JP2013170188A - Water absorption preventing coating material for inorganic base material, surface coated concrete structure having coating film obtained from the same, and method of producing the structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water absorption preventing coating material for inorganic base materials capable of maintaining its water absorption properties even when exposed to running water for a long period under outdoor natural environments, maintaining a blackening prevention effect, and having excellent application properties.SOLUTION: A water absorption preventing coating material for inorganic base materials is an aqueous dispersion including: an acid modified polyolefin resin (A) having an unsaturated carboxylic acid content of 0.1-10 mass%; alkyl alkoxysilane and/or a condensate thereof (B); and an aqueous medium. In the water absorption preventing coating material for inorganic base materials, a mass ratio ((A)/(B)) of the acid modified polyolefin resin (A) to the alkyl alkoxysilane and/or the condensate thereof (B) is 90/10 to 1/99.

Description

  The present invention relates to a water absorption preventing coating agent for an inorganic substrate, a surface-coated concrete structure having a film obtained from the coating agent, and a method for producing the structure.

Inorganic base materials such as concrete and brick are used in large quantities as civil engineering and building materials. In particular, concrete structures obtained by mixing water, sand, gravel, etc. with cement and curing in any shape are essential for life, society, and industry as roads, bridges, tunnels, dams, houses, buildings, etc. It has become something that can not be.
However, the concrete structure has problems such as cracks, peeling and white flower due to long-term use, and these problems are largely caused by the concrete structure absorbing water. In addition, the blackening of the surface of the concrete structure due to long-term use is also a problem because it impairs the beauty.
Many attempts to prevent water absorption of a concrete structure have been studied. For example, Patent Documents 1 to 3 disclose silane-based compound-containing paints having an effect of preventing water absorption.
However, even if the paint described in these patent documents is applied to a concrete structure, the effect of preventing the water absorption of the paint is not sufficient when used for a long time in an outdoor natural environment. In particular, the tendency was remarkable in places that are easily exposed to running water, such as portions that become rainwater flow paths when it rains. Furthermore, these patent documents do not describe the effect of suppressing the blackening of the surface caused by black mold or the like.
Moreover, the coating material containing the silane compound described in Patent Documents 1 to 3 has an active ingredient content of about 40% by mass, and in order to develop its effect, 300 g / m ^{2 on} the surface of the concrete structure. There is a problem in coating properties, such as a large amount of coating required, and therefore a long time for drying, and uneven coating due to liquid dripping. Moreover, since the coating material of patent document 3 has a high viscosity, there existed a problem in the coating by a spray.

Japanese Patent Application Laid-Open No. 11-76797 Japanese Patent Laid-Open No. 11-80552 JP 2008-291225 A

  The present invention solves the above problems, and can maintain water absorption prevention even when exposed to running water for a long period of time in an outdoor natural environment, and can also maintain the effect of suppressing blackening, and can be coated. An object of the present invention is to provide a water-absorption-preventing coating agent for an inorganic substrate which is excellent in the above.

As a result of intensive studies to solve the above problems, the present inventors have found that an aqueous dispersion containing a specific acid-modified polyolefin resin, an alkylalkoxysilane and / or a condensate thereof, and an aqueous medium is the above-mentioned problem. The present invention has been found.
That is, the gist of the present invention is as follows.
(1) An aqueous dispersion containing an acid-modified polyolefin resin (A) having an unsaturated carboxylic acid content of 0.1 to 10% by mass, an alkylalkoxysilane and / or its condensate (B), and an aqueous medium The mass ratio ((A) / (B)) of the acid-modified polyolefin resin (A) to the alkylalkoxysilane and / or its condensate (B) is 90/10 to 1/99. A water-absorption-preventing coating agent for inorganic substrates.
(2) The water absorption preventing coating agent for an inorganic base material according to (1), wherein the number average particle diameter of the dispersed particles in the aqueous dispersion is 0.02 to 0.50 μm.
(3) The water-absorbing inorganic base material according to (1) or (2), wherein the acid-modified polyolefin resin (A) is an ethylene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer Prevention coating agent.
(4) The melt flow rate value (190 ° C., 2.16 kg load according to JIS K7210: 1999) of the acid-modified polyolefin resin (A) is 1 to 500 g / 10 minutes, (1) to (3 The water absorption preventing coating agent for an inorganic base material according to any one of 1).
(5) The alkylalkoxysilane of the alkylalkoxysilane and / or the condensate thereof (B) is a compound represented by the following general formula (1), and is described in any one of (1) to (4) Water-absorbing coating agent for inorganic substrates.
Si (R) _n (R ¹ ) _4-n (1)
In (Equation (1), R is an alkyl group, a substituted alkyl group or aryl group having 1 to 30 carbon atoms, ^{R 1} is an alkoxy group having 1 to 6 carbon atoms, n represents is an integer from 1 to 3 .)
(6) The surface-coated concrete structure, wherein the whole or part of the surface of the concrete structure has a film obtained from the water-absorbing coating agent for inorganic substrates according to any one of (1) to (5). .
(7) A method for producing a surface-coated concrete structure as described in (6) above, wherein the water absorption preventing coating agent for an inorganic substrate according to any one of (1) to (5) is applied to the surface of the concrete structure. A method for producing a surface-coated concrete structure, which is applied to the whole or a part of the structure.

The water-absorption-preventing coating agent for an inorganic base material of the present invention is applied to the whole or a part of the surface of the inorganic base material to obtain an inorganic base material that is excellent in water-absorption-preventing property and suppressed water absorption into the inside. Can do. Moreover, when an inorganic base material is a concrete structure, generation | occurrence | production of various problems, such as a crack of a concrete structure resulting from water absorption, peeling, and a white flower, can be suppressed.
In addition, the film obtained from the water-absorption-preventing coating agent for an inorganic base material of the present invention firmly adheres to the surface of an inorganic base material such as a concrete structure, and therefore when used for a long time in an outdoor natural environment, Even under use conditions such as exposure to running water, the water absorption preventing effect is high, and as a result, the effect of suppressing the occurrence of various problems in the concrete structure is also high. Furthermore, it also has the effect of suppressing blackening of the concrete structure surface caused by black mold or the like.
Further, the water absorption preventing coating agent for an inorganic base material of the present invention brings about the above effect even if the coating amount is small, so that it is possible to suppress coating unevenness due to liquid dripping at the time of coating and shorten the drying time, Excellent coatability.

Hereinafter, the present invention will be described in detail.
The water absorption preventing coating agent for an inorganic base material of the present invention is an acid-modified polyolefin resin (A) having an unsaturated carboxylic acid content of 0.1 to 10% by mass [hereinafter abbreviated as acid-modified polyolefin resin (A). The alkylalkoxysilane and / or its condensate (B), and an aqueous medium.
The acid-modified polyolefin resin (A) contains an olefin component as a main component, and the olefin component includes carbon such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, 1-hexene. Alkenes of 2 to 6 are preferable, and a mixture thereof may be used. Among these, from the viewpoints of adhesion to an inorganic base material and ease of polymerization of the resin, an alkene having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene and 1-butene is more preferable, and ethylene and propylene are particularly preferable. More preferred is ethylene.
The content of the olefin component is preferably 45 to 99.9% by mass of the acid-modified polyolefin resin (A), more preferably 55 to 99.8% by mass, and 60 to 99.7% by mass. It is particularly preferable that it is 70 to 99.5% by mass, and most preferably 80 to 99.0% by mass. When the content of the olefin component is out of the range of 45 to 99.9% by mass, the adhesion to the inorganic base material and the water absorption preventing property may be deteriorated.

