JP3429524B2 - Water-based silicone modified resin and water-based paint - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based resin and a water-based coating, and more particularly to a water-based silicone modified resin and a water-based coating using the same.

[0002]

2. Description of the Related Art Silicone resin can form a coating film having good weather resistance, but it is difficult to form a coating film having high mechanical strength by itself. Therefore, the silicone resin is often used as a modifying resin for the epoxy resin, polyester resin, acrylic resin, or the like in order to improve the weather resistance of the coating film. For example, a silicone-modified acrylic resin has both properties as an acrylic resin capable of forming a coating film with high mechanical strength and a characteristic as a silicone resin capable of forming a coating film with good weather resistance, and therefore, it has high usability. Is high.

From the viewpoint of preventing environmental pollution, the above silicone-modified acrylic resin is also required to be water-based. For example, JP-A-2-150475 discloses an aqueous silicone-modified acrylic resin composed of a polymer of an organopolysiloxane macromonomer and an α, β-ethylenically unsaturated monomer. A film made of such an aqueous silicone-modified acrylic resin has good weather resistance because the resin contains a polysiloxane segment, but at the same time exhibits high water repellency and thus has low stain resistance.

An object of the present invention is to improve the stain resistance of a coating film made of an aqueous silicone modified resin.

[0005]

The aqueous silicone resin of the present invention comprises a repeating unit of at least one silicone compound selected from the group of silicone compounds represented by the following average composition formulas (1) and (2). And α, β
A film-forming copolymer containing repeating units of ethylenically unsaturated monomers.

[0006]

[Chemical 3]

The film-forming copolymer contains, for example, 5 to 30% by weight of a silicone compound and 95 to 70% by weight of an α, β-ethylenically unsaturated monomer. The water-based paint of the present invention has the following average composition formulas (1) and (2).
An aqueous dispersion of a film-forming copolymer containing a repeating unit of at least one silicone compound selected from the group of silicone compounds each represented by the following, and a repeating unit of an α, β-ethylenically unsaturated monomer. Is included.

[0008]

[Chemical 4]

In this water-based paint, the film-forming copolymer contains, for example, 5 to 30% by weight of a silicone compound and 95 to 70% by weight of an α, β-ethylenically unsaturated monomer. ******* silicone compounds Silicone compounds employed in the present invention are those represented respectively by the following average compositional formula (1) and (2). These silicone compounds may be used alone or in combination of two or more.

[0010]

[Chemical 5]

In these silicone compounds, the group X
Is a 3-acryloxypropyl group or a 3-methacryloxypropyl group. These silicone compounds are
The unsaturated bond portion contained in the group X can copolymerize with an α, β-ethylenically unsaturated monomer described later.
In the silicone compound, the group Y is -CO.
It is a monovalent substituent containing OM. In addition, M is Li, N
It is an alkali metal selected from a and K. Such a group Y may be linear or branched.

Two or more groups X and Y may be contained in one silicone compound. In the silicone compound, R is a phenyl group or an alkyl group having 1 to 6 carbon atoms. From an industrial viewpoint, R is preferably a methyl group or a phenyl group. Two or more types of R may be contained in one silicone compound. For example, a silicone compound having a dimethylsiloxane unit as a main unit and containing a diphenylsiloxane unit or a methylphenylsiloxane unit can be used as an α, β-
The reactivity and compatibility with the ethylenically unsaturated monomer are further improved.

In the silicone compound, a, b,
c is the following range, respectively.

[0014]

[Equation 1]

When a is less than 1, a coating film having good weather resistance cannot be formed. On the contrary, when it exceeds 20, α, β-
The reactivity and compatibility with the ethylenically unsaturated monomer decrease. When b is less than 0.5, the silicone compound and α,
The copolymerization ratio with the β-ethylenically unsaturated monomer decreases, and unreacted silicone compounds are likely to remain, which may deteriorate the physical properties of the copolymer resin. On the other hand, when b exceeds 3, gelation of the system occurs during polymerization of the silicone compound and the α, β-ethylenically unsaturated monomer, and good film-forming properties are not exhibited. When c is less than 1, it becomes difficult to form a coating film having sufficient hydrophilicity. On the other hand, when C exceeds 10, the viscosity of the compound increases and α, β-
The reactivity and compatibility with the ethylenically unsaturated monomer decrease.

