GB2301102A - Aqueous silane emulsion compositions - Google Patents

Description

AQUEOUS SILANE EXUSION CD"OSITICN - s G-.\ 1 1C 2- FTELD OF THE INVENTION

This Invention relates to an aqueous allane emulsion composition in which fine particles of a hydrolyzable alkylalkoxysilane or alkylhalogencellane are emulsified and dispersed In water and a method for preparing the same. The emulsion obtained by the Invention is excellent in storage stability and is suited to various uses, particularly as a water repellent or a waterproofing agent for stone-made or concrete structures in the field of architecture and civil engineering.

BACXraROUND OF THZ INVENTION Solutions obtained by dissolving an alkylalkoxyailane, such as ethyltriethoxysilane, propyltriathoxysilane and hexyltriethoxysilane, in a medium are used as a water repellant or waterproofing agent. When the alkylalkoxyailana in coatad on a base material. such an concrete or mortar structures, it penetrates into the interior of the base material along with the medium. The alkylalkoxysilane Is then banded to the surface of the base material by an alcohol-releasing reaction and also subjected to condensation reactions of Itself, whereby the surface of the base material is covered by hydrophobic alkyl groups. By making the surface hydrophobic, in general, water absorption of the base material, such a& concrete or mortar structures, - 1 extremely decreases by 115 to 1110 in comparison to the base material that is not coated with the alkylalkoxysilane.

An alkylalkoxyallane or alkylhalogenosilane (hereinafter sometimes referred to as nhydrolyzable organosilicone compoundw) has been conventionally used In the form of a solution in an organic solvent. However, usage of solvent type water repellant or water proofing compositions has been limited due to the toxicity and flammability of the solvent and environmental pollution. Hence an aqueous emulsion comprising an aqueous medium having dispersed therein fine particles of a hydrolyzable organozilicone compound has recently been attracting attention In place of solvent type silane compositions. (This type of emulsion will be referred to as,aqueous allane emulsion" hereinafter.) Since hydrolyzable organosillcone compounds are ready to undergo hydrolysis on contact with water, an aqueous emulsion thereof has poor storage stability. in order to overcome this problem, addition of a specific nonionic surface active agent having an HLB of 4 to 15 (see JP-A62-197369, the term "JP-A" as used herein means an 1'unexamined published Japanese patent application") or addition of both a nonionic surface active agent and an anionic surface active agent (800 JP-A-3-232527) as an emulsifier has been proposed. And yet an aqueous allane emulsion which is stable over a prolonged period of time has not been developed.

Further, where an aqueous allane emulsion containing an emulsifier is applied to concrete as a waterproofing agent, the coating film tends to be made hydrophilic by the residual emulsifier and, an a result, fails to exhibit its full water repellent effect or undergoes reduction in waterproofness.

SlY OF THE INVENTION An object of the present Invention Is to provide an aqueous allane emulsion composition having excellent storage stability and a method of preparing the emulsion composition.

Another object of the invention Is to provide an aqueous ailane emulsion composition which has excellent storage stability and forms d COdti!Lg film having excellent water repellency and waterprootnees and in therefore particularly useful as a permeating aqueous water repellant and a method of preparing the emuls-on componition.

The above and other objects and effects of the present invention will be more apparent from the following description.

The present invention provides in its first emb odiment a method of preparing an aqueous silane emulsion composition, which comprises the steps aft (a) hydrolyzing an alkylalkoxyallane or alkylhalogenosilane (hydrolyzable arganosilicone compound) by heating in the presence of an acid catalyst and a small amount of water, to obtain a mixture of the alkylalkoxysilane or alkylhalogenoollane and its oligomer; (b) adding water and an emulsifier to the mixture obtained in the stop (a); and (c) stirring the mixture obtained in the step (b).

in the above embodiment, it is preferable that the emulsifier is at least one m emb er selected from a polymeric emulsifier comprising a ellicone graft polymer and a polymeric emulsifier comprising a fluorine-containing graft polymer.

It is still preferable that the emulsifier be at least one member selected from polymeric emulsifiers (2a) and (2b) according to the second and third embodiments of the invention hereinafter described.

The alkylalkoxysilane or alkylhalogenosilane used in the first emb odiment is preferably a compound represented by formula (1)a R,Si (R') 4_.

wherein R represents an alkyl group, a substituted alkyl group or an aryl group, each having from 1 to 30 carbon atoms; R' represents an alkoxy group having from 1 to 6 carbon atoms or a halogen atom; and n represents 1 or 2, In (1) which a plurality of groups represented by R or R' may be the same or different.

The step (a) of the method of the first embodiment preferably comprises hydrolyzing the alkylalkoxysilane or alkylhalogenosilane by heating a mixture comprising 100 parts by weight of the alkylalkoxysilane or alkylhalogenosilane, from 0.01 to 2.0 parts by weight of the acid catalyst, and from 0.2 to 4.0 parts by weight of water.

The invention further provides in its second embodiment an aqueous allane emulsion composition comprising; (1) at least one of an alkylalkoxysilane or alkylhalogenoollane and a oligomer thereof; (2a) a polymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymerization of a radical-polymerizable macromolecular monomer containing a polysiloxane unit as a skeleton, an ec,A-ethylenically unsaturated carboxylic acid, and another radicalpolymerizable monomer; and (3) water.

The invention furthermore provides in its third embodiment an aqueous silane emulsion composition comprising:

(1) at least one of an alkylalkoxysilane or alkylhalogenosilane and an ollgomer thereof; (2b) a polymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymerization of a radical-polymerizable macromolecular monomer containing a - 5 perflucroalkyl group-containing polymer unit an a skeleton, an CZ,Pethylenically unsaturated carboxylic acid, and another radicalpolymerizable monomer; and (3) water.

In the second and third emb odiments of the invention, the alkylalkoxysilane or alkylhalogenoollane (1) is preferably a compound represented by formula (1).

The aqueous silane emulsion composition according to the second or third embodiment is preferably the one prepared by the method of the first emb, odiment.

The invention furthermost provides in its fourth emb odiment a waterbased penetrating water repellant sealer comprising the aqueous ellane emulsion composition according to the second or third embodiment.

nPTATT.Pn DESCRIPTION OF THE INVENTION

The first embodiment of the Invention is described below.

Typical examples or the hydrolyzable organosillcone compound include those represented by formula (1); kS 1 (R') 4, (I) In formula (I), R represents a hydrophobic group which in stable against hydrolysis and includes a substituted or unsubstituted alkyl group having from 1 to 30 carbon atoms or an aryl group.

Examples of the alkyl group as represented by R are methyl, ethyl, propyl, butyl, hexyl, cyclohexyl, octyl, decyl, dodecyl, tatradecyl, hexadecyl, octadecyl, and eicosyl groups. Examples of the substituted alkyl group as represented by R are a halogenated alkyl group and an aromatic nucleussubstituted alkyl group. The halogenated alkyl group includes a fluoride, a chloride or bromide of the above-mentioned alkyl group, e.g., a 3chloropropyl group, a 6-chlorohexyl group, and a 6,6,6-triflucrohexyl group. Examples of the aromatic nucleus-substituted alkyl group Include a benzyl group and a halogen-substituted benryl group, e.g., a 4chlorobenzyl group and a 4-bromobenzyl group. Examples of the aryl group as represented by R are phenyl, tolyl, mesityl and naphthyl groups.

R' represents a hydrolyzable functional group Including an alkoxy group having from 1 to 6 carbon atoms and a halogen atom. Exanples of the alkoxy group are methoxy, ethoxy and propoxy groups. The halogen atom preferably includes a chlorine atom and a bromine atom.

Where the hydrolyzable organosilicone compound has a plurality of R or R', these groups may be the same or different. n represents an Integer of from 0 to 3.

Of the hydrolyzable organosilicone compounds represented by formula (1) those in which n is 1 or 2 are preferred; for an aqueous emulsion composition prepared therefrom provides a coating film having particularly excellent water repellency and waterproctness as compared with the emulsion prepared by using the hydrolyzable organosilicone compounds in which n is 0 or 3.

Examples of suitable hydrolyzable organosilicone compounds are shown below.

(1) Compounds of formula (1) wherein R is an alkyl group, a halogenated alkyl group or an aromatic nucleussubstituted alkyl group; R1 is an alkoxy group and n is 1 z Examples of those wherein R is an alkyl group are methylt=j.methoxyeilane, methyltriathoxysi lane, methyltri-n-propoxyallane, ethyltrinethoxysilane, ethyltriethexysilane, ethyl-tri-n-propoxysilane, propyltriathoxysilane. propyl-tri-n-propoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, inobutyltriethoxyallane, nhexyltrimethoxysilane, cyclohexyltrinethoxyallane, octyltrimethoxysilane, octyltriethoxysilane, cetyltriiaopropoxyailane, 2athylhaxyltrimathoxyallane decyltrimethcxysilane, dodecyltrimethoixysilane, tetradecyltriethoxysilane, hexadecyltriethoxysilane, octadecyltriethoxyallane, and aicosyltrimethexysilane.

Examples of those wherein R is a halogenated alkyl group are 6chlorohexyltrimethoxyallane and 6,6,6-trifluorohexyltrimethoxyallane.

Examples of those wherein R is an aromatic nucleussubstituted alkyl group are benzyltrimethoxysilane, 8 - 4-chlorobanzyltrimethoxysilane, 4-chlorobanzyltriethoxysilane, and 4- bromobanzyltri-n-propoxysilane.

(2) Compounds of formula (1) wherein R in an alkyl group; R' is a halogen atom; and n is 1:

Dodecyltrichloroollane and dodacyltribromosilane.

(3) Compounds of formula (1) wherein R is an aryl group; R' is an alkoxy group; and n is 1:

Phonyltrimethoxysilane and phenyltriethoxyallane.

(4) Compounds of formula (I) wherein R Is an alkyl group; R' is an alkoxy group; and n is 2:

Dimethyldimethoxysilane, dimethyldlethoxyallane, dibutyldimethoxyallane, and diisobutyldimethoxysilane.

Of the above-mentioned organoEilicone compounds of formula (I), those in which R is an alkyl group; R' is an alkoxy group; and n ia 1,!.a., alkyltrialkoxysilanes are still preferred; for they provide an emulsion having particularly excellent storage stability and a small particle size.

The above-mentioned organoollicone compounds may be used either individually or as a combination of two or more thereof.

The acid catalyst which can be used in the first embodiment includes Bronsted acids, Lewls acids, and various others. Suitable Bronsted acids include inorganic acids, such as hydrochloric acid, Eulturic acid, phosphoric acid, and chloroauric acid; monocarboxylic acids, such as benzoic acid; polycarboxylic acids, such as phthalic acid, tetrahydrophthalic acid, hexahydrophthallc acid, methyltetrahydrophthalic acid, methylnudic acid, dodacylauccinic acid, chlorendic acid, pyromellitic acid, and benzophenonetetracarboxylic acid; anhydrides of these polycarboxyllc acids; and organic acids, such as p-toluenesulfonic acid. Suitable Lewis acids include inorganic halides, such as baron fluoride, aluminum chloride, and tin chloride; and those forming an acid on photolysis, such as aromatic diazonium salter aromatic lodonium salts, and aromatic sulfonium salts. The other acid catalyst& include ultra-strong acids, such as perchloric acid, flucrosulturic acid, and magic acid; solid acids, such an proton type or polyvalent cation exchange type zeolite; silica- alumina, silica-magnesia, alumina-boria, active clay, antimonic acid, and zirconium phosphate; and proton type ion exchange resins, such as polystyrenesulfonic acid type Ion exchange resins. For the economical consideration, sulfuric acid or p_toluenesulfonic acid are preferably used.

The acid catalyst In preferably used In an amount of from 0.01 to 2.0 parts by weight, still preferably from 0.05 to 1.0 part by weight, per 100 parts by weight of the hydrolyzable organosilicane compound. If the amount of the acid catalyst is less than 0.01 part, the resulting emulsion tends to have Insufficient stability. If It exceeds 2.0 parts, considerable side reactions tend to occur.

- The emulsifier which can be used in the first emb odiment Include nonionic emulsifiers, anionic emulsifiers, and cationic emulsifiers. Nonionic or anionic emulsifiers are preferred for their emulsifying power and the stability of the emulsified organosilicone compound.

Suitable nonionic emulsifiers include glycerol monooleate, glycerol monostearate, sorbitan monolauzete, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, sorbitan monosesquioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbItan monooleate, polyoxyethylene sorbitan trioleate, polyoxyathylene sorbitol tetraoleate, polyoxyethylene lauryl ether, polyoxysthylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ethers, polyoxyethylene octylphenyl ether, and polyoxyethylene nonylphenyl ether. Fluorine-containing or silicone type emulsifiers are also useful.

Suitable anionic emulsifiers include sodium lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfatef sodium dodecylbenzenesulfonate, a sodium alkylnaphthalenesulfanate, a sodium dialkyloulfosuccinate, a sodium alkyldiphenyl ether disulfonate, an alkylphosphoric acid diethanolamine salt, a potassium alkylphosphate, sodium polyoxyethylene lauryl other sulfater a sodium pclyoxyethylene alkyl ether sulfate, a polyoxyethylene alkyl ether sulfuric acid triathanolamine salt, a sodium polyoxyathylene alkylphenyl ether sulfate, a sodium alkanesultonato, sodium stearate, potassium oleate, castor oil potassium salt, a sodium higher alcohol sulfate, a sodium salt of a Anaphthalonesulfonic acid-formalin condensate, and an aromatic sulfonic acid-formalin condensate.

Suitable cationic emulelf lers Include ammonium salts, such as trimathyloctaducylammonium chloride, trimethyldodecylammonium chloride, trimethylhexadecylammonium chloride, an alkyldimethylammonium chloride, distearylammonium chloride, and trimethyletearylammonium chloride.

Particularly preferred emulsifiers are polymeric emulsifiers which are used In the second and third embodimente hereinafter described.

The emulsifier is preferably used in an amount of from 0.1 to 30% by weight, atill preferably from 0.5 to 20% by weight, based on the hydrolyzable organosilicone compound.

The above-mentioned emulsifiers may be used either individually or as a combination of two or more thereof.

The method of the Invention comprises the steps of heating the abovedescribed hydrolyzable organocilicone compound In the presence of an acid catalyst and a small amount of water to obtain a reaction product comprising the organosilicone compound as a major component and an oligomer of the organoollicone compound as a minor component (hereinafter referred to as a first step) and adding an emulsifier and water to the reaction product obtained in the first step, followed by stirring to obtain an aqueous cilane emulsion composition (hereinafter refer to a second step).

The amount of water used In the first step preferably ranges from 0.2 to 4.0 parts by weight, still preferably from 0.5 to 2.0 parts by weight, per 100 parts by weight of the hydrolyzable organosilicone compound. If It is less than 0.2 part, some resulting emulsion compositions have Insufficient stability. If it exceeds 4.0 parts, a large amount of by- products tend to be produced in addition to the oligomer of the organosillcone compound, reducing the proportion of the active components.

The heating temperature of the mixture consisting of the hydrolyzable organosilicone compound, acid catalyst, and water Is preferably from 40 to 150C, still preferably from 40 to 1000C. At temperatures lower than 40C, the reaction is slow and requires a long time for the preparation. At temperatures higher than 150C, the reaction tends to be accompanied by coloration or occurrence of side reactions. The heating time is appropriately decided according to the kinds and amounts of the organosillcone compound and acid catalyst used, the amount of water, the heating temperature, and the like, and preferably ranges from 1 to 10 hours, still preferably 2 to 6 hours. The ollgomer of the organosilicone compound in the reaction product as obtained in the first stop in a mixture of a dimer, a trimer, and higher polymers.

It is preferable that a base is added to the reaction product obtained in the first step to neutralize a part or the whole of the acid catalyst so as to inhibit the organosilicone compound in the resulting emulsion from being hydrolyzed. The neutralization may be carried out after emulsification of the second step hereinafter described. The base to be used for neutralization includes alkali metal bases, such an sodium hydroxide and potassium hydroxide; primaryp secondary or tertiary aminee, such as triethylamine, trimethylamine, diisopropylamine, monoethanolamine, diethanolamine, triethanolamine, and dimethylethanolamine; heteracyclic amines, such as pyridine and piperidine; ammonium type ion exchange resins; and a=onia. These bases may be used either individually or as a combination of two or more thereof. Where the neutralization results in formation of a solid neutralized product, It Is recommended to remove the solid by, for example, filtration.

The second step comprises adding an emulsifier and water to the reaction product obtained In the first step followed by stirring to emulsify the organosilicone compound. Water is preferably added in an amount of 35 to 99% by weight, still preferably 50 to 95% by weight, based on the resulting emulsion. If the proportion of water is less than 35% by weight, emulsification of the organosilicone compound is difficult, or the resulting emulsion is instable and liable to phase separation. it it exceeds 99% by weight, the proportion of the organoollicone compound In the resulting emulsion Is so small that a coating film of the emulsion can hardly exhibit sufficient water repellency and waterproofness for use as a coating or a waterproofing agent.

The dispersed particle size of the resulting emulsion is preferably 1 = or smaller, still preferably 0.5 gm or smaller. Emulsions having a dispersed particle size larger than 1 gm tend to be instable and liable to phase separation.

The aqueous silane emulsion compositions according to the second and third embodiments of the invention will then be explained.

The hydrolyzable organosillcone compound (1) which can be used in the second and third embodiments preferably includes the above-described compounds represented by formula (I).

The polymeric emulsifier (2a) used in the second embodiment comprises a base-neutralized carboxylcontaining graft copolymer (hereinafter simply referred to as a graft copolymer (2a)) which is obtained by copolymerization of a radical -polyrneri z able macromolecular monomar (hereinafter referred to as a macromonomer) containing a polyalloxane unit as a skeleton (preferably a silicone compound having a (meth)acryloyl group at one end thereof), an - is - CZ,P-ethylenically unsaturated carboxylic acid, and another radical- polymerizable monomer.

The term h(meth)acryll, and the like used herein means "acryl or methacryl" and the like.

The silicone compound having a (neth)acryloyl group at one end thereof (hereinafter referred to as a silicone macromonomer) includes various kinds. Silicone macromonomers having a number average molecular weight of 1,000 to 50,000 are preferred. If the number average molecular weight of the silicone macromonomer in less than 1,000, the resulting graft copolymer (2a) tends to tall to manifest the properties attributed to polysiloxane, such as water resistance, and, in some cases, exhibit insufficient emulsifying power. on the other hand, silicone macromonomers whose molecular weight exceeds 50,000 have poor polymerizability and tend to remain unpolymerized. When an emulsion composition containing a polymeric emulsifier prepared from such macromonomers is applied to a subetrate as a waterproofing agent, the unpolymerized silicone compound tends to bleed out on the surface of the coating film.

The number average molecular weight as used herein Is measured by a gelpermeation chromatography-low angle light scattering method (GPC-LALS).

The silicone macromonamers to be used include those prepared by anionic polymerization, such as those prepared by polymerizing a cyclic trisiloxane or a cyclic tetrasiloxane In the presence of a polymerization initiator (e.g., lithium trialkylailanolate) to obtain a silicone living polymer, which is then reacted with y-mathacryoyloxypropylmonochlorldinethylellane, etc. (see, e. g., JP-A-59-78236); those prepared by condensation of. for example, silanol-terminated silicone compound and ymothacryoyloxypropyltrimathoxyallane, etc. as disclosed in JP-A-58-167606 and JP-A-60-123518; those prepared by reacting a polyfunctional alkoxyallane (or allanol) with a (meth)acryloylalkylalkoxysilene an disclosed in JP-A-1-123814; and those prepared by reacting a cyclic silaxane with 1,3-bio(methacryloylpropyl)tetramethyldialloxane in the presence of a trifluoromethanesulfonic acid catalyst as described in Hannosei Polymer no Gosel to Ohyo (supervised by T5uyoshl Endo), CMC Co.

The graft copolymer obtained by copolymerization of the above-mentioned silicone macromonomer, an a,D-ethylenically unsaturated carboxylic acid, and another radical-polymerizable monamer comprises a carboxyl-contaúning vinyl polymer as a backbone (main chain) to which silicone is grafted. The proportion of the grafted component, I.e., silicone unit is from 0.5 to 60% by weight, still preferably from 2 to 50% by weight, based on the total weight of the components constituting the graft copolymer. if the proportion of the silicone unit Is less than 0.5% by weight, there is a tendency that characteristics attributed to silicone such as water resistance cannot be fully manifested and the emulsifying power is not sufficient. If the proportion of the silicone unit exceeds 60% by weight, It Is difficult to render the graft copolymer (2a) water-soluble, or the polymerization system or the graft copolymer (2a) tends to undergo phase separation.

The a,P-ethylenically unsaturated carboxylic acid includes (meth)acrylic acid, crctonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and maleic anhydride. The a,p-ethylenically unsaturated carboxylic acid is preferably used in such an amount that the resulting graft copolymer may have an acid value of 30 to 260 mgKOEIg-resin. Such an amount of the cL,P-ethylenically unsaturated carboxylic acid generally corresponds to about 3 to 40% by weight based on the total radicalpolymerizable components subjected to polymerization, though somewhat varying depending on the kind of the a,p-ethylenically unsaturated carboxylic acid used. If the acid value of the graft copolymer Is less than 30 mgKOH/g-resin, cases are sometimes met with In which the graft copolymer cannot be watersolubilized even by neutralization with a base. If it exceeds 260 mgKOH19-resin, on the other hand, the graft copolymer tends to have poor water resistance.

Other various kinds of radical-polymerizable monomerB can be used for preparation of the graft copolymer (2a).

Specific examples of other useful monornere are alkyl (meth)acrylates, such as methyl (math)acrylate, ethyl - is (ineth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lsobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (rfteth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylatee benzyl (meth)acrylate, phenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (math)acrylate, polyalkylene glycol (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and a perfluoroalkyl (meth)acrylate; aromatic vinyl compounds, such as styrene, vinyltoluene, and a- methyletyrene; (math)acrylonitrile, vinyl acetate, vinyl propionate, Nmathylol(meth)acrylamide, vinyl chloride, vinyl fluoride, vinylidene chloride, vinylldene fluoride, and trichloroathylene. These monomere may be used either individually or as a combination of two or more thereof. Preferred of them are monomers mainly comprising an alkyl (meth)acrylate. A preferred proportion of the radicalpolymerizable monomer unit(s) in the graft copolymer (2a) is preferably 10 to 96% by weight.

Copolymerization of the above-described monomers for preparing the graft copolymer (2a) is carried out by, for example, irradiation or use of a radical polymerization initiator In a conventional manner. The latter method is preferred for ease of operation and ease of molecular weight control. Solution polymerization using an organic solvent is still preferred.

Solvents used for solution polymerization include ketone&, such as acetone, methyl ethyl ketone, and methyl lsobutyl ketone; acetic eaters, such as ethyl acetate and butyl acetate; aromatic hydrocarbons, such as benzene, toluene, and xylene; aliphatic hydrocarbons, such as cyclohexane, hexane, and heptane; alcohols, such as methanol, ethanol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, n-butyl callosolve, ethylene glycol, propylene glycol, triraethylolpropane, and glycerol; tetrahydrofuran, dioxane, dimethylformamide, dimethyl sulfoxide, and hexamothylphosphoric amide. Preferred are alcoholat acetone.. tetrahydrofuran, and dioxane, which are miscible with water in an arbitrary ratio and therefore do not need to be removed when the resulting graft copolymer (2a) is dispersed in water.

Any initiators generally used for radical polymerization can be used as far as the choice is proper for the polymerization method adopted. For example, inorganic radical initiators include ammonium persulfate and hydrogen peroxide; and organic radical Initiators include peroxy ketals, such as 2,2-bie(t-butylperoxy)octane; hydroperoxides, such as cumene hydroperoxide; dialkyl peroxides, such as t-butylcumyl peroxide; diacyl peroxides, such an benzoyl peroxide; peroxy dicarbonatest peroxy eaters, and azo compounds, such as 2,21-azobialsobutyronitrile.

Organic peroxides and azo compounds having a low decomposition temperature are recommended because they permit a relatively low polymerization temperature and suppress side reactions to provide a structurally distinct graft copolymer at high purity. Azo compounds are particularly preferred. Specific examples of suitable azo compounds are 2, 21-azobisisobutyronitrile, 2,21-azobis(2-methylbutyronitrile), azobis-4eyanovaleric acid, azobia(2,4-dimethylvaleronitrile), azobis(4-methoxy2,4dimethylvaleronitrile), dimethyl-2,21-azobisisobutyrate, and azobia-ieyclohexacarbonitrile.

If desired, an adequate amount of a chain transfer agent may be used in order to control the molecular weight and viscosity of the graft copolymer (2a). Suitable chain transfer agents include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 1-butanethiol, 2-methyl-2propanethiol, 2-mercaptoethanol, ethyl mercaptoacetate, thiophanol, 2naphthalonothiol, dodecylmercaptan, and thioglycerol. The radical copolymerization is preferably carried out at a temperature of

about 50 to 150C, still preferably 60 to 1001C, for a periocr of 3 to 100 hours, still preferably 5 to 10 hours.

The polymeric emulsifier (2a) can be prepared by adding a base to an organic solvent solution of the aforesaid carboxyl-containing graft copolymer to neutralize at least a part of the carboxyl groups of the graft copolymer to obtain a water- soluble or dIspersible graft copolymer (2a).

The base to be used for neutralization includes alkali metal bases, such as sodium hydroxide and potassium hydroxide; primary, secondary or tertiary amines, such as triethylamine, trimethylamine, diieopropylazaine, monoethanolamine, diethanolamine, triethanolamine, and dimethylethanclamine; haterocyclic amines, such as pyridine and piperidine; and ammonia. These bases may be used either individually or as a combination of two or more thereof.

A preferred degree of neutralization of the graft copolymer (2a) Is such that at least 0.5 mol% of the carboxyl group In the graft copolymer (2a) be neutralized. if the degree of neutralization In loss than 0.5 mol%, the graft copolymer (2a) can hardly be made water-soluble or dispersible and tends to precipitate in water.

The polymeric emulsifier (2a) is preferably used in an amount of from 0.1 to 30% by weight, still preferably from 0.5 to 20% by weight, based on the hydrolyzable organoollicone compound or Its oligomer. If used in lesser amounts, the polymeric emulsifier (2a) sometimes fails to emulsify the organoollicane compound sufficiently. If used in amounts exceeding 30% by weight, the coating film of the resulting emulsion tende to have insufficient penetrability into a substrate or poor water repellency.

- 22 The aqueous silane emulsion composition according to the second embodiment comprises the aforesaid hydrolyzable organoollicone compound, polymeric emulsifier (2a), and water. The proportion of water in the emulsion composition is preferably 35 to 99% by weight, still preferably 50 to 95% by weight. if the water is less than 35% by weight, emulsification of the organosilicone compound Is difficult, or the resulting emulsion is instable and liable to phase separation. if it exceeds 99% by weight, the proportion of the organosilicone compound in the resulting emulsion is so low that a coating film of the emulsion can hardly exhibit sufficient water repellency and waterproofneas.

The polymeric emulsifier (2b) which is used in the third embodiment of the invention comprises a baseneutralized carboxyl-containing graft copolymer (hereinafter simply referred to as a graft copolymer (2b)) obtained by =polymerization of a macromonomer containing a perfluoroalkyl group and having at one and thereof a radicalpolymerizable group, an a,gethylenically unsaturated carboxylic acid, and another radicalpolymerizable monomer.

The macromonorner having a perfluoroalkyl group and also having at one end thereof a radical-polymerizable group (hereinafter referred to as a perfluoroalkyl-containing macromonomer) includes various kinds. In particular, perflucroalkyl-containing macromonomers derived from copolymers obtained by copolymerization of 20 to 80% by weight of a perfluaroalkyl-oubstituted alkyl (meth)acrylate and 20 to 80% by weight of a radical-polymerizable monomer containing no fluorine are preferred for their excellent solubilityi less coloration and less foaming. Various perfluoroalkyl-substituted alkyl (meth)acrylates can be used. Specific examples are shown below.

CH3CH20COC (CH3) -CH21 CF3CF2CH20COCH=CH21 CF.3 (CF2) &CH2.OCOC (CH3) =CH21 CF3 (CH2) 5 (CH2) 20COC (CH3) =CH2, CF3 (CH2) 6 (CE2) 20COC (CH3) CH2, CP3 (CH2) 7 (CH2) 20COCH-CH2, CIP3 (CH2) 7 (CH2) 20COC (CH3) -CH21 CP3 (CH2) 7 (CH2) 40COC (CH3) =CH2,1 (CP3) 2W (CF2) -5 (CH2) 20COCH-CH2, (CF3) AF (CF2) 6 (CH2) 30COCH=CH2, (CP3) 2CP (CF2) a (CH2) 30COCH-CH2, (CF3)2CF(CF2)10(CH2)30COCH=CH2, and (CF3)ZCF(CF2)ISCH2CH(OH)CH20COCH=CH2.

The radical-polymerizable monomere containing no fluorine include various kinds. Specific examples are alkyl meth)acrylates containing no fluorine, such as methyl math)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (math)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, 2ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, behenyl (math)acrylate, cyclohexyl (meth)acrylate, banzyl (meth)acrylate, phenyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, polyalkylena glycol (meth)acrylate, glycidyl (meth)acrylate, and dimethylaminoethyl,(meth)acrylate; aromatic vinyl compounds, such as styrene, vinyltoluene, and a-methyletyrene; (meth)acrylonitrile, vinyl acetate, vinyl propionate, Nmethylol(meth)acrylamide, vinyl chloride, and trichloroothylene. These monomers may be used either Individually or as a combination of two or more thereof. Preferred of them are monomers mainly comprising an alkyl (meth)acrylate containing no fluorine.

The perfluoroalkyl-containing macromonomers can be synthesized by various processes disclosed, e.g., In Yuya Yamashita (ed.), Macromonomer no Kacaku to Kocmo, Ch. 2 "Macromonomer no Geosel", ICP Shuppan (1989).

A typical process of synthesis is as follows. A perfluoroalkylsubstituted alkyl (meth)acrylate and a radical-polymerizable monomer containing no fluorine are radical polymerized In the presence of a mercapto type chain transfer agent having a carboxyl group, such as mercaptoacetic acid or mercaptopropionic acid, to obtain a polymer having a carboxyl group at one end thereof, and reacting the resulting polymer with a monomer having a radical-polymerizable group and a group reactive with a carboxyl group (preferably an epoxy group). The monomer having a radical-polymerizable group and an epoxy group Includes glycidyl (meth)acrylate.

The perfluoroalkyl-containing macromonomer preferably has a number average molecular weight of 1,000 to 50,000. Graft copolymers obtained from perfluoroalkyl-containing macromonomers whose number average molecular weight of less than 1,000 tend to fall to manifest the properties attributed to a perfluoroalkyl group, such as oil repellency and water repellency and, in some cases, exhibit insufficient emulsifying power. Perfluoroalkyl-containing macromonomers whose molecular weight exceeds 50,000 have poor polymerizability and tend to remain unpolymerized. When an emulsion composition containing a polymeric emulsifier prepared from such macromonomers Is applied to a substrate as a water repellent, the unpolymerized macromonomer tends to bleed out on the surface of the coating film.

The terminology "number average molecular weight" as used herein means a molecular weight based on the standard polystyrene as measured by GPCLALS.

The graft copolymer (2b) used in the third embodiment in obtained by copolymerization of the above-mentioned perfluoroalkyl-containing macromonomer, an a,O-ethylenically unsaturated carboxylic acid and another radical-polymerizable monomer and neutralization of the resulting copolymer with a base. The graft copolymer (2b) comprises a carboxylcontaining vinyl polymer as a backbone (main chain) to which a side chain having a perfluoroalkyl group at the and thereof is grafted. The proportion of the grafted component, i.e., the perflucroalkyl unit is from 0.5 to 60% by weight, still preferably from 1 to 50% by weight, based on the total weight of the components constituting the graft copolymer (2b). if the proportion of the perfluoroalkyl unit is less than 0.5% by weight, there is a tendency that characteristics attributed to a perfluoroalkyl group, such as oil repellency and water repellency, cannot be fully manifested and the emulsifying power is not sufficient. if the proportion of the perfluoroalkyl unit exceeds 60% by weight, the graft copolymer (2b) is difficult to make water-soluble and vigorously foame and is difficult to use as an emulsifier. Further, the polymerization system or the resultant graft copolymer (2b) tends to undergo phase separation.

The aio-ethylenically unsaturated carboxylic acid and other radicalpolymerizable monomers which can be used In the preparation of the polymeric emulsifier (2b) are selected from those described as to the polymeric emulsifier (2a).

The graft copolymer used for the preparation of the polymeric emulsifier (2b), and the polymeric emulsifier (2b) can be prepared in the same manner as described an to the polymeric emulsifier (2a).

The polymeric emulsifier (2b) is preferably used In an anount of from 0.1 to 20% by weight, still preferably from 0.5 to 15% by weight, based an the hydrolyzable organosilicone compound or its oligomer. If used In lesser amounts, the polymeric emulsifier (2b) sometimes fails to emulsify the organosilicone compound sufficiently. if used in amounts exceeding 20% by weight, the coating film of the resulting emulsion tends to have insufficient penetrability into a substrate or poor water repellency.

The aqueous ailane emulsion composition according to the third embodiment comprises the aforesaid hydrolyzable organosilicone compound, polymeric emulsifier (2b), and water. The proportion of a mixture of the hydrolyzable organosilicone compound and the polymeric emulsifier In total in the emulsion composition is preferably 1 to 65% by weight (I.e., the proportion of water Is preferably 99 to 35% by weight), still preferably 5 to 50% by weight. if it is more than 65% by weighto emulsification of the organoollicone compound is difficult, or the resulting emulsion is instable and liable to phase separation. If it is loss than 1% by weight, the proportion of the organosillcone compound in the resulting emulsion is so low that a coating film of the emulsion can hardly exhibit sufficient water repellency and waterproofness.

if desired. the aqueous allane emulsion composition prepared by the first embodiment and the aqueous silane emulsion compositions according to the second and third embodiments may contain commonly employed amounts of other emulsifiers, protective colloids, and the like.

The emulsion compositions may also contain buffering agents for inhibiting hydrolysis of the hydrolyzable organosillcone compound in the emulsion. Such buffering agents include organic acids, inorganic acids, bases, and salts of the acids. Examples of the Inorganic acids are carbonic acid, phosphoric acid, sulfuric acid, and hydrosulfuric acid. Examples of the organic acids are organo and mono- or polycarboxylic acids having 1 to 6 carbon atoms. Examples of organic acid salts include monoor polyalkali metal salts, alkaline earth metal salts or amine salts of alkyleneiminopolycarboxylic acids having 2 to 30 carbon atoms. Examples of bases are ammonia and organic bases having 1 to 30 carbon atoms.

Inorganic acid salts are preferably used as a buffering agent. Suitable Inorganic acid salts include sodium hydrogencarbonate, sodium carbonate, ammonium carbonate, sodium borate, sodium primary, secondary or tertiary phosphate, potassium primary, secondary or tertiary phosphate, sodium ammonium phosphate, sodium hydrogensulfate, codi= sulfate, sodium acetate, potassium acetate, ammonium acetate, calcium acetate, sodium formate, sodium hydrogensulfide, sodium sulfide. ammonia, mono-, di- or triethylamine, mono-, di- or triethanolamine, sodium othylenedinitrilotetraacetate (EDTA, Na), pyridine, aniline, and sodium silicate. These buffering agents may be used either individually or as a combination of two or more thereof. The buf tering agent is used in an amount commonly used in general aqueous silane emulsions, preferably 0.01 to 5% by weight based on the emulsion composition.

The emulsion compositions may further contain other additives, such as antifungal agents, bactericidal agents, perfumes, colorants, thickeners, foaming agents. antifoaming agents, and the like, as long as the performance as a water repellent in not impaired.

The aqueous silane emulsion compositions of the second and third embodiments of the invention can be prepared in various manners. For example, a hydrolyzable organosillcone compound Is added to an aqueous solution of a polymeric emulsifier as obtained as described above and, if desired, as further dissolved in water, and stirring the mixture at a high speed to emulsify.

The dispersed particle size of the resulting emulsion is preferably 1 gm or smaller, still preferably 0.5 wm or smaller. Emulsions having a dispersed particle size larger than 1 un tend to be Instable and liable to phase separation.

The aqueoue ellane emulsion compositions according to the present invention are applicable to various uses. In particular, they can be applied as permeating water repallant to substrates made of various materials, such as concrete, to make the substrates oil-repellant, water-repallant, and waterproof.

Substrates to which a permeating water repellant comprising the aqueous allane emulsion of the Invention Is applied include various materials and constructions or structures made of the materials. in particular, the aqueous silane emulsion is suitably applied to inorganic constructive or structural materials having a silanol group, for example, cement-based materials, such as mortar, concrete, ALC, and air entrained concrete; materials using cement as a bonding agent, such as slates and siding boards; ceramics, such as tiles, bricks, and roof tiles; calcium silicate plates, and building stone. It is also applicable to wood, plastics, etc.

The water-based penetrating water repellant sealer of the Invention Is used in a conventional manner. For example, it is applied to a substrate by brush coating, roller coating, air spraying, airless spraying, Impregnation, or curtain roll coating, and then dried. The amount of the permeating water repellent to be applied depends on Its solids content and the porosity and surface conditions of a substrate, but is generally from 0.05 to 2.0 kg/m2.

The aqueous allane emulsion composition obtained by the method of the first embodiment of the invention exhibits extremely high storage stability over an extended period of time. The emulsion composition is broadly applicable, especially as a water repellant in the field of civil engineering and architecture.

The aqueous allane emulsion compositione according to the second embodiment of the invention form a coating film which is free from adverse influences by the emulsifier used and excellent in water repellency and waterproofness. These advantages are attributed to the polymeric emulsifier used therein. The polymeric emulsifier used comprises a silicone graft copolymer (2a) having a hydrophobic silicone as a grafted component. Because the polymeric emulsifier Is compatible with a hydrolyzable organosillcone compound and also exhibits water repellency, a coating film of the resultant aqueous silane emulsion composition does not show hydrophilic properties which might have been manifested due to existence of a residual emulsifier and, as a result, exhlblts excellent water repellency.

The aqueous silane emulsion compositions according to the third embodiments of the Invention form a coating film which is tree from adverse influences by the emulsifier used and excellent in oil repellency, water repellency and waterproofness. These advantages are attributed to the polymeric emulsifier used therein. The polymeric emulsifier used comprises a fluorine-containing graft copolymer (2b) having an oilrepellent and water-repellent perfluoroalkyl group as a grafted component. Because the polymeric emulsifier is compatible with a hydrolyzable organosilicone compound and also exhibits water repellency and oil repellency, a coating film of the resultant aqueous allane emulsion composition does not show hydrophilic properties which might have been manifested due to existence of a residual emulsifier and, as a result, exhibits excellent water repellency and oil repellency.

Furthermore, when the emulsions according to the second and third embodiments of the present invention are prepared by the method according to the first embodiment of the present invention, the emulsion compositions exhibit excellent storage stability without undergoing apparent phase separation.

The present invention will now be illustrated in greater detail with reference to Examples, but it should be understood that the invention is not deemed to be limited thereto. Unless otherwise indicated, all the parts and percents are given by weight.

EXAMPLE 1 in a flask equipped with a stirrer, a condenser, and a thermometer were charged 100 parts of hexyltriethoxysilane (produced by Shin-Etau Chemical Cc., Ltd.), 0.1 part of p-toluenesulfonic acid, and 1.0 part of water, and the mixture was heated at 800C for 4 hours while stirring. The mixture was allowed to cool to room temperature, and 10% aqueous ammonia was added thereto to neutrali2e the acid catalyst. Any precipitate formed on neutralization was removed by filtration to obtain a composition containing about 8% of an organosillcone oligomer.

Forty parts of the resulting composition were added to a mixture consisting of 50 parts of water, 4 parts of a nonionic emulsifier, octylphenol polyethyleneoxyethanol (a 7:3 (by weight) mixture of TRITON X100 and TRITON X-305, both produced by Rohm & Haas Cc.), and 0.2 part of sodium hydrogencarbonate, followed by stirring at a high speed to prepare an aqueous allane emulsion.

The resulting emulsion was stable and underwent no phase separation when stored at room temperature over 6 months. The average particle size of the dispersed emulsion particles was 0.31 gm with a narrow size distribution.

COMPARATIVE EXAKFLE 1 An aqueous silane emulsion was prepared In the same manner as in Example 1, except that 40 parts of hexyltriethoxyallane was not heated together with an acid catalyst and water and was emulsified as such.

The resulting emulsion had poor stability and underwent phase separation In 24 hours from the preparation. The average particle size was 3.0 wm.

EXAMPLE 2

In a mixed solution consisting of 60 parts of methyl methacrylate, 20 parts of methacrylic acid, and 100 parts of isopropyl alcohol were dissolved 20 parts of a silicone macromonomer having a methacryl group at one end thereof (FM0725, produced by Chisso Corp.; number average molecular weight: about 10,000), 1.0 part of n-dodecylrnercaptan, and 1.0 part of 2,21-azobisisobutyronitrile (hereinafter abbreviated as AIBN), and the solution was charged in a flask equipped with a stirrer, a condenser, a thermometer, and a tube for introducing nitrogen. The solution was heated at SOOC for 4 hours In a nitrogen atmosphere, and 0.5 part of AIBN was added thereto, followed by further heating at the same temperature for an additional period of 4 hours, to obtain a silicone graft copolymer having a nonvolatile content of 49.7% and an acid value of 130 mgKOHlg-resin.

To the resulting reaction mixture was slowly added 200 g of 2.0% aqueous affi=onia with stirring to give a clear aqueous solution having a pH of B. O.

Twenty parts of the resulting aqueous solution containing a polymeric emulsifier were dissolved in 50 parts of water. In the same manner as in Example 1, an aqueous silane emulsion was prepared by using the aqueous solution containing a polymeric emulsifier, 0.2 part of sodium hydrogencarbonate, and 40 parts of the hexyltriethoxyailane obtained in Example 1 containing organosilicone oligomers.

The resulting emulsion was stable and underwent no phase separation when preserved at room temperature over 6 months. The average particle size of the dispersed emulsion particles was 0.31 gm with a narrow size distribution.

In the following Examples, all the hexyltriethoxyallanes were that obtained in Example 1 containing oraganosilicone oligomers.

EXAMPLE 3

An aqueous solution of a polymeric emulsifier was prepared In the same manner as in Example 2, except that 10 parts of a macromonomer having a methacryloyl group at one molecular end thereof (AX-32, produced by Toagoeoi Chemical Industry Co., Ltd.; number average molecular weight: 20, 000) and, as comonomer, 75 parts of octyl methacrylate and 15 parts of acrylic acid were used and that the solution of the resulting graft copolymer (nonvolatile contents 49.8%; acid value: 194 mgxoHlg-romin) was water molubilized, with triethylamine.

Forty parts of hexyltriethoxyallane ware emulsified using the resulting polymeric emulsifier aqueous solution In the same manner as in Example 2 to obtain an aqueous silane emulsion.

The resulting emulsion was stable and underwent no phase separation when stored at room temperature over - 36 6 months. The average particle size of the dispersed particles was 0.29 wm with a narrow size distribution.

Each of the emulsions prepared in Examples 2 and 3 was applied to a 70 mm x 70 mm x 20 mm mortar undercoat aged 4 months (J15R.5201) at a rate of 300 g/m2 and stored at 200C and 60% RH for a prescribed time. Water was sprayed onto the coated mortar to observe water repellency.

Furthermore, the emulsion obtained in Example 1, In which the above polymeric emulsifier was not used, was evaluated in the same manner as above for comparison.

It was confirmed that the coating film of the emulsions of Examples 2 and 3 manifested water repellency after 3 hours from application, whereas that of the emulsion of Example 1 did not even after 1 week from application.

The results of the above evaluation are shown in Table 1 below.

- 37 TABLE 1

Average Room Initial Particle Temperature Water Size -Stability Rooellency Example 2 0.31 stable for manifested 6 months after 3 hours Example 3 0.29 stable for manifested 6 months after 3 hours Example 1 0.31 stable for not manifest 6 months ed after 1 week -EXAMPLE- t

1) Synthesis of Macromonomer:

In a glass flank equipped with a stirrert two dropping funnels, a tube for gas introduction, and a thermometer wore charged 30 g of a monomer mixture consisting of 43 parts of perfluorooctylethyl methacrylate and 57 parts of 2-ethylhexyl methacrylate, 1.8 g of mercaptopropionic acid as a chain transfer agent, and 30 g of methyl isobutyl ketone as a solvent, and the mixture was heated to 900C.

To the inixture was added dropwise 70 g of the same monomer mixture from one of the dropping funnel over a 2-hour period. At the same time, 0.8 g of azoble-2-methylbutyronitrile (hereinafter abbreviated as ABN-E) dissolved in 54 g of methyl lsobutyl ketone was added dropwise from the other dropping funnel over a 5-hour period. After the addition, the mixture was allowed to further react for an additional - 38 period of 1 hour to obtain a polymer having a carboxyl group at one end thereof. The number average molecular weight of the polymer was 7,000.

To the resulting polymer solution were added 0.04 g of hydroquinone monomethyl ether, 1 g of tetrabutylammonium bromide, 10 g of methyl isobutyl ketone, and 2.7 g of glycidyl methacrylate, and the mixture was allowed to react at 900C for 6 hours while blowing air therethrough to obtain a macromonomer having a methacryloyl end group purity of 99.7%. 2) Synthesis of Polymeric Emulsifier:

In a glass flask equipped with a stirrer, a dropping funnel, a tube for gas introduction, and a thermometer were charged 22 g of the aboveprepared macromanomer, 14 g of methacrylic acid, 46 g of 2-ethylhexyl methacrylate, 10 g of 2-hydroxyethyl methacrylate, 44 g of methyl ethyl ketone as a solvent, and 1.5 g of mercaptopropionic acid as a chain transfer agent, and the mixture was heated to 750C in a nitrogen atmosphere. A solution of 1.0 g of ABN-E In 50 g of methyl ethyl ketone was added thereto dropwise over 3 hours. After 30 minutes from the completion of the dropwise addition, a solution of 0.5 g of ABN-E In 4 g of methyl ethyl ketone was further added, followed by heating to 850C, at which the reaction was continued for 4 hours to obtain a graft copolymer.

To the reaction mixture were added 380 9 of water and 11 g of 25% aqueous ammonia while stirring to neutralize the graft copolymer.

The solvent was removed at 50C under reduced pressure (200 =nHg) to obtain an aqueous solution containing a polymeric emulsifier (nonvolatile content: 31.3%; pH: 7.3).

In 50.4 parts of water wan dissolved 7.7 parts of the polymeric emulsifier aqueous solution. Forty-one parts of hexyltriathoxysilane were emulsified using the resulting polymeric emulsifier aqueous solution and 0.1 part of sodium hydrogencarbonate in the same manner as in Example 1.

The resulting aqueous allane emulsion was stable and underwent no phase separation when stored at room temperature over 6 months. The average particle size of the dispersed particles was 0.31 gm with a narrow size distribution. EXAMELE 5 An aqueous ailane emulsion was prepared in the same manner an In Example 4, except that 15.6 parts of the polymeric emulsifier aqueous solution as synthesized In 45 parts of water.

The resulting aqueous silane emulsion was stable and underwent no phase separation when stored at room temperature over 6 months. The average particle size of the dispersed particles was 0.29 gm with a narrow size distribution.

Each of the emulsions prepared in Examples 4 and 5 was applied to a 70 mm x 70 mm x 20 mm mortar undercoat aged - 40 4 months (J15R 5201) at a rate of 300 g/m' and stored at 200C and 60% RH for a prescribed time. n-Hexadecane or n-decane was sprayed onto the coated mortar to observe all repellency.

Furthermore, the emulsion obtained in Example 1, in which the above polymeric emulsifier was not used, wan evaluated in the same manner as above for comparison.

It was confirmed that the coating film of the emulsion& of Examples 4 and 5 manifested oil repellency after 3 hours from application, whereas that of the emulsion of Example 1 did not even after 1 week from application.

The mortar coated with each emulsion in the same manner an described above was sprayed with water, and water repellency of the coating film was observed with the naked eye. As a result, water repellency was observed after 3 hours from application in Examples 4 and 5, while no water repellency was manifested in Example 1.

According to the method of the first embodiment of the Invention, the aqueous ailane emulelon composition obtained exhibits extremely high stability over an extended period of time. The emulsion composition is broadly applicabler especially as a water repellent in the field of civil engineering and architecture.

The aqueous allane emulsion composition according to the second embodiment of the Invention exhibits excellent stability. When applied as a permeating water repellent to a substrate, the emulsion provides the substrate with excellent water repellency and does not undergo reduction in its water repellent effect.

The aqueous silane emulsion composition according to the third embodiment of the invention exhibits excellent stability. When applied as a permeating water repellent to a substrate, the emulsion provides the substrate with excellent oil repellency and water repellency and protects the eubstrate against adhesion of chemical substances, thereby brings about improved contamination resistance. Besides, the water-repellent effect of the emulsion does not undergo reduction.

The first, second, and third embodiments of the Invention can be combined appropriately to provide an aqueous allane emulsion having more excellent performance.

While the Invention has been described In detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims (18)

1. A method of preparing an aqueous silane emulsion composition, which comprises the steps ofi (a) hydrolyzing an alkylalkaxysilane or alkylhalogenosilane by heating in the presence of an acidic catalyst and a small amount of water, to obtain a mixture of said alkylalkoxysilane or alkylhalogenosilane and its oligomer; (b) adding water and an emulsifier to said mixture obtained by the step (a); and (c) stirring said mixture obtained in the step (b).

2. A method as claimed In claim 1, wherein said amuleifier is a polymeric emulsifier comprising a silicone graft polymer.

3. A method as claimed In claim 2, wherein said e=ulsifier In a polymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymerization of a radical-polymerizable macromolecule monomer containing a polysilaxane unit as a skeleton, an c&,9-ethylenically unsaturated carboxyl acid, and an other radical-polymerizable monomer.

4. A method as claimed in claim 3, wherein said radical-polymerizable macromolecule monomer is a silicone compound having at one end thereof an acryloyl group or a mathacryloyl group.

5. A method as claimed in claim 1, wherein said emulsifier is a polymeric emulsifier comprising a fluorinecontaining graft polymer.

6. A method an claimed in claim 5, wherein said emulsifier is a polymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymerization of a radical-polymerizable macromolecule monomer containing a perfluoroalkyl group-containing polymer unit as a skeleton, an cz,o-ethylenically unsaturated carboxyl acid, and an other radicalpolymerizable monomer.

7. A method an claimed in claim 6, wherein said radical-polymerizable macromolecule monomer is derived from a copolymer obtained by copolymerization of a perfluoroalkyl group-containing alkyl acrylate or a perf luoroalkyl groupcontaining alkyl methacrylate, and a radicalpolymerizable monomer containing no fluorine.

R. A method as claimed in claim 1, wherein said alkylalkoxyallane or alkylhalogenosilane is represented by formula (I):

R,Si (R),.., (1) wherein R represents an alkyl group, a substituted alkyl group, or an aryl group, each having from 1 to 30 carbon atoms; R' represents an alkyl group having f rom 1 to 6 carbon atoms or a halogen atom; and n represents 1 or 2, provided that plurality of groups represented by R or R' may be the same or different.

9. A method as claimed in claim 1, wherein the stop (a) comprises hydrolyzing said alkylalkoxysilane or alkylhalogenosilane by heating a mixture comprising 100 parts by weight of said alkylalkoxysilane or alkylhalogenosilane, from 0.01 to 2.0 parts by weight of said acidic catalyst, and from 0.2 to 4.0 parts by weight of water.

10. An aqueous allane emulsion composition comprising:

(1) at least one of an alkylalkoxyallane or alkylhalogenosilane and its oligorner; (2a) a polymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymerization of a radical-polymerizable macromolecule monomer containing a polysiloxane unit as a skeleton, an a,o-ethylenically unsaturated carboxyl acid, and an other radical-polymerizable monomer; and (3) water.

11. An aqueous allane emulsion composition ae claimed in claim 10, wherein said radical-polymerizable macromolecule monomer is a silicone compound having at one end thereof an acryloyl group or a mathacryloyl group.

12. An aqueous silane emulsion composition as claimed in claim 10, wherein said alkylalkoxysilane or alkylhalogenosilene (1) Is represented by formula (I):

kSI (R'),.-, (1) wherein R represents an alkyl group, a substituted alkyl group, or an aryl group, each having from 1 to 30 carbon atoms; R' represents an alkyl group having f rom 1 to 6 carbon atoms or a halogen atom; and n represents 1 or 2, provided that plurality of groupe represented by R or R1 may be the same or different.

13. An aqueous allane emulsion composition &c claimed in claim 10, wherein said aqueous wilane emulsion composition Is produced by a method c=prizing the stops oft (a) hydrolysing said alkylal)coxysilane or alkylhalogenoullene (1) by heating In the presence of an acidic catalyst and a small amount of water, to obtain a mixture of said alkylalkoxyailane or alkylhalogenosilane and its Cligomer; (b) adding water (3) and said polymeric emulsifier (2a) to said mixture obtained by tho atop (a); and (c) atirring said mixture obtained In the stop (h).

14. An aqueous &!lane emulsion composition comprising:

(1) at least one of an alkylalkoxysilane or alkylhalogenoollane and!to uligomer; (2b) a polymeric emulaitior comprising a neutralized agunous graft copolymer obtained by copolywmrl=atlon of a radical-polymerizable macromolecule monomer containing a perfluoroalkyl group-contaInIng polymer unit as a skeleton, an cz,R-ethylenically unsaturated carboxyl acid, and an other radical-polymerizable monomer; and (3) water.

15. An aqueous allane emulcion 00ftTORitiOn as claimed In claim 14, wherein said radical-polymerizable macromolecule monomer In derived from a copolymer obtained by copolymerization of a perfluoroalkyl group-containing alkyl acrylate or a perfluornal.lryl group-containing Alky.t. methacrylatc, and a radical-polymerizable monomer containing no LluorIne.

16. An aqueous silane emulsion composition an claimed in claim 14, wherein said alk-ylalkoxya i lane or alkylhaloclonowilano (1)!a represented by formula (I) RUS1 (P.') 4..

(1) wherein R represents an alkyl group, a substituted alkyl group, or an aryl group, each having from 1 to 30 carbon atoms; R' represents an alkyl group having from 1 to 6 carbon atoms or a halogen atom; and n represents 1 or 2, provided that plurality of groups represented by R or R' may be the acme c= differant.

17. An aqueous allane emulsion composition as claimed in claim 14, wherein maid aqueous allana emulsion composition is produced by a method comprising the steps ofs (a) hydrolyzIng said alkylalkoxyollano or alkylhalogonosilane (1) by beating in the presence of an acidic catalyst and a small amount of water, to obtain a mixturo of said alkylalkoxysilane or alkylhalogencallane and Its ollgomez; (b) adding water (3) and said polymeric emulsifier (2b) to said mixture obtained by the stop (a); and (c) stirring acid mixture obtained in the stop (b).

18. A water-based penetrating water'repallant sealer comprising at least on of: (I) an aqueous allane emulsion composition comprisingi (1) at least one of an alkylalkoxysilane or alkylhalocjenoollane and its clig=or; (2a) a pul"exic emulalúler comprising a neutralized aqueous graft copolymer obtained by copolymorization of a radical-polymorizable macromolecule monomer containing a polysiloxane unit as a skeleton, an a, D-ethylenically unsaturated carboxyl acid, and an other radicalpolymorizabl& monomer; and (3) water, and (11) an aqueous silane Ginulgion composition comprising:

(1) at least Unu uf all alkylalkoxysilane or a13cylhalogenceilane and its oligomer; (2b) a pulymeric emulsifier comprising a neutralized aqueous graft copolymer obtained by copolymarization of a radical-polymerizable macromolecule monomer containing a perfluoroalkyl group-containing polymez unIL as a skeleLon, an cz,p-othylenically unzaturated carboxyl acid, and an other radical-polymerizable monomar; and (3) water.

- so -