JPH10176015A - Production of curable emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable emulsion having excellent water absorption suppressing property and adhesivity to inorganic material and useful as a coating material, etc., by polymerizing raw materials in the presence of a hydrolyzable silane compound. SOLUTION: This emulsion can be produced by the radical polymerization of (A) a radically polymerizable monomer having an alkoxysilyl group, (B) a radically polymerizable monomer copolymerizable with the component A and (C) a radically polymerizable surfactant expressed by the formula Z-(AO)n -Y (Z is a constituent unit having radically polymerizable double bond; AO is an oxyalkylene; (n) is >=2; Y is an ionizable group) in the presence of (D) a monomer, dimer, trimer or oligomer of a silane compound expressed by the formula R<1> -Si(R<2> )4-n ((n) is 1-3; R<1> is a stable hydrophobic group; R" is a hydrolyzable group).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a curable emulsion comprising a polymer having an alkoxysilyl group, that is, a polymer having a functional group in which a hydrolyzable alkoxy group is bonded to a silicon atom, and a silane compound, The emulsion can be used as a paint or a coating agent.

[0002]

2. Description of the Related Art, represented by γ-methacryloxypropyltriethoxysilane or vinyltriethoxysilane,
A polymer obtained by copolymerizing a radical polymerizable monomer having an alkoxysilyl group with another monomer is widely used for applications such as adhesives, sealing materials, paints and coating agents. However, in these applications, in order to avoid harm to the human body and environmental pollution due to volatilization of the organic solvent, an aqueous material that does not use an organic solvent is required. Aqueous emulsions comprising a polymer containing an alkoxysilyl group have a problem of storage stability because the functional groups are inherently hydrolyzed, and many proposals have been made for the purpose of improving that point. ing.

[0003] In other words, JP-A-3-227312 discloses that when a monomer having an alkyl (meth) acrylate and an alkoxysilyl group is subjected to aqueous emulsion polymerization, acrylamide, acrylic acid or styrene may be used in addition to the above monomer. A method of copolymerizing a specific water-soluble monomer such as sulfonic acid at about 0.1 to 5% by weight has been proposed.
No. 5,354, proposes a method in which a monomer having an alkoxysilyl group is copolymerized with an amine imide group-containing monomer in an alcohol solvent, water is added thereto to emulsify, and then the alcohol is evaporated. .

Further, JP-A-59-152972 discloses that a specific amount of colloidal silica is added to an aqueous emulsion obtained by aqueous emulsion polymerization of vinylsilane, an acrylic monomer and a polymerizable emulsifier. It is disclosed that an aqueous emulsion which forms a coating film having excellent water resistance can be obtained.

However, conventionally known curable emulsions are still insufficient in storage stability, and in addition to this, the resulting coating film is not satisfactory in water resistance and adhesion to inorganic materials and the like. There was a problem. The present inventors have studied for the purpose of providing a curable emulsion that is an aqueous emulsion composed of a polymer having an alkoxysilyl group, has excellent storage stability, and can form a coating film having excellent physical properties. Using an ionic surfactant having a polyoxyalkylene unit and a radically polymerizable double bond, in the presence of a pH buffer, by copolymerizing a radically polymerizable alkoxysilane and another vinyl monomer, It has been found that a curable emulsion containing a curable polymer excellent in both storage stability and coating film properties can be obtained (Japanese Patent Application No. 7-49129).