The silicone compound represented by each of the average composition formulas (1) and (2) may have repeating units arranged in a block form or a random form. Specific examples of the silicone compound used in the present invention include:
It is as follows. In the structural formulae, Me represents a methyl group and Ph represents a phenyl group. A silicone compound represented by the average composition formula (1).

[0017]

[Chemical 6]

A silicone compound represented by the average composition formula (2).

[0019]

[Chemical 7]

The silicone compound used in the present invention is
For example, it can be manufactured as follows. A silicone compound represented by the average composition formula (1). First, a silicone compound represented by the following average composition formula (3) is synthesized. .

[0021]

[Chemical 8]

This silicone compound can be synthesized by a hydrosilylation reaction of phenylmethyl hydrogen polysiloxane and an organic functional group-containing alkene. Here, phenylmethyl hydrogen polysiloxane is
For example, it can be synthesized by the following reaction (A).

[0023]

[Chemical 9]

The desired silicone compound can be synthesized from phenylmethyl hydrogen polysiloxane, for example, by the following reaction (B).

[0025]

[Chemical 10]

In the case of synthesizing the specific examples (a), (b) and (c) of the silicone compound represented by the above-mentioned average composition formula (1), the following silicone compound is prepared according to the above-mentioned synthetic method. (A ') is synthesized.

[0027]

[Chemical 11]

Then, the silicone compound (a ') is modified with an acid anhydride to obtain the desired silicone compound (a). Specifically, it is as follows.

[0029]

[Chemical 12]

A silicone compound represented by the average composition formula (2). First, a silicone compound represented by the following average composition formula (4) is synthesized. Note that X, Z, R ¹ , a and b in the formula are the same as in the case of the average composition formula (3).

[0031]

[Chemical 13]

This silicone compound is obtained by reacting tetramethyldisiloxane, 3-methacryloxypropylmethyldimethoxysilane, and water with an acid catalyst, octametylcyclotetrasiloxane, and octaphenylcyclotetrasiloxane. It can be synthesized from an alkali equilibrium product by a trifluoromethanesulfonic acid equilibration reaction. This synthetic route is as in (C) below.

[0033]

[Chemical 14]

In the case of synthesizing the specific example (c) of the silicone compound represented by the above-mentioned average composition formula (2), the following silicone compound (c ') is synthesized according to the above-mentioned synthetic method.

[0035]

[Chemical 15]

Then, the silicone compound (c ') is modified with an acid anhydride to obtain the desired silicone compound (c). Specifically, it is as follows.

[0037]

[Chemical 16]

The specific examples (b) and (d) of the silicone compound represented by the average composition formula (2) mentioned above are the same as those in the synthetic route (C) of the silicone compound represented by the average composition formula (4). The compound (II) can be synthesized by adding the following allyl compounds (i) and (ii) to the compound (II) and neutralizing them with an alkali metal (KOH, NaOH or LiOH).

[0039]

[Chemical 17]

Α, β-ethylenically unsaturated monomer The α, β-ethylenically unsaturated monomer used in the present invention includes acrylic monomers, styrene, α-methylstyrene, α-methylstyrene dimer, Examples thereof include itaconic acid, itaconic anhydride, maleic acid, maleic anhydride, vinyl acetate, allyl acetate, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane and vinylmethyldiethoxysilane.

