JPH0873543A - Alkoxysilylated acryl emulsion - Google Patents

Abstract

PURPOSE: To obtain an alkoxysilylated acryl emulsion which has excellent storage stability and can give a coating film excellent in durability and weather resistance by forming the core and the shell with specified monomer component under specified conditions. CONSTITUTION: This emulsion is a core/shell type emulsion in which the sore of an emulsified particle and its shell are different in composition and prepared by emulsion-polymerizing a mixture of a monomer component I for forming the core comprising 50-99wt.% 1-18 C alkyl (meth)acrylate (A), 1-20wt.% organosilicon compound represented by the formula: R<1> SiX3 (wherein R<1> is a monovalent organic group having a polymerizable double bond; and X is 1-4C alkoxyl) and 0-30wt.% comonomer with a monomer component II for forming the shell comprising 50-99wt.% component A; 1-20wt.% organosilicon compound represented by the formula: R<2> R<3> (3-n) SiYn (wherein R<2> is R<1> ; R<3> is 1-4 C alkyl; Y is X; and n is 1 or 2) and 0-30wt.% comonomer in an I/II weight ratio of 50/50 to 90/10 in the presence of a reactive surfactant.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an acrylic emulsion having a hydrolyzable alkoxysilyl group,
The present invention relates to an acrylic emulsion which has good long-term storage stability, excellent durability and weather resistance of a film formed from the emulsion, and is useful as a base emulsion for paints and sealants.

[0002]

2. Description of the Related Art Water resistance for coating agents such as paints,
Durability and weather resistance including acid resistance, alkali resistance, and moisture resistance are required, and it is well known that a solution type hydrolyzable silyl group-containing room temperature curable polymer is used as one of the countermeasures. As this polymer,
Examples thereof include polymers obtained by solution polymerization having a number average molecular weight of 300 to 30,000 in which silyl groups having at least two hydrolyzable groups are introduced into one molecule. However, in recent years, from the viewpoints of low pollution, resource saving, and safety and hygiene, these coating agents are also required to be an emulsion type that is water-based, but the hydrolyzable silyl group easily hydrolyzes and condenses in water, and storage stability It was difficult to produce an emulsion type with good properties.

JP-A-5-25354 discloses that a hydrolyzable silyl group and an amine imide group are each added to improve storage stability.
A reactive resin emulsion containing a resin having at least one in the molecule has been proposed. For its production, a method in which solution polymerization is carried out in an organic solvent and then the solution is topped to emulsify the remaining resin, or The method of adding water and emulsifying and then topping is adopted, and the process is complicated and the economical disadvantage cannot be avoided. Furthermore, the condensation reaction of the hydrolyzable silyl group during storage cannot be sufficiently prevented, and gelation of the emulsion is not observed when stored for a long period of time. There is a problem in that crosslinking progresses, the film-forming property of the emulsion deteriorates, and it becomes difficult to form a good film at room temperature.

[0004]

Under the circumstances as described above, the present invention provides a film which is excellent in long-term storage stability and film forming property and is formed by remarkably reducing intra-particle crosslinking by alkoxysilyl groups. The present invention has been made to provide an acrylic emulsion containing an alkoxysilyl group having excellent durability.

[0005]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in the raw material monomer of the polymer forming the core of the emulsion particles, the condensation rate Add a monomer containing a large alkoxysilyl group, and add a monomer containing an alkoxysilyl group with a very low condensation rate to the raw material monomer of the polymer that forms the outer shell (shell). In addition, we found that a specific core-shell type alkoxysilyl group-containing acrylic emulsion emulsion-polymerized using a reactive surfactant has the potential to solve problems. The present invention was accomplished by conducting tests on the type and amount of reactive surfactant.

The present invention has solved the above-mentioned problems, and the present invention is a core-shell type emulsion in which the composition of the core and the outer shell of the emulsion particles are different, and the core portion thereof is (A) Alkyl ester of (meth) acrylate having an alkyl group having 1 to 18 carbon atoms 50 to 99% by weight (b) Formula R ¹ SiX ₃ (wherein R ¹ represents a polymerizable double bond). 1 to 20% by weight of an organic silicon compound represented by a monovalent organic group having, X is an alkoxyl group having 1 to 4 carbon atoms (c) A monomer copolymerizable with the above (a) and (b) 0 30% by weight [however, the total of (a), (b) and (c) is 100% by weight], and (A) an alkyl group having 1 to 18 carbon atoms in the shell part. having a group (meth) alkyl es ether 50-99% by weight of acrylic acid (B) formula R ² R ³ in _(3-n) SiY _n (wherein, R ² is Monovalent organic group having a polymerizable double bond, R ³ is an alkyl group having 1 to 4 carbon atoms, Y is an organic silicon compound represented alkoxyl group having 1 to 4 carbon atoms, n represents 1 or 2) In 1 From 20 to 20% by weight (C) 0 to 30% by weight of a monomer copolymerizable with the above (A) and (B) [however, the total of (A), (B) and (C) is 100% by weight] The ratio of the monomer component (II) is (I) / (I
I) = 50/50 to 90/10 (weight ratio), and a core / shell type alkoxysilyl group-containing acrylic emulsion obtained by emulsion polymerization using a reactive surfactant,
It is the gist.

The present invention will be described in more detail below. The (meth) acrylic acid alkyl ester which is the component (a) and (A) in the present invention is a main component monomer for forming the skeleton of the acrylic polymer, and is a straight chain having 1 to 18 carbon atoms or It is an ester compound of an alcohol having a branched alkyl group or an alcohol having a cyclic alkyl group with acrylic acid or methacrylic acid. Examples of this monomer include methyl or ethyl of acrylic acid or methacrylic acid, propyl, isopropyl, butyl, isobutyl, octyl, 2-ethylhexyl, lauryl,
Examples thereof include stearyl or cyclohexyl ester, and one or a mixture of two or more selected from these groups can be used. The component (a) is 50 to 99% by weight of the total amount of the monomer component (I) in order to exert the characteristics of the acrylic polymer, and the component (A) is the same as the total amount of the monomer component (II). 50 to 99% by weight.

The organosilicon compound represented by the formula R ¹ SiX ₃ (wherein R ¹ and X are the same as described above) of the component (b) has an alkoxysilyl group having a high condensation rate as a side chain to an acrylic polymer. It is a monomer for introduction. As this monomer, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane,
γ-methacryloxypropyltrimethoxysilane, γ-
Examples thereof include acryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane and γ-methacryloxypropyltributoxysilane. Further, if necessary, a monomer having a dialkoxysilyl group other than the above can be used in combination. Examples of such monomers include vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropylmethyldimethoxysilane, Examples include γ-methacryloxymethyldibutoxysilane and the like. As long as these monomers do not impair the effects of the present invention, 30% of the total amount of component (b) monomer is used.
It can be used in the range of not more than wt%. When one kind or a mixture of two or more kinds of these monomers is used for polymerizing the core part, 1 to 20% by weight of the total amount of the monomer component (I) is used as the component (b). When the amount is less than 1% by weight, the formed film has a low crosslink density and the durability such as water resistance and weather resistance is insufficient. When the amount exceeds 20% by weight, the crosslink density is too high and the formed film is brittle. Furthermore, the storage stability of the emulsion is impaired.

The formula of the component (B) R ² R ³ _(3-n) SiY _n (wherein
The organic silicon compound represented by R ² , R ³ , Y and n is the same as above) is a monomer for introducing an alkoxysilyl group having a very low condensation rate into the acrylic polymer as a side chain. Examples of the monomer include vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinyldimethylmonomethoxysilane, vinylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, and γ. -Methacryloxypropyldimethylmonomethoxysilane, γ-methacryloxypropyldimethylmonoethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-acryloxypropyldimethylmonomethoxysilane, γ-methacryloxymethyldibutoxysilane and the like are exemplified. It The shell polymer obtained by copolymerizing these monomers is very stable even in the presence of water,
When water is evaporated, condensation between silanol groups or dealcoholization condensation between silanol groups and alkoxysilyl groups proceeds to form a crosslinked film having a high crosslink density. When one or a mixture of two or more of the above-mentioned monomers is polymerized in the shell part, 1 to 20% by weight of the total amount of the monomer component (II) is used as the component (B). If it is less than 1% by weight, the cross-link density of the formed film is low and the durability such as water resistance and weather resistance is insufficient. If it exceeds 20% by weight, the cross-link density is too high and the formed film is brittle. Furthermore, the storage stability of the emulsion is impaired.

The component (c) is a polymerizable monomer copolymerizable with the components (a) and (b), and the component (C) is a polymerizable monomer copolymerizable with the components (A) and (B). It is a quantity. These monomers, if necessary, the mechanical stability of the emulsion,
It is used for imparting water resistance, gloss, and other functions to the formed film, but the component (c) is used in an amount of 30% by weight or less based on the total amount of the monomer component (I) because it does not impair the object of the present invention. The amount of the component (C) is 30% by weight or less based on the total amount of the monomer component (II). Examples of such a monomer include a carboxyl group such as acrylic acid, methacrylic acid and maleic anhydride or an anhydride-containing monomer thereof, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and the like. Hydroxyl group-containing monomer, (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-
Amido group-containing monomers such as butoxymethyl (meth) acrylamide and diacetone (meth) acrylamide, amino group-containing monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate, methoxyethyl (meth) Alkoxyl group-containing monomers such as acrylate and butoxyethyl (meth) acrylate, glycidyl (meth) acrylate, glycidyl group-containing monomers such as glycidyl allyl ether, divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) Monomers such as acrylate, diethylene glycol di (meth) acrylate, and trimethylolpropane tri (meth) acrylate that have two or more radically polymerizable unsaturated groups in one molecule, vinyl acetate, vinyl propionate, and other vinyl ethers. Termonomer, aromatic vinyl monomer such as styrene, vinyltoluene and α-methylstyrene, vinyl cyanide monomer such as acrylonitrile and methacrylonitrile, vinyl halide unit such as vinyl chloride and vinyl bromide The body and the like are exemplified, and among these, one kind or a mixture of two or more kinds is used.

Further, in order to remarkably improve the durability such as water resistance of the film formed from the emulsion of the present invention and obtain the performance close to that of the solution polymerized product, the reactive surfactant is used as the surfactant (emulsifier). I found it to be good to use.
Examples of this reactive surfactant include:

Embedded image

[0012]

Embedded image Anionic reactive surfactants such as, and

[0013]

[Chemical 3] And the like, or a cation-type reactive surfactant containing a quaternary ammonium salt or a tertiary amine salt and a polymerizable group.

This reactive surfactant may be used alone or in combination of two or more, but if the amount is too small, a lot of agglomerates will be generated in the produced emulsion, and it will be obtained. The resulting coating also does not exhibit good physical properties.
Also, when the amount is too large, the particle size of the polymer becomes fine, the viscosity of the emulsion increases too much, and the water resistance of the film also deteriorates. Therefore, the amount of the reactive surfactant used is preferably 0.5 to 15% by weight, and more preferably 1 to 7% by weight, based on the total monomers. Further, as long as the object of the present invention is not impaired, it is possible to use a non-reactive surfactant used in ordinary emulsion polymerization in combination with this reactive surfactant, and the total amount of the surfactant is 30% by weight. One or two or more kinds may be used in combination in the range of not more than%. These non-reactive surfactants include anionic surfactants such as alkyl or alkylallyl sulphates, alkyl or alkylallyl sulfonates and dialkyl sulfosuccinates, and cationic such as alkyl trimethyl ammonium chloride and alkyl benzyl ammonium chloride. Examples include surfactants, nonionic surfactants such as polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, and polyoxyethylene carboxylic acid ester.

As the radical polymerization initiator used in the present invention, persulfates such as potassium persulfate and ammonium persulfate, hydrogen peroxide solution, t-butyl hydroperoxide,
Water-soluble types such as azobisamidinopropane hydrochloride,
Benzoyl peroxide, cumene hydroperoxide, dibutyl peroxide, diisopropyl peroxydicarbonate, cumyl peroxy neodecanoate,
Examples include oil-soluble types such as cumyl peroxy octoate and azobisisobutyronitrile. Further, if necessary, a redox system in which a reducing agent such as acidic sodium sulfite, Rongalite, or ascorbic acid is used together can be used. The amount of the polymerization initiator used is usually 0.1 to 10% by weight with respect to the monomer, but preferably
It is 0.5 to 5% by weight.

In order to produce the core-shell type acrylic emulsion containing an alkoxysilyl group of the present invention, first, the above-mentioned various monomers (a), (b) and (c) are mixed and the surface-active substance is added thereto. An emulsion forming a core part is polymerized in an aqueous system by adding an agent, a polymerization initiator and the like. In this case, various methods such as a batch polymerization method and a method of continuously supplying each component can be applied. At the time of polymerization of the core part, in order to suppress hydrolysis and condensation of the alkoxysilyl group, it is preferable to use a pH buffer to adjust the pH during the polymerization to the range of 6.5 to 7.5. The polymerization is usually carried out at a temperature of 10 to 90 ° C. In core part polymerization, it is essential that the reactive surfactant is almost completely polymerized and does not substantially remain in the aqueous phase of the core part polymer emulsion. During the polymerization, new particles may be generated by the shell part monomer, and the effect of the present invention is diminished. Next, a polymerization initiator and the above-mentioned various monomers (A), (B) and (C) are further added to this system and polymerized to form a shell part. At the end of emulsion polymerization, it is preferable to adjust the pH to 6 to 8 by adding a basic substance in order to prevent undesired crosslinking reaction of the polymer and to further improve the storage stability which is the object of the present invention. Examples of these substances include ammonia, amines, alkanolamines and caustic.

When the emulsion of the present invention is used for paints and the like, the alkoxysilyl groups introduced into the polymer side chains in the emulsion particles are condensed by the evaporation of water to form a crosslinked film. A reaction catalyst can be added to promote film formation by crosslinking. As the condensation reaction catalyst, organic titanate compounds such as isopropyl triisostearoyl titanate, isopropyl tri (dioctyl pyrophosphate) titanate, organic aluminum compounds such as acetoalkoxy aluminum diisopropylate, dibutyl tin dilaurate, dibutyl tin malate, dioctylic acid Carboxylic acid type tin compounds such as tin, dialkyltin compounds such as dibutyltin oxide, dioctyltin oxide, lead octylate, carboxylic acid metal salts such as cobalt naphthenate, acidic phosphoric acid esters, carboxylic acids and their acid anhydrides, triethylamine And amines such as dibutylamine-2-hexoate and salts thereof. These catalysts may be added as they are if they are water-soluble, but oil-soluble ones are preferably added in the form of an aqueous dispersion, and the addition amount is preferably 0.01 to 10% by weight with respect to the emulsion of the present invention. .

Although the reason for the effect of the present invention is not clear, a shell polymer containing a mono- or dialkoxysilyl group having a very slow condensation reaction rate is coated on the surface of a core polymer containing a trialkoxysilyl group having a fast condensation rate. Therefore, it is presumed that, in the emulsion state, the crosslinking reaction in the polymer particles or between particles was prevented, and an emulsion excellent in storage stability and film-forming property was obtained. On the other hand, the water in the emulsion volatilizes, and after film formation, dehydration condensation or dealcoholization condensation of the hydrolyzed silanol group proceeds without using any other cross-linking agent such as a polyfunctional epoxy compound at room temperature. Crosslink sufficiently. The reason for this is unclear, but the fine particles each have a core-shell structure, and the low molecular weight non-reactive surfactant, which is a contaminant that inhibits water volatilization and fusion between particles during film formation, is zero or very small. As a result, the fusion between the particles and the mutual diffusion or extremely fine dispersion of the core polymer / shell polymer are achieved, and the mono- or dialkoxysilyl group is involved mainly in the trialkoxysilyl group having a high condensation reaction rate. It is envisioned that they will be sufficiently condensed and crosslinked.

[0019]

EXAMPLES The present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the examples. In the examples, parts and% are parts by weight and% by weight, respectively.
Indicates. Further, the properties of each of the obtained emulsions were evaluated by the following measuring methods immediately after production and after storage for 3 months or 6 months at room temperature. a. Minimum film forming temperature The minimum film forming temperature was measured with a minimum film forming temperature measuring device manufactured by Rigaku Kogyo. b. Emulsion state The change in the viscosity of the emulsion or the presence or absence of gelation was observed, and the results are shown below. ◯: Little change, ×: Large change In addition, the ones that have reached gelation are indicated as “gelation”. c. Emulsion was applied to a water-resistant glass plate so that the dry film thickness was about 25 μm, and it was aged for 7 days under the condition of 23 ° C × 68% RH and immersed in warm water of 80 ° C for 60 minutes to observe the surface condition. And shown by: ◯: No abnormality, Δ: slightly whitened, ×: whitened, blister occurred d. Gel fraction An emulsion was applied to an aluminum foil so that the dry film thickness was about 25 μm, and it was aged for 7 days under the condition of 23 ° C. × 68% RH. The gel fraction was calculated from the amount.

Example 1 A polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet was charged with 1,033 parts of deionized water, 0.47 parts of sodium carbonate as a pH buffer, and 4.70 parts of boric acid, and stirred while stirring. After the temperature was raised to ° C, the atmosphere was replaced with nitrogen. Add 1.75 parts of Rongalit and 1 part of disodium ethylenediaminetetraacetate.
% Aqueous solution 0.12 part, ferrous sulfate 1% aqueous solution 0.04 part, and at the same time, methyl methacrylate 280 parts, butyl acrylate 350 parts, γ-methacryloxypropyltrimethoxysilane 70 parts, t-butyl hydroperoxide ( Pure content
69%) 2.1 parts, reactive surfactant Aqualon RN-20
While maintaining the internal temperature at 60 ° C, 723.1 parts of a mixed solution of 14.0 parts of [Daiichi Kogyo Seiyaku Co., Ltd., trade name] and 7.0 parts of AQUARON HS-10 [Daiichi Kogyo Seiyaku Co., Ltd., trade name] It was added uniformly over 2.5 hours, and further reacted at 60 ° C. for 1 hour to obtain a core emulsion. Rongalit at the same temperature
0.75 parts was added, and at the same time, 105 parts of methyl methacrylate, 150 parts of butyl acrylate, 30 parts of styrene, 15 parts of γ-methacryloxypropylmethyldimethoxysilane, 6.0 parts of reactive surfactant Aqualon RN-20 (previously mentioned), 309.9 parts of a mixed solution of 3.0 parts of AQUARON HS-10 (described above) and 0.9 part of t-butyl hydroperoxide (69% of pure content) was heated to an internal temperature of 60.
While maintaining at ℃, add uniformly over 1 hour, and add 60 more
Polymerization was completed by reacting at 0 ° C for 1 hour. The obtained core-shell type emulsion has a solid content concentration of 49.5% and a pH of 7.0.
Met. The reactive surfactants used for the polymerization are Aqualon RN-20, 13 of which were previously exemplified, and Aqualon HS.
-10 belongs to 6). The properties of the emulsion obtained above are as shown in Table 1.

Example 2 A polymerization vessel equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet was charged with 1,033 parts of deionized water, 0.47 parts of sodium carbonate as a pH buffer and 4.70 parts of boric acid, and stirred at 60 ° C. After the temperature was raised to 1, the atmosphere was replaced with nitrogen. 1.75 parts of Rongalit, 1% of disodium ethylenediaminetetraacetate
0.12 parts of an aqueous solution and 0.04 part of a 1% ferrous sulfate aqueous solution are added, and at the same time, 640 parts of butyl acrylate, 80 parts of acrylonitrile, 80 parts of γ-methacryloxypropyltrimethoxysilane, and t-butyl hydroperoxide (purity: 69 %)
2.4 parts, reactive surfactant Aqualon RN-10 [manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name] 16.0 parts and Aqualon HS-
826.4 parts of a mixed solution of 8.0 parts of 10 (previously mentioned) was uniformly added over 2.5 hours while maintaining the internal temperature at 60 ° C, and further reacted at 60 ° C for 1 hour to obtain a core emulsion. To this, 0.75 parts of Rongalit was added at the same temperature, and simultaneously 66 parts of methyl methacrylate, 90 parts of butyl acrylate and 20 parts of styrene were added.
Parts, acrylic acid 4 parts, γ-methacryloxypropyldimethylmonomethoxysilane 20 parts, t-butyl hydroperoxide (pure content 69%) 0.6 parts, reactive surfactant Aqualon RN-10 (previously mentioned) 4.0 parts and Aqualon HS-10
(Previously mentioned) 206.6 parts of a mixed solution of 2.0 parts was uniformly added over 1 hour while maintaining the internal temperature at 60 ° C, and further reacted at 60 ° C for 1 hour to terminate the polymerization, and cooled to 30 ° C or lower. Soon after
Neutralized with 10% aqueous ammonia. The obtained core / shell type emulsion had a solid content concentration of 49.1% and a pH of 7.2.
Furthermore, 100 parts of this emulsion was used as an emulsion of dibutyltin dilaurate as a condensation reaction catalyst (active ingredient 30
%) 2 parts were uniformly mixed to obtain an emulsion. The reactive surfactants used for the polymerization belong to 13) and 13) among the examples of AQUALON RN-10 previously exemplified by AQUALON RN-10. The properties of the emulsion obtained above are as shown in Table 1.

Comparative Example 1 A polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet was charged with 1,033 parts of deionized water, 0.47 parts of sodium carbonate as a pH buffer, and 4.70 parts of boric acid, and stirred while stirring. After the temperature was raised to ° C, the atmosphere was replaced with nitrogen. Add 1.75 parts of Rongalit and 1 part of disodium ethylenediaminetetraacetate.
% Aqueous solution 0.12 part, ferrous sulfate 1% aqueous solution 0.04 part, and at the same time, methyl methacrylate 280 parts, butyl acrylate 350 parts, γ-methacryloxypropyltrimethoxysilane 70 parts, t-butyl hydroperoxide ( Pure content
69%) 2.1 parts, non-reactive surfactant Neugen EA-170
723.1 parts of a mixed solution of 14.0 parts of [Daiichi Kogyo Seiyaku Co., Ltd., trade name] and 7.0 parts of Emar O [Kao Co., Ltd., trade name] is homogeneous over 2.5 hours while maintaining the internal temperature at 60 ° C. To 60 ° C. for 1 hour to obtain a core emulsion. To this, 0.75 parts of Rongalit was added at the same temperature, and at the same time, 105 parts of methyl methacrylate, 150 parts of butyl acrylate, 30 parts of styrene, 15 parts of γ-methacryloxypropylmethyldimethoxysilane, and non-reactive surfactant Neugen EA- 170 (above) 6.0 copies, Emar O (above)
3.0 parts and t-butyl hydroperoxide (purity 69
%) 0.99 parts of a mixed solution (309.9 parts) was uniformly added over 1 hour while maintaining the internal temperature at 60 ° C., and the mixture was further reacted at 60 ° C. for 1 hour to complete the polymerization. The solid content of the obtained core-shell type emulsion was 49.6% and the pH was 6.9. The properties of the emulsion obtained above are as shown in Table 1.

Comparative Example 2 A polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen gas inlet was charged with 1,033 parts of deionized water, 0.47 parts of sodium carbonate as a pH buffer, and 4.70 parts of boric acid, and stirred with stirring. After the temperature was raised to ° C, the atmosphere was replaced with nitrogen. Add 2.5 parts of Rongalit and 1 part of disodium ethylenediaminetetraacetate.
% Aqueous solution 0.12 parts, ferrous sulfate 1% aqueous solution 0.04 parts, and at the same time, methyl methacrylate 400 parts, butyl acrylate 500 parts, γ-methacryloxypropyltrimethoxysilane 100 parts, t-butyl hydroperoxide ( Pure 69%) 3.0 parts, reactive surfactant Aqualon RN-20
A mixture of 20 parts (previously mentioned) and 10 parts of Aqualon HS-10 (previously mentioned) 1,033 parts was uniformly added over 3.5 hours while keeping the internal temperature at 60 ° C, and further reacted at 60 ° C for 1 hour. And the polymerization was completed. The solid concentration of the obtained emulsion is 49.7.
%, PH 7.0. The properties of the emulsion obtained above are as shown in Table 1.

Comparative Example 3 A polymerization vessel equipped with a stirrer, a condenser, a thermometer and a nitrogen gas inlet was charged with 1,033 parts of deionized water, heated to 60 ° C. with stirring, and then replaced with nitrogen. To this, 2.5 parts of Rongalit, 0.12 parts of a 1% aqueous solution of disodium ethylenediaminetetraacetate and 0.04 parts of a 1% aqueous solution of ferrous sulfate are added, and at the same time 66 parts of methyl methacrylate, 730 parts of butyl acrylate, 20 parts of styrene, acrylonitrile are added. 80 copies,
Acrylic acid 4 parts, γ-methacryloxypropyltrimethoxysilane 80 parts, γ-methacryloxypropyl dimethylmonomethoxysilane 20 parts, t-butyl hydroperoxide (pure content 69%) 3.0 parts, reactive surfactant Aqualon RN -10 (previous) 20 copies, Aqualon HS-10 (previous) 10
While maintaining the internal temperature at 60 ° C, 1,033 parts of the mixed solution of 3 parts were uniformly added over 3.5 hours, and the mixture was further reacted at 60 ° C for 1 hour to complete the polymerization. After cooling to 30 ° C or less, 10% ammonia was immediately added. Neutralized with water. The obtained emulsion had a solid content concentration of 49.2% and a pH of 7.1. Furthermore, this emulsion
An emulsion was obtained by uniformly mixing 100 parts of 2 parts of an emulsion of dibutyltin dilaurate as a condensation reaction catalyst (30% of active ingredient). The properties of the emulsion obtained above are as shown in Table 1.

[0025]

[Table 1]

[0026]

EFFECTS OF THE INVENTION The alkoxysilyl group-containing acrylic emulsion of the present invention has excellent long-term storage stability because the hydrolysis and condensation of the alkoxysilyl groups in the emulsion can be greatly suppressed, making it a practical coating material. It is useful as a base emulsion for sealants and sealants.

Claims (1)

[Claims] 1. A core-shell type emulsion having different compositions for a core and an outer shell of an emulsion particle, the core part of which comprises (a) an alkyl group having 1 to 18 carbon atoms. Alkyl ester of (meth) acrylate having 50 to 99% by weight (b) Formula R ¹ SiX ₃ (In the formula, R ¹ is a monovalent organic group having a polymerizable double bond, and X is an alkoxyl having 1 to 4 carbon atoms. 1 to 20% by weight (c) a monomer copolymerizable with the above (a) and (b) 0 to 30% by weight [where (a), (b) and ( The total amount of c) is 100% by weight], and the shell component has (A) an alkyl ester of (meth) acrylate having an alkyl group having 1 to 18 carbon atoms 50 to 99% by weight % (B) formula _{^{R 2 R 3 (3-n}} ) SiY n ( wherein, R ² is a monovalent organic group having a polymerizable double bond, R ³ is from 1 to 4 carbon atoms Alkyl group, Y is an alkoxyl group having 1 to 4 carbon atoms, n is an organic silicon compound represented by 1 or 2) 1 to 20% by weight (C) Monomer copolymerizable with the above (A) and (B) A monomer component (II) consisting of 0 to 30% by weight of the monomer (however, the total of (A), (B) and (C) is 100% by weight), the ratio of which is (I) / (I
I) = 50/50 to 90/10 (weight ratio), a core-shell type alkoxysilyl group-containing acrylic emulsion obtained by emulsion polymerization using a reactive surfactant.