[0006]

However, the curable emulsion obtained by the production method described in Japanese Patent Application No. 7-49129 has a coating film whose water absorption preventing property and water adhesion to inorganic materials have poor performance. The present inventors have conducted intensive studies in order to find a method capable of producing a curable emulsion excellent in these properties.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have conceived of a combination of the curable emulsion and a hydrolyzable silane compound in order to solve the above-mentioned problems. As a result of study, if each raw material of the curable polymer is polymerized in the presence of a silane compound having hydrolyzability, a curable emulsion having excellent water absorption prevention properties and excellent adhesion to inorganic materials can be obtained. Thus, the present invention has been completed. Hereinafter, the present invention will be described in detail.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

-Radical polymerizable monomers having alkoxysilyl groups
(A) radical polymerizable monomer having an alkoxysilyl group (a)
Various compounds can be used as [hereinafter referred to as monomer (a)]. The radically polymerizable group in the monomer (a) is preferably an ethylenically unsaturated group, more preferably a vinyl group or a (meth) acryloyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group, and a methoxy group and an ethoxy group are preferable. Specific examples of the monomer (a) include vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltriethoxysilane, and vinylmethyldiethoxysilane. , Γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, vinyltripropoxysilane, vinylmethyldipropoxysilane, γ-methacryloxypropyltripropoxysilane and γ-methacryloxypropylmethyldipropoxysilane Is mentioned.

A radical polymerizable monomer copolymerizable with the monomer (a) (b) a radical polymerizable monomer copolymerizable with the monomer (a) [hereinafter referred to as the monomer (b) ] Include (meth) acrylates, vinyl acetate, vinyl propionate, styrene, α-methylstyrene and the like. Examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, and n- (meth) acrylate.
Butyl, cyclohexyl (meth) acrylate, (meth)
(Meth) such as 2-ethylhexyl acrylate, lauryl (meth) acrylate and stearyl (meth) acrylate
Alkyl acrylate, hydroxylalkyl (meth) acrylate such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate, perfluoroalkyl (meth) acrylate, glycidyl (meth) acrylate, and ( (Meth) acrylic acid N, N-
Diethylaminoethyl and the like.

The preferred monomer (b) is a monomer that imparts film-forming properties to the curable polymer.
An alkyl (meth) acrylate having an alkyl group of 8;
Styrene, hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 2 to 3 carbon atoms, and glycidyl (meth) acrylate. On the other hand, it is desirable not to use an acidic monomer such as (meth) acrylic acid which promotes hydrolysis of the alkoxyl group.

Radical polymerizable surfactant (c) Next, the radical polymerizable surfactant (hereinafter referred to as surfactant (c)) in the present invention is a polyoxyalkylene represented by the following general formula (1): It is a radically polymerizable surfactant containing a group and an ion-dissociable group.

[0012]

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

(Wherein, Z is a structural unit having a radical polymerizable double bond copolymerizable with the above component (a), AO is an oxyalkylene group, n is an integer of 2 or more, and Y is an ion-dissociable group. The preferred Z in the general formula (1) is a radical polymerizable double bond with a hydrophobic group such as an aromatic hydrocarbon group, an alkyl-substituted aromatic hydrocarbon group, a higher alkyl group or an alicyclic hydrocarbon group. A structural unit in which a bond is combined. Furthermore, Z
Is preferably a (meth) allyl group, a propenyl group or a butenyl group.

The preferred ionicity of the surfactant (c) is an anion. Therefore, as Y, a salt in which an anion is covalently bonded to the group (AO) n side and a cation is ionically bonded to the anion is preferable. Preferred specific examples of Y include -SO
_{3 Na, -SO 3 NH 4,} -COONa, -COONH
_4, -PO ₃ Na _2, and -PO ₃ (NH _{4) 2} and the like, more preferably -SO ₃ Na or -SO ₃ NH
₄ N in the group (AO) n is an integer of 2 or more. When n is 1, the alkoxysilyl group in the monomer (a) becomes unstable and easily decomposed. Preferred n is 300 or less, more preferably 5 to 5
0. When n is less than 5, the stability of the alkoxysilyl group in the monomer (a) tends to be insufficient, while when n exceeds 300, a coating film formed from a curable emulsion obtained. May show a tendency for the physical properties to decrease. The unit A in the group (AO) n, that is, the alkylene group, is preferably an ethylene group or a propylene group.

Representative examples of the surfactant (c) include compounds represented by the following chemical formulas (2), (3) or (4). In each formula, Y is an ion-dissociable group, and preferred specific examples are as described above.