Among these, as the acrylic monomer,
Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, t-butyl acrylate, t-methacrylate. Butyl, t-butyl methacrylate, acrylic acid 2
-Ethylhexyl, 2-ethylhexyl methacrylate,
Lauryl acrylate, lauryl methacrylate, phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, cyclohexenyl methyl acrylate, cyclohexenyl methyl methacrylate, 2-hydroxyethyl acrylate , Methacrylic acid 2
-Hydroxyethyl, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate and ε-caprolactone Adduct (for example, Placcel FM1 manufactured by Daicel Chemical Industries Ltd.), acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acrylic Acid 3,4-epoxycyclohexyl or 3,4-epoxycyclohexyl methacrylate (for example, Cyclomer M-100 and Cyclomer A-200 manufactured by Daicel Chemical Industries, Ltd.), 3-trimethyl acrylate Xysilylpropyl, 3-trimethoxysilylpropyl methacrylate, 3-triethoxysilylpropyl acrylate, 3-triethoxysilylpropyl methacrylate, 3-dimethoxymethylsilylpropyl acrylate, 3-dimethoxymethylsilylpropyl methacrylate, acrylic Acid tributyltin, methacrylate tributyltin, acrylamide, methacrylamide, acryloyl isocyanate, methacryloyl isocyanate, acrylic acid 2-isocyanate, methacrylic acid 2
-Isocyanate etc. can be illustrated.

The α, β-ethylenically unsaturated monomers may be used alone or as a mixture of two or more kinds. Copolymer Resin The copolymer resin of the present invention comprises a repeating unit of the above silicone compound and a repeating unit of the above α, β-ethylenically unsaturated monomer. This copolymer resin is a graft polymer in which a branch polymer made of a silicone compound is bonded to a trunk polymer made of an α, β-ethylenically unsaturated monomer.

Such a copolymer resin can be obtained, for example, by emulsion polymerization of a silicone compound and an α, β-ethylenically unsaturated monomer. At this time, the mixing ratio of the silicone compound and the α, β-ethylenically unsaturated monomer is
5 to 30% by weight of the silicone compound (more preferably 1
0 to 20% by weight), 70 to 95% by weight of α, β-ethylenically unsaturated monomer (more preferably 80 to 90% by weight)
It is preferable to set to. 5% by weight of silicone compound
And the α, β-ethylenically unsaturated monomer is less than 95
If the content is more than wt%, the properties of the silicone compound,
That is, it becomes difficult for the coating film surface to exhibit good hydrophilicity. On the other hand, if the silicone compound content exceeds 30% by weight and the α, β-ethylenically unsaturated monomer content is less than 70% by weight, the mechanical strength of the coating film decreases, which is not preferable.

The glass transition point (T
g) is preferably 30 ° C. or lower. If the Tg exceeds 30 ° C, the copolymer resin may not exhibit good film-forming properties. The copolymer resin used in the present invention may contain a repeating unit other than the above-mentioned silicone compound and α, β-ethylenically unsaturated monomer.

The weight average molecular weight of the copolymer resin is 10,000 to 2,000,000, preferably 100,000 to 1,000,000.
When the molecular weight is out of the above range, the copolymer resin cannot exhibit good film-forming properties. The molecular weight is a value calculated in terms of polystyrene by GPC (gel permeation chromatography) method. Method for producing copolymer resin The resin of the present invention is a method of emulsion-polymerizing an α, β-ethylenically unsaturated monomer using the above-mentioned silicone compound as a surfactant, the above-mentioned silicone compound and α, β- It can be produced by two methods including a method of copolymerizing with an ethylenically unsaturated monomer and dispersing this in water.

In the copolymerization reaction between the silicone compound and the α, β-ethylenic monomer, the unsaturated group contained in the X group of the silicone compound during the polymerization reaction between the α, β-ethylenically unsaturated monomers. A bond is involved, and as a result, a branch polymer made of a silicone compound is introduced into a trunk polymer made of an α, β-ethylenically unsaturated monomer. Aqueous Paint The aqueous paint of the present invention is an aqueous dispersion of the above-mentioned aqueous silicone modified resin. The water dispersion here includes an emulsion.