The acid-modified polyolefin resin (A) needs to contain an unsaturated carboxylic acid component from the viewpoint of improving the adhesion to an inorganic base material and facilitating processing into an aqueous dispersion described later. The content of the unsaturated carboxylic acid component is required to be 0.1 to 10% by mass of the acid-modified polyolefin resin (A), preferably 0.2 to 8% by mass, More preferably, it is 6 mass%, It is especially preferable that it is 1-5 mass%, It is more preferable that it is 2-4 mass%. When the content of the unsaturated carboxylic acid component is less than 0.1% by mass, the adhesion to the inorganic base material tends to decrease, and it is difficult to process into an aqueous dispersion, while 10% by mass. When it exceeds%, the adhesion to the inorganic base material, the water absorption prevention property, and the sustainability of the water absorption prevention effect tend to decrease.
Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, and the like, as well as unsaturated dicarboxylic acid half esters and half amides. It is done. Of these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferable, and (maleic anhydride) is particularly preferable. Here, (anhydrous) maleic acid means maleic acid or maleic anhydride.
The unsaturated carboxylic acid component only needs to be copolymerized with the olefin component, and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification). Is mentioned.

In addition to the olefin component and unsaturated carboxylic acid component, the acid-modified polyolefin resin (A) is copolymerized with other components, so that it has adhesion to an inorganic base material, water absorption prevention, water absorption prevention effect The sustainability may be further improved.
Specific examples of such components include (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate, dimethyl maleate, diethyl maleate, and maleate. Basic maleic diesters such as dibutyl acid, alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, and vinyl esters Examples thereof include vinyl alcohol obtained by saponification with a compound, (meth) acrylic acid amides, and the like, and mixtures thereof. Among them, (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl versatate, etc. (Meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate are more preferred. In addition, “(meth) acrylic acid˜” means “acrylic acid˜ or methacrylic acid˜”.
These components may be copolymerized in the acid-modified polyolefin resin (A), and the form thereof is not limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization ( Graft modification).
As content of these components in acid-modified polyolefin resin (A), it is preferable that it is 1-45 mass% of acid-modified polyolefin resin (A), it is more preferable that it is 2-35 mass%, 3- The content is particularly preferably 25% by mass, and more preferably 5 to 20% by mass. When the content of these components is outside the preferred range, the adhesion to the inorganic base material, the water absorption preventing property, and the sustainability of the water absorption preventing effect tend to decrease.

  Based on the above points, the acid-modified polyolefin resin in the present invention specifically includes ethylene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer, ethylene-propylene- (meth) acrylic acid ester- (Anhydrous) maleic acid copolymer, ethylene-butene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer, propylene-butene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer, ethylene -Propylene-butene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene- (anhydrous) maleic acid copolymer, ethylene- Propylene- (anhydrous) maleic acid copolymer, ethylene-butene- (anhydrous) maleic acid copolymer, propylene Butene- (anhydrous) maleic acid copolymer, ethylene-propylene-butene- (anhydrous) maleic acid copolymer, ethylene-vinyl acetate- (anhydrous) maleic copolymer, ethylene-vinyl acetate-acrylic- (anhydrous) maleic Examples include ethylene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer, which is excellent in adhesion to an inorganic base material, water absorption prevention, and water absorption prevention effect. preferable.

As melting | fusing point of acid-modified polyolefin resin (A) in this invention, 50 degreeC or more is preferable, 60-250 degreeC is more preferable, and 80-200 degreeC is especially preferable. When the melting point is less than 50 ° C., the sustainability of the water absorption preventing effect tends to decrease.
The weight average molecular weight of the acid-modified polyolefin resin (A) is preferably 10,000 to 100,000, more preferably 20,000 to 70,000, particularly preferably 35,000 to 50,000, and further preferably 40,000 to 50,000. When the weight average molecular weight is less than 10,000, the water absorption preventing effect tends to decrease. On the other hand, when the weight average molecular weight exceeds 100,000, the adhesion to the inorganic base material tends to be lowered or it becomes difficult to process into an aqueous dispersion.
However, in general, a polyolefin resin is hardly soluble in a solvent, and thus it may be difficult to measure the molecular weight. In such a case, the melt flow rate value indicating the fluidity of the molten resin is set to the molecular weight. A good guideline.
The melt flow rate value of the acid-modified polyolefin resin (A) (190 ° C. according to JIS K7210: 1999, 2.16 kg load) is preferably 1 to 500 g / 10 min, and preferably 2 to 200 g / 10 min. Is more preferably 3 to 80 g / 10 minutes, and further preferably 3 to 10 g / 10 minutes. When the melt flow rate value exceeds 500 g / 10 min, the water absorption preventing effect tends to be lowered. On the other hand, when the melt flow rate value is less than 1 g / 10 minutes, the adhesion to the inorganic base material tends to be lowered or it becomes difficult to process into an aqueous dispersion.

  The acid-modified polyolefin resin (A) in the present invention may be chlorinated. Examples of the chlorination method include a method in which an acid-modified polyolefin resin is dissolved in a chlorinated solvent and then gaseous chlorine is blown while irradiating with ultraviolet rays or in the presence of a radical generator.

Next, the alkyl alkoxysilane and / or its condensate (B) will be described. The alkylalkoxysilane in the present invention is a silane compound having at least one alkyl group and at least one alkoxy group in the molecule, and is preferably an alkylalkoxysilane represented by the following general formula (1).
Si (R) _n (R ¹ ) _4-n (1)
In the formula (1), R is a stable hydrophobic group that hardly causes hydrolysis, and examples thereof include an alkyl group having 1 to 30 carbon atoms, a substituted alkyl group, and an aryl group. Examples of the substituted alkyl group include a halogenated alkyl group and an aromatic substituted alkyl group. Examples of the halogenated alkyl group include fluorinated products, chlorinated products, and brominated products of the above alkyl groups. Examples of the aromatic substituted alkyl group include halogen-substituted benzyl groups such as benzyl group, 4-chlorobenzyl group and 4-bromobenzyl group. Examples of the aryl group include a phenyl group, a tolyl group, a mesityl group, and a naphthyl group. Among these, an alkyl group having 1 to 30 carbon atoms is preferable from the viewpoint of water absorption prevention and processability to an aqueous dispersion described later. R ¹ is a hydrolyzable functional group and is preferably an alkoxy group having 1 to 6 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. n is an integer of 1 to 3. When n is 0, there is a problem that water absorption prevention is not sufficient.
Alkyl alkoxysilane If having a plurality of R or R ^1, may be the same or different, each.
In addition, the alkylalkoxysilane condensate in the present invention is a condensate of the above alkylalkoxysilane, and examples thereof include dimers, trimers and oligomers of alkylalkoxysilane.

  As described above, the water-absorption-preventing coating agent for inorganic substrates of the present invention is an aqueous dispersion containing an acid-modified polyolefin resin (A), an alkylalkoxysilane and / or a condensate thereof (B), and an aqueous medium. It is.

  The mass ratio ((A) / (B)) of the acid-modified polyolefin resin (A) and the alkylalkoxysilane and / or its condensate (B) in the water-absorption-preventing coating agent for inorganic substrates is 90/10 to 10/10. 1/99 is necessary, 70/30 to 2/98 is preferable, 60/40 to 3/97 is more preferable, and 50/50 to 3/97 is particularly preferable. Preferably, it is 40/60 to 3/97, more preferably 70/30 to 3/97. If the acid-modified polyolefin resin (A) exceeds 90% by mass, the adhesiveness to the inorganic substrate and the sustainability of the water absorption preventing effect may be lowered. If it is less than 1% by mass, the effect of the present invention is obtained. It tends to decrease.

