JP3113452B2 - Coating composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based coating composition having excellent water resistance, chemical resistance, weather resistance, hardness, heat resistance and excellent flexibility such as flexibility, and a process for producing the same.
The present invention relates to an anticorrosion paint on a metal surface containing the coating composition.

[0002]

2. Description of the Related Art In recent years, water-based paints have been developed from the viewpoints of environmental pollution and safety and health, and water-based emulsion paints are being replaced with conventional solvent-based paints. Under these circumstances, emulsion paints have been required to have higher physical properties. Conventionally, an emulsion polymerization method has been widely used as a method for obtaining an emulsion paint, but the resulting resin has poor water resistance and chemical resistance.

[0003] On the other hand, polysiloxanes obtained by hydrolyzing and condensing alkoxysilanes have excellent properties such as weather resistance, hardness and heat resistance in addition to water resistance and chemical resistance. However, polysiloxane is inferior in flexibility and film formability such as flexibility, and in aqueous systems, the alkoxysilanes, which are monomers, react with water, so that polymerization stability and storage stability are extremely poor. I had.

Conventionally, a chromic acid treatment or a phosphoric acid treatment has been performed for the purpose of imparting corrosion resistance to a metal surface treatment or imparting a coating base property for improving adhesion to a paint.

[0005] Among them, the chromic acid treatment method can provide considerable corrosion resistance, but is insufficient as a paint base material. As a method of improving the chromic acid treatment, for example, Japanese Patent Publication No. 45-38891 proposes a treatment method