A solvent, a pigment and various additives may be added to the water-based paint of the present invention, if necessary. As the solvent, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, 2,2,4-trimethylpentadiol-1,3-monoisobutyrate,
Diethylene glycol mono-tert-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monoisobutyl ether acetate, toxol, benzyl alcohol, butyl carbitol acetate, hexylene glycol, toluene,
Examples include xylol and terpen.

These solvents can be used as a film forming auxiliary agent for adjusting the film forming temperature of the above-mentioned aqueous silicone modified resin to about 10 ° C. or lower. When the water-based paint is an emulsion of the above-mentioned water-based silicone modified resin, when a solvent is used as a film-forming aid, the addition amount is 1 to 30 parts by weight, preferably 1 part by weight based on 100 parts by weight of the solid content of the emulsion. Set to 10 parts by weight. If the addition amount is less than 1 part by weight, the film-forming property of the coating composition is deteriorated and the adhesion between the coating film and the article to be coated is deteriorated. In addition, cracks are likely to occur in the coating film. On the other hand, when the amount added exceeds 30 parts by weight, the coating material is remarkably thickened and the coating workability is deteriorated. Further, since the tackiness of the coating film remains for a long period of time, the stain resistance of the coating film also decreases.
In addition to the above-mentioned solvents, film-forming aids include DPO and D
It is also possible to use a plasticizer such as BP.

Examples of pigments include titanium oxide, zinc white, calcium carbonate, clay, talc, mica, silica powder, glass powder, white carbon and pearlite powder.
The titanium oxide is preferably rutile type titanium oxide which has been surface-treated with a hydrous oxide of Al, Si or Zn. When adding a pigment, the pigment volume concentration (PV
C: Pigment volume content) 5 to 30%,
It is preferably set to 10 to 20%. If the PVC content is less than 5%, the hiding property of the coating film is lowered. Conversely, PVC is 3
If it exceeds 0%, the gloss of the coating film decreases.

As additives, surface-active agents such as antifreezing agents, wetting agents, dispersants, defoaming agents, thickeners, preservatives, antifungal agents, p-toluenesulfonate, and the like, which are usually used in water-based paints, Examples include cross-linking accelerators such as dodecylbenzene sulfonate, and curing agents such as melamine formaldehyde resin and blocked isocyanate. The water-based paint of the present invention can be mainly used as a paint for outer walls of buildings. In addition, they are used as various coating materials such as coating agents for electronics such as electrically insulating coating resins and coating agents for biomedical.

The water-based silicone modified resin itself can be used as a film-forming material such as a molding material or a medical material.

[0052]

Example 1 130 parts by weight of water was charged into a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas introducing tube, and 8
Hold at 0 ° C. Then, in this reaction vessel, a mixed solution of 80 parts by weight of butyl methacrylate and 20 parts by weight of a silicone compound represented by the following structural formula (5), and 4,4′-
A mixed solution of 1.0 part by weight of azobis-4-cyanovaleric acid and 0.3 part by weight of sodium hydroxide was added dropwise at a constant rate over 2 hours separately.

When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained. The obtained emulsion had a particle size of 100 nm, a weight average molecular weight of 1,000,000, and a nonvolatile content concentration of 35.2% by weight.

[0054]

[Chemical 18]

Example 2 A reactor similar to that used in Example 1 was charged with 130 parts by weight of water and kept at 80 ° C. Then, in this reaction vessel, a mixed liquid of 90 parts by weight of butyl methacrylate and 10 parts by weight of the same silicone compound as used in Example 1, and 4,4′-azobis-4-cyanovaleric acid 1.0
2 parts by weight of a mixed solution of 0.3 parts by weight of sodium hydroxide
It was added dropwise at a constant velocity separately over time.