  The aqueous medium contained in the inorganic base water-absorbing coating agent is an aqueous medium contained in an aqueous dispersion of an acid-modified polyolefin resin (A) described later, and an aqueous dispersion of an alkylalkoxysilane and / or its condensate (B). It is the same as the aqueous medium contained in the body. Specifically, it is a medium composed of water or a liquid containing water, and may contain a neutralizing agent, a water-soluble organic solvent, an emulsifier, a pH adjuster, etc. Good. Furthermore, you may contain another water-soluble compound and a liquid in the range which does not impair the effect of this invention.

  The concentration of the acid-modified polyolefin resin (A) and the alkylalkoxysilane and / or its condensate (B) in the water-absorption-preventing coating agent for inorganic base materials (hereinafter sometimes referred to as an active ingredient) is 1 to It is preferably 65% by mass, more preferably 5 to 50% by mass, and particularly preferably 10 to 40% by mass. When the total concentration of (A) and (B) is less than 1% by mass, the amount applied to the inorganic base material may increase, which may make application difficult. In some cases, unevenness may occur.

  Although the manufacturing method of the water absorption prevention coating agent for inorganic base materials is not specifically limited, the aqueous dispersion of acid-modified polyolefin resin (A) and the aqueous dispersion of alkyl alkoxysilane and / or its condensate (B) are mixed. The method is simple and preferred. The mixing may be carried out under mild conditions, and high speed stirring, long time stirring, heating, pressurization, decompression, etc. are not particularly required.

The above-mentioned acid-modified polyolefin resin (A) can be processed into an aqueous dispersion, and in the production of the water-absorption-preventing coating agent for inorganic substrates of the present invention, such an acid-modified polyolefin resin (A) is used. Aqueous dispersions can be utilized.
Next, the aqueous dispersion of acid-modified polyolefin resin (A) will be described.
As a method for producing the aqueous dispersion of the acid-modified polyolefin resin (A), a known dispersion method such as a self-emulsification method or a forced emulsification method may be employed. As the aqueous dispersion, an anionic aqueous dispersion obtained by neutralizing the acid-modified polyolefin resin (A) with a basic compound in an aqueous medium is preferable from the viewpoint of adhesion to an inorganic substrate. .
When the acid-modified polyolefin resin (A) containing an acid anhydride as the unsaturated carboxylic acid component is dispersed in an aqueous dispersion, the acid anhydride component in the aqueous dispersion is in a ring-opened and / or ring-closed state. It doesn't matter.

  The aqueous medium used in the aqueous dispersion of the acid-modified polyolefin resin (A) is a medium composed of water or a liquid containing water, and includes a neutralizing agent such as a basic compound that contributes to stabilization of the dispersion, a water-soluble medium. Organic solvent or the like may be contained.

  The basic compound is not particularly limited as long as it can neutralize the carboxyl group of the acid-modified polyolefin resin (A), and ammonia or an organic amine compound that volatilizes during film formation is preferable from the viewpoint of water resistance of the film. Specific examples of the organic amine compound include triethylamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, and 3-ethoxypropylamine. , 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like.

  As the water-soluble organic solvent, those which volatilize during film formation are preferable from the viewpoint of water resistance of the film. Specific examples include ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether and the like.

  In addition, in the case of aqueous dispersion of the acid-modified polyolefin resin (A), a non-volatile aqueous dispersion such as a surfactant, a high acid value wax, an emulsifier or a dispersant, which is optionally added for the purpose of promoting dispersion. In order to reduce the content of the non-volatile aqueous dispersion aid contained in the water-absorption-preventing coating agent for inorganic substrates, it is preferable to employ a dispersion method that does not substantially use a solubilizing aid. In addition, when there is much content of a non-volatile aqueous | water-based dispersion | distribution adjuvant, the adhesiveness to an inorganic base material, water absorption prevention property, the sustainability of a water absorption prevention effect, etc. may be reduced.

  The number average particle size of the dispersed particles in the aqueous dispersion of the acid-modified polyolefin resin (A) is preferably 0.02 to 0.5 μm, and more preferably 0.05 to 0.3 μm. When the number average particle size is less than 0.02 μm, wetting and spreading during application may be reduced, and when it exceeds 0.5 μm, spots may occur when applied, and the effect of the present invention is achieved. May decrease.

On the other hand, alkylalkoxysilane and / or its condensate (B) can also be processed into an aqueous dispersion. In the production of the water-absorbing coating agent for inorganic substrates of the present invention, such alkylalkoxysilane and An aqueous dispersion of the condensate (B) can be used.
Next, the aqueous dispersion of alkyl alkoxysilane and / or its condensate (B) will be described.
The content of the alkylalkoxysilane and / or its condensate (B) in the aqueous dispersion of the alkylalkoxysilane and / or its condensate (B) is preferably 1 to 65% by mass, and 5 to 50% by mass. It is more preferable that the water content is 35 to 99% by mass, and more preferably 50 to 95% by mass. When the content of the alkylalkoxysilane and / or the condensate thereof (B) is less than 1% by mass, the storage stability of the aqueous dispersion is impaired, or water absorption prevention for an inorganic base material obtained from the aqueous dispersion The coating agent may be difficult to apply. When the content of the alkylalkoxysilane and / or its condensate (B) exceeds 65% by mass, aqueous dispersion tends to be difficult.

  As a method for producing an aqueous dispersion of alkylalkoxysilane and / or its condensate (B), a known dispersion method may be employed. Specifically, a method of stirring the alkylalkoxysilane and / or its condensate (B) in an aqueous medium at high speed can be mentioned. The aqueous medium used for the aqueous dispersion of the alkylalkoxysilane and / or its condensate (B) is a medium composed of water or a liquid containing water, such as an emulsifier or pH that contributes to dispersion stabilization. A regulator or the like may be included.

In aqueous dispersion of the alkylalkoxysilane and / or its condensate (B), an emulsifier such as a surfactant is added in order to promote aqueous dispersion or maintain stability during storage of the aqueous dispersion. May be.
As the emulsifier, any of nonionic, anionic and cationic types can be used. From the viewpoint of stability when mixed with an aqueous dispersion of the acid-modified polyolefin resin (A), nonionic, Anionic ones are preferred. Among these, nonionic emulsifiers are preferable because of their excellent emulsion stability. As the nonionic emulsifier, those having a type of HLB = 4 to 22 or a mixture thereof are preferably used. Specific examples include polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene derivatives, sorbitan monolaurate, sorbitan monostearate, polyoxyethylene sorbitan monolaurate and polyoxyethylene Examples thereof include ethylene sorbitan monostearate. The HLB of other emulsifiers is preferably 1.5 to 22, more preferably 4 to 15. Two or more of these emulsifiers can be used in combination.
The content of the emulsifier is preferably 50% by mass or less, and more preferably 0.1 to 20% by mass of the alkylalkoxysilane and / or its condensate (B). When it exceeds 50% by mass, the effect of addition does not change, and the effect of the obtained water-absorbing coating agent for inorganic base materials tends to decrease.

  The pH adjuster is not particularly limited. Considering effects such as performance and stability of the alkylalkoxysilane and / or its condensate (B) to be used, a basic compound, an acidic compound, and a pH buffering agent may be added as necessary.

  The number average particle size of the dispersed particles of the aqueous dispersion of alkylalkoxysilane and / or condensate thereof (B) thus obtained is preferably 0.5 μm or less, and preferably 0.1 to 0 More preferably, it is 4 μm. When the number average particle diameter exceeds 0.5 μm, the resulting aqueous dispersion may be unstable and easily separated.