[0016]

Embedded image

R ^{3 in} Chemical Formula 2 is preferably a linear or branched alkyl group having 6 to 18 carbon atoms.

[0018]

Embedded image

R ^{3 in} Chemical Formula ³ is preferably a linear or branched alkyl group having 6 to 18 carbon atoms.

[0020]

Embedded image

R ^{4 in} Chemical Formula ⁴ is a hydrogen atom or a methyl group, and R ⁵ is preferably an alkyl group having 8 to 24 carbon atoms.

When a normal surfactant is used without copolymerizing the surfactant (c), the resulting curable emulsion coating film has poor water whitening resistance and insufficient water adhesion. It will be something.

The silane compound having a hydrolyzable functional group (d) The silane compound having a hydrolyzable functional group (d) in the present invention (hereinafter referred to as silane compound (d)) is represented by the following structural formula. Monomer, dimer, trimer or oligomer thereof.

[0024]

Embedded image R ¹ _n —Si— (R ² ) _4-n

Here, n is an integer of 1, 2 or 3;
Preferably it is 3. R ¹ is a stable hydrophobic group, for example, a hydrocarbon-based substituent such as an alkyl group or a phenyl group, and among them, a saturated alkyl group is preferable in terms of hydrophobicity. R ² is a hydrolyzable group, such as an alkoxy group such as a methoxy group and an ethoxy group, a hydroxyl group, a halogen atom, an acetoxy group, a carboxyl group, and an isocyanate group. In the present invention, an alkoxy group is preferable from the viewpoint of storage stability and ease of handling. When there are a plurality of R ¹ and R ² , they may be the same or different.

Silane compounds useful in the present invention
Specific examples of (d) include the following. Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethylditriethoxysilane, ethyltri-n-propoxysilane, butyltrimethoxysilane, butyltriethoxysilane,
Butyldimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, cyclohexyltrimethoxysilane, benzyltrimethoxysilane, phenyltrimethoxysilane, octyltrimethoxysilane, octyl Triisopropoxy silane, 2-ethylhexyl trimethoxy silane, decyl trimethy silane, dodecyl trimethoxy silane and tetradecyl triethoxy silane, etc.
Or dimers, trimers and other oligomers thereof, and mixtures thereof. In the present invention, among these compounds, alkylalkoxysilane is preferable, and particularly preferable one is alkyltrialkoxysilane.

Two or more silane compounds (d) can be used in combination.

The monomer (a) containing no silane compound (d)
In the case of a curable emulsion containing only a curable polymer composed of the monomer (b) and the surfactant (c), the coating film has poor water adhesion.

The method of producing a curable emulsion The present invention relates to a method for producing a monomer (a), a monomer (b) and a surfactant (c).
Is radically polymerized in the presence of the silane compound (d),
This is a method for producing a curable emulsion comprising a curable polymer containing a silane compound (d). Thereby, the coating film of the obtained curable emulsion can be made excellent in water-resistant adhesion.

Here, the use ratio of each component is defined as the total amount of the monomer (a), the monomer (b) and the surfactant (c)
(a) (b) (c) referred to as the total amount).
Is preferably in the range of 0.5 to 49.5% by weight, more preferably 3 to 20% by weight, and the amount of the monomer (b) is 99%.
It is preferably in the range of 50 to 50% by weight, more preferably 96 to 75% by weight, and the surfactant (c) is 0.5 to 50% by weight.
It is preferably in the range of 20% by weight, more preferably in the range of 1 to 5% by weight. The use ratio of the silane compound (d) is 5% based on the total amount of (a), (b) and (c).
To 300% by weight, more preferably 10 to 10% by weight.
0% by weight.

