution containing the above-described coating to at least a portion of the surface of a structure to provide a coating-containing layer (hereinafter, also referred to as an application step ) and a step of providing a coating layer by reducing the content of a solvent containing water from the coating agent-containing layer (hereinafter also referred to as a solvent amount reduction step). The construction method may be, for example, coating, spraying, or the like. Application may be done with a brush or roller. Further, the above-described coating agent may be further applied to the surface that has been coated once, and may be recoated.

A solution containing the coating agent described above includes the coating agent described above and a solvent. The solvent may be water or a solvent such as alcohol. Preferably, the solvent is water, as the application of the coating may be done indoors.

The coating agent and the solution containing the coating agent are prepared immediately before application of the coating agent from the viewpoint of further suppressing the precipitation of the inorganic powder and further improving the appearance of the coating layer obtained by applying the coating agent. is preferred. That is, the coating application method described above may further include the step of preparing the coating.

The object to which the coating agent is applied may be, for example, a structure such as a house or a building. The structure may be installed outdoors or indoors. The structure may be composed of, for example, concrete and mortar. That is, the structure may be a concrete structure, a mortar structure, or the like.

The coating amount (for example, application amount) of the coating agent is preferably 50 to 600 g/m ² , more preferably 100 to 400 g/m ² .

The solvent amount reduction step may be, for example, natural drying and heat drying. The solvent to be reduced in the solvent amount reduction step includes the dispersion medium contained in the synthetic resin emulsion that constitutes the coating material. The environmental temperature in the solvent amount reduction step may be, for example, 10 to 40°C. The time for the solvent amount reduction step may be 1 to 5 hours.

The thickness of the covering layer may be, for example, 0.05-2.00 mm, or 0.10-1.20 mm. By setting the thickness of the coating layer within the above range, the effect of reducing cracks is sufficiently exhibited. When the thickness of the coating layer is 0.05 mm or more, it is possible to suppress the occurrence of scraping and peeling of the coating layer that may be caused by impact. When the coating layer has a thickness of 2 mm or less, cracking of the coating due to shrinkage of the coating layer during drying can be suppressed.

As described above, the coating agent of the present disclosure is excellent in weather resistance and adhesiveness, so that it is excellent in workability to existing construction structures and has little coating unevenness. Also, the color can be easily adjusted by adjusting the type and content of the inorganic powder. Furthermore, it is inexpensive and highly versatile, has high durability even after application of the coating agent, and can protect the construction structure from deterioration factors derived from the external environment.

Although several embodiments have been described above, the present disclosure is not limited to the above embodiments. Also, the descriptions of the above-described embodiments can be applied to each other.

Hereinafter, the contents of the present disclosure will be described in more detail with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples.

(Example 1)
<Preparation of mortar structure>
In a container, 764 parts by mass of ordinary Portland cement (manufactured by Ube-Mitsubishi Cement Co., Ltd., Blaine specific surface area: 3260 cm ² /g, density: 3.16 g/cm ³ , SO ₃ amount: 2.31%) and fine aggregate 1212 parts by mass of mixed sand (surface dry density: 2.62 g/cm ³ , water absorption: 1.69%, coarse particle rate: 2.66%), and 9.17 parts by mass of high-performance AE as an admixture A water reducing agent (manufactured by BASF Japan Ltd., trade name: Master Glenium SP8S) was weighed out, added with 251 parts by mass of water (tap water), and kneaded to obtain a kneaded product. The resulting kneaded product was molded into a plate and cured in water at 20°C to prepare a mortar structure (high strength, nominal strength: 50 N/mm ² or more). The obtained mortar structure had a plate-like coating surface with a length of 10 cm and a width of 20 cm. The high performance AE water reducing agent was adjusted so that the content of the cement was 1.20% by mass.

<Preparation of coating>
In a container, 100 parts by mass of synthetic resin emulsion, 150 parts by mass of inorganic powder, 0.43 parts by mass of defoaming agent, 0.43 parts by mass of thickening agent, and 8.7 parts by mass of pigment in terms of solid content was measured and mixed with a stirrer at 800 rpm for 30 minutes until the inorganic powder and the like were sufficiently dispersed to prepare a coating agent.