  In the water absorption preventing coating agent for an inorganic base material of the present invention produced by the above method, the number average particle diameter of the dispersed particles is preferably 0.02 to 0.50 μm, and preferably 0.04 to 0.40 μm. More preferably, it is particularly preferably 0.05 to 0.30 μm. When the number average particle diameter is less than 0.02 μm, wetting and spreading may be reduced during application, and when it exceeds 0.50 μm, spots may occur when applied, and the effect of the present invention. May decrease.

  When applying to an inorganic base material, the viscosity measured at 20 ° C. with a B-type viscometer of the water absorption prevention coating agent for an inorganic base material is preferably 1000 mPa · S or less, preferably 500 mPa · S or less. More preferably, it is 100 mPa · S or less, and more preferably 50 mPa · S or less. If the viscosity exceeds 1000 mPa · S, cracks and unevenness of the coated surface may occur. Moreover, when the viscosity is high, application by spray coating becomes difficult.

The water-absorption-preventing coating agent for an inorganic substrate of the present invention includes a crosslinking agent, a silane coupling agent, a resin other than the acid-modified polyolefin resin (A) (hereinafter, may be abbreviated as other resin), inorganic fine particles, and various additives. In particular, the crosslinking agent and the silane coupling agent are preferably contained because the effects of the present invention are further improved.
In addition, the above crosslinking agents, silane coupling agents, other resins, inorganic fine particles, various additives, etc. are processed into aqueous solutions or aqueous dispersions, and then mixed with the water absorption preventing coating agent for inorganic substrates. It is preferable to use it.

As the crosslinking agent, a crosslinking agent having self-crosslinking property, a crosslinking agent having a plurality of functional groups that react with the carboxylic acid contained in the acid-modified polyolefin resin (A), and a metal complex having a polyvalent coordination site Etc. can be used. Specific examples include hydrazide compounds, isocyanate compounds, blocked isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline group-containing compounds, zirconium salt compounds, organic peroxides, and the like. You may use it in combination. The crosslinking agent may be a low molecular weight compound or a polymer type.
Among these, a crosslinking agent having a plurality of functional groups in the molecule that react with the carboxylic acid contained in the acid-modified polyolefin resin is more preferable. Examples of such cross-linking agents include oxazoline compounds, epoxy compounds, carbodiimide compounds, isocyanate compounds, hydrazide compounds, amine compounds, melamine compounds, and polyols, and oxazoline compounds, hydrazide compounds, amine compounds, carbodiimide compounds, and isocyanate compounds. Oxazoline compounds, hydrazide compounds, and amine compounds are particularly preferred because of excellent crosslinking effects.
The content of the crosslinking agent is preferably 0.01 to 50 parts by mass, and 0.1 to 20 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin (A), from the viewpoint of sufficiently forming a crosslinked structure. Part is more preferable, 0.2 to 10 parts by weight is particularly preferable, and 0.5 to 5 parts by weight is further preferable.

A silane coupling agent is a compound having at least one functional group having affinity or reactivity with an organic material and a hydrolyzable silicon group in the molecule, and is represented by the following general formula (2). Silane compounds are preferred.
Y—R ² —Si (R ³ ) _n (R ⁴ ) _3-n (2)
In the formula (2), Y is a functional group having affinity or reactivity with organic materials such as various synthetic resins, for example, vinyl group, epoxy group, styryl group, acryloxy group, methacryloxy group, amino group, mercapto group. Ureido group, sulfide group, isocyanate group, ketimino group and the like. Epoxy group and amino group are preferable from the viewpoint of reactivity with acid-modified polyolefin resin (A), and epoxy group is more preferable.
R ² is a linear or branched alkylene group having 0 to 10 carbon atoms.
R ³ may be the same group as R in Formula (1), and R ⁴ may be the same group as R ¹ in Formula (1).
When the silane coupling agent has a plurality of R ³ or R ⁴ , each may be the same or different. n is an integer of 0-2. Moreover, you may use a silane coupling agent in mixture of 2 or more types.
Among the silane coupling agents, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane are preferable.
The content of the silane coupling agent is preferably 0.01 to 10 parts by mass, particularly preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin resin (A). More preferably, it is 0.5-3 mass parts. If the content of the silane coupling agent is less than 0.01 parts by mass, the effect of the addition is too low, and if it exceeds 10 parts by mass, the stability of the water-absorption-preventing coating agent for inorganic substrates tends to be impaired, which is costly. It is also disadvantageous.

  Examples of other resins include polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, acrylic resin, acrylic silicon resin, ethylene-vinyl acetate copolymer, vinyl acetate-acrylic copolymer, ethylene-aminoacrylamide copolymer, Ethylene-aminoacrylate copolymer, poly (vinylidene chloride), ethylene- (meth) acrylic acid copolymer, styrene-maleic acid resin, styrene-aminoalkylmaleimide copolymer, styrene-butadiene resin, styrene elastomer, butadiene resin, Acrylonitrile-butadiene resin, poly (meth) acrylonitrile resin, (meth) acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, modified nylon resin, polyurethane resin, phenol resin, Corn resins, epoxy resins, fluorine-containing resins, polyethylene imine, and the like UV-curable resin. These can be used alone or in admixture of two or more.

Examples of the inorganic fine particles include magnesium oxide, tin oxide, titanium oxide, calcium carbonate, silica, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, magnesium carbonate, calcium sulfate, mica, talc, pseudoboehmite, alumina, and silicic acid. Examples include inorganic particles such as aluminum, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide. These may be used alone or in combination of two or more.
The average particle diameter of the inorganic fine particles is preferably 0.0005 to 100 μm, more preferably 0.005 to 10 μm from the viewpoint of dispersion stability of the aqueous dispersion.

  Furthermore, the water-absorption-preventing coating agent for the inorganic base material is additionally provided with a leveling agent, an antifoaming agent, a foaming agent, an anti-waxing agent, a pigment dispersant, an ultraviolet absorber, a catalyst, a photocatalyst, a UV curing agent, as necessary. Various agents such as wetting agents, penetrating agents, softeners, thickeners, dispersants, fungicides, bactericides, fragrances, colorants, thickeners, antistatic agents, anti-aging agents, pigments or dyes, carbon black, carbon You may add various additives, such as a nanotube and glass fiber, in the range which does not impair the effect of this invention. These may be used alone or in combination of two or more.

The water-absorption-preventing coating agent for an inorganic base material of the present invention can impart a water-absorption-preventing effect to the inorganic base material by applying it to the surface of the inorganic base material. Next, the inorganic base material to which the water absorption preventing coating agent for inorganic base material is applied will be described.
The inorganic base material is a base material containing an inorganic material and having the inorganic material on at least a part of the surface, and may have a porous structure. Specific examples include concrete and brick. Among these, concrete is a preferable base material because the effect of the present invention can be sufficiently exerted when the water absorption preventing coating agent for an inorganic base material of the present invention is applied.
The concrete is not particularly limited, and those of known types and compositions can be used. As the concrete composition, it is possible to use a composition prepared by mixing cement and water, as well as aggregate, glue, admixture and the like into any known blend composition as necessary. In addition, an aqueous dispersion of the acid-modified polyolefin resin (A) used in the present invention may be added to the composition. Furthermore, for reinforcing the concrete structure, reinforcing bars can be provided, and high-strength and high-modulus fibers such as carbon fiber and aramid fiber can be blended into the concrete. Various raw materials such as cement to be used can be used. Such a concrete composition can be kept in an arbitrary shape and hardened by a hydration reaction to obtain a concrete structure. In the present invention, concrete and mortar are not roughly divided, and mortar is included in concrete.