If the copolymerization ratio of the monomer (a) is less than 0.5% by weight, the curability of the resulting curable emulsion becomes insufficient, and the coating film may be whitened,
On the other hand, if it exceeds 49.5% by weight, the storage stability may be easily reduced. If the proportion of the monomer (b) is less than 50% by weight, the resulting curable emulsion may have poor film-forming properties and poor adhesion of the coating film to the substrate. Surfactant
If the proportion of (c) is less than 0.5% by weight, the polymerization stability tends to decrease, while if it exceeds 20% by weight, the water resistance of the coating film may be insufficient. Further, the ratio of the silane compound (d) is
(a) (b) (c) When the amount is less than 5% by weight based on the total amount, the effect of preventing water absorption of the base material is insufficient. May decrease.

Further, in the present invention, various methods are used for radical polymerization of the monomer (a), the monomer (b) and the surfactant (c), and an oil-soluble polymerization initiator is used. Microsuspension polymerization in which the monomer is polymerized in fine particles of the oil-soluble monomer used, emulsion polymerization in which the monomer is polymerized by a water-soluble polymerization initiator in a micelle with an emulsifier, and the like can be used.
It is preferable to employ microsuspension polymerization because the polymerization stability of the monomer (a) is excellent.

In order to carry out microsuspension polymerization, first, fine particles comprising the monomer (a), the monomer (b) and the oil-soluble polymerization initiator are dissolved in an aqueous medium, preferably by dissolving a pH buffer. In an aqueous medium. In the operation of dispersing the monomer and the like in the aqueous medium, the surfactant (c) may be dissolved in the aqueous medium in advance similarly to the pH buffer. The ratio of the aqueous medium and the monomer to be dispersed is suitably about 20 to 150 parts by weight of the aqueous medium per 100 parts by weight of the monomer.

The oil-soluble radical polymerization initiator used in microsuspension polymerization has a solubility in water at 20 ° C. of 1
Those having 0% by weight or less are preferably used. For example,
2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4 dimethylvaleronitrile, 1-azobis-1-cyclohexanecarbonitrile and dimethyl-
Azo initiators such as 2,2′-azobisisobutyrate,
Organic peroxides such as lauroyl peroxide, benzoyl peroxide, dicumyl peroxide, cyclohexanone peroxide di-n-propylperoxydicarbonate and t-butylperoxypivalate are preferably used. The amount of these polymerization initiators is suitably from 0.1 to 10% by weight, preferably from 0.2 to 3% by weight, based on the total amount of (a), (b) and (c).

In this case, it is preferable to add a pH buffer to stabilize the alkoxysilyl group in the monomer (a). As the pH buffer, the pH of the aqueous medium is 6 to
Buffers suitable for holding at 10 are preferred, organic acids,
Inorganic acids, bases and salts thereof are mentioned, and specific compounds include sodium hydrogen carbonate, sodium carbonate,
Examples include ammonium carbonate, sodium borate, sodium phosphate, sodium sulfate, sodium acetate, ammonium acetate, mono-, di- or triethanolamine, aniline, and sodium silicate. Among them, sodium hydrogencarbonate is most preferable in terms of safety, low cost, and the like. The buffers may be used alone or in combination of two or more. In general, the amount used is preferably 0,3 in the aqueous emulsified dispersion.
It is preferably from 0.01 to 5% by weight.

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

The ratio of the aqueous medium for emulsifying the mixture of the monomer (a) and the monomer (b) is 20 to 100 parts by weight of the mixture of the monomer (a) and the monomer (b). It is preferably set to 150 parts by weight.

The aqueous dispersion of fine particles composed of monomers and the like obtained by the above operation is placed in an aqueous medium containing a silane compound (d) heated to a temperature not lower than the decomposition temperature of the polymerization initiator.
Alternatively, the aqueous dispersion and the silane compound (d) are supplied into a heated aqueous medium to copolymerize the monomer (a), the monomer (b) and the surfactant (c). The polymerization temperature may be selected depending on the polymerization initiator used, and is usually about 40 to 100 ° C, preferably 70 to 90 ° C.

In the production method of the present invention, a more preferred method is to prepare the monomer (a), the monomer (b) and the oil-soluble radical polymerization initiator in an aqueous medium in the presence of a surfactant (c). [A] and a step [B] of emulsifying and dispersing the silane compound (d) in an aqueous medium in the presence of a surfactant. The aqueous emulsion dispersion is mixed and subjected to radical polymerization. According to this method, a curable emulsion can be stably manufactured.

In the above-mentioned production method, as the step [A], various methods as described in the microsuspension polymerization can be adopted.

In addition, a silane compound is added in the presence of a surfactant.
Various methods can be adopted as the step of producing the aqueous emulsified dispersion B by emulsifying and dispersing (d) in an aqueous medium (step [B]).

As the surfactant used in this case, any of nonionic, anionic and cationic surfactants can be used. The surfactant may be used alone or
More than one species may be used in combination. Among them, an aqueous emulsion of a silane compound using a nonionic surfactant is preferable because of its excellent emulsion stability. When an anionic surfactant or a cationic surfactant is used, hydrolytic condensation of the silane compound may occur relatively quickly. In the present invention, the nonionic surfactant suitably used is preferably one having an HLB of 1.5 to 22, and if it is out of this range, the aqueous emulsified dispersion is easily separated. More preferably, HLB = 4-15. Specific examples of the nonionic surfactant suitably used in the present invention include polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene derivatives, sorbitan monolaurate, and sorbitan. Examples thereof include monostearate, sorbitan monostearate, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan monostearate. These may be used in combination with other surfactants.

The surfactant is preferably used in an amount of 0.5 to 50% by weight, more preferably 1 to 20% by weight, based on the silane compound (d). When the amount is less than 0.1% by weight, the aqueous dispersion is easily separated, and when the amount exceeds 50% by weight, the performance of the obtained composition tends to be deteriorated. The selection of the type of surfactant and the concentration of the compound varies depending on the silane compound to be used or a mixture thereof, and therefore, it is preferable to experimentally study and determine it as necessary.

In this case, it is preferable to add a pH buffer for stabilizing the alkoxysilyl group in the silane compound (d). As the pH buffer, the same kind as described above can be used in the same ratio.

Since the aqueous emulsified dispersion has a large particle size and is easily separated, it is preferably adjusted to 10 μm or less, more preferably 1 μm or less. Therefore, instead of the usual rotary homomixer or after processing by a rotary homomixer, a high-pressure emulsifying and dispersing machine (homogenizer),
It is desirable to reduce the particle size using a dispersing device having a high degree of shear energy such as a turbine mixer.

The proportion of the aqueous medium in which the silane compound (d) is to be emulsified is preferably set to 20 to 150 parts by weight of the aqueous medium per 100 parts by weight of the silane compound (d).

In the production method of the present invention, the aqueous emulsified dispersion obtained in the step [A] (hereinafter referred to as “aqueous emulsified dispersion A”)
There are various modes for mixing the aqueous emulsion dispersion obtained in the step [B] (hereinafter referred to as “aqueous emulsion dispersion B”) and performing radical polymerization, for example, the following methods (1) to (4). is there. (1) The aqueous emulsified dispersion A is supplied to the heated aqueous emulsified dispersion B with stirring to polymerize the monomer (a), the monomer (b) and the surfactant (c). (2) The aqueous emulsified dispersion A and the aqueous emulsified dispersion B are charged into separate dropping funnels, and they are supplied to a heated aqueous medium with stirring, and the monomers (a) and (b) are supplied. And the surfactant (c). (3) Charge half of the aqueous emulsion dispersion B into a polymerization vessel, and charge the aqueous emulsion dispersion A and the other half of the aqueous emulsion dispersion B into separate dropping funnels. Heated aqueous emulsified dispersion B
Then, the aqueous emulsified dispersion A and the aqueous emulsified dispersion B are supplied under stirring to polymerize the monomer (a), the monomer (b) and the surfactant (c). (4) After mixing the aqueous emulsified dispersion A and the aqueous emulsified dispersion B, the mixture is supplied to a heated aqueous medium with stirring to obtain a monomer (a), a monomer (b) and a surfactant. The agent (c) is polymerized. Among these methods, since the hydrolysis of the silane compound (d) can be suppressed, the production method of the above (2) (step [C]
) Is preferably employed.

As a method of supplying the aqueous emulsified dispersion A and / or the aqueous emulsified dispersion B to the aqueous medium or the aqueous emulsified dispersion B, there is a method of continuously or intermittently dropping and supplying.

The proportion of the aqueous medium in the curable emulsion obtained is preferably from 40 to 80% by weight in the curable emulsion.

In the above method (2), that is, in the step [C], the aqueous emulsified dispersion A and the aqueous emulsified dispersion B are separately dropped into an aqueous medium heated to a temperature not lower than the decomposition temperature of the polymerization initiator. This is to produce a curable emulsion containing a silane compound (d) while copolymerizing the monomer (a), the monomer (b) and the surfactant (c).

In the production method (2), the preferable amount of the aqueous medium previously charged in the polymerization vessel is in the range of 5 to 30 parts by weight based on 100 parts by weight of the aqueous medium in the finally obtained curable emulsion. It is.

It is preferable to add a catalyst to the curable emulsion obtained by the production method of the present invention since a condensation reaction of silanol groups generated by hydrolysis of alkoxysilyl groups can be promoted. Examples of such a catalyst include organic titanate compounds such as isopropyl triisostearoyl titanate and isopropyl tri (dioctyl pyrophosphate) titanate, tin dioctylate,
Organic tin compounds such as dibutyltin dilaurate and dibutyltin malate; and organic acids such as paratoluenesulfonic acid.

Various additives can be added to the curable emulsion depending on the purpose. For example, a fungicide, a biocide, a defoaming agent, a lubricant, a fragrance, a thickener, a fluorine polymer and a silicone polymer as a water repellency imparting agent, which prevent the generation of mold in the aqueous emulsified dispersion, and a film forming. Auxiliaries and pigments can be used in combination, and if necessary, paint additives such as anti-sagging agents, anti-settling agents, antifoaming agents, silane coupling agents or matting agents can also be added.

Use Method The curable emulsion obtained by the production method of the present invention is suitable as a coating agent. Examples of the substrate applicable as the coating agent include glass; metals such as aluminum, iron, stainless steel, tinplate and nickel; and resins such as acrylic resin, vinyl chloride resin, polyester resin, polycarbonate resin and ABS resin. Further, a permeable base material such as a cement base material such as concrete, slate, mortar, calcium silicate-based material, gypsum / slag-based material, wood and paper such as cedar and hinoki constitutes a curable emulsion. It is particularly preferable because an effect of preventing water absorption due to penetration of the silane compound into the substrate and an effect of increasing the adhesion of the coating film to the substrate can be expected. As a method of coating the curable emulsion on the substrate, it may be performed by a generally known method,
Specific examples include spray coating, roller coating, and brush coating. Curing of the curable emulsion can be carried out by drying at room temperature or by heating. Preferred drying conditions are 3 to 14 days at room temperature and 100 to 150 days.
It is about 3 to 30 minutes at ° C.

[0055]

The details of the reason why the curable emulsion of the present invention has excellent water adhesion resistance are unknown, but it is presumed to be due to the following reasons. That is, in the present invention, the monomer
The curable polymer comprising (a), the monomer (b) and the surfactant (c) is obtained by forming a three-dimensional network structure by hydrolyzing and condensing the alkoxysilyl groups of each other. Provides water resistance, weather resistance, acid resistance and toughness to the film. At the same time, the silane compound (d) has a low molecular weight as compared with the curable polymer, so that the silane compound (d) penetrates into the base material, and by subsequent hydrolysis and condensation, forms a hydrophobic layer on the base material. Form.
When an emulsion obtained by simply mixing a curable polymer and a silane compound (d) is applied to a substrate and cured,
A layer containing a large amount of a cured product of the silane compound (d) and a layer containing a large amount of a cured product of a curable polymer are more likely to be formed on the base material. Was insufficient in water adhesion. In contrast, the curable emulsion of the present invention comprises a silane compound (d)
In order to produce a curable polymer in the presence of a silane compound (d), the proportion of those containing a silane compound (d) in the micelles of the curable polymer emulsion (hereinafter referred to as the third component) increases, When the curable emulsion of the present invention is applied to a substrate and cured as a result, a layer containing a large amount of a cured product of the silane compound (d) on the substrate,
A layer containing a cured product of the third component is further formed thereon, and a layer containing a large amount of a cured product of a curable polymer is further formed thereon with an appropriate gradient, so that the layer has excellent water resistance to a substrate. It is presumed that.

[0056]

Next, the present invention will be described more specifically with reference to examples and comparative examples. All parts in Examples and Comparative Examples are parts by weight, and test methods in Examples are as shown below. Aqualon HS20 (Daiichi Kogyo Seiyaku Co., Ltd., trade name) used as a radical polymerizable surfactant is a compound represented by the following chemical formula (6).

[0057]

Embedded image

Test method The curable emulsion obtained in each example was placed on a slate plate
200 g per ² was applied and dried for 14 days under the condition of a temperature of 25 ° C. and a humidity of 60% to prepare the following test pieces for measuring coating film properties.

Recoating property test 100 g of various finishing materials were applied to a slate plate per m ² , dried and then applied a second time again, and repelling of the liquid was observed. (○: no problem, △: slight repelling, × repelling)

Water resistance test The test piece was immersed in ion-exchanged water at 25 ° C. for 7 days, and the degree of whitening of the coating film was observed. (○: no change, Δ: slightly whitened, ×: completely whitened)

Water Absorption The test piece was immersed in ion-exchanged water at 25 ° C. for seven and a half days with the coated surface facing down, and the water absorption (% by weight) was measured.

Adhesiveness A 100 mm square of 1 mm square was cut with a cutter and peeled off with cellophane tape.
100 to 90, Δ: 90 to 50, ×: 50 or less).

Water-resistant adhesiveness A 100 mm square 1 mm square was cut with a cutter, and the coated surface was immersed in ion-exchanged water at 25 ° C. for 7 days with the coated surface down. The water was cut off and dried at room temperature for 1 hour. After peeling in the above, the number of squares of the remaining coating film was determined as the standard (○: 100 to 9).
0, Δ: 90 to 50, ×: 50 or less).

Using a sunshine weather meter manufactured by Suga Test Machine, the coating film was forcibly deteriorated under the conditions of JIS 5400, and the gloss (6 hours after the lapse of 2000 hours with respect to the initial gloss (60 °)) was obtained.
(0 °), the weather resistance was evaluated.

Example 1 Monomer (a), monomer (b) and surfactant described in Table 1
In (c), 1 part of a polymerization initiator was dissolved, and this was added to 100 parts of deionized water in which 0.2 part of sodium hydrogen carbonate was dissolved as a pH buffer, mixed with a homomixer, and further used with a homogenizer. An aqueous emulsified dispersion A was prepared. Separately, deionized water in which sodium bicarbonate and a surfactant shown in Table 1 are dissolved and a silane compound (d) shown in Table 1 are mixed with a homomixer, and further mixed with a homogenizer. And aqueous emulsified dispersion B were prepared. After charging 40 parts of deionized water to a flask equipped with a stirrer, a thermometer and a cooler, and raising the liquid temperature to 80 ° C., while stirring the aqueous medium at high speed, the aqueous emulsion dispersion A and the aqueous The emulsified dispersion B was added dropwise over 2 hours. After the completion of the dropwise addition, the mixture was kept at a temperature of 80 ° C. for 2 hours to complete the polymerization, and then cooled to room temperature.
A curable emulsion having a ratio of (d) of 2: 1 was produced. The evaluation results of this curable emulsion are as shown in Table 2.

Examples 2 to 4 Curable emulsions were produced in the same manner as in Example 1 except that the components shown in Table 1 were used. The evaluation results of the obtained curable emulsion are as shown in Table 2.

Comparative Example 1 A curable emulsion was produced in the same manner as in Example 1 except that the components shown in Table 1 were used and the monomer (a) was not used. The evaluation results of the obtained curable emulsion are as shown in Table 2.

Comparative Example 2 An aqueous emulsified dispersion A alone was prepared in the same manner as in Example 1 except that the components shown in Table 1 were used. This was a curable emulsion. The evaluation results of the obtained curable emulsion are as shown in Table 2.

Comparative Example 3 The components shown in Table 1 were used, and no surfactant (c) was used.
A curable emulsion was produced in the same manner as in Example 1 except that the aqueous emulsified dispersion A was prepared using polyoxyethylene phenyl ether sulfate instead. The evaluation results of the obtained curable emulsion are as shown in Table 2.

Comparative Example 4 An aqueous emulsified dispersion A was prepared in the same manner as in Example 1 except that the components shown in Table 1 were used. Polymerization was carried out under the same conditions as described above to obtain a curable polymer emulsion. An aqueous emulsified dispersion B was prepared in the same manner as in Example 1 except that the components shown in Table 2 were used. A curable emulsion was prepared by mixing the curable polymer emulsion and the aqueous emulsified dispersion B. The evaluation results of the obtained curable emulsion are as shown in Table 2.

[0071]

[Table 1]

[0072]

[Table 2]

[0073]

The curable emulsion of the present invention has excellent storage stability, and the coating film of the emulsion has excellent adhesion and weather resistance, and further impedes the penetration of water into the substrate.
It also has excellent water resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masafumi Achinami 1 at Funamicho, Minato-ku, Nagoya-shi, Aichi Prefecture Toagosei Co., Ltd. Nagoya Research Institute (72) Inventor Koichi Fukushima 1 Funamicho, Minato-ku, Nagoya-shi, Aichi No. 1 Toagosei Co., Ltd. Nagoya Research Laboratory

Claims (3)

[Claims] 1. A radical polymerizable monomer (a) having an alkoxysilyl group, a radical polymerizable monomer (b) copolymerizable with the monomer (a), and a radical polymerizable surfactant described below.
(c) a silane compound having a hydrolyzable functional group
A method for producing a curable emulsion, which comprises radically polymerizing in the presence of (d). -Radical polymerizable surfactant (c): General formula; Z- (A
O) a radically polymerizable surfactant represented by n-Y (wherein Z is a structural unit having a radically polymerizable double bond;
O represents an oxyalkylene group, n represents an integer of 2 or more, and Y represents an ion dissociable group. ○ Silane compound (d) having a hydrolyzable functional group: a monomer, dimer, trimer or silane compound represented by the general formula: R ¹ _n —Si— (R ² ) _4-n The oligomer (n is an integer of 1, 2, or 3, R ¹ is a stable hydrophobic group, and R ² is a hydrolyzable group). 2. Use of an oil-soluble radical polymerization initiator as a polymerization initiator, a radical polymerizable monomer (a) having an alkoxysilyl group, and a radical polymerizable monomer copolymerizable with the monomer (a). Monomer (b) and an oil-soluble radical polymerization initiator,
A step [A] of emulsifying and dispersing in an aqueous medium in the presence of a radically polymerizable surfactant (c), and a silane compound (d) having a hydrolyzable functional group in an aqueous medium in the presence of the surfactant. [A] and the step [A]
2. The method for producing a curable emulsion according to claim 1, wherein the aqueous emulsion dispersion obtained in [B] is mixed and subjected to radical polymerization. 3. The curable composition according to claim 2, wherein the aqueous emulsified dispersions obtained in the step [A] and the step [B] are separately supplied into a heated aqueous medium and subjected to radical polymerization. A method for producing an emulsion.