<Preparation of covering structure (application of coating agent to surface of mortar structure)>
The coating agent prepared as described above is applied with a brush (brush width: 30 mm) onto the surface of the mortar structure (height: 10 cm, width: 20 cm plane) so that the coating amount is about 300 g/m ² . Then, a coating layer was provided. After that, the coating layer was dried at room temperature for 1 hour to obtain a coated structure (a structure provided with a coating layer).

(Examples 2-4)
A coating agent was prepared in the same manner as in Example 1, except that the raw materials and the charging ratio (mass ratio) were changed as shown in Table 1. A coated structure was prepared in the same manner as in Example 1 using the obtained coating agent.

(Comparative example 1)
Using the same synthetic resin emulsion as the synthetic resin emulsion used in Example 1, a coating agent consisting only of the synthetic resin emulsion was prepared. Next, a coated structure was prepared in the same manner as in Example 1 using the coating agent.

The raw materials shown in Table 1 were used as follows.

[Synthetic resin emulsion]
Emulsion containing alkyl acrylate/methacrylic acid copolymer (glass transition temperature of alkyl acrylate/methacrylic acid copolymer: 9°C, viscosity of emulsion at 23°C: 300 mPa·s, pH of emulsion: 8. 5, average dispersed particle size of emulsion: 60 nm, solid content concentration: 36%)

[Inorganic powder]
Crushed stone powder (content of particles with a particle diameter of 150 μm or more: 0.3 parts by mass per 100 parts by mass of the total amount, activity index: 68%, flow value ratio: 91%, density: 2.73 g/cm ³ , Moisture content: 0.33% or less)
[Antifoaming agent]
A mixture of mineral oil, magnesium stearate, and a nonionic surfactant (pH: 8.0-10.0 (2.5% aq), flash point: 165°C, specific gravity at 25°C: 0.90)
[Thickener]
N-methyl-2-pyrrolidone solution containing lithium chloride and urea urethane resin (density at 20°C: 1.12 g/cm ³ , initial boiling point: 203°C, flash point: 85.9°C)
[Pigment]
A mixture of titanium (IV) oxide and aluminum oxide (60 to 70% by mass of titanium oxide, less than 2% by mass of aluminum oxide, and a pasty mixture of water, pH: 8.5 to 9.5, density: 2.0 to 2.2 g/ ^cm3 )

[Weather resistance imparting agent]
α-3-(3-(2H-benzotrisol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionyl-ω-hydroxypoly(oxyethylene), and α-3-(3- (2H-benzotrisol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionyl-ω-3-(3-(2H-benzotrisol-2-yl)-5-tert-butyl- UV absorber containing 4-hydroxyphenyl)propionyloxypoly(oxyethylene) (boiling point: 166°C, melting point: -40°C, specific gravity at 20°C: 1.17)

[Stabilizer]
Sterically hindered amine light stabilizers including bis(1,2,2,6,6-pentamethyl-4-piperidyl)decanedioate and methyl(1,2,2,6,6-pentymetal-4-piperidyl) sebacate (Bis (1,2,2,6,6-pentamethyl-4-piperidyl) decanedioate is 70 to 80% by mass, methyl (1,2,2,6,6-pentimetal-4-piperidyl) sebacate is 15 to 30% by mass)

[Evaluation of Coating Agent]
The coating agents prepared in Examples 1 to 4 and Comparative Example 1 were evaluated for viscosity at 23° C., uniformity (precipitation suppression property), and applicability to the surface of a structure.

<Evaluation of viscosity of coating agent at 23°C>
Using the coating agents prepared in Examples 1 to 4 and Comparative Example 1, using a BM type viscometer (manufactured by Tokyo Keiki Co., Ltd., measurement conditions: rotor No. 1, 12 rpm, 1 minute), under the conditions of 23 ° C. The viscosity was measured by and evaluated according to the following criteria. Table 2 shows the results.
A: Viscosity is 2000 MPa·sec or less.
B: Viscosity is more than 2000 MPa·sec and 3000 MPa·sec or less.
C: Viscosity is more than 3000 MPa·sec and 4000 MPa·sec or less.
D: Viscosity is over 4000 MPa·sec.

<Evaluation of coating uniformity>
The uniformity of the coating agents prepared in Examples 1 to 4 and Comparative Example 1 was visually observed and evaluated according to the following criteria. Table 2 shows the results.
A: No precipitation.
B: Precipitation is slightly observed C: Precipitation is observed.
D: Many precipitates are confirmed.