Next, the surface-coated concrete structure of the present invention will be described.
The surface-coated concrete structure of the present invention is such that the whole or part of the surface has a film obtained from the water-absorbing coating agent for inorganic substrates, and the water-absorbing coating agent for inorganic substrates of the present invention is applied to concrete. It can be manufactured by applying to all or part of the surface of the structure during or after the curing process.
In addition, the hardening process of a concrete structure means the period until it hardens a concrete composition and a concrete structure reaches practical strength.

As a method for applying the water-absorption-preventing coating agent for the inorganic base material, known methods such as spray coating, shower coating, roll coating, brush coating, brush coating, dip coating, knife coating, and air knife coating can be employed. In addition, application | coating does not need to be implemented at once and it may carry out recoating after the drying mentioned later.
The coating amount on the surface of the concrete structure is 0 as the amount of the effective component (total sum of acid-modified polyolefin resin (A) and alkylalkoxysilane and / or its condensate (B)) of the water absorption preventing coating agent for inorganic substrates. is preferably .01~200g / ^{m 2,} more preferably from 0.1 to 150 g / ^{m 2,} particularly preferably from 1 to 100 g / ^{m 2,} a 2~70g / ^{m 2} Is more preferable, and it is most preferable that it is 5-50 g / m < ² >. When the coating amount is less than 0.01 g / m ² , the effect of the present invention tends to decrease. When the coating amount exceeds 200 g / m ² , the coating amount is too large, so that dripping occurs or a film is formed. In some cases, unevenness may occur, and this is disadvantageous in terms of cost.

It is preferable to provide a drying step after the step of applying the water absorption preventing coating agent for the inorganic base material. The drying method is not particularly limited, and a film is formed by natural drying for about 2 hours, and the effect can be sufficiently exhibited by natural drying for 24 hours. In addition, when shortening drying time or when stronger adhesiveness is required, you may dry by heating. A known method may be adopted as the heating method, and the heating temperature is preferably 120 ° C. or lower because of excellent film forming properties.
Moreover, you may perform a heating and / or humidification process in order to accelerate | stimulate hardening of a concrete structure during the drying after application | coating, or after drying.

  The thickness of the film formed on the surface of the concrete structure is preferably 0.01 to 180 μm, more preferably 0.1 to 120 μm, particularly preferably 1 to 80 μm, and 2 to 50 μm. More preferably, it is most preferably 5 to 30 μm. When the thickness of the film is less than 0.01 μm, the effect of the present invention tends to be reduced, and when it exceeds 180 μm, it is difficult to form the film or it is disadvantageous in terms of cost.

  The surface-coated concrete structure thus obtained may have a coating on at least a part of the surface, but the coating is applied to the entire surface where the surface-coated concrete structure and water can contact in the intended use. It is preferable to have a film on the entire exposed portion of the surface-coated concrete structure, and it is particularly preferable to have a film on the entire surface of the surface-coated concrete structure. The film may be a continuous film or a discontinuous film. In addition, the concrete structure usually has a porous structure, but a part of the film may be formed in this hole.

Since the surface-coated concrete structure of the present invention thus obtained is excellent in water absorption prevention, it has an effect of suppressing various problems (cracking, peeling, white flower, etc.) of the concrete structure resulting from water absorption. In addition, water absorption prevention property is effective also with respect to salt water (seawater), and has the effect which prevents salt damage as a result.
The surface-coated concrete structure of the present invention is limited as long as it is made of concrete such as civil engineering such as roads, bridges, tunnels, dams, outer walls, outer wall materials, buildings, houses, pillars, and other buildings and shaped objects. It can be used without.

Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited by these.
Various characteristics were measured or evaluated by the following methods.

1. Characteristics of acid-modified polyolefin resin (1) Configuration
^{It was determined from 1} H-NMR analysis (ECA 500, 500 MHz manufactured by JEOL Ltd.). Tetrachloroethane (d ₂ ) was used as a solvent and measurement was performed at 120 ° C.
(2) Melting point 10 mg of acid-modified polyolefin resin was used as a sample, and the melting point was determined by performing measurement using a DSC (Differential Scanning Calorimetry) apparatus (DSC7 manufactured by PerkinElmer Co., Ltd.) under a temperature rising rate of 10 ° C / min.
(3) Weight average molecular weight The mass average molecular weight was measured at 40 degreeC using the GPC apparatus (The Tosoh company make HLC-8020GPC, column: TSK-GEL). Ortho-dichlorobenzene was used as an eluent, and was calculated from TSK standard polystyrene conversion. In addition, when it did not melt | dissolve in trichlorobenzene and a weight average molecular weight was not measurable, the melt flow rate value of following (4) was made into the parameter | index of molecular weight.
(4) Melt flow rate value (MFR)
It was measured by the method described in JIS K7210: 1999 (190 ° C., 2.16 kg load).

2. Characteristics of water-absorption-preventing coating agent for inorganic base material (1) Number average particle diameter of dispersed particles Determined using a Microtrac particle size distribution meter (UPA150, MODEL No. 9340, dynamic light scattering method manufactured by Nikkiso Co., Ltd.). The refractive index used for particle size calculation was 1.50.
(2) Viscosity Using a B-type viscometer (DVL-BII type digital viscometer manufactured by Tokimec Co., Ltd.), the rotational viscosity (mPa · S) at 20 ° C. was determined.

3. Treatment of surface-coated concrete structures In evaluating the adhesion and water absorption prevention properties of the surface-coated concrete structures obtained in Examples and Comparative Examples, the following treatments were performed on the concrete structures.
(1) Flowing water treatment 50 L of water is put into a 60 L plastic bucket, the surface-coated concrete structure is immersed in it, a stirrer (three-one motor manufactured by HEIDON, model BL1200, stirring blade diameter 80 mm) is set, and stirring is performed at 50 rpm for 7 days. did. The water depth of the concrete structure was about 500 mm, and the water temperature was in the range of 20-23 ° C.
(2) Exposure treatment The surface-coated concrete structure was exposed to a testing machine (Sunshine weather meter) specified in JIS-B7753 for 1000 hours. The surface-coated concrete structure after 1000 hours was dried at 25 ° C. for 10 days.
The 1000-hour evaluation in the exposure process is generally equivalent to an evaluation for 5 years in a natural environment, and the excellent adhesion and water absorption prevention measured after the treatment are the adhesion performance and water absorption. It shows that the prevention performance is excellent in weather resistance.

4). Evaluation of surface-covered concrete structure (1) Adhesiveness Surface-coated concrete structure (flowing / unexposure treated structure, flowing water treated structure, exposed structure) 25 square grid cuts were made at intervals of 2 mm in length and width. Cellophane tape (TF-12 manufactured by Nichiban Co., Ltd.) was applied to the grid, and the number of square films remaining on the surface of the structure without peeling when the tape was peeled off at once was measured to evaluate the adhesion. The test was performed at n = 5, and the average value was evaluated (rounded off the decimal point of the average value). When there is no peeling of the film, it is 25/25, and when all the film is peeled off, it is 0/25. It shows that it is excellent in adhesiveness, so that there is little peeling.
In the evaluation of the structure subjected to running water, the film is dissolved or peeled off, and the structure without the film is most undesirable as a result.