When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained. The obtained emulsion had a particle size of 100 nm, a weight average molecular weight of 1,000,000, and a nonvolatile content concentration of 35.2% by weight. Example 3 A reaction vessel similar to that used in Example 1 was charged with 130 parts by weight of water and kept at 80 ° C. Then, in this reaction vessel, a mixed solution of 80 parts by weight of butyl methacrylate and 20 parts by weight of a silicone compound represented by the following structural formula (6), and 4,4′-azobis-4-cyanovaleric acid 1. A mixed solution of 0 parts by weight and 0.3 parts by weight of sodium hydroxide was separately added dropwise at a constant rate over 2 hours.

When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained. The obtained emulsion had a particle size of 120 nm, a weight average molecular weight of 900,000 and a nonvolatile content of 35.3% by weight.

[0058]

[Chemical 19]

Example 4 A reaction vessel similar to that used in Example 1 was charged with 130 parts by weight of water and kept at 80 ° C. Then, 40 parts by weight of methyl methacrylate and methacrylic acid-2 were added to this reaction vessel.
A mixed solution of 40 parts by weight of ethylhexyl and 20 parts by weight of a silicone compound represented by the following structural formula (7), and 1.0 part by weight of 4,4′-azobis-4-cyanovaleric acid and 0% lithium hydroxide. The mixed liquid with 2 parts by weight was added dropwise at a constant rate over 2 hours separately.

When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained. The obtained emulsion had a particle size of 150 nm, a weight average molecular weight of 800,000 and a nonvolatile content of 35.5% by weight.

[0061]

[Chemical 20]

Example 5 In a reaction vessel similar to that used in Example 1, 50 parts by weight of ethoxypropanol was charged and kept at 105 ° C. And butyl methacrylate 70 parts by weight, methacrylic acid 1
A mixed solution containing 0 part by weight, 20 parts by weight of a silicone compound represented by the following structural formula (8) and 1.0 part by weight of t-butylperoxy-2-ethylhexanoate was added dropwise at a constant rate over 3 hours. . After that, the reaction system is kept warm at 105 ° C,
Thirty minutes after the completion of dropping, 5 parts by weight of ethoxypropanol and t
-Butylperoxy-2-ethylhexanoate 0.5
The mixed liquid containing parts by weight was further added dropwise over 30 minutes. When this was kept warm at 105 ° C. for 2 hours and then ethoxypropanol was distilled off, a silicone-acryl graft resin solution was obtained. The obtained resin has a number average molecular weight of 90.
00, the concentration of nonvolatile components was 79.5% by weight. The obtained resin has a number average molecular weight of 9000 and a nonvolatile content of 7
It was 9.5% by weight.

2.6 parts by weight of potassium hydroxide and 300 parts by weight of water were added to the obtained resin and dispersed in water to obtain a water-dispersed silicone graft acrylic resin. The nonvolatile content of this resin was 30% by weight.

[0064]

[Chemical 21]

Comparative Example 1 130 parts by weight of water was charged into a reaction vessel similar to that used in Example 1 and kept at 80 ° C. Then, in this reaction vessel, a mixed solution of 80 parts by weight of butyl methacrylate and 20 parts by weight of a silicone compound represented by the following structural formula (9), and 4,4′-azobis-4-cyanovaleric acid 1. A mixed solution of 0 parts by weight and 0.8 parts by weight of dimethylethanolamine was separately added dropwise at a constant rate over 2 hours.

When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained. The obtained emulsion had a particle size of 160 nm, a weight average molecular weight of 800,000 and a nonvolatile content of 35.2% by weight.

