JP2019157124A - Aqueous coating material - Google Patents

Abstract

To provide an aqueous coating material which exhibits sufficient permeability to an inorganic porous substrate and water stop performance and gives uniform finishing.SOLUTION: There is provided an aqueous coating material for an inorganic porous substrate, which comprises a synthetic resin emulsion (A) and a water-soluble silane compound (B), wherein the synthetic resin emulsion (A) has an average particle diameter of 100 nm or less and a pH of 2 or more and 6 or less and the aqueous coating material contains 0.1 to 20 pts.wt. of the water-soluble silane compound (B) based on 100 pts.wt. of the solid content of the synthetic resin emulsion (A).SELECTED DRAWING: None

Description

  The present invention relates to a novel aqueous coating material.

As a method for imparting water-stopping performance and improving durability to inorganic porous substrates such as concrete and cement mortar that have been used in the past for buildings and civil engineering structures, silane compounds are the main components. A method of applying a solvent-based penetrable water absorption inhibitor is widely used. However, in recent years, there has been an increasing demand for water-based materials even in such materials because of consideration for the surrounding environment and occupational hygiene.

As such an aqueous material, for example, Patent Document 1 discloses an aqueous primer solution containing a copolymer mainly composed of a cationic monomer, an alkoxysilane monomer, and an ethylenically unsaturated monomer. Liquid is described. This aqueous liquid causes a cross-linking reaction to form a water-stop coating, and improves the base material permeability, base material reinforcement, and water resistance by using a resin liquid with a high concentration and low viscosity. Is described.

JP-A-6-1680

However, in the process of impregnating the inorganic porous substrate with the aqueous liquid as in Patent Document 1, the aqueous liquid is gelled (cured) on the surface layer of the substrate, and the aqueous liquid component is sufficiently impregnated to the inside of the substrate. In some cases, a sufficient water-stopping effect cannot be obtained. In addition, the aqueous liquid component remaining on the substrate surface without being impregnated may cause unevenness and adversely affect the water stopping performance and aesthetics. In addition, when a wetting agent or a penetrating agent is added to improve the impregnation property, the aqueous medium in the aqueous solution is easily impregnated into the base material, but the resin component that forms the water-stopping film is not sufficiently impregnated and desired. There was a case where the performance of could not be obtained.

The present invention has been made in view of such problems, and provides an aqueous coating that exhibits sufficient permeability and water-stopping performance with respect to an inorganic porous substrate and can obtain a uniform finish. The purpose is to obtain materials.

  As a result of intensive studies on such problems, the present inventors have found an aqueous coating material containing a specific synthetic resin emulsion (A) and a water-soluble silane compound (B) at a specific weight ratio, and completed the present invention. I let you.

That is, the present invention has the following characteristics.
1. An aqueous coating material for an inorganic porous substrate,
Including a synthetic resin emulsion (A) and a water-soluble silane compound (B),
The synthetic resin emulsion (A) has an average particle size of 100 nm or less, a pH of 2 or more and 6 or less,
An aqueous coating material comprising 0.1 to 20 parts by weight of the water-soluble silane compound (B) with respect to 100 parts by weight of the resin solid content of the synthetic resin emulsion (A).
2. The water-soluble silane compound (B) is characterized in that the pH of a 1% by weight aqueous solution is less than 7. The water-based coating material described in 1.
3. The water-soluble silane compound (B) is an epoxy group-containing silane compound. Or 2. The water-based coating material described in 1.

  The aqueous coating material of the present invention exhibits sufficient permeability and water stopping performance with respect to an inorganic porous substrate, and can obtain a uniform finish.

  The aqueous coating material of the present invention is an aqueous coating material for an inorganic porous substrate and contains a synthetic resin emulsion (A) and a water-soluble silane compound (B).

As the synthetic resin emulsion (A) of the present invention,
(1) The average particle size is 100 nm or less (preferably 10 nm or more and 90 nm or less),
(2) pH is 2 or more and 6 or less (preferably 2.5 or more and 5 or less),
It is characterized by being.

When the average particle diameter of the resin particles of the synthetic resin emulsion (A) is in the range of (1), it is possible to exhibit excellent permeability, reinforcement, and adhesion to the inorganic porous substrate. . Thereby, the outstanding water stop performance can be exhibited. On the other hand, when the average particle diameter of the resin particles exceeds the above range (1), sufficient water stopping performance may not be obtained due to a decrease in permeability and reinforcement. In the present invention, the average particle diameter of the resin particles is a value measured by a dynamic light scattering method. Specifically, it can be measured using a dynamic light scattering measurement device (“LB-550” manufactured by Horiba, Ltd.). (Measurement temperature is 25 ° C.)

Moreover, when the pH of the synthetic resin emulsion (A) is in the above range (2), it is possible to exhibit excellent permeability, reinforcement, and adhesion to the inorganic porous substrate. Thereby, the outstanding water stop performance can be exhibited. Although the mechanism of its action is not clear, the surface of the inorganic porous substrate is alkaline except for a part, and it can be firmly adhered to the inorganic substrate by forming a film in an alkaline environment. It is done.

  Such a synthetic resin emulsion (A) is not particularly limited, but is preferably an acrylic resin emulsion, and more preferably an acrylic silicon resin emulsion. In this case, good adhesion to the inorganic porous substrate can be obtained.

Furthermore, as the synthetic resin emulsion (A) of the present invention, a cationic acrylic resin emulsion satisfying the above (1) and (2) is preferably included. Such a cationic acrylic resin emulsion is preferably an aqueous dispersion of a polymer obtained by polymerizing (meth) acrylic acid alkyl ester and a cationic monomer as essential components as constituent monomers.

The (meth) acrylic acid alkyl ester is the main component of the resin skeleton. In the present invention, the acrylic acid alkyl ester and the methacrylic acid alkyl ester are collectively referred to as (meth) acrylic acid alkyl ester. A monomer is a general term for compounds having a polymerizable unsaturated double bond.

Specific examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl ( (Meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) Examples include acrylate, octadecyl (meth) acrylate, and cyclohexyl (meth) acrylate. These can be used alone or in combination of two or more.

The cationic monomer is not particularly limited as long as it is a cationic monomer having an unsaturated double bond. For example, a cationic (meth) acrylamide monomer, a cationic maleic acid amide monomer, a cationic pyridine monomer Etc. These can be used alone or in combination of two or more.

Specifically,
Examples of cationic (meth) acrylamide monomers include (meth) acrylamides such as 3-acrylamidopropyltrimethylammonium chloride, 2- (meth) acrylamide ethyltrimethylammonium methosulfate, 2- (meth) acrylamide ethyltrimethylammonium methosulfate, and the like. Trialkylammonium salts;
(Meth) such as 3- (meth) acrylamide-2-hydroxypropyltrimethylammonium chloride, 3- (meth) acrylamide-2-hydroxypropyltrimethylammonium methosulfate, 3- (meth) acrylamide-2-hydroxypropyltrimethylammonium chloride Acrylamide hydroxyalkyltrialkylammonium salt;
Dialkylaminoalkyl (meth) acrylamide salts such as 2-dimethylaminoethyl (meth) acrylamide hydrochloride, 2-diethylaminopropyl (meth) acrylamide sulfate, 2-dimethylaminoethyl (meth) acrylamide hydrochloride;
Dialkylaminohydroxyalkyl (meth) acrylamide salts such as 3-dimethylamido-2-hydroxypropyl (meth) acrylamide hydrochloride, 3-diethylamino-2-hydroxypropyl (meth) acrylamide sulfate;
Etc.

Examples of the cationic maleic acid amide monomer include maleic acid (N, N-dimethylpropylenediamine monoamide) salt. By including such a cationic monomer, it is possible to exhibit high adhesion to the inorganic porous substrate.

Furthermore, as the synthetic resin emulsion (A) of the present invention, a cationic acrylic silicone resin emulsion satisfying the above (1) and (2) is suitable. The cationic acrylic silicone resin emulsion is preferably an aqueous dispersion of a polymer obtained by polymerizing the above (meth) acrylic acid alkyl ester, the above cationic monomer, and an alkoxysilane monomer as essential components.

  The alkoxysilane monomer preferably has a polymerizable double bond and a hydrolyzable alkoxy group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriacetoxysilane. Γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, vinyltrichlorosilane, γ- (meth) acryloxypropyltris (β-methoxyethoxy) silane, and the like. it can. These can be used alone or in combination of two or more.

In the present invention, for example, an aromatic monomer, a vinyl ester monomer, an acrylonitrile monomer or the like may be added as a component constituting the synthetic resin emulsion (A) in addition to the monomer.
Examples of the aromatic monomer include styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene, phenyl (meth) acrylate, benzyl (meth) acrylate, and the like. .
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, and the like.
Examples of the acrylonitrile monomer include acrylonitrile and methacrylonitrile. These can be used alone or in combination of two or more.

The polymerization method of the synthetic resin emulsion (A) is not particularly limited. For example, a polymerization initiator, a polymerization catalyst, a reducing agent, a surfactant, a pH adjuster, and the like can be used, and polymerization is performed by a known method such as a batch method or an injection method. Is possible. The polymerization temperature at this time can also be appropriately selected.

The resin solid content of the synthetic resin emulsion (A) is preferably 1 to 50% by weight (more preferably 5 to 40% by weight). The synthetic resin emulsion (A) contains water as a medium, but can also contain a water-soluble solvent or the like. The minimum film-forming temperature and / or glass transition temperature of the synthetic resin emulsion (A) is preferably 5 ° C. or lower (more preferably 0 ° C. or lower). By using the component (A) having such a minimum film-forming temperature and / or glass transition temperature, it is possible to reduce the amount of film-forming aids used.

The aqueous coating material of the present invention includes a water-soluble silane compound (B) as an essential component. By including the water-soluble silane compound (B), the permeability of the synthetic resin emulsion (A) is further increased, and a film is formed inside the inorganic porous substrate, and a uniform film is formed on the surface of the inorganic porous substrate. Can be formed. For this reason, while exhibiting the still more outstanding water stop performance, the finish excellent in aesthetics can be obtained. In particular, in a low temperature environment, a sufficient film can be formed up to the inside of the inorganic porous substrate, and a sufficient water stopping property can be obtained. Although this action mechanism is not limited, generally, in a low temperature environment, the viscosity increase of the aqueous coating material tends to increase, and therefore, the aqueous coating material reaches the inside of the inorganic porous substrate. It becomes difficult to penetrate. On the other hand, since the aqueous coating material of the present invention has a reduced viscosity due to the action of the water-soluble silane compound (B), the impregnation property of the synthetic resin emulsion (A) can be improved. As a result, a sufficient film can be formed inside the inorganic porous substrate. Sufficient permeability is exhibited by the above action, and a film can be formed inside the inorganic porous substrate, and a uniform film can be formed on the surface of the inorganic porous substrate. In addition, the water-soluble silane compound in the present invention is not particularly limited as long as it is soluble in water, and preferably capable of producing a 1% by weight silane aqueous solution. When preparing this 1 wt% silane aqueous solution, the pH may be adjusted as necessary.

  Examples of the water-soluble silane compound (B) include 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycol. Epoxy group-containing silane compounds such as sidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane; amino group-containing silane compounds such as 3-aminopropyltriethoxysilane and 3-aminopropyltriethoxysilane; (Meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropylmethyldiethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, etc. ) Acrylic group containing Emissions compounds; Other, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, and 3-isocyanate propyl triethoxysilane, and the like. These can be used alone or in combination of two or more.

  Further, the water-soluble silane compound (B) preferably has a 1 wt% silane aqueous solution having a pH of less than 7 (more preferably 1 or more and 6.5 or less, and further preferably 1.5 or more and 6 or less). (That is, the solubility in water having a pH of less than 7 (more preferably 1 or more and 6.5 or less, more preferably 1.5 or more and 6 or less) is preferably at least 1 g / 100 g or more.) The stability of the aqueous coating material can be increased (gelling and the like can be suppressed), and the effects of the present invention can be further enhanced. In the present invention, an epoxy group-containing silane compound is suitable as the water-soluble silane compound (B). The pH of the 1 wt% silane aqueous solution is a pH measured when a 1 wt% silane aqueous solution is prepared.

The water-soluble silane compound (B) is used in an amount of 0.1 to 20 parts by weight (preferably 0.3 to 15 parts by weight, more preferably 0.8 parts by weight based on 100 parts by weight of the resin solid content of the synthetic resin emulsion (A). 5 to 10 parts by weight). As a result, the aqueous coating material can form a uniform finished film having sufficient permeability to the inorganic porous substrate and excellent water-stopping performance.

The aqueous coating material of the present invention preferably has a pH of 1.5 to 7 (more preferably 2 to 6.5). The heating residue is preferably 2 to 30% by weight (more preferably 5 to 20% by weight), and the viscosity by Iwata Cup NK-2 is 20 sec or less (more preferably 15 sec or less) (temperature 23 ° C.). is there. In such a case, sufficient permeability and water stopping performance can be imparted to the inorganic porous substrate, and a uniform finish can be obtained. The heating residue of the aqueous coating material is a value measured by the method of JIS K 5601-1-2, and the heating temperature is 105 ° C. and the heating time is 60 minutes.

  It does not specifically limit as a manufacturing method of the aqueous coating material of this invention, What is necessary is just to mix the said synthetic resin emulsion (A) and the said water-soluble silane compound (B) by a conventional method, and can also stir at the time of mixing. The aqueous coating material of the present invention preferably has a mode in which the water-soluble silane compound (B) is dissolved in water, and is mixed with the synthetic resin emulsion (A) in a state where the water-soluble silane compound (B) is not emulsified. It is preferable.

  The aqueous coating material of the present invention preferably contains a film-forming aid (C). Thereby, the film-forming property in an inorganic porous base material can fully be exhibited. The film-forming aid (C) is preferably 10 parts by weight or less (more preferably 0.5 to 5 parts by weight) with respect to 100 parts by weight of the resin solid content of the synthetic resin emulsion (A). Even when the mixing amount of the film-forming auxiliary (C) is within the above range, the water-based coating material penetrates into the inorganic porous base material to form a film, so that the water-stopping performance can be sufficiently exhibited. . In general, a synthetic resin emulsion containing a film-forming aid swells and increases the viscosity of the aqueous coating material. However, in the present invention, the water-based coating material is reduced in viscosity by the action of the water-soluble silane compound (B), so even if the amount of the film-forming aid (C) used is in the above range, the effect is obtained. It can be fully demonstrated.

As the film-forming auxiliary (C), any of water-insoluble, hardly soluble, water-soluble and the like can be used, and is not particularly limited. For example, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether Acetate, ethylene glycol diethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate 2,2,4-trimethyl-1,3-pentanediol diisobutyrate and benzyl alcohol. Preferred are propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether and the like. These can be used alone or in combination of two or more.

In the aqueous coating material of the present invention, in addition to the above-described components, if necessary, a color pigment, an extender pigment, a rust preventive pigment, a pH adjuster, a plasticizer, an antiseptic agent, an antifungal agent, an antialgae agent, an antifoaming agent, Mixing leveling agents, pigment dispersants, anti-settling agents, anti-sagging agents, matting agents, catalysts, crosslinking agents, curing accelerators, UV absorbers, light stabilizers, etc., as long as the effects of the present invention are not impaired. can do.

(Inorganic porous substrate)
As the inorganic porous substrate of the present invention, for example, those used for exposed surfaces, non-combustible boards, tunnel interior boards, floor surfaces, floor materials, etc., for example, mortar, concrete, gypsum board, siding board, Extruded plates, slate plates, fiber-mixed cement plates, calcium silicate plates, ALC plates, and the like can be mentioned.

When the above-mentioned aqueous coating material is applied to such an inorganic porous substrate, it has sufficient permeability, imparts water-stopping performance to the inorganic porous substrate, and is beautiful without causing unevenness. Excellent finish is obtained.

In the coating of the aqueous coating material, for example, various methods such as brush coating, roller coating, and spray coating can be employed. Moreover, when painting in a factory, it can also paint using a roll coater, a flow coater, etc. besides the above.

The coating amount of the aqueous coating material is preferably about 0.01 to 0.5 kg / m ² (more preferably 0.05 to 0.3 kg / m ² ). The number of application of the aqueous coating material may be appropriately set depending on the state of the base, but is preferably 1 to 2 times. The drying time of the aqueous coating material is preferably 1 hour or longer. The drying temperature is preferably 0 ° C. or higher and 50 ° C. or lower, more preferably 5 ° C. or higher and 40 ° C. or lower.

  The coating film formed by the aqueous coating material of the present invention has excellent adhesion to a wide variety of top coating materials. The top coating material is not particularly limited as long as it is generally used for painting a building or a civil engineering structure.

The method for coating the top coat material is not particularly limited and can be applied by a known method. For example, it can be applied by various methods such as brush coating, spray coating, roller coating, roll coater, and flow coater. That is, each top coating material may be applied based on a normal process with the optimum coating specifications for each top coating material.

  Examples and comparative examples are shown below to clarify the features of the present invention.

(Manufacture of aqueous coating materials 1-15)
According to the formulation shown in Table 1, (A) component, (B) component, additive, and water were mixed by a conventional method to obtain aqueous coating materials 1 to 15.
In addition, the following were used as a raw material.
(A1) Acrylic resin emulsion (solid content: 40% by weight, average particle size: 70 nm, pH: 5.1)
(A2) Cationic acrylic resin emulsion (solid content: 30% by weight, average particle size: 60 nm, pH: 3.7)
(A3) Cationic acrylic silicone resin emulsion (solid content: 30% by weight, average particle size: 40 nm, pH: 3.5)
(A4) Acrylic resin emulsion (solid content: 40% by weight, average particle size: 125 nm, pH: 4.0)
(A5) Acrylic resin emulsion (solid content: 40% by weight, average particle size: 70 nm, pH: 8.7)
(B1) 3-Glycidoxypropyltrimethoxysilane (active ingredient: 100% by weight, water solubility: pH 5.3 of 1% by weight aqueous solution)
(B2) 3-Glycidoxypropyltriethoxysilane (active ingredient: 100% by weight, water-soluble: pH 4.0 of a 1% by weight aqueous solution)
(B3) 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (active ingredient: 100% by weight, water solubility: pH 4.0 of 1% by weight aqueous solution)
(B4) N-phenyl-3-aminopropyltrimethoxysilane (active ingredient: 100% by weight, water solubility: pH 4.0 of an aqueous solution of 1% by weight)
(B5) 3-Aminopropyltrimethoxysilane (active ingredient: 100% by weight, water solubility: pH 10 of 1% by weight aqueous solution)
(B6) P-styryltrimethoxysilane (active ingredient: 100% by weight, water-insoluble)
(B7) Propylene trimethoxysilane emulsion (active ingredient: 30% by weight, including surfactant)
Additive 1: Propylene glycol monobutyl ether Additive 2: Antifoaming agent, thickener, etc.

(Examples I-1 to I-10, Comparative Examples I-1 to I-5)
With respect to the aqueous coating materials 1 to 15, specimens [I] were prepared, and the following evaluations were performed. The results are shown in Table 1.
<Preparation of Specimen [I]>
An inorganic porous substrate (slate plate: L100 × W100 × T3 mm) was coated with a water-based coating material at a coating amount of 0.1 kg / m ² and cured at room temperature (25 ° C.) for 24 hours. I].

<Permeability and aesthetic evaluation>
About the state of the said test body [I] surface, the permeability of the aqueous coating material and the aesthetics (appearance) were evaluated by visual observation. The evaluation criteria are as follows.
A: Good finish and uniform finish.
B: Penetration is generally good, but unevenness occurs partially.
C: A film is formed on the surface (entire surface) of the substrate, and the permeability is insufficient.
D: Cracks or the like occur in the coating film on the surface of the substrate, and the permeability is insufficient.

<Waterproof evaluation>
Water was sprayed on the specimen [I] with a spray to evaluate water permeability. The evaluation criteria are as follows.
A: There is no penetration of water (it does not become wet color).
B: Water penetrates partially (partially gets wet color).
C: Water penetrates the substrate (almost the entire surface becomes wet color).
D: Water penetrates the substrate (the entire surface becomes wet color).

(Examples II-1 to II-10)
For the aqueous coating materials 1 to 10, the following specimens [II] were prepared, and the same evaluation was performed. The results are shown in Table 2.
<Preparation of Specimen [II]>
An inorganic porous substrate (slate plate: L100 × W100 × T3 mm) was coated with a water-based coating material at a coating amount of 0.1 kg / m ² and cured at a low temperature (5 ° C.) for 24 hours. II].

Claims (3)

An aqueous coating material for an inorganic porous substrate,
Including a synthetic resin emulsion (A) and a water-soluble silane compound (B),
The synthetic resin emulsion (A) has an average particle size of 100 nm or less, a pH of 2 or more and 6 or less,
An aqueous coating material comprising 0.1 to 20 parts by weight of the water-soluble silane compound (B) with respect to 100 parts by weight of the resin solid content of the synthetic resin emulsion (A).   The aqueous coating material according to claim 1, wherein the water-soluble silane compound (B) has a pH of a 1 wt% aqueous solution of less than 7. The aqueous coating material according to claim 1, wherein the water-soluble silane compound (B) is an epoxy group-containing silane compound.