(2) Water absorption prevention Surface-coated concrete structures (two types of unexposed and exposed structures) are treated with running water, and the surface-coated concrete structure surface is lightly wiped with a soft towel. The weight taken was measured, and the water absorption was determined based on the following formula (3). The test was performed at n = 5, and the average value was evaluated (rounded off to the nearest decimal point). The smaller the water absorption rate, the better the water absorption prevention property.
Water absorption rate (%) = (weight after running water treatment−weight before running water treatment) / weight before running water treatment × 100 (3)

(3) Blackening suppression effect 5 g of physiological saline containing black mold (a towel with black mold extracted with physiological saline) was dropped on the surface-coated concrete structure and spread to about 25 cm ^2. It was kept for 10 months in a constant temperature and humidity chamber (Yamato Chemical Co., IG400) at 80 ° C. × RH. The degree of blackening of the surface after 10 months was visually evaluated using the following indices.
○: Almost not black △: Slightly black ×: Blackened

The raw materials used in the examples and comparative examples were as follows.
1. Aqueous dispersion of acid-modified polyolefin resin (A) An aqueous dispersion of acid-modified polyolefin resin (A) was produced by the following method.
<Production of aqueous dispersion (A-1 to A-5) of ethylene-ethyl acrylate- (anhydrous) maleic acid copolymer>
The ethylene-ethyl acrylate-maleic anhydride copolymers PO1, PO2, PO3, PO4, and PO5 were prepared based on the methods described in British Patents 2091745, US Pat. No. 4,617,366, and US Pat. No. 4,644,044. Table 1 shows the characteristics of PO1, PO2, PO3, PO4 and PO5.
Next, in a 2 liter glass container equipped with a stirrer and a heater, 50 g of PO1, PO2, PO3, PO4 or PO5 obtained above, 150 g of n-propanol, 3 g of 2-dimethylaminoethanol, and distilled water were added. 297 g was charged. When the stirring blade was rotated at a rotational speed of 300 rpm, the resin bottoms were not observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 120 minutes to be dispersed. Then, when it cooled to about 80 degreeC, stirring at a rotational speed of 300 rpm, the system inside was pressure-reduced gradually and n-propanol and water were removed. After removing 300 g or more of n-propanol and water, when the system temperature is 35 ° C., water is added so that the concentration of the acid-modified polyolefin resin (A) in the aqueous dispersion becomes 20% by mass. It was adjusted and pressure filtered through a 180 mesh stainless steel filter to obtain a milky white uniform aqueous dispersion of PO1, PO2, PO3, PO4 and PO5. An aqueous dispersion of PO1 is “A-1”, an aqueous dispersion of PO2 is “A-2”, an aqueous dispersion of PO3 is “A-3”, an aqueous dispersion of PO4 is “A-4”, and PO5 The aqueous dispersion is designated “A-5”.

<Production of Aqueous Dispersion (A-6) of Ethylene-Ethyl Acrylate- (Anhydrous) Maleic Acid Copolymer (Aqueous Dispersion with Large Dispersion Particle Diameter)>
In a 2 liter glass container equipped with a stirrer and a heater, 200 g of PO1 obtained above, 5 g of 2-dimethylaminoethanol, 160 g of isopropanol, and 635 g of distilled water were charged. When the stirring blade was rotated at a rotational speed of 300 rpm, the resin bottoms were not observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 60 minutes to be dispersed. Thereafter, when the system was cooled to about 80 ° C. with stirring at a rotational speed of 300 rpm, the system was gradually depressurized to remove isopropanol and water. After 240 g or more of isopropanol and water were removed, when the system temperature reached 35 ° C., pressure filtration was performed with a 78 mesh stainless steel filter. Water was added to the recovered aqueous dispersion to adjust the PO1 concentration to 20% by mass to obtain an aqueous dispersion of PO1 having a large dispersed particle diameter (hereinafter referred to as “A-6”). In addition, the aqueous dispersion (A-6) was produced by reducing the amount of the organic amine as the neutralizing agent for PO1 and the amount of isopropanol as the water-soluble organic solvent from the amount in the aqueous dispersion (A-1). The number average particle diameter of the obtained dispersed particles was larger than that of the aqueous dispersion (A-1).

<Production of aqueous dispersion (A-7) of propylene- (anhydride) maleic acid copolymer>
An aqueous dispersion was produced by the following method using a propylene-maleic anhydride copolymer (manufactured by Sanyo Chemical Co., Ltd., Umex 1001). Table 1 shows the characteristics of Umex 1001.
A 2-liter glass container equipped with a stirrer and a heater was charged with 75 g of Umex 1001, 200 g of tetrahydrofuran, 8 g of 2-dimethylaminoethanol, and 217 g of distilled water. When the stirring blade was rotated at a rotational speed of 300 rpm, the resin bottoms were not observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 120 minutes to be dispersed. Then, when it cooled to about 80 degreeC, stirring with a rotational speed of 300 rpm, the inside of a system was pressure-reduced gradually and tetrahydrofuran and water were removed. After removing 280 g or more of tetrahydrofuran and water, when the system temperature reached 35 ° C., water was added to adjust the concentration of Umex 1001 in the aqueous dispersion to 20% by mass, and 180 mesh stainless steel The mixture was filtered under pressure using a filter made to obtain a white uniform UMEX 1001 aqueous dispersion. The aqueous dispersion of Umex 1001 is indicated as “A-7”.

<Production of Aqueous Dispersion of Ethylene- (Meth) acrylic Acid Copolymer (A-8 to A-11)>
Ethylene-methacrylic acid copolymer (Mitsui / DuPont Polychemical Co., Ltd., Nuclerel AN42115C, hereinafter referred to as AN42115C), Ethylene-methacrylic acid copolymer (Mitsui / DuPont Polychemical Co., Ltd., Nucrel N0903HC, hereinafter referred to as N0903HC) ), Ethylene-methacrylic acid copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd., Nucrel N1560, hereinafter referred to as N1560), and ethylene-acrylic acid copolymer (manufactured by Dow Chemical Co., Ltd., Primacol 5990, hereinafter, 5990). These aqueous dispersions were produced by the following method. Table 1 shows the characteristics of AN42115C, N0903HC, N1560, and 5990.

(Production of AN42115C, N0903HC aqueous dispersion (A-8 to A-9))
A 2 liter glass container equipped with a stirrer and a heater was charged with 75 g of AN42115C or N0903HC, 175 g of n-propanol, 20 g of 2-dimethylaminoethanol, and 230 g of distilled water. When the stirring blade was rotated at a rotational speed of 300 rpm, the resin bottoms were not observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 150 ° C. and further stirred for 120 minutes to be dispersed. Then, when it cooled to about 80 degreeC, stirring at a rotational speed of 300 rpm, 200g of water was added, Then, the inside of a system was pressure-reduced gradually and n-propanol and water were removed. After removing 350 g or more of n-propanol and water, when the system temperature is 35 ° C., water is added so that the concentration of the acid-modified polyolefin resin (A) in the aqueous dispersion becomes 20% by mass. It was adjusted and pressure filtered through a 180 mesh stainless steel filter to obtain a milky white uniform AN42115C or N0903HC aqueous dispersion. An aqueous dispersion of AN42115C is indicated as “A-8”, and an aqueous dispersion of N0903HC is indicated as “A-9”.