[0067]

[Chemical formula 22]

Comparative Example 2 180 parts by weight of water, 8 parts by weight of dodecylbenzene sulfonic acid, 80 parts by weight of butyl methacrylate, 1.0 part by weight of 4,4'-azobis-4-cyanovaleric acid, dimethylethanolamine. 8 parts by weight and a dimethylsiloxane macromer having a molecular weight of about 1000 (Silaplane FM-
0711: manufactured by Chisso Co., Ltd. (20 parts by weight) was stirred using a homomixer and emulsified and dispersed to obtain a dispersion liquid. next,
100 parts by weight of water was charged into a reaction vessel similar to that used in Example 1 and kept at 80 ° C. The above-mentioned dispersion liquid was added dropwise thereto at a constant rate over 2 hours. When this was kept at 80 ° C. for 3 hours and then cooled, an emulsion was obtained.
The obtained emulsion had a particle size of 200 nm, a weight average molecular weight of 800,000 and a nonvolatile content of 35.5% by weight. Comparative Example 3 A reaction vessel similar to that used in Example 1 was charged with 350 parts by weight of water and 8 parts by weight of dodecylbenzenesulfonic acid,
Hold at 80 ° C. And butyl methacrylate 100
By weight, a mixed solution of 0.5 parts by weight of 2,2'-azobis (2-amidinopropane) hydrochloride and 50 parts by weight of water was added dropwise at a constant rate separately over 2 hours. When this was kept at 80 ° C. for 3 hours and then cooled, a water-dispersed acrylic resin was obtained. The obtained resin had a particle size of 60 nm, a weight average molecular weight of 900,000 and a nonvolatile concentration of 19.5% by weight. Coating film test A coating film was formed from the emulsion or water dispersion resin obtained in Examples 1 to 5 and Comparative Examples 1 to 3, and the hydrophilicity and stain resistance of the coating film were examined. Examples 1 to 4 and Comparative Example 1,
For No. 2, each resin was applied to a thickness of 100 μm and dried at 60 ° C. for 24 hours to form a coating film. Also,
For Example 5 and Comparative Example 3, 1/4 of the resin solids
Add water-soluble melamine resin at a ratio of 100
The coating film was formed by applying the coating solution to a thickness of μm and baking at 140 ° C. for 30 minutes.

The results are shown in Table 1. The hydrophilicity was evaluated by measuring the contact angle of water droplets. The lower the contact angle value, the higher the hydrophilicity. The stain resistance was evaluated by a natural exposure test for 6 months. The evaluation criteria are as follows. ⊚: No stain. ○: Almost no stain Δ: There is dirt. X: There is remarkable dirt.

[0070]

[Table 1]

[0071]

EFFECTS OF THE INVENTION The aqueous silicone-modified resin of the present invention has a polysiloxane segment portion forming a metal salt, and therefore can form a coating film having good stain resistance. In the water-based paint of the present invention, since the polysiloxane segment of the film-forming copolymer contained therein forms a metal salt, a coating film having good stain resistance can be formed.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuhiko Ueno 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (72) Koji Osugi, 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Nippon Paint Co., Ltd. (56) References JP-A-6-25369 (JP, A) JP-A-6-32903 (JP, A) JP-A-2-80415 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 290/00-290/14 C08F 299/00-299/08 C09D 1/00-201/10 C08G 77/00-77/62

Claims (2)

(57) [Claims] 1. A repeating unit comprising at least one silicone compound selected from the group of silicone compounds represented by the following average composition formulas (1) and (2), respectively:
A film-forming copolymer containing a repeating unit of α, β-ethylenically unsaturated monomer, wherein the film-forming copolymer contains 5 to 5 parts of the silicone compound.
30% by weight, 9% of the α, β-ethylenically unsaturated monomer
An aqueous silicone-modified resin containing 5 to 70% by weight and having a weight average molecular weight of 10,000 to 2,000,000. [Chemical 1] 2. A repeating unit comprising at least one silicone compound selected from the group of silicone compounds represented by the following average composition formulas (1) and (2), respectively:
An aqueous dispersion of a film-forming copolymer containing a repeating unit of an α, β-ethylenically unsaturated monomer, wherein the film-forming copolymer contains 5 to 5 parts of the silicone compound.
30% by weight, 9% of the α, β-ethylenically unsaturated monomer
A water-based paint containing 5 to 70% by weight of each and having a weight average molecular weight of 10,000 to 2,000,000. [Chemical 2]