JPH11279364A - Curable aqueous emulsion excellent in stain resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable aq. emulsion which is excellent in safeness and storage stability, can be applied to a substrate in one step, forming a coating film excellent in resistances to solvents and water and in resistances to staining and whitening, and can impart capability for preventing water absorption to a substrate. SOLUTION: This emulsion is prepd. by dispersing, in an aq. medium, a block copolymer which is formed by the free radical polymn. of a monomer component mainly comprising a (meth)acrylic ester having a polyoxyalkylene group in the presence of (A) an alkoxysilylated (meth)acrylic polymer, (B) a hydrolyzable silane compd., and (C) a free radical polymn. initiator having azoic groups and a polydimethylsiloxane unit in the main chain. The emulsion may further contain (D) colloidal silica.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention can form a permeation-type water-absorbing prevention layer and a coating layer which complements the weather resistance of the water-absorbing prevention layer on a substrate with a single material. ,
The coating film is a stain-resistant, a curable aqueous emulsion having excellent solvent resistance and water resistance, and further relates to a curable aqueous emulsion having excellent whitening resistance, which can be applied to various technical fields, In particular, it can be awarded in the fields of civil engineering and architecture.

[0002]

2. Description of the Related Art In general, concrete and other architectural and civil engineering materials are first coated with a water repellent and a water absorption preventive for the purpose of water repellency and water absorption prevention for the purpose of surface protection. A coating for surface coating is applied on the dried surface in order to impart design, waterproofness, weather resistance, and the like.

As a water repellent and a water absorption inhibitor, a hydrolyzable silane compound represented by an alkoxysilane is often used. When the hydrolyzable silane compound is applied to a porous material such as a masonry or concrete, the hydrolyzable silane compound penetrates into pores of the porous material and forms a bond with a substrate in the pores to form a three-dimensional structure. Therefore, a waterproof layer having excellent durability is formed, and further, the appearance is not changed.

[0004] In general, these hydrolyzable silane compounds are diluted with various organic solvents or used as emulsions. However, in recent years, from the viewpoints of environmental protection and safety and health, emulsions are preferably used. Have been. Examples of the emulsion used as an emulsion include, for example, a silane-based aqueous emulsion using an emulsifier having an HLB of 4 to 15 (Japanese Patent Application Laid-Open No. 62-197369) and a silane-based aqueous emulsion combining a nonionic emulsifier and an anionic emulsifier ( JP-A-3-232527) and the like have been reported.

[0005] Next, paints composed of various resins are used as surface coating paints. In particular, in the case of outdoor paints requiring weather resistance, they are made of fluororesins or acrylic silicone resins. Solvent-based paints and water-based paints are used. However, the appearance of pollutants and rain streak-like stains on the paint film surface due to automobile exhaust gas, sand dust, iron powder, acid rain, sun rays, etc. has caused a problem that the appearance is impaired. Therefore, materials having excellent contamination resistance are required. As a solution to the above-mentioned problem of the organic solvent type acrylic silicone resin paint, a paint composition comprising an alkyl silicate or a partial hydrolyzate and a curing catalyst using an acrylic silicone resin as a base resin has been proposed (JP-A-6-248237). issue). However, this gives the coating film hydrophilicity and oil repellency in water, and removes dirt by a so-called rolling-up mechanism in which the coating film gets wet with rainwater and contaminants run down with the rainwater. Until now, no paint has been developed that has sufficiently satisfactory stain resistance, for example, the paintability is insufficient or the storage stability of the paint decreases over time.

On the other hand, in the surface coating paint, an aqueous paint has attracted attention instead of a conventional paint using an organic solvent, and a composition comprising an acrylic silicone resin emulsion has been proposed. However, the acrylic silicone resin is difficult to be made aqueous, or has a problem in storage stability of the obtained emulsion. Further, the conventional acrylic silicone resin emulsion has insufficient water resistance and solvent resistance in terms of stain resistance, although the coating film has water resistance and solvent resistance. Furthermore, the conventional acrylic silicone resin emulsion is insufficient in that the surface of the coating film may be whitened due to rainfall or the like.

[0007]

Further, a method of applying a water repellent agent or the like to the surface of concrete or the like and applying a coating material for surface coating on the dried surface includes a step of applying the water repellent agent and the like. It is necessary to perform two or more steps of application of the coating material for coating, so there is a problem that the work becomes complicated or time is required for the application, and since the coating such as a water repellent has water repellency, the It was difficult to apply a water-based surface coating paint thereon. The present inventors have excellent safety and storage stability, it is possible to coat the substrate in one step,
The resulting coating film is an aqueous curable emulsion that is excellent in solvent resistance and water resistance, is also excellent in stain resistance and whitening resistance, and can also provide a substrate with water absorption prevention performance. We worked diligently to find out.

[0008]

As a result of various investigations, the present inventors have found that a specific (meth) acrylic copolymer, a hydrolyzable silane compound and a specific block An emulsion containing a polymer has excellent storage stability, and the resulting coating film has excellent solvent resistance and water resistance, and also has good stain resistance, and can also provide a substrate with water absorption prevention performance. Further, the stain resistance is also improved, and the base material can also be provided with a water absorption preventing performance. Further, the emulsion in which colloidal silica is added to the emulsion has excellent whitening resistance, and the present invention has been completed. did. Hereinafter, the present invention will be described in detail.
In this specification, an acrylic copolymer or a methacrylic copolymer is referred to as a (meth) acrylic copolymer, and an acrylic monomer or a methacrylic monomer is referred to as a (meth) acrylic monomer. Acrylic ester or methacrylic acid ester is called (meth) acrylic acid ester, and acrylic acid or methacrylic acid is called (meth) acrylic acid.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION (A) (Meth) acrylic copolymer having an alkoxysilyl group (meth) acrylic copolymer having an alkoxysilyl group (hereinafter referred to as acrylic silicon copolymer) in the present invention is , Various copolymers can be used, preferably a radical polymerizable monomer having an alkoxysilyl group
(a), a radical polymerizable monomer (b) copolymerizable with the monomer (a), and a radical polymerizable surfactant (c) having a specific structure.
Is a constituent unit. Hereinafter, each component will be described.

A radical polymerizable monomer having an alkoxysilyl group (a) A radical polymerizable monomer having an alkoxysilyl group (a)
Various compounds can be used as [hereinafter referred to as monomer (a)]. The radical polymerizable group in the monomer (a) is preferably an ethylenically unsaturated group, more preferably a vinyl group and a (meth) acryloyl group. Examples of the alkoxy unit in the alkoxysilyl group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group,
Examples include a pentanoxy group and a hexanoxy group. Among these, an alkoxy group having 4 or less carbon atoms is preferable because of its excellent reactivity, and is more stable than a methoxy group.
An ethoxy group or a propoxy group is more preferred because of its higher reactivity than a butoxy group. The number of alkoxy groups bonded to a silicon atom may be any number as long as it is in the range of 1 to 3, but is preferably 2 or 3 because of excellent curability. Specific examples of the monomer (a) include vinyltriethoxysilane, vinylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, vinyltripropoxysilane, and vinylmethyldiethoxysilane. Examples thereof include propoxysilane, γ-methacryloxypropyltripropoxysilane, and γ-methacryloxypropylmethyldipropoxysilane.

A radical polymerizable monomer copolymerizable with the monomer (a) (b) a radical polymerizable monomer copolymerizable with the monomer (a)
Examples of (b) [hereinafter referred to as monomer (b)] include (meth) acrylates, vinyl acetate, vinyl propionate, styrene and α-methylstyrene. As the (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) Alkyl (meth) acrylates such as lauryl acrylate and stearyl (meth) acrylate; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate;
Perfluoroalkyl (meth) acrylate, glycidyl (meth) acrylate, and N (meth) acrylate
N-diethylaminoethyl and the like.

Among these monomers (b), (meth) acrylates and styrene are preferred because of their excellent copolymerizability and physical properties of the coating film, and more preferred are those having 1 carbon atom.
Alkyl (meth) acrylate having an alkyl group of -8, hydroxyalkyl (meth) acrylate having an alkylene group having 2 to 3 carbon atoms, and glycidyl (meth) acrylate. On the other hand, it is desirable not to use an acidic monomer such as (meth) acrylic acid having reactivity with an alkoxylyl group or promoting hydrolysis.

In the present invention, the monomer (a) and the monomer
At least one of (b) is a (meth) acrylic monomer.

Radical polymerizable surfactant (c) The radical polymerizable surfactant (c) [hereinafter referred to as surfactant (c)] in the present invention is a polyoxyalkylene represented by the following general formula (1): Anionic or cationic surfactant containing a group and an ionic dissociating group.

[0015]

Embedded image Z- (AO) n-Y (1)

(In the formula, Z is an organic group having a radical polymerizable double bond, AO is an oxyalkylene group, n is an integer of 2 or more, and Y is an ion-dissociable group.) Desirable Z is an organic group in which a hydrophobic group such as an aromatic hydrocarbon group, an alkyl-substituted aromatic hydrocarbon group, a higher alkyl group or an alicyclic hydrocarbon group is combined with a radical polymerizable double bond. As the radical polymerizable double bond for Z, a (meth) allyl group, a propenyl group, a butenyl group, or the like is preferable.

The preferred ionicity of the surfactant (c) in the present invention is an anion. Therefore, Y can be bonded to the group (AO) n by an anionic group, and a cation is attached to the anionic group. Ion-bound salts are preferred. Specific examples of the preferred _Y, -SO 3 _Na, -S
O ₃ NH ₄ , -COONa, -COONH ₄ , -PO ₃
Na ₂ and —PO ₃ (NH ₄ ) _{2 and the} like, and more preferably —SO ₃ Na or —SO ₃ NH ₄ . N in the group (AO) n is an integer of 2 or more. When n is 1, the alkoxysilyl group in the monomer (a) becomes unstable and is easily decomposed. Preferred n is 3
00, more preferably 5 to 50. n
Is less than 5, the stability of the alkoxysilyl group in the monomer (a) may be liable to be insufficient.
If it exceeds 00, the physical properties of the coating film formed from the obtained curable emulsion may tend to decrease. or,
The unit A in the group (AO) n, that is, the alkylene group, is preferably an ethylene group or a propylene group.

Specific examples of the component (c) include, for example, compounds represented by the following formulas (2) to (4). In the formulas (2) and (3), R ¹ and R ² are preferably a linear or branched alkyl group having 6 to 18 carbon atoms. In (4), R ³ is a hydrogen atom or a methyl group, and R ⁴ is preferably an alkyl group having 8 to 24 carbon atoms. In the formulas (2) to (4), A ¹ , A ² and A ^{3 each} represent an alkylene group, and in any of the compounds, n is an integer of 2 or more. In the formulas (2) to (4), Y ¹ , Y ² and Y ^{3 each} represent an ion dissociable group;
Specific examples thereof include those similar to Y.

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image

Preferred examples of these surfactants (c) are commercially available, for example, Aqualon [manufactured by Daiichi Kogyo Seiyaku Co., Ltd.] represented by the following formula (5) and Adeka represented by the following formula (6). Real Leap (made by Asahi Denka Kogyo Co., Ltd.) and the like. Aqualon HS05, HS10 and HS20 each have a polyoxyethylene group condensation degree n of 5, 10 and 20 in the formula (5), and the adecali lip SE-10N is represented by the formula (6) Is a compound wherein n is 10.

[0023]

Embedded image

The compound of the formula (5) is represented by the formula (2)
R ¹ is a nonyl group, A ¹ is an ethylene group, Y ¹ is SO ₃ NH
_{4 is} an example.

[0025]

Embedded image

The compound of the formula (6) is represented by the formula (3)
R ² is a nonyl group, A ² is an ethylene group, Y ² is SO ₃ NH
_{4 is} an example.

In the present invention, the proportion of the acrylic silicone copolymer in the curable aqueous emulsion is preferably from 5 to 70% by weight, more preferably from 15 to 60% by weight. When the content of the acrylic silicon copolymer is less than 5% by weight, the film thickness per coating becomes thin and the number of times of application increases, which is not economical. In some cases, the thickness may increase, and problems such as whitening may occur.

Production Method The acrylic silicone copolymer of the present invention can be obtained by radical polymerization of the above-mentioned monomer (a), monomer (b) and surfactant (c) in an aqueous medium. . Here, as the usage ratio of each component, the total amount of the monomer (a), the monomer (b) and the surfactant (c) (hereinafter referred to as the total amount of (a) (b) (c)) is used. Based on the basis, it is preferable that the monomer (a) is in the range of 0.5 to 49.5% by weight, more preferably 3 to 20% by weight, and the monomer (b) is 99 to 50% by weight. And more preferably 96 to 75% by weight, and surfactant (c) preferably in the range of 0.5 to 20% by weight, more preferably in the range of 1 to 5% by weight. is there. If the copolymerization ratio of the monomer (a) is less than 0.5% by weight, the curability of the resulting curable emulsion becomes insufficient, and the coating film may be whitened.
If the amount is more than the weight percentage, the storage stability may be easily reduced. If the proportion of the monomer (b) is less than 50% by weight, the resulting curable emulsion may have poor film-forming properties, poor adhesion of the coating film to the substrate, and the like. If the proportion of the surfactant (c) is less than 0.5% by weight, the polymerization stability tends to decrease, while if it exceeds 20% by weight, the water resistance of the coating film may be insufficient.

Monomer (a), monomer (b) and surfactant
As a method for radical polymerization of (c), various methods are adopted, microsuspension polymerization in which the oil-soluble polymerization initiator is used to polymerize in the fine particles of the oil-soluble monomer, in micelles using an emulsifier. Emulsion polymerization in which a monomer is polymerized with a water-soluble polymerization initiator can be employed, but microsuspension polymerization is preferably employed because the polymerization stability of the monomer (a) is excellent. In micro-suspension polymerization, since the oil-soluble radical polymerization initiator is contained in the dispersed particles of the monomer, the polymerization occurs in each monomer-dispersed fine particle, and in the micelle formed by the emulsifier. This is distinguished from the emulsion polymerization method in which polymerization is caused by a water-soluble initiator.

In order to carry out the microsuspension polymerization, first, a mixture comprising the monomer (a), the monomer (b) and the oil-soluble polymerization initiator is added to an aqueous medium by a surfactant (c). Preferably, it is dispersed in an aqueous medium in which a pH buffer is dissolved. In the operation of dispersing the monomer or the like in an aqueous medium, the surfactant (c) may be mixed with the monomer or the like and dissolved in the aqueous medium in advance similarly to the pH buffer. Is also good. The ratio of the monomer to be dispersed in the aqueous medium is the monomer (a) and the monomer
Aqueous medium 20 to 150 per 100 parts by weight of total amount of (b)
A suitable amount is about parts by weight.

The oil-soluble radical polymerization initiator used in the microsuspension polymerization preferably has a solubility in water at 20 ° C. of 10% by weight or less. For example, 2,2 '
-Azobisisobutyronitrile, 2,2'-azobis-
2,4-dimethylvaleronitrile, 1-azobis-1-cyclohexanecarbonitrile and dimethyl-2,2'-
Azo-based initiators such as azobisisobutyrate, and organic peroxides such as lauroyl peroxide, benzoyl peroxide, dicumyl peroxide, cyclohexanone peroxide di-n-propylperoxydicarbonate and t-butylperoxypivalate The thing is used suitably. The amount of these polymerization initiators is 0.1 to the total amount of the monomers.
10 to 10% by weight is appropriate, and preferably set in the range of 0.5 to 5% by weight.

In this case, it is preferable to add a pH buffer to stabilize the alkoxysilyl group in the monomer (a). The pH buffer adjusts the pH of the aqueous medium in the aqueous emulsified dispersion to a neutral to weakly alkaline region, specifically, p.
Those having a buffer function suitable for holding at H6 to 10 are preferably used. As this kind of pH buffer,
Examples include organic acids, inorganic acids, bases, and salts thereof.
Examples of the inorganic acid include carbonic acid, phosphoric acid, sulfuric acid and hydrosulfuric acid. Organic acids include organo-, mono- or polycarboxylic acids having 1 to 6 carbon atoms, and salts of organic acids include mono- or poly-alkali metal salts of alkylene imino polycarboxylic acids having 2 to 30 carbon atoms, alkaline earth metals Salts and amine salts. Examples of the base include ammonia, an organic base having 1 to 30 carbon atoms, and the like. In the present invention, it is preferable to use a salt of an inorganic acid, specifically, sodium hydrogen carbonate, sodium carbonate, ammonium carbonate,
Sodium borate, 1, 2 or 3 sodium phosphate, 1, 2 or 3 potassium phosphate, sodium ammonium phosphate,
Sulfuric acid 1 or 2 sodium, sodium acetate, potassium acetate, ammonium acetate, calcium acetate, sodium formate, 1 or 2 sodium sulfide, ammonia, mono, di or triethylamine, mono, di or triethanolamine, (ethylene dinitrilo) 4 Sodium acetate (E.
D. T. A. Sodium), pyridine, aniline, sodium silicate and the like, and it is particularly preferable to use sodium hydrogen carbonate whose pH is stabilized by addition of a small amount. p
The H buffer may be used in combination of two or more,
For example, by using sodium bicarbonate and monosodium phosphate in combination, the pH can be maintained at around 7.5. A suitable amount of the pH buffer is in the range of 0.01 to 5% by weight based on water. By using a pH buffer, the pH of the aqueous medium in the aqueous emulsified dispersion is controlled in the range of 6 to 10, and the radically polymerizable monomer (a) having an alkoxylyl group or a polymer containing the monomer as one component is used. Hydrolysis of the alkoxysilyl group in the coalescence is suppressed.

As a method of emulsifying and dispersing, sufficient emulsifying and dispersing can be carried out using a usual rotary homomixer. The particle size of the emulsified dispersion comprising the monomer (a), the monomer (b) and the surfactant (c) is preferably an aqueous emulsified dispersion having a small particle size, specifically 1 μm The following is preferred, and more preferably 0.2 to 0.05 μm. By making the emulsion having such a particle size, the particle size of the emulsified dispersion obtained after the polymerization can be reduced,
Further, the coating film obtained therefrom has excellent solvent resistance and water resistance. In order to obtain such a particle size, after the treatment with a rotary homomixer, the particle size is reduced using a high-pressure type emulsifying disperser (homogenizer), a dispersing device having a high shear energy such as a turbine type mixer. Is desirable.

In the polymerization operation of the emulsion comprising the monomer (a) and the monomer (b) obtained by the above operation (hereinafter referred to as "monomer emulsion"), the monomer emulsion is heated under stirring. It is carried out by a method of continuously or intermittently supplying the aqueous medium. As a method for supplying the monomer emulsion, it is preferable to employ a means for gradually dropping the solution from a dropping funnel. At this time, the preferred amount of the aqueous medium charged into the polymerization vessel is in the range of 10 to 50 parts by weight per 100 parts by weight of the monomer emulsion. The polymerization temperature varies depending on the polymerization initiator used, but is usually about 40 to 100 ° C, and preferably 70 to 90 ° C.

According to the polymerization method, the average particle size is 0.1 μm.
An aqueous dispersion in which about m 2 of acrylic silicone copolymer particles are stably emulsified and dispersed is produced.

◎ (B) Hydrolyzable silane compound The hydrolyzable silane compound used in the present invention (hereinafter also simply referred to as silane compound) is one capable of imparting water absorption and water repellency to a substrate. If so, various ones can be used, and both monomers and oligomers can be used. The oligomer is a condensate of a dimer or more of a silane compound, and a preferable oligomer is a dimer to a dimer.
When an oligomer having more than 10 mer is used, the resulting emulsion may have poor water absorption prevention performance.
In the present invention, it is preferable to use a compound represented by the following general formula (7) as the silane compound.

[0037]

Embedded image R ⁵ _n Si (R ⁶ ) _4-n (7)

Here, in the formula (7), R ⁵ is a stable hydrophobic group which hardly causes hydrolysis and has 1 to 30 carbon atoms.
An alkyl group, a substituted alkyl group or an aryl group.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group,
Octyl, decyl, dodecyl, tetradecyl,
Examples include a hexadecyl group, an octadecyl group, and an eicosyl 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 a fluorinated product, chlorinated product and brominated product of the above alkyl group, and specifically, 3-chloropropyl group, 6-chlorohexyl group, 6,6,6-trifluorohexyl group and the like. Can be mentioned. As the aromatic-substituted alkyl group, a benzyl group,
Examples thereof include a halogen-substituted benzyl group such as a 4-chlorobenzyl group and a 4-bromobenzyl group. Examples of the aryl group include a phenyl group, a tolyl group, a mesityl group, and a naphthyl group. R ⁶ is a hydrolyzable functional group, which is an alkoxy group having 1 to 6 carbon atoms, a halogen atom, an amino group, a hydroxy group or a carboxyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group and the like. As the halogen atom, a chlorine atom or a bromine atom is preferable. When the silane compound has a plurality of R ⁵ or R ⁶ , each may be the same or different. n is 1 or 2. n
Is 0, there is a problem that the water repellency and waterproofness of the resulting emulsion film are not sufficient.

Specific examples of the silane compound include the following silane compounds or oligomers thereof.

In the formula (7), R ⁵ is an alkyl group,
A halogenated alkyl group or an aromatic substituted alkyl group;
Examples of silane compounds in which ⁶ is an alkoxy group and n is 1 Examples of R ⁵ are alkyl groups include methyltrimethoxysilane, methyltriethoxysilane, methyl-tri-n-
Propoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyl-tri-n-propoxysilane, propyltriethoxysilane, propyl-tri-
n-propoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexyltrimethoxysilane, octyltrimethoxysilane, octyl Triethoxysilane, octyltriisopropoxysilane, 2-ethylhexyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltriethoxysilane, hexadecyltriethoxysilane, octadecyltriethoxysilane, eicosyltrimethoxysilane, etc. Is mentioned. As an example of the case where R ⁵ is a halogenated alkyl group, 6-
Chlorohexyltrimethoxysilane and 6,6,6-trifluorohexyltrimethoxysilane are exemplified. Examples of the aromatic-substituted alkyl group for R ⁵ include benzyltrimethoxysilane, 4-chlorobenzyltrimethoxysilane, 4-chlorobenzyltriethoxysilane, and 4-bromobenzyltri-n-propoxysilane.

In the formula (7), examples of silane compounds wherein R ⁵ is an alkyl group, R ⁶ is a halogen atom and n is 1 include dodecyltrichlorosilane, dodecyltribromosilane and the like.

In the formula (7), examples of the silane compound wherein R ⁵ is an aryl group, R ⁶ is an alkoxy group and n is 1 include phenyltrimethoxysilane, phenyltriethoxysilane and the like.

In the formula (7), an example of a silane compound in which R ⁵ is an alkyl group, R ⁶ is an alkoxy group and n is 2 dimethyldimethoxysilane, dimethyldiethoxysilane, dibutyldimethoxysilane, diisobutyldimethoxysilane and the like. No.

In the present invention, in formula (7), the use of a silane compound in which R ⁵ is an alkyl group, R ⁶ is an alkoxy group, and n is 1, ie, an alkyltrialkoxysilane, is excellent in storage stability, It is more preferable because an emulsion having a small particle size can be obtained.

These silane compounds may be used in combination of two or more.

The silane compound used in the present invention may contain a compound having a silanol group, which is an impurity at the time of production, or a residual catalyst.

In the present invention, the concentration of the silane compound in the curable aqueous emulsion is preferably 5 to 60% by weight,
More preferably, it is 8 to 45% by weight. If the concentration of the silane compound is less than 5% by weight, the permeability to the substrate may be reduced. If the concentration exceeds 60% by weight, the curability of the acrylic silicon copolymer may be reduced, and the coating film may not be coated. May be difficult to form.

Aqueous dispersion of silane compound In the production of the emulsion of the present invention, the silane compound is preferably used as an aqueous dispersion of the silane compound. As the aqueous dispersion of the silane compound, those produced by various methods can be used.

In the aqueous dispersion of the silane compound, an emulsifier is added for the purpose of converting the silane compound into an aqueous emulsion or a state similar thereto. As the emulsifier, any of nonionic, anionic and cationic types can be used. Among these, an aqueous emulsion of a hydrolyzable silane compound using a nonionic emulsifier is preferred because of its excellent emulsion stability. When a nonionic or anionic emulsifier is used, the hydrolysis-condensation reaction occurs relatively quickly and the efficacy is reduced. Therefore, it is preferable to use the nonionic and anionic emulsifiers immediately after preparation. As the nonionic emulsifier, those having a type of HLB = 4 to 22,
Alternatively, a mixture thereof is suitably 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 Ethylene sorbitan monostearate and the like can be mentioned. The HLB of other emulsifiers is 1.5
To 22 are preferable, and 4 to 15 are more preferable. The emulsifier is preferably used in the range of 0.1 to 50% by weight based on the silane compound, more preferably 1% by weight.
-20% by weight. Since the type and concentration of the emulsifier vary depending on the hydrolyzable silane compound used, it is preferable to experimentally study and determine the emulsifier when using the emulsifier. These emulsifiers can be used in combination of two or more kinds.

In the aqueous dispersion of the silane compound, the proportion of the silane compound is preferably 1 to 65% by weight, more preferably 5 to 50% by weight, and the water of the dispersion medium is 35 to 99% by weight. And more preferably 50
~ 95% by weight. When the proportion of the silane compound is less than 1% by weight, the resulting emulsion may not be able to exhibit desired properties such as water absorption preventing property and water repellency to the substrate, and when it exceeds 65% by weight. In some cases, emulsification of the silane compound becomes difficult, and the resulting emulsion is unstable and easily separated.

As a method for producing an aqueous dispersion of a silane compound, for example, an emulsifier as described in JP-A-1-292889 or JP-A-62-197369 may be added to water if necessary. Dispersion, a silane compound is added thereto, and the mixture is emulsified by high-speed stirring.
The particle size of the dispersed particles in the dispersion is preferably 1 μm or less, more preferably 0.5 μm or less. If the particle size exceeds 1 μm, the resulting aqueous dispersion may be unstable and easily separated.

The aqueous dispersion of the silane compound may contain other emulsifiers, protective colloid agents and the like in a usual ratio, if necessary. It is preferable to add a pH buffer for the purpose of suppressing the hydrolysis reaction of the hydrolyzable silane compound in the aqueous dispersion. As the pH buffer, those similar to those mentioned in the section of the method for producing the acrylic silicone copolymer can be used, and it is preferable to use a salt of an inorganic acid, and the pH is stabilized by adding a small amount. It is particularly preferred to use sodium bicarbonate. The mixing ratio of the buffer is
The ratio added to the usual silane-based aqueous emulsion may be sufficient, and specifically, 0.01 to 5% by weight in the aqueous dispersion.
Is preferred. In addition, fungicides, bactericides, fragrances, coloring agents, thickeners, foaming agents, antifoaming agents, and the like can be added to such an extent that the performance of the water absorption inhibitor is not impaired.

The aqueous dispersion of these silane compounds is
Commercially available silicone-based and silane-based water repellents and water-absorbing inhibitors can be used, and specific examples include tight silane (Toyo Ink Co., Ltd.) and Aquaproof (Toagosei Co., Ltd.).

◎ (C) Block polymer The block polymer constituting the emulsion of the present invention is:
In the presence of a radical polymerization initiator having a polydimethylsiloxane unit and a plurality of azo groups in the main chain, a (meth) acrylic ester having a polyoxyalkylene group (hereinafter referred to as (meth) acrylic acid polyoxyalkylene ester) It is obtained by subjecting a monomer as a main component to radical polymerization. The block polymer preferably has a number average molecular weight in terms of polystyrene of 40,000 to 1,000,000 measured by GPC, more preferably 50,000 to 200,000.

(Polyoxyalkylene (meth) acrylate) As the polyoxyalkylene (meth) acrylate, various compounds can be used, such as a compound represented by the following formula (8).

[0056]

CH ₂ = CR ⁷ CO (OR ⁸ ) _n OR ⁹ (8) wherein R ⁷ is a hydrogen atom or a methyl group, R ⁸ is an alkylene group, and R ⁹ is a hydrocarbon residue. , N represents an integer of 1 to 30.

In the formula (8), the alkylene group of R ⁸ includes an ethylene group, a propylene group and a butylene group, and the hydrocarbon residue of R ⁹ includes a methyl group, an ethyl group, a propyl group and a phenyl group. And the like. Preferable polyoxyalkylene esters of (meth) acrylic acid include alkoxypolyethylene glycol mono (meth) acrylate represented by the following formula (9), and the following formula (1)
0), phenoxyethylene glycol mono (meth) acrylate represented by the following formula (11), and alkoxypolytetramethylene glycol mono (meth) acrylate represented by the following formula (12) A) Acrylate and the like.

[0058]

CH ₂ ＣＲCRCO (OCH ₂ CH ₂ ) _n OR ′ (9) (wherein R is hydrogen or methyl, R ′ is methyl, ethyl or propyl, and n is 1) It is an integer of ~ 30.)

[0059]

Embedded image CH ₂ ＣＲCRCO (OCH ₂ CH ₂ ) _n OPh (10) (wherein, R is hydrogen or a methyl group, and n is an integer of 1 to 30.)

[0060]

Embedded image CH ₂ ＣＲCRCO (OCH ₂ CH ₂ (CH ₃ )) _n OR ′ (11) (wherein R is hydrogen or a methyl group, and R ′ is a methyl, ethyl or propyl group) , N is an integer of 1 to 30.)

[0061]

CH ₂ ＣＲCRCO (OCH ₂ CH ₂ CH ₂ CH ₂ ) _n OR ′ (12) (wherein R is a hydrogen or methyl group, and R ′ is a methyl, ethyl or propyl group) , N is an integer of 1 to 30.

The proportion of these monomers is 50% in all the monomers.
% Or more, more preferably 70% by weight or more.
% By weight or more. These may be used alone or in combination of two or more.

○ Other monomers In the present invention, the solubility of the obtained block polymer
For the purpose of improving stability, dispersibility, compatibility and co-crosslinkability, in addition to the above-mentioned essential component (meth) acrylic acid polyoxyalkylene ester, other monomers copolymerizable therewith may be used. it can. Such monomers include:
Methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, (meth)
S-butyl acrylate, t-butyl (meth) acrylate, neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, (meth) acryl Tridecyl acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecynyl (meth) acrylate,
Tetrahydrofurfuryl (meth) acrylate, (meth)
Methoxyethyl acrylate, dimethylaminoethyl (meth) acrylate, chloroethyl (meth) acrylate,
(Meth) acrylates such as trifluoroethyl (meth) acrylate and pentafluoropropyl (meth) acrylate; hydroxyethyl (meth) acrylate;
Hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, terminal hydroxyl polyethylene oxide macromonomer of (meth) acrylic acid and N
-An unsaturated monomer having a hydroxyl group such as methylolated (meth) acrylamide; an unsaturated monomer having an epoxy group such as glycidyl (meth) acrylate and allyl glycidyl ether; (meth) acrylic acid and itaconic acid Unsaturated monomers containing a carboxyl group, such as acetic acid, maleic acid, fumaric acid, and vinyl acetic acid; unsaturated monomers containing an amino group, such as aminoethyl (meth) acrylate; γ- (meth)
Acryloyloxypropyltrimethoxysilane, γ-
Examples thereof include unsaturated monomers containing an alkoxysilyl group such as (meth) acryloyloxypropylmethyldiethoxysilane and triethoxyvinylsilane. Among these other monomers, an unsaturated monomer containing a hydroxyl group or an alkoxysilyl group is preferable from the viewpoint of excellent compatibility with the acrylic silicon copolymer and co-crosslinking property.

Other than these, if necessary, olefins such as ethylene, propylene and isobutylene, chloroethylenes such as vinyl chloride and vinylidene chloride, vinyl acetate, vinyl propionate, vinyl caproate, vinyl pivalate, Veova-9 (manufactured by Shell Chemical), vinyl carboxylate such as vinyl cyclohexanecarboxylate, vinyl benzoate and vinyl laurate, (meth) acrylamides, styrene and α
-Styrenes such as methylstyrene may be copolymerized. The proportion of other monomers is preferably 50 mol% or less, more preferably 30 mol% or less of all monomers.

Method for Producing Block Polymer The block polymer of the present invention is prepared by preparing the above polyoxyalkylene ester (meth) acrylate in the presence of a radical polymerization initiator having a polydimethylsiloxane unit and a plurality of azo groups in the main chain. Alternatively, it can be obtained by radically polymerizing a mixture of this and another monomer capable of copolymerization. Thereby, a block polymer having a polyoxyalkylene skeleton and a polydimethylsiloxane skeleton can be produced. The polymerization initiator preferably has a number average molecular weight of 5,000 to 150,000, more preferably 20,000 to 100,000. The number average molecular weight of the polysiloxane moiety is preferably from 3,000 to 15,000. As the polymerization initiator, a polymeric azo compound represented by the following formula (13) is preferable.

[0066]

Embedded image

(Where x is an integer of 10 to 500, and n is 2
It is an integer of １００100. )

The polymeric azo compound of the above formula (13) is commercially available, for example, from Wako Pure Chemical Industries, Ltd., and is known to have a polydimethylsiloxane moiety having a molecular weight of 5,000 or 10,000.

The ratio of the polymerization initiator used in the present invention is as follows:
With respect to 100 parts by weight of the total amount of the (meth) acrylic acid polyoxyalkylene ester or the other monomer,
1 to 10 parts by weight is preferred.

The radical polymerization can be carried out by a usual method, that is, bulk polymerization, solution polymerization in an organic solvent, emulsion polymerization in water, and the like can be employed. Examples of the solvent in the solution polymerization include cyclic ethers such as tetrahydrofuran and dioxane; aliphatic hydrocarbons such as n-hexane, cyclohexane, mineral spirit, industrial gasoline No. 4, volatile oil No. 3, kerosene and turpentine oil; Aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone and cyclohexanone; organics such as alcohols such as ethanol, isopropanol, n-butanol and n-butyl cellosolve. Solvents are exemplified, and one or more of these can be used. Among these, cyclic ethers, esters, ketones, and alcohols are preferable because of excellent solubility of the obtained block polymer. The amount of the organic solvent used is preferably 20 to 200 parts by weight based on 100 parts by weight of all monomers. In the emulsion polymerization, the polymerization can be carried out in an aqueous medium in the presence or absence of an emulsifier such as sodium salt of a higher alcohol sulfate and polyethylene glycol ether. When using an emulsifier, 0.01 to 100 parts of all monomers
50 parts is desirable. After completion of the polymerization, the block polymer may be isolated and purified, and redissolved in an organic solvent or suspended in water for use. The polymerization conditions may be appropriately set depending on the monomer used, the polymerization method to be applied, and the like. Preferably, the polymerization temperature is 20 to 100 ° C., and the polymerization pressure is 1 to 200 kg / c.
m ² , and the polymerization time is 3 to 40 hours.

The block polymer in the present invention is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the acrylic silicone copolymer.
It must be contained in parts by weight. If this proportion is less than 0.1 part by weight, the improvement of the stain resistance may be insufficient, while if it exceeds 30 parts by weight, the weather resistance of the coating film tends to decrease.

(D) Colloidal silica The emulsion comprising the acrylic silicone copolymer, the silane compound and the block polymer of the present invention has a coating film excellent in solvent resistance, water resistance and stain resistance. However, under severe environmental conditions, a problem of whitening resistance may occur due to the block polymer to be blended. In the present invention, colloidal silica is blended in order to further impart the whitening resistance to the obtained coating film. Colloidal silica refers to a dispersion of silica fine particles in an organic solvent such as water or alcohol, and particularly in water, SiOH groups and SiOH ^- ions are present on the particle surface, and are generally negatively charged. The dispersion is stabilized by the repulsion between the particles. The colloidal silica in the present invention preferably has a particle diameter of 10 μm or less, more preferably 1 μm or less. When the colloidal silica has a particle size of more than 10 μm, the dispersibility in the emulsion is poor, and the obtained coating film may be brittle. As the colloidal silica, any of silica fine particles dispersed in water and those dispersed in an organic solvent such as alcohol can be used. Further, in the present invention, aqueous colloidal silica in which silica fine particles are dispersed in water is preferable in that it has excellent dispersibility in the obtained emulsion. The pH of the aqueous colloidal silica is preferably 3 to 11. p
When H is less than 3 or more than 11, the stability of the obtained emulsion may decrease. Colloidal silica is commercially available, Snowtex [Nissan Chemical Industries, Ltd.
Cerazole (manufactured by Colcoat), Ludox (manufactured by DuPont), Mittens (manufactured by Monsanto Chemical Co.), silica doll (manufactured by Nippon Chemical Co., Ltd.), cataloids (manufactured by Kato Kasei Kogyo Co., Ltd.) and Adelite (Asahi Denka) Industrial Co., Ltd.)
Etc.

[0073] The blending ratio of the colloidal silica in the emulsion, to acrylic silicone copolymer 100 parts by weight, preferably 0.1 to 20 parts by weight in terms of SiO ₂ of silica, more preferably, 1-10 wt. Department. If this proportion is less than 0.1 part by weight, the whitening resistance of the coating film may be insufficient, while if it exceeds 20 parts by weight, the coating film may become brittle.

◎ Method for Producing Curable Aqueous Emulsion The emulsion of the present invention comprises an acrylic silicone copolymer,
The silane compound and the block polymer can be produced by mixing according to a conventional method in an aqueous medium in the presence of an emulsifier. When silica is blended, these are further mixed with silica and mixed as described above. It can be manufactured by the following. A method of mixing an aqueous dispersion of an acrylic silicon copolymer, an aqueous dispersion of a silane compound, and a block polymer is preferable because of easy production, and the same applies when silica is blended.

As the manufacturing method, various methods can be adopted.
Specifically, an aqueous dispersion of an acrylic silicon copolymer and an aqueous dispersion of a silane compound are mixed, and then a method of adding and mixing a block polymer, or an aqueous dispersion of a silane compound and a block polymer are mixed, Next, a method of mixing an aqueous dispersion of an acrylic silicon copolymer may be used. When silica is blended, specifically, a method of mixing an aqueous dispersion of an acrylic silicon copolymer and an aqueous dispersion of a silane compound, and then adding a block polymer and further adding silica, or And a block polymer, and then an aqueous dispersion of an acrylic silicone copolymer is mixed, and silica is added and mixed.

In the present invention, the block polymer can be blended as it is, but it is also possible to use a solution in which the block polymer is dissolved in advance in a film-forming aid which is one of paint additives. Can be used by emulsifying and dispersing them in the presence or absence of a surfactant.

In the present invention, it is preferable to incorporate a film-forming aid into the emulsion. As the film-forming aid, those usually used in aqueous paints can be used. For example, straight-chain, branched or cyclic aliphatic alcohols having 5 to 10 carbon atoms, alcohols containing an aromatic group; Formula HO- (CH ₂ CH
XO) _n- R ¹⁰ (R ¹⁰ : a linear or branched alkyl group having 1 to ¹⁰ carbon atoms, X: hydrogen or a methyl group, an integer of n ≦ 5) (poly) ethylene glycol or (poly) monoethers and propylene glycol; general formula _{^{R 11 COO- (CH 2 CHXO)}} n -R 12 (R 11,
R ¹² : a linear or branched alkyl group having 1 to 10 carbon atoms;
X: hydrogen or a methyl group, an integer of n ≦ 5) (poly) ethylene glycol ether ester or (poly)
Propylene glycol ether esters; aromatic organic solvents such as toluene and xylene, mono- or diisobutyrate of 2,2,4-trimethyl-1,3-pentanediol, 3-methoxybutanol, 3-methoxybutanol acetate; Examples include 3-methyl-3-methoxybutanol and 3-methyl-3-methoxybutanol acetate.

As will be specifically described in Examples, the emulsion maintains a stable emulsion state even when left at a temperature of 60 ° C. for one month, and has good self-curing performance and permeability, Excellent contamination resistance as film properties.

The emulsion of the present invention is cured by a condensation reaction mainly caused by a silanol group generated by hydrolysis of an alkoxysilylsilyl group derived from the monomer (a). If necessary, a curing catalyst may be added. You can also. As curing catalysts, for example, organic titanate compounds such as isopropyl triisostearoyl titanate and isopropyl tri (dioctyl pyrophosphate) titanate, organic tin compounds such as tin dioctylate, dibutyltin dilaurate and dibutyltin malate, and organic compounds such as paratoluenesulfonic acid Acid catalysts can be mentioned.
In addition, when the emulsion of the present invention is used together with the curing catalyst, an appropriate amount of an inorganic acid is added, and the pH of the emulsion is adjusted to an acidic range of about 3 to 5 to produce a film having further improved crosslinkability. Becomes possible. The addition of these catalysts and acids promotes the reaction of the silane compound constituting the emulsion with the substrate.

The emulsion of the present invention may contain, if necessary, a pigment, an antifoaming agent, a thickener, a fungicide, a preservative, an antibacterial agent, an ultraviolet absorber, a light stabilizer, a leveling agent, a slipping agent, a sagging prevention agent. Additives commonly used in aqueous paints, such as agents, anti-separation agents, antioxidants and heat stabilizers, may be added. or,
When dispersing a pigment, a pigment dispersant may be added. Before blending the polyorganosiloxane block polymer, these may be previously blended in an aqueous dispersion of an acrylic silicone copolymer, an aqueous dispersion of a silane compound or an aqueous dispersion of an acrylic silicone copolymer and a silane compound. it can.

The emulsion of the present invention is suitable as a coating agent, and applicable substrates include stone, cement concrete, cement mortar, glass, slate, metal, wood and plastic.
It is preferably applicable to porous inorganic materials such as cement concrete and cement mortar. In addition, in addition to paints for building materials, paints for acid rain resistance, antifouling paints and water repellents for inorganic building materials, hardening finishes for fibers, water repellents and sealing agents, and the like can be mentioned. In particular, it can be preferably used as an architectural coating.

The coating of the emulsion of the present invention may be carried out in accordance with a method generally used for aqueous paints, and can be applied by, for example, spray coating, brushing, rolls or the like. In this case, the thickness of the paint may be selected according to the purpose, but is preferably from 10 to 50 μm from the viewpoint of the balance between the protection of the base and the drying property.

[0083]

The reason why the curable aqueous emulsion of the present invention is excellent in solvent resistance and water resistance as well as in stain resistance and whitening resistance in the resulting coating film is unknown. Inferred. That is, in the emulsion of the present invention, the block polymer of the constituent component causes the polyorganosiloxane block polymer to be localized on the coating film surface due to the low interfacial tension of the polyorganosiloxane segment, and the hydrophilic polyoxyalkylene segment Are arranged on the coating film surface, and as a result, the coating film surface can be made hydrophilic,
It is presumed that this is because the pollutants are likely to run down due to rainwater or the like. On the other hand, it is presumed that the colloidal silica particles crosslink with the acrylic silicon copolymer, thereby strengthening the coating film surface and imparting whitening resistance. In particular, when the acrylic silicone copolymer used in the present invention is composed of a monomer (a), a monomer (b) and a surfactant (c), the monomer (a) ) And a surfactant having a polyoxyalkylene group and an ion-dissociable group (c), the surfactant (c)
Not only functions as an emulsifier at the time of copolymerization,
Radical polymerization with the monomer (a) makes it close to the alkoxysilyl group in the copolymer, and the polyoxyalkylene group of the surfactant (c) can effectively protect the alkoxysilyl group in the copolymer Therefore, the storage stability of the finally obtained curable emulsion is improved.

[0084]

The present invention will be described more specifically below with reference to examples and comparative examples. In each example, “parts” means “parts by weight” and “%” means “% by weight”. Production Example 1 (Production of aqueous dispersion of acrylic silicone copolymer)-Synthesis of preliminary emulsion Monomer (a), monomer (b), surfactant (c), oil-soluble radical polymerization initiator and The aqueous medium was mixed in the amounts shown in Table 1, mixed with a homomixer, and further subjected to emulsification and dispersion treatment with a homogenizer (manufactured by Gorin Co.) to obtain a pH of 8.5.
Was prepared.

[0085]

[Table 1] * Aqualon HS20 is a compound in which n is 20 in the formula (5).

Polymerization reaction A flask equipped with a stirrer, a thermometer, and a cooler was charged with 40 parts of deionized water as an aqueous medium, and the liquid temperature was raised to 85 ° C. Was added dropwise over 2 hours. After dropping, 8
The copolymer was kept at a temperature of 5 ° C. for 2 hours for copolymerization, and then cooled to room temperature. During the polymerization, aggregates slightly adhered to the inner wall of the flask, but liquid separation and blocking did not occur, and the polymerization was stably performed. By this polymerization operation, the resin solid content becomes 4
0% by weight, the average particle size of the polymer particles is 0.11 μm,
An aqueous dispersion of an acrylic silicon copolymer having an H of 8.5 was obtained.

Production Example 2 (Production of aqueous dispersion of silane compound) 200 g of hexyltriethoxysilane and H as an emulsifier
8 g of polyoxyethylene octyl phenyl ether having an LB of 15 was mixed, and the mixture was mixed with sodium bicarbonate as a pH buffer (having a content of 0.1% in an aqueous dispersion).
Was added to 292 g of deionized water containing, and stirred at high speed. The obtained aqueous dispersion of the silane compound had a silane compound concentration of 40% and an average particle size of 0.3 μm.

Block Polymer Synthesis Example 1 A four-necked flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a dropping funnel was charged with 300 parts of ethyl acetate as a solvent and methoxy poly as a polyoxyalkylene ester of (meth) acrylate. Oxyethylene glycol (n = 23) methacrylate [M230G manufactured by Shin-Nakamura Chemical Co., Ltd.]
After the parts were charged and the flask was sufficiently purged with nitrogen, the temperature was raised to 70 ° C. From the dropping funnel, a polymer azo compound represented by the above formula (13) [VPS05 manufactured by Wako Pure Chemical Industries, Ltd.
01, a number average molecular weight of 40,000, a polysiloxane molecular weight of 5,000, and an azo content of 6.2% determined by UV absorption in a UV spectrum] 5 parts of an initiator solution in which 50 parts of ethyl acetate was dissolved was added dropwise over 1 hour. Further, a polymerization reaction was carried out at 70 ° C. for 7 hours, and the content was precipitated in a mixed solvent of naphtha No. 6 (manufactured by Exxon Chemical Co., Ltd.) / Acetone = 90/10 (weight ratio) to obtain 148 parts of a block polymer. The number average molecular weight of the obtained block polymer was 75,000. 100 parts of the obtained block polymer was dissolved in 200 parts of 3-methyl-3-methoxybutyl acetate (Kuraray Co., Ltd., Solfit acetate), and a block polymer solution (solid content: 33%, hereinafter referred to as B-1) was dissolved. Obtained.

Block Polymer Synthesis Example 2 The monomers used were 145 parts of M230G as a polyoxyalkylene (meth) acrylate and γ-methacryloxypropyltriethoxysilane (hereinafter referred to as MPTS) as another monomer. And the polymer azo compound represented by the above formula (13) was converted to a VPS1001 manufactured by Wako Pure Chemical Industries, Ltd. [number average molecular weight 9000].
0, the molecular weight of the polysiloxane was 10,000, and the azo content was 2.5% as determined by UV absorption in the UV spectrum.] A block polymer was obtained in the same manner as in Synthesis Example 1. The number average molecular weight of the obtained block polymer is 1
8000, and its monomer unit is M230G / MPT
S = 95/5 (weight ratio). In the same manner as in Synthesis Example 1, a block polymer solution (solid content: 33%, hereinafter referred to as B-2) was prepared.

Block Polymer Synthesis Example 3 The monomer used was a methoxypolyoxyethylene glycol (n = 9) acrylate [A (manufactured by Shin-Nakamura Chemical Co., Ltd.) as a polyoxyalkylene ester of (meth) acrylic acid.
M90G], and a block polymer was obtained in the same manner as in Synthesis Example 1 except that the amount of other monomers was changed to 20 parts of hydroxyethyl acrylate (hereinafter referred to as HEA). The number average molecular weight of the obtained block polymer was 80000, and its monomer unit was AM90G / HE.
A = 86/14 (weight ratio). Ion exchange water 20
In 0 parts, 5 parts of polyoxyethylene nonylphenyl ether was dissolved as an emulsifier. 2000 by Disper
While stirring at rpm, 100 parts of the block polymer heated to 80 ° C. was slowly added dropwise to obtain an emulsion of the block polymer (solid content: 33%, hereinafter referred to as B-3).

Example 1 50 parts of the aqueous dispersion of the acrylic silicon copolymer obtained in the production example and 50 parts of the aqueous dispersion of the silane compound were mixed (the acrylic silicon copolymer in the aqueous dispersion after mixing and The silane compounds were mixed at a concentration of 20% (mixture A). To 100 parts of the mixture A, 9 parts of the block polymer solution B-1 obtained in Synthesis Example 1 (a ratio of the block polymer to 15 parts with respect to 100 parts of the acrylic silicon copolymer) was added, and the mixture was stirred and mixed. A curable aqueous emulsion was thus obtained. The obtained emulsion was evaluated according to the following. Table 3 shows the results.

Evaluation: Stability of the emulsion The obtained emulsion was placed in a sealed container for 60 months for one month.
After maintaining at a temperature of ° C., the amount of alcohol generated by the decomposition of the alkoxy group of the acrylic silicon copolymer or the silane compound was analyzed by gas chromatography. Assuming that the charged monomer (a) and the alkoxy group of the silane compound were all hydrolyzed, the ratio of the alcohol to the alcohol amount was calculated [hydrolysis ratio (% by weight)]. In addition, the state of separation was visually confirmed.

Water resistance The obtained emulsion was applied to a slate plate at a rate of 15 per m ^2.
0 g was applied and dried for 7 days to prepare a test body A. After immersing the test body A in clear water (20 ° C.) for 7 days, the presence or absence of whitening was confirmed, and the gloss change before and after immersion in water was measured, and evaluated on the following three levels. Gloss retention: 100-80%; ○, 80-40%; Δ,
40-0%; ×

Penetration depth The obtained emulsion was spread on a mortar plate at a rate of 15 per m ^2.
After applying 0 g and drying and curing for 14 days, the film was split, and the cross section was sprayed with water to measure the depth of the water-repellent portion to determine the penetration depth.

Acid resistance A 1% drop of 5% sulfuric acid was added dropwise to the coating film of the test piece A in the same manner as in the water resistance test, the mixture was kept at 60 ° C. for 10 minutes, and the state of the coating film was observed. evaluated. ；: No change, △: mark is formed, ×: coating film floats or peels

Water Absorption Prevention The obtained emulsion was added to a mortar plate at a rate of 15 per m ^2.
0 g was applied, dried and cured for 7 days, and weighed. The test piece was immersed halfway in clear water (20 ° C.)
It was taken out after a day, weighed, and the weight increase before and after immersion was divided by the weight before immersion and multiplied by 100 to determine the water absorption.

Stain Resistance The stain resistance was evaluated using the concrete blocks shown in FIGS. This concrete block 1
Has an inclined surface 12 having an upward angle of 45 degrees formed on the vertical surface 11. On the vertical surface 11 and the inclined surface 12,
The obtained emulsion was applied in an amount of 150 g per 1 m ² , dried and cured for 7 days, and then subjected to an outdoor exposure test for 6 months in an industrial zone in the southern part of Nagoya City. The comparison is made visually,
；: Almost no stain adhered (same as indoor storage product), ×: Evaluated in two stages of stain adhesion.

Whitening Resistance A coating film of the test piece A similar to the water resistance test was coated with warm water (4
(0 ° C.), the presence or absence of whitening on the coated surface was confirmed, the whitening area before and after immersion in water was measured, and evaluated by the following six steps. 0: No whitening of the slate-coated surface 1: Whitening area of the slate-coated surface is less than 20% 2: Whitening area of the slate-coated surface is 20 to 40% 3: Whitening area of the slate-coated surface is 40 to 60% 4: Slate The whitening area of the coated surface is 60 to 80% 5: The whitening area of the slate coated surface is 80% or more

Example 2 In 100 parts of the mixed solution A of Example 1, 9 parts of the block polymer solution B-2 obtained in Synthesis Example 2 (15 parts of the block polymer solution relative to 100 parts of the acrylic silicon copolymer) And the mixture was stirred and mixed to obtain a curable aqueous emulsion. Table 3 shows the results of evaluation of the obtained emulsion in the same manner as in Example 1.

Example 3 To 100 parts of the mixed solution A of Example 1, 9 parts of the block polymer solution B-3 obtained in Synthesis Example 3 (the block polymer was added to 100 parts of the acrylic silicon copolymer) 15 parts) and stirred and mixed to obtain a curable aqueous emulsion. About the obtained emulsion, Example 1
Table 3 shows the results of the evaluation performed in the same manner as described above.

Example 4 In 100 parts of the mixed solution A of Example 1, 9 parts of the block polymer solution B-1 obtained in Synthesis Example 1 (15 parts of the block polymer solution relative to 100 parts of the acrylic silicon copolymer) Parts) and colloidal silica [Nissan Chemical Co., Ltd. product name: Snowtex 40, solid content SiO _2]
40% by weight, pH = 9-10.5, particle size 10-2
0 nm] of 2.5 parts (acrylic silicone copolymer 100
SiO ₂ ratio is 5 parts in terms of solid content) was added to part, to obtain a curable aqueous emulsion by stirring and mixing. Table 3 shows the results of evaluation of the obtained emulsion in the same manner as in Example 1.

Example 5 100 parts of the mixed solution A of Example 1 was mixed with 9 parts of the block polymer solution B-2 obtained in Synthesis Example 2 (the block polymer was mixed with 100 parts of the acrylic silicon copolymer). 15 parts), and 2.5 parts of colloidal silica (Snowtex 40) (acrylic silicon copolymer 1)
(Ratio of 5 parts in terms of SiO ₂ solid content to 00 parts)
It was added and mixed with stirring to obtain a curable aqueous emulsion.
Table 3 shows the results of evaluation of the obtained emulsion in the same manner as in Example 1.

[0103]

[Table 2]

[0104]

[Table 3]

Comparative Example 1 Only the mixture A in Example 1 in which no block polymer and colloidal silica were blended was used. Table 5 shows the evaluation results of the curable aqueous emulsion in the same manner as in Example 1.

Comparative Example 2 2.5 parts of colloidal silica (Snowtex 40) was added to 100 parts of the mixed solution A of Example 1 (5 parts in terms of SiO ₂ solid content with respect to 100 parts of the acrylic silicon copolymer). And the mixture was stirred and mixed to obtain a curable aqueous emulsion containing no block polymer. The obtained emulsion was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

[0107]

[Table 4]

[0108]

[Table 5]

[0109]

Since the curable aqueous emulsion of the present invention is water-based, it is excellent in safety, has no environmental problems, and has excellent storage stability, and can be applied to a substrate in one step. It becomes possible. Also, the acrylic silicone copolymer of the present invention,
Emulsions composed of silane compounds and block polymers have a coating film formed that has high-quality coating film properties with excellent stain resistance, water resistance and solvent resistance, and at the same time imparts water absorption prevention performance to the substrate. The emulsion containing colloidal silica is also excellent in whitening resistance. Therefore, the emulsion of the present invention is extremely useful for various uses such as paints, sealing agents, and coating agents, including outdoor use.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a concrete block used for evaluation of stain resistance.

FIG. 2 is a right side view showing a concrete block used for evaluation of stain resistance.

[Explanation of symbols]

 1: Concrete block 11: Vertical surface 12: Inclined surface

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 55/00 C08L 55/00 (72) Inventor Takashi Tsuda 1 Toagosei Co., Ltd. Nagoya, Minami-ku, Nagoya City, Aichi Prefecture Within the Research Institute (72) Inventor Takehisa Yamamura 1 Toagosei Co., Ltd., Nagoya Research Institute, 1 Minami-ku, Minato-ku, Nagoya City, Aichi Prefecture

Claims (4)

[Claims] 1. A (meth) acrylic copolymer having an alkoxysilyl group, (B) a hydrolyzable silane compound, and (C) a polydimethylsiloxane unit and a plurality of azo groups in the main chain. In the presence of a radical polymerization initiator,
A curable aqueous emulsion excellent in stain resistance, wherein a block polymer obtained by radically polymerizing a monomer mainly containing a (meth) acrylate having a polyoxyalkylene group is dispersed in an aqueous medium. 2. The curable aqueous emulsion according to claim 1, wherein the components (A), (B), (C) and (D) colloidal silica are dispersed in an aqueous medium. 3. The curable aqueous emulsion according to claim 1, wherein the component (A) is a polymer having a unit based on a radically polymerizable surfactant represented by the following formula as one constituent unit. General formula; Z- (AO) n-Y (wherein, Z is an organic group having a radical polymerizable double bond,
AO represents an oxyalkylene group, n represents an integer of 2 or more, and Y represents an ion dissociable group. The component (A) is obtained by emulsifying a monomer forming the component and an oil-soluble radical polymerization initiator with a radically polymerizable surfactant represented by the above formula, and heating the resulting emulsified dispersion. The curable aqueous emulsion according to claim 3, wherein the curable aqueous emulsion is a polymer obtained by polymerizing the monomer by dropping the monomer into the aqueous medium.