(Production of aqueous dispersion (N-10 to A-11) of N1560 and 5990)
A 1 liter glass container equipped with a stirrer and a heater was charged with 75 g of N1560 or 5990, 50 g of isopropanol, 7 g of 2-dimethylaminoethanol, and 368 g of distilled water. When the stirring blade was rotated at a rotational speed of 300 rpm, the resin bottoms were not observed at the bottom of the container, and it was confirmed that the container was in a floating state. Therefore, while maintaining this state, the heater was turned on and heated after 10 minutes. Then, the system temperature was maintained at 130 ° C. and further stirred for 120 minutes to be dispersed. Thereafter, when the system was cooled to about 80 ° C. with stirring at a rotational speed of 300 rpm, the system was gradually depressurized to remove isopropanol and water. After removing 130 g or more of isopropanol and water, when the temperature inside the system reached 35 ° C., water was added to adjust the concentration of the acid-modified polyolefin resin in the aqueous dispersion to 20% by mass, and 180 mesh The mixture was subjected to pressure filtration with a stainless steel filter to obtain a milky white uniform aqueous dispersion of N1560 or 5990. The aqueous dispersion of N1560 is indicated as “A-10”, and the aqueous dispersion of 5990 is indicated as “A-11”.

  Table 1 shows the characteristics of the acid-modified polyolefin resin used and its aqueous dispersion.

2. Aqueous dispersion of alkyl alkoxysilane and / or condensate thereof (B) An aqueous dispersion of alkyl alkoxysilane and / or condensate thereof (B) was produced by the following method.
<Production of Aqueous Dispersion of Hexyltriethoxysilane (B-1)>
210 g of hexyltriethoxysilane (hereinafter sometimes referred to as HTES) as alkylalkoxysilane and / or its condensate (B) and 5 g of polyoxyethylene octylphenyl ether (HLB = 15) as an emulsifier are mixed. The mixture was added to 285 g of a pH buffer solution (0.1% by mass aqueous sodium hydrogen carbonate solution) and dispersed by high-speed stirring. After dispersion, pressure filtration was performed with a 180 mesh stainless steel filter to obtain an aqueous dispersion (HTES concentration 42 mass%) of alkylalkoxysilane and / or its condensate (B). The number average particle diameter of the dispersed particles was 0.30 μm. The obtained aqueous dispersion is designated as “B-1”.

<Manufacture of Aqueous Dispersion of Hexyltriethoxysilane (B-2) (Aqueous Dispersion with Large Dispersion Particle Diameter)>
210 g of hexyltriethoxysilane (HTES) as an alkylalkoxysilane and / or its condensate (B) and 2 g of polyoxyethylene octylphenyl ether (HLB = 15) as an emulsifier are mixed, and the mixture is mixed with a pH buffer solution. It was added to 288 g (0.1 mass% sodium hydrogen carbonate aqueous solution) and dispersed by high-speed stirring. After dispersion, pressure filtration was performed with a 180 mesh stainless steel filter to obtain an aqueous dispersion (HTES concentration 42 mass%) of alkylalkoxysilane and / or its condensate (B). The number average particle diameter of the dispersed particles was 0.60 μm. The obtained aqueous dispersion is designated as “B-2”.

3. Aqueous dispersion of acrylic resin 250 g of ion-exchanged water was placed in a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube, and a cooler, and was purged with nitrogen for 1 hour while stirring. To this, 1.5 g of ammonium persulfate (polymerization initiator) was added, the temperature was adjusted to 60 ° C., and then 500 g of n-butyl acrylate, 50 g of isobutyl methacrylate, 10 g of acrylic acid, n-dodecyl mercaptan (chain transfer agent). 5 g and 20 g of sulfosuccinic acid diester ammonium salt emulsified with 120 g of water were added dropwise over 3 hours to effect emulsion polymerization. Next, water was added to adjust the acrylic resin concentration in the dispersion to 20% by mass, and pressure filtration was performed with a 180 mesh stainless steel filter to obtain an aqueous dispersion of acrylic resin. The number average particle diameter of the dispersed particles was 0.1 μm. The aqueous dispersion of acrylic resin is indicated as “S-1”.

4). Aqueous dispersion of polyurethane resin In a reactor equipped with a stirrer, thermometer, nitrogen seal tube and condenser, 345 g of polytetramethylene glycol with a number average molecular weight of 1970, 77.8 g of isophorone diisocyanate, 0.03 g of dibutyltin dilaurate The mixture was charged and reacted at 80 ° C. for 2 hours. Subsequently, after cooling this reaction liquid to 50 degreeC, 11.7g of 3-dimethylamino propanol, 8.85g of triethylamine, and 177g mass part of acetone were added, and it was made to react for 3 hours. Further, 175 g of acetone was added to the reaction liquid and cooled to 30 ° C., and a liquid mixture consisting of 13.4 g of isophorone diisocyanate, 1.07 g of monoethanolamine, 87.9 g of isopropanol and 1039 g of water was added and stirred at a high speed. Acetone, water and isopropanol were distilled off from the mixture. Next, water was added to adjust the concentration of the polyurethane resin in the dispersion to 20% by mass, and pressure filtration was performed with a 180 mesh stainless steel filter to obtain an aqueous dispersion of polyurethane resin. The number average particle diameter of the dispersed particles was 0.1 μm. The aqueous dispersion of polyurethane resin is indicated as “S-2”.

5. Concrete structure As a concrete structure, a JIS mortar (70 × 70 × 20 mm rectangular parallelepiped) conforming to JIS R5201 was prepared, and the bottom surface (one surface of 70 × 70 mm) of the JIS mortar was solidified with a two-component epoxy paint. I used something.

Example 1
“A-1” is used as the aqueous dispersion of the acid-modified polyolefin resin (A), “B-1” is used as the aqueous dispersion of the alkylalkoxysilane and / or its condensate (B), and “A-1”. So that the mass ratio ((A) / (B)) between the acid-modified polyolefin resin (A) in the resin and the alkylalkoxysilane and / or its condensate (B) in “B-1” is 90/10. Both were mixed and stirred to obtain a water absorption preventing coating agent for an inorganic substrate.
Next, the obtained water-absorbing coating agent for an inorganic substrate was applied to the surface of the concrete structure other than the bottom surface (the surface solidified with a two-component epoxy paint) with a brush. The coating amount was such that the effective component amount of the water absorption preventing coating agent for an inorganic substrate was 40 g / m ² . After coating, the surface-coated concrete structure was obtained by drying at 25 ° C. for 5 days.

Examples 2-6
The mass ratio ((A) / (B)) of the acid-modified polyolefin resin (A) in “A-1” and the alkylalkoxysilane and / or its condensate (B) in “B-1” A water-absorbing anti-coating agent for an inorganic base material and a surface-coated concrete structure were obtained by the same operation as in Example 1 except that it was shown in FIG.

Examples 7-13
Except that the type of the aqueous dispersion of the acid-modified polyolefin resin (A) is as shown in Table 2, a water-absorbing coating agent for an inorganic base material and a surface-coated concrete structure are obtained in the same manner as in Example 4. It was.

Examples 14 and 15
A water-absorbing coating agent for an inorganic substrate and a surface-coated concrete structure are obtained in the same manner as in Example 4 except that the active ingredient coating amount of the water-absorbing coating agent for an inorganic substrate is as shown in Table 2. It was.

Example 16
In the same operation as in Example 4, “A-1” and “B-1” were mixed and stirred, and the oxazoline-based additive as an additive with respect to 100 parts by mass of the acid-modified polyolefin resin (A) in the mixed solution. The inorganic base material was added and stirred so that the solid content of Epocross WS700 (Nippon Shokubai Co., Ltd., oxazoline group-containing acrylic resin, solid concentration 25 mass%, hereinafter referred to as WS700) as a crosslinking agent was 5 parts by mass. A water absorption preventive coating agent was obtained.
Next, a surface-coated concrete structure was obtained in the same manner as in Example 4 using the obtained water-absorbing coating agent for inorganic substrates.

