JP2006193469A - Silicate composition and water-based coating containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a silicate composition capable of giving coating film having good hydrophilicity, slight in the increase of water contact angle when exposed to water and having long-term resistance to staining, and to provide a water-based coating containing the silicate composition. <P>SOLUTION: The silicate composition is obtained by modifying an alkyl silicate with a compound of formula(1):R-X-(CH<SB>2</SB>CH<SB>2</SB>O)<SB>3</SB>-H(wherein, R is a 4-18C hydrocarbon group; and X is -O- or -COO-). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a silicate composition and a water-based paint containing the same.

Alkyl silicates are used in various applications. For example, by adding them to organic solvent-type paints, the surface of the obtained paint film can be made hydrophilic and a paint film with excellent stain resistance can be obtained. It is conventionally known that it can be done. Thus, when hydrophilizing a coating film, it is guessed that the hydrophilization function is expressed by hydrolyzing after the alkyl silicate transfers to the surface.

However, since alkyl silicate has high lipophilicity and lacks affinity for water, it has been difficult to apply it to an aqueous coating as it is. As a low-contaminating agent for water-based paints that solves this problem, Patent Document 1 discloses a low-fouling agent for water-based paints containing a modified condensate of alkoxysilane having a polyoxyalkylene group and an alkoxyl group.

Here, what modified | denatured the condensate of alkoxysilane with polyoxyalkylene chain containing compounds, such as polyoxyethylene glycol of average molecular weight 150-2000, is disclosed as a modified condensate. Since the polyethylene oxide unit has high hydrophilicity, when a coating film is formed using an aqueous paint containing a silicate compound modified with this, a hydrophilic coating film can be obtained immediately after the formation. However, when the obtained coating film is exposed to water, the water contact angle increases, which has a problem of poor long-term contamination resistance.

International Publication No. 99/05228 Pamphlet

In view of the above-mentioned present situation, the present invention is a silicate capable of obtaining a coating film having good hydrophilicity, little increase in water contact angle when exposed to water, and excellent long-term stain resistance. An object of the present invention is to provide a composition and an aqueous paint containing the composition.

The present invention provides an alkyl silicate represented by the following formula (1):
R—X— (CH ₂ CH ₂ O) ₃ —H (1)
(Wherein R represents a hydrocarbon group having 4 to 18 carbon atoms, X represents —O— or —COO—), and is obtained by modification with a compound represented by It is a composition.

R is preferably an alkyl group or alkenyl group having 8 to 18 carbon atoms.
X is preferably —O—.
The alkyl silicate is preferably ethyl silicate.

The present invention is also a water-based paint characterized by containing the above-described silicate composition.
The present invention is also a substrate characterized by having a coating film obtained by applying the above-mentioned water-based paint.
The present invention is described in detail below.

The silicate composition of the present invention is obtained by modifying an alkyl silicate with a compound represented by the above formula (1). Since hydrophilicity can be imparted by introducing an ethylene oxide unit into an alkyl silicate, it becomes possible to obtain a coating film having good hydrophilicity. The problem of elution occurs when exposed to water. Since the silicate composition of the present invention is obtained by modification with a compound having three ethylene oxide units represented by the above formula (1), when an aqueous paint containing this is used, a good hydrophilic property is obtained. Thus, it is possible to obtain a coating film that has excellent elution characteristics when exposed to water and has excellent long-term stain resistance.

The silicate composition is obtained by modifying an alkyl silicate with a compound represented by the above formula (1).
As said alkylsilicate, the tetraalkoxysilane which has a C1-C4 alkoxy group, and its condensate can be mentioned, for example.
Among the alkoxy groups having 1 to 4 carbon atoms, a methoxy group and an ethoxy group are preferable from the viewpoint of hydrophilicity of the coating film, and an ethoxy group is more preferable in terms of hydrolysis resistance. In the alkyl silicate, the alkoxy group having 1 to 4 carbon atoms may be the same or different, but is preferably the same because it is easily available.

Specific examples of the tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms include tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane. Among these condensates, a tetramethoxysilane condensate and a tetraethoxysilane condensate are commercially available from Mitsubishi Chemical as the MKC silicate MS series and from Colcoat as the ethyl silicate series, respectively. In addition, the preferable condensation degree of a condensate is 5-50.

The alkyl silicate may be one in which a part of the alkoxy group contained in the tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms and the condensate thereof is substituted with an alcohol. In this case, the substitution ratio of the alkoxy group with an alcohol is preferably 4 to 70%. If it is less than 4%, the effect of substitution cannot be obtained. If it exceeds 70%, the effect as an alkyl silicate may not be obtained. More preferably, it is 8 to 50%.

In the alkyl silicate in which a part of the alkoxy group contained in the condensate is substituted with an alcohol, the purpose of the modification of the substitution of the alkoxy group of the condensate with an alcohol depends on whether the alcohol used is a monoalcohol or a diol. That is, in the case of a monoalcohol, it is possible to control the compatibility in the paint and / or coating film by substituting the alkoxy group of the condensate with the alkoxy group of the monoalcohol. Objective.

On the other hand, when the alcohol used is a diol, an alkoxy group of the condensate and a hydroxyl group of the diol react between one molecule of the diol and two molecules of the condensate, whereby the two molecules of the condensate are converted. A modified product linked by a diol is obtained. Furthermore, by repeating this reaction, the molecular weight of the alkyl silicate can be increased without performing condensation which is difficult to adjust.

When the alkoxy group of the condensate is substituted with a monoalcohol, it can be obtained by performing an exchange reaction using a necessary amount of monoalcohol with respect to 1 mol of the condensate. The amount of the monoalcohol can be appropriately increased or decreased in accordance with the desired number of substituents. The above reaction is preferably carried out under heating conditions up to about 150 ° C., for example. Moreover, in order to advance reaction, it is preferable to distill off produced | generated methanol or ethanol out of the system. The reaction is terminated when a predetermined amount of substitution with alcohol is performed. After completion of the reaction, the target silicate compound can be obtained by performing separation and purification as necessary. The silicate compound thus obtained is generally a colorless to light yellow oily substance. Note that the determination of the amount of substitution with the alcohol is performed by checking the amount of methanol or ethanol produced or using an analytical instrument.

As the monoalcohol, ethanol, propanol, butanol, benzyl alcohol, 2-butoxyethanol, 3-methoxy-1-propanol, 2-ethylhexanol, octanol and the like can be used. Of these, ethanol for alkyl silicates other than ethyl silicate is preferred because it is inexpensive and excellent in hydrolysis resistance.

On the other hand, when the alkoxy group of the condensate is substituted with a diol, it can be obtained by performing an exchange reaction using 1 mol of the condensate in an amount of 0.6 mol times or less. If the amount exceeds 0.6 mole times, gelation may occur. The reaction can be carried out in the same manner as for the monoalcohol, but the resulting product can be further reacted by adding a diol of 0.5 mole times or less. The modified product thus obtained is a silicate obtained by removing one alkoxy group from the condensate of tetraalkoxysilane to the oxygen atoms at both ends of the diol unit obtained by removing hydrogen atoms from the two hydroxyl groups of the diol. Each unit has a structure bonded to each other, but at least one of the silicate units may be bonded to another silicate unit via another diol unit.

In addition, in the substitution of the alkoxy group of the condensate with an alcohol, a solvent is not particularly required. preferable. Specific examples of the solvent include, for example, aromatic hydrocarbons such as toluene, benzene and xylene, halogenated hydrocarbons such as dichloroethane, ethers such as THF and dioxane, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate and Examples include esters such as butyl acetate, dimethyl carbonate, and acetonitrile.

In the exchange reaction, an acid or a base can be used as a catalyst as necessary. Examples of the acid include Bronsted acids such as hydrochloric acid, sulfuric acid, phosphoric acid and sulfonic acid, and Lewis acids such as organotin compounds. Examples of the base include triethylamine, dimethylbenzylamine, diazabicyclo [2.2.2. ] Octane, 1,8-diazabicyclo [5.4.0. A tertiary amine such as undecene-7 can be used.

In the above formula (1), R represents a hydrocarbon group having 4 to 18 carbon atoms. Hydrophobicity can be imparted by the hydrocarbon group having 4 to 18 carbon atoms, and higher hydrophobicity can be imparted particularly when the hydrocarbon group is a long chain. For this reason, when an aqueous paint containing the above silicate composition is used, when the formed coating film is exposed to water, the dissolution of the silicate composition in the coating film is suppressed. The hydrophilicity of the film can be prevented from being lowered, and the fixability of the coating film can be improved. When it exceeds 18, there exists a possibility that the gloss value of the coating film obtained using the aqueous coating material containing the said silicate composition may fall.

R is preferably a C 4-18 alkyl group or alkenyl group from the viewpoint of obtaining the effects of the present invention. The alkyl group or alkenyl group may be linear or branched. Examples of the alkyl group or alkenyl group include n-butyl group, i-butyl group, s-butyl group, t-butyl group, butenyl group, pentyl group, cyclopentyl group, hexyl group, cyclohexyl group, hexenyl group and heptyl. Group, heptenyl group, octyl group, octenyl group, nonyl group, nonenyl group, decyl group, decenyl group, undecyl group, undecenyl group, dodecyl group, tridecyl group, tridecenyl group, tetradecyl group, tetradecenyl group, pentadecyl group, hexadecyl group, A heptadecyl group, an octadecyl group, an oleyl group, etc. can be mentioned. Especially, the C8-C18 alkyl group or alkenyl group is more preferable at the point which can suppress the increase in the water contact angle of the coating film obtained. The R may be the same or different in the silicate composition.

In the above formula (1), X represents —O— or —COO—. Of these, -O- is preferable.
In the above formula (1), there are three ethylene oxide units (—CH ₂ CH ₂ O—). If it is less than 3, there is a possibility that a coating film having good hydrophilicity cannot be obtained. If it exceeds 3, the film is eluted when exposed to water, and long-term stain resistance is obtained. There is a possibility that it cannot be obtained.

The silicate composition can be obtained by an exchange reaction between the alkyl silicate and the compound represented by the formula (1).
In the said reaction, it is preferable that the compounding quantity of the compound represented by the said Formula (1) exists in the range of 0.1-4 mol with respect to 1 mol of said alkylsilicates. If the amount is less than 0.1 mol, hydrophilicity may be insufficiently provided. If the amount exceeds 4 mol, the equivalent of the alkoxyl group may be reduced. More preferably, it exists in the range of 0.1-3 mol.

The above reaction can be carried out in the same manner as the reaction for replacing the alkoxy group of the condensate with a monoalcohol.
The above reaction is preferably carried out under heating conditions up to about 170 ° C., for example. Moreover, in order to advance reaction, it is preferable to distill off produced | generated alcohols, such as methanol or ethanol, out of the system. The reaction is terminated when a predetermined amount of substitution with alcohol is performed. After completion of the reaction, the desired silicate composition can be obtained by performing separation and purification as necessary.
In carrying out the above reaction, a catalyst can be used if necessary.
As said catalyst, the catalyst quoted by description of the previous exchange reaction can be used.

The modification rate can be determined from the amount of alcohol distilled during the reaction. In addition to this, the progress of the substitution is due to the fact that the compound represented by the above formula (1) does not remain or decreases by measuring ¹ H-NMR of the product. Can be confirmed. The modification rate can be confirmed by determining the ratio between the alkoxysilyl group and the ethylene oxide unit located next to the SiO group, but this is an average value when viewed as the entire product, The silicate composition obtained by modifying the alkyl silicate with the compound represented by the above formula (1) is usually a mixture of various silicate compounds. Moreover, the compound represented by the said unreacted said Formula (1) and the said unreacted said alkyl silicate may be included.

Examples of the compound represented by the above formula (1) include butyl triglycol and the like. Examples of commercially available products include New Coal 1103 and New Coal 1203 (trade names, both manufactured by Nippon Emulsifier Co., Ltd.).
The silicate composition may contain other components as long as the effects of the present invention are not impaired.

When the above silicate composition is used as a component in an aqueous paint, it can impart high hydrophilicity to the resulting coating film, and reduce the increase in contact angle when the coating film is exposed to water. Can do. As a result, it is possible to obtain a coating film excellent in stain resistance over a long period of time.

The aqueous paint of the present invention is usually used as a two-component paint comprising the above silicate composition and other film forming components including an aqueous emulsion.
Examples of the aqueous emulsion contained in the aqueous paint include acrylic resin-based emulsions, acrylic silicon resin-based emulsions, fluororesin-based emulsions, and urethane resin-based emulsions.

Examples of the acrylic resin emulsion include those obtained by radical copolymerization of an acrylic monomer and another monomer copolymerizable with the acrylic monomer.

The acrylic monomer is not particularly limited. For example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Alkyl group-containing (meth) acrylic monomers such as cyclohexyl (meth) acrylate; hydroxyl-containing (meth) acrylic monomers such as 2-hydroxyethyl (meth) acrylate; ethylenic such as (meth) acrylic acid Unsaturated carboxylic acids; amino group-containing (meth) acrylic monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate; amides such as (meth) acrylamide and ethyl (meth) acrylamide (meta ) Acrylic monomers; Nitriles such as acrylonitrile Containing (meth) acrylic monomer; glycidyl (meth) an epoxy group-containing acrylates such as (meth) acrylic monomer and the like. In addition, (meth) acrylate in this specification means both acrylate and methacrylate.

Other monomers copolymerizable with the acrylic monomer include aromatic hydrocarbon vinyl monomers such as styrene, methylstyrene, chlorostyrene, vinyltoluene; maleic acid, itaconic acid, crotonic acid, Α, β-ethylenically unsaturated carboxylic acids such as fumaric acid and citraconic acid; sulfonic acid-containing vinyl monomers such as styrene sulfonic acid and vinyl sulfonic acid; acid anhydrides such as maleic anhydride and itaconic anhydride; vinyl chloride Chlorine-containing monomers such as vinylidene chloride and chloroprene; hydroxyl-containing alkyl vinyl ethers such as hydroxyethyl vinyl ether and hydroxypropyl vinyl ether; alkylene glycol monoallyl ethers such as ethylene glycol monoallyl ether and propylene glycol monoallyl ether diethylene glycol monoallyl ether Ters; α-olefins such as ethylene, propylene and isobutylene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl pivalate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether and cyclohexyl vinyl ether; ethyl allyl ether And allyl ethers such as butyl allyl ether. The acrylic resin emulsion is advantageous in terms of durability, high gloss, cost, and high degree of freedom in resin design.

Examples of the acrylic silicon resin emulsion include those obtained by radical copolymerization of a silicon-containing acrylic monomer and another monomer copolymerizable with the silicon-containing acrylic monomer. Can do.

The silicon-containing acrylic monomer is not particularly limited. For example, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyl Examples include hydrolyzable silyl group-containing vinyl monomers such as dimethoxysilane and γ- (meth) acryloxypropylmethyldiethoxysilane.

Examples of the other monomer copolymerizable with the silicon-containing acrylic monomer include, for example, an acrylic monomer used in the above-mentioned acrylic resin emulsion and other copolymerizable with the acrylic monomer. These monomers are not particularly limited and can be used. The acrylic silicone resin emulsion is advantageous in terms of weather resistance, yellowing resistance, durability, chemical resistance, stain resistance, and the like.

Examples of the fluororesin emulsion include those obtained by radical copolymerization of a fluorine-containing monomer and another monomer copolymerizable with the fluorine-containing monomer.

The fluorine-containing monomer is not particularly limited, and examples thereof include fluoroolefins such as vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, pentafluoroethylene, hexafluoropropylene; trifluoroethyl (meth) acrylate, pentafluoropropyl Fluorine-containing (meth) acrylates such as (meth) acrylate and perfluorocyclohexyl (meth) acrylate can be mentioned.

Examples of other monomers copolymerizable with the fluorine-containing monomer include, for example, acrylic monomers used in the above-mentioned acrylic resin emulsions and other monomers copolymerizable with acrylic monomers. A monomer or the like can be used without any particular limitation. When the above fluororesin emulsion is used, weather resistance, yellowing resistance, durability, chemical resistance, stain resistance, etc. are advantageous.

The urethane resin emulsion is a generic term for an emulsion having urethane bonds in the coating film after the coating film is formed. That is, it may have a urethane bond before the coating film is formed, or may form a urethane bridge by a reaction after the coating film is formed. The form of the emulsion may be a one-pack type or a two-pack type.

As the one-pack type, a method of copolymerizing a polymerizable monomer having a urethane bond with another copolymerizable monomer, a polymerizable unsaturated monomer in the presence of an aqueous resin having a urethane bond. Examples thereof include a method of polymerization, a method of mixing an aqueous urethane resin having a reactive group, and an emulsion containing a group capable of reacting with the reactive group. Examples of the two-component type include a combination of a water-miscible isocyanate and a hydroxyl group-containing emulsion. When the urethane resin emulsion is used, durability, solvent resistance, chemical resistance, stain resistance and the like are advantageous.

Examples of the aqueous emulsion include a carbonyl group and a hydrazide group, a carboxylic acid and a metal ion, an epoxy group and an amine, an epoxy group and a carboxyl group, a carboxylic acid and an aziridine, It is also possible to use an emulsion (crosslinking reaction type emulsion) that forms a crosslinking reaction using acid and carbodiimide, carboxylic acid and oxazoline, acetoacetate and ketimine, or the like. The crosslinking reaction type emulsion may be a one-component type or a multi-component type having two or more components. The crosslinking reaction type emulsion is advantageous in terms of durability, solvent resistance, chemical resistance, stain resistance, and the like.

It does not specifically limit as a manufacturing method of the said aqueous emulsion, For example, it can manufacture by methods, such as batch polymerization, monomer dripping polymerization, emulsion monomer dripping polymerization, as an emulsion polymerization method. The emulsifier used for polymerization is not particularly limited as long as it is generally used, and anionic, cationic, nonionic, amphoteric, nonionic-cationic, nonionic-anionic ones may be used alone or in combination. Can do. Moreover, an emulsifier having a reactive group can be used for the purpose of improving water resistance.

As the polymerization initiator, known radical initiators used in the production of synthetic emulsions can be used without limitation. From a combination of persulfates such as ammonium persulfate, hydrogen peroxide and sodium hydrogen sulfite, and the like. A redox initiator, a mixture of inorganic initiators such as ferrous salt and silver nitrate, a dibasic peroxide such as disuccinic acid peroxide and diglutaric acid peroxide, and an organic initiator such as azobisbutyronitrile Etc.

The usage-amount of the said polymerization initiator can be normally used by 0.01-5 mass parts with respect to 100 mass parts of monomers. In addition, inorganic salts such as sodium hydroxide, sodium carbonate, potassium carbonate and sodium thiosulfate and organic bases such as triethylamine and triethanolamine can be added to adjust the pH of the emulsion.

A curing catalyst can be added to the water-based paint of the present invention as necessary. 0.1-10 mass parts is suitable for the addition amount of the said curing catalyst with respect to 100 mass parts of resin solid content in the said aqueous coating material. If the amount is less than 0.1 parts by mass, the reaction rate becomes slow, and as a result, the effect of low contamination of the cured coating film may be reduced. When it exceeds 10 mass parts, there exists a possibility that the external appearance and durability of a coating film may fall.

If necessary, the water-based paint of the present invention can be blended with a film-forming aid, an inorganic color pigment, an organic color pigment, an extender pigment, etc., which are usually used in paints. When a pigment is included, the volume pigment concentration is preferably 25% or less. If it exceeds 25%, the stability of the paint may be inferior. The lower limit is not particularly specified because it may contain a small amount of color pigment called color clear. In the case of using an enamel-type water-based paint having a high volume pigment concentration, higher hydrophilicity can be expressed, so that more excellent antifouling performance can be imparted.

The water-based paint of the present invention also includes plasticizers, antiseptics, antifungal agents, antifoaming agents, leveling agents, pigment dispersants, anti-settling agents, anti-sagging agents, matting agents that do not affect the present invention, Additives such as UV absorbers and antioxidants can be used alone or in combination.

Various methods can be applied as the method for applying the water-based paint. When the base material is a housing of a building or civil structure, brush coating, spray coating, or roller coating is applied, and when it is a building material such as a siding board or extrusion molding board, a roll coater, a flow coater, etc. Automatic coating machine can be used.
After coating, drying can be performed by drying at room temperature or forced drying with hot air of about 110 ° C.

It is preferable that the water contact angle of the coating film formed by applying the water-based paint is 65 ° or less. High hydrophilicity can be provided to the obtained hydrophilic coating film because it is 65 ° or less. More preferably, it is 55 ° or less. In addition, since the water contact angle of the coating film is often affected by the binder component and additives, the same kind and amount of the silicate composition of the present invention is always the same for all paints. It does not always indicate a correct value.
The dry film thickness of the coating film obtained by the water-based paint is not particularly defined and can be set to 10 to 40 μm, for example.

The water-based paint can be used for surface finishing of various base materials such as metal, glass, porcelain tile, concrete, siding board, extruded board, plastic, etc., and is mainly used for buildings and civil engineering installed outdoors. It is preferable to use it for protection of a housing such as a construct. At this time, the water-based paint containing the silicate composition is applied to the final finished surface, and can be applied directly to the base material, or after being subjected to a surface treatment such as a ground treatment. It is also possible to paint.

Since the silicate composition of the present invention is obtained by modifying an alkyl silicate with the compound represented by the above formula (1), it has good hydrophilicity and has a water contact angle when exposed to water. Thus, it is possible to obtain a coating film having a long-term stain resistance.

Since the silicate composition of this invention consists of the structure mentioned above, the coating film which has long-term stain resistance can be obtained.

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “part” means “part by mass” unless otherwise specified, and “%” means “% by mass” unless otherwise specified.

Example 1
A 100 ml flask equipped with a calcium chloride tube, a serpentine tube, and a decanter was charged with ethyl silicate 40 (manufactured by Colcoat, average condensation degree 5, hereinafter abbreviated as “ES-40”) 26.04 g with an ethylene oxide unit (hereinafter “EO”). (Abbreviated) 18.35 g of polyoxyethylene octyl ether containing 3 and 0.2 g of triethylamine were added, and the mixture was heated and stirred at 110 ° C. for 1 hour, 125 ° C. for 2 hours, and 145 ° C. for 1 hour. In the decanter, 3.22 g of ethanol was distilled. After cooling, the mixture was concentrated under reduced pressure to obtain 38.2 g of an ethyl silicate composition (1) substituted with polyoxyethylene octyl ether. ^The modification rate calculated by ¹ H-NMR spectrum was 13.73%. A ¹ H-NMR chart of the resulting silicate composition (1) is shown in FIG.

Examples 2-4
Silicate compositions (2) to (4) in the same manner as in Example 1 except that the type and blending amount of polyoxyethylene alkyl ether and the blending amounts of ES-40 and triethylamine were changed as shown in Table 1. Manufactured.

Comparative Examples 1-6
The substituted ethyl silicate compounds (1) to (6) were the same as in Example 1 except that the type and blending amount of polyoxyethylene alkyl ether and the blending amounts of ES-40 and triethylamine were changed as shown in Table 2. ) Was manufactured.

A paint was prepared by adding 6.6 g of the silicate composition obtained in Examples and the substituted silicate compound obtained in Comparative Example to 100 g of Odefresh U100 (acrylic paint for building exterior manufactured by Nippon Paint Co., Ltd.). The water contact angle of the coating film obtained using the prepared water-based paint, the change in water contact angle before and after the coating film submergence ΔCA (coating fixability) was evaluated by the following method, and the results are shown in Tables 1 and 2 Indicated.

(Water contact angle of coating film (CA))
The paint prepared as described above was applied to a tin plate with a 10 mil film applicator, dried for 14 days, and then the water contact angle of the coating film was measured with a water contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.). If it is 65 degrees or less, it is favorable. In addition, the water contact angle of the coating film obtained only from Oudefresh U100 was 75 degrees.

(Change in water contact angle before and after submersion of coating film △ CA (Coating property of coating film))
The coating film obtained above was immersed in water for 2 hours and then dried for one day. The water contact angle of the coating film was measured, and the change value of the water contact angle was taken as ΔCA.
ΔCA = (CA after water immersion) − (CA before water immersion)

The water-based paints containing the silicate compositions obtained in the examples were measured for water contact angles representing the degree of hydrophilization of the coating films obtained from these, and it was confirmed that both showed good values. It was confirmed that the membrane was hydrophilized, and ΔCA was also small. In Example 2, ΔCA shows a negative value. This is presumably because the alkoxysilyl group of the silicate composition was hydrolyzed to become a silanol group due to submergence and the surface was hydrophilized. Therefore, it is assumed that the silicate composition remains in the coating film. On the other hand, the coating film obtained from the water-based paint to which the substituted silicate compound of the comparative example was added had a large ΔCA.

The silicate composition of the present invention can be suitably applied to water-based paints and can be suitably used for various building materials and the like.

1 is a diagram showing a ¹ H-NMR chart of a silicate composition obtained in Example 1. FIG.

Claims (6)

An alkyl silicate is represented by the following formula (1);
R—X— (CH ₂ CH ₂ O) ₃ —H (1)
(In the formula, R represents a hydrocarbon group having 4 to 18 carbon atoms. X represents —O— or —COO—.)
A silicate composition obtained by modification with a compound represented by the formula: The silicate composition according to claim 1, wherein R is an alkyl group or alkenyl group having 8 to 18 carbon atoms. The silicate composition according to claim 1 or 2, wherein X is -O-. The silicate composition according to claim 1, 2 or 3, wherein the alkyl silicate is ethyl silicate. An aqueous paint containing the silicate composition according to claim 1, 2, 3 or 4. A substrate having a coating film obtained by coating the water-based paint according to claim 5.

Images