<Evaluation of the workability of the coating agent on the surface of the structure>
The coating agents prepared in Examples 1 to 4 and Comparative Example 1 were applied with a brush (brush width: 30 mm), and the elongation of the coating agents was evaluated according to the following criteria. In addition, the said evaluation evaluated by the trained panel of 10 persons, and employ|adopted the average of the evaluation. Table 2 shows the results.
A: The coating exhibits very good elongation.
B: The coating exhibits good elongation.
C: The coating material has poor elongation.

[Evaluation of coating layer performance]
The coated structures prepared in Examples 1 to 4 and Comparative Example 1 were evaluated for coating unevenness of the coating layer, gloss of the coating layer, Hunter color difference of the coating layer, and weather resistance of the coating layer. In the following evaluations, the mortar structure prepared in Example 1 was used as Reference Example 1 for reference in each evaluation. 1 to 4 show an example of surface observation of each covering structure and mortar structure.

<Evaluation of coating unevenness of coating layer>
The surfaces of the coated structures prepared in Examples 1 to 4 and Comparative Example 1 were visually observed and evaluated according to the following criteria. Table 3 shows the results.
A: No coating unevenness.
B: Coating unevenness is observed very slightly.
C: Coating unevenness is observed.
D: Many coating irregularities are observed.

<Evaluation of Glossiness of Coating Layer>
Regarding the coated structures prepared in Examples 1 to 4 and Comparative Example 1, and the mortar structure of Reference Example 1, the glossiness of the coating layer surface after completion of 3 cycles was measured with a gloss meter in the weather resistance evaluation described later. , was evaluated according to the following criteria. Table 3 shows the results.
A: The gloss value is 3 or less.
B: The gloss value is more than 3 and 10 or less.
C: The gloss value is more than 10 and 30 or less.
D: The gloss value is over 30.

<Evaluation of Color Difference (ΔE) of Coating Layer>
Regarding the coated structures prepared in Examples 1 to 4 and Comparative Example 1, and the mortar structure of Reference Example 1, the color difference of the coating layer surface immediately after application of the coating agent and after completion of 3 cycles in the weather resistance test described later was measured. It was measured by a color difference meter, and the color difference was calculated from the tristimulus values using the Hunter color difference formula (ΔE = [(ΔL) ² + (Δa) ² + (Δb) ² ] ^1/2 . ΔL is after the completion of the 3-cycle test. Table 3 shows the difference between the L value of the coating film surface and the L value of the coating film surface immediately after application.The same applies to Δa and Δb.The color difference was evaluated according to the following criteria.
A: The color difference is 5.0 or less.
B: The color difference is more than 5.0 and 30 or less.
C: The color difference is more than 30.

<Evaluation of weather resistance of coating layer>
The coated structures prepared in Examples 1 to 4 and Comparative Example 1 and the mortar structure of Reference Example 1 were evaluated for weather resistance. Specifically, the surfaces of the coating structure and the mortar structure were irradiated with ultraviolet light (lamp output: 30 W/cm ² , wavelength: over 220 nm) for 2 hours, and then immersed in water for 2 hours. Taking this as one cycle, 1 to 3 cycle tests were carried out. Each surface was visually observed. Based on the final surface conditions of the covering structure and the mortar structure, evaluation was made according to the following criteria. Table 3 shows the results.
A: No abnormality is observed on the surface.
B: Slight discoloration and sinking were observed on the surface, but no cracks were observed.
C: Remarkable discoloration and sinking were observed on the surface, but no cracks were observed.
D: Blisters are observed on the surface, or cracks are observed on the surface.

As shown in FIGS. 1 and 2, when a coating layer is provided using the coating agents prepared in Examples 1 to 4, there is no coating unevenness, color unevenness is suppressed, and gloss is also suppressed. was confirmed. FIG. 1 is a diagram showing the state of a coating layer formed on a mortar structure using the coating agents prepared in Examples 1-4. FIG. 2 shows a mortar structure (Reference Example 1) and a state of a coating layer formed on the mortar structure using the coating agent prepared in Comparative Example 1. FIG.

As shown in FIGS. 3 and 4, when a coating layer was provided using the coating agents prepared in Examples 1 to 4, no abnormality was observed on the coating layer even after the weather resistance test. It was confirmed that a coating layer having excellent properties can be provided. FIG. 3 is a diagram showing the state after a UV irradiation test of a coating layer formed on a mortar structure using the coating agents prepared in Examples 1-4. FIG. 4 is a diagram showing the state of the mortar structure (Reference Example 1) and the coating layer formed on the mortar structure using the coating agent prepared in Comparative Example 1 after the UV irradiation test. As shown in FIG. 4, on the surface of a mortar structure without a coating layer formed using the coating agent according to the present disclosure, and on the coated structure having a coating layer formed only with a synthetic resin emulsion, ultraviolet irradiation It was confirmed that cracks and the like occur due to

According to the present disclosure, it is possible to provide a coating agent capable of suppressing the occurrence of coating unevenness and gloss and forming a coating layer having excellent weather resistance.

Claims (16)

A coating agent containing a synthetic resin emulsion, an inorganic powder, an antifoaming agent, a thickening agent and a pigment and used for surface coating of a structure,
The inorganic powder includes at least one selected from the group consisting of sand, ferronickel slag, ground granulated blast furnace slag, silica fume, calcium carbonate powder and fly ash,
The antifoaming agent comprises a mineral oil antifoaming agent,
The thickener contains a urea urethane resin,
A coating agent, wherein the pigment comprises aluminum oxide and titanium oxide. The synthetic resin contains a (meth)acrylic acid-(meth)acrylic acid alkyl ester copolymer having a glass transition temperature of 5 to 10 ° C.,
The emulsion has a viscosity at 23° C. of 100 to 500 mPa·s, a pH of 7 to 10, a solid content concentration of 20 to 60% by mass, and an average dispersed particle size of 20 to 100 nm. Item 1. The coating agent according to item 1. The content of the inorganic powder is 30 to 200 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion,
The content of the antifoaming agent is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion,
The content of the thickener is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the synthetic resin emulsion,
2. The coating agent according to claim 1, wherein the content of said pigment is 1.0 to 20.0 parts by mass with respect to 100 parts by mass of said synthetic resin emulsion. The sand is composed of a plurality of particles,
The sand contains 5 parts by mass or less of particles having a particle diameter of 150 μm or more, has an activity index of 50 to 80, a flow value ratio of 80 to 110, and a density of 1.5 to 3.5. The coating of claim 1, having 0 g/cm ³ and a moisture content of 1% or less. The coating material according to claim 1 or 2, wherein the antifoaming agent has a specific gravity of 0.80 to 1.0. Coating agent according to any one of the preceding claims, wherein the thickening agent has a density of 1.0-1.3 g/cm ³ . The pigment further contains 0.5 to 1.0% by weight of a surfactant and 29 to 39% by weight of water, has a pH of 8.0 to 10.0, and has a density of 1.9 to 2.3 g. /cm ^3. The coating according to any one of the preceding claims. The coating material according to any one of claims 1 to 6, further comprising a weather resistance imparting agent, said weather resistance imparting agent comprising a benzotriazole compound. 9. The coating material according to claim 8, wherein said benzotriazole-based compound has a poly(oxyethylene) group. The weathering agent is α-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionyl-ω-hydroxypoly(oxyethylene), and α -3-(3-(2H-benzotriazol-2-yl)-5-Tert-butyl-4-hydroxyphenyl)propionyl-ω-3-(3-(2H-benzotriazol-2-yl)-5 -tert-butyl-4-hydroxyphenyl)propionyloxypoly(oxyethylene). The coating according to any one of claims 8 to 10, wherein the weathering agent has a solubility of 7.0-9.0 mg/L and a density of 1.0-1.3 g/cm ³ . agent. The coating material according to any one of claims 8 to 11, wherein the content of said weather resistance imparting agent is 0.1 to 10.0 parts by mass with respect to 100 parts by mass of said synthetic resin emulsion. The coating material according to any one of claims 1 to 12, further comprising a stabilizer, said stabilizer comprising a compound having a 1,2,2,6,6-pentamethylpiperidine skeleton. Said stabilizer consists of bis(1,2,2,6,6-pentamethyl-4-piperidyl) decanedioate and methyl (1,2,2,6,6-pentymetal-4-piperidyl) sebacate 14. The coating according to claim 13, comprising at least one selected from the group. The coating agent according to claim 13 or 14, wherein the stabilizer has a viscosity of 100-600 Pa·s and a density of 0.9-1.1 g/cm ³ . The coating material according to any one of claims 13 to 15, wherein the content of said stabilizer is 0.1 to 10.0 parts by mass with respect to 100 parts by mass of said synthetic resin emulsion.

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