Example 17
In the same operation as in Example 4, “A-1” and “B-1” were mixed and stirred, and silane cup as an additive with respect to 100 parts by mass of the acid-modified polyolefin resin (A) in the mixed solution. 3-glycidoxypropylmethyldiethoxysilane (KBS-402, manufactured by Shin-Etsu Silicone Co., Ltd., hereinafter referred to as KBE-402), which is a ring agent, is added and stirred so as to be 1 part by mass, and water absorption for inorganic substrate A preventive coating agent was obtained.
Next, a surface-coated concrete structure was obtained in the same manner as in Example 4 using the obtained water-absorbing coating agent for inorganic substrates.

Example 18
The same as in Example 4 except that the type of the aqueous dispersion of the acid-modified polyolefin resin (A) and the type of the aqueous dispersion of the alkylalkoxysilane and / or its condensate (B) are as shown in Table 2. By the operation, a water absorption preventing coating agent for an inorganic base material and a surface-coated concrete structure were obtained.

Comparative Example 1
Various evaluations were made using a concrete structure that was not coated with a water-absorption-preventing coating agent for an inorganic base material and had no surface coated.

Comparative Example 2
As the water absorption preventing coating agent for the inorganic base material, only “B-1” which is an aqueous dispersion of alkyl alkoxysilane and / or its condensate (B) is used, and “B-1” is used as the bottom surface of the concrete structure (2 It was applied with a brush to the surface other than the surface solidified with liquid epoxy paint. The amount of coating was such that the amount of HTES in “B-1” was 40 g / m ² . After coating, the surface-coated concrete structure was obtained by drying at 25 ° C. for 5 days.

Comparative Example 3
A surface-coated concrete structure was obtained in the same manner as in Comparative Example 2 except that the amount applied to the concrete structure was as shown in Table 2.

Comparative Examples 4 and 5
A water-absorbing coating agent for an inorganic substrate and a surface-coated concrete structure were obtained in the same manner as in Example 4 except that the type of the aqueous dispersion of the acid-modified polyolefin resin was changed to that shown in Table 2.

Comparative Examples 6 and 7
Instead of the aqueous dispersion of the acid-modified polyolefin resin (A), the aqueous dispersion of acrylic resin is “S-1” (Comparative Example 6) or “S-2” (Comparative Example) which is an aqueous dispersion of polyurethane resin. Except that 7) was used, a water-absorbing coating agent for an inorganic base material and a surface-coated concrete structure were obtained in the same manner as in Example 4.

  Various evaluation was performed using the water absorption preventing coating agent for an inorganic base material and the concrete structure obtained in Examples 1 to 18 and Comparative Examples 1 to 7. The evaluation results are shown in Table 2. The weight of the epoxy coating on the bottom surface of the concrete structure was 1 g, and this weight was included in the weight of the concrete structure in the evaluation of water absorption prevention.

As is apparent from Table 2, the surface-coated concrete structure obtained by using the water-absorbing coating agent for inorganic substrates of the present invention obtained in Examples 1 to 18 has a surface coating adhesion and water absorption prevention. It was excellent in properties. Moreover, even under harsh conditions such as long-term use under running water or outdoor natural environment, the performance was excellent in sustainability, and the surface blackening suppression effect was also confirmed. By applying the water-absorption-preventing coating agent for inorganic base materials of the present invention to concrete structures, various problems of concrete such as cracks, peeling and white flower caused by water absorption are suppressed, and the suppression effect is maintained for a long time. be able to.
From the results of Examples 1 to 6, the effect is that the mass ratio of the acid-modified polyolefin resin (A) to the alkylalkoxysilane and / or its condensate (B) is within the preferred range defined in the present invention. It was confirmed that it became more prominent.
From the comparison between Examples 4, 9, 10, 12, and 13 and Comparative Examples 4 and 5, the content of the unsaturated carboxylic acid contained in the acid-modified polyolefin resin (A) is within the range specified in the present invention. Thus, it was confirmed that an excellent effect was exhibited, and it was confirmed that the effect became more remarkable when the content was within a preferable range defined in the present invention.
From the comparison of Examples 4, 11, and 12, it was confirmed that the olefin component of the acid-modified polyolefin resin (A) is ethylene, so that a more excellent effect can be obtained, and the acid-modified polyolefin resin is ethylene- ( It was confirmed that the effect was particularly high by being a (meth) acrylic acid ester- (anhydrous) maleic acid copolymer.
From the results of Examples 4, 7, and 8, it was confirmed that the MFR of the acid-modified polyolefin resin is within the preferable range defined in the present invention, so that a more excellent effect can be obtained.
From the results of Examples 4, 14, and 15 and Comparative Example 3, it was confirmed that the water-absorption-preventing coating agent for an inorganic base material of the present invention can provide excellent effects even when the amount applied to the concrete structure is small.
From the results of Examples 16 and 17, it was confirmed that the water absorption preventing coating agent for an inorganic base material of the present invention exhibits a more excellent effect by including a crosslinking agent or a silane coupling agent.
From a comparison between Examples 4 and 18, a more excellent effect was confirmed when the number average particle diameter of the dispersed particles of the water-absorption-preventing coating agent for an inorganic base material was within a preferable range defined in the present invention.
In Comparative Examples 2 and 3, an aqueous dispersion of alkylalkoxysilane, which is generally considered to have a waterproof effect, was used as a water absorption preventing coating agent for an inorganic base material. Under conditions of long-term use in the environment, effects such as water absorption prevention did not last.
In Comparative Examples 6 and 7, an aqueous dispersion of a resin (acrylic resin, polyurethane resin) other than the acid-modified polyolefin resin (A) was used, but the effect of the present invention was not recognized.

Claims (7)

  An aqueous dispersion containing an acid-modified polyolefin resin (A) having an unsaturated carboxylic acid content of 0.1 to 10% by mass, an alkylalkoxysilane and / or its condensate (B), and an aqueous medium, Inorganic substance characterized in that mass ratio ((A) / (B)) of acid-modified polyolefin resin (A) and alkylalkoxysilane and / or its condensate (B) is 90/10/1/99 Water absorption prevention coating agent for substrates.   The water absorption preventing coating agent for an inorganic base material according to claim 1, wherein the number average particle diameter of the dispersed particles in the aqueous dispersion is 0.02 to 0.50 µm.   The water-absorptive coating agent for inorganic substrates according to claim 1 or 2, wherein the acid-modified polyolefin resin (A) is an ethylene- (meth) acrylic acid ester- (anhydrous) maleic acid copolymer.   The melt flow rate value of the acid-modified polyolefin resin (A) (190 ° C in accordance with JIS K7210: 1999, 2.16 kg load) is 1 to 500 g / 10 min. The water-absorption-preventing coating agent for inorganic substrates as described. The alkylalkoxysilane of the alkylalkoxysilane and / or its condensate (B) is a compound represented by the following general formula (1), for an inorganic substrate according to any one of claims 1 to 4 Water absorption prevention coating agent.
Si (R) _n (R ¹ ) _4-n (1)
In (Equation (1), R is an alkyl group, a substituted alkyl group or aryl group having 1 to 30 carbon atoms, ^{R 1} is an alkoxy group having 1 to 6 carbon atoms, n represents is an integer from 1 to 3 .)   A surface-coated concrete structure characterized in that the whole or part of the surface of the concrete structure has a film obtained from the water-absorbing coating agent for inorganic substrates according to any one of claims 1 to 5. It is a method of manufacturing the surface covering concrete structure of Claim 6, Comprising: The water absorption prevention coating agent for inorganic base materials in any one of Claims 1-5 is apply | coated to the whole or part of concrete structure surface A method for producing a surface-coated concrete structure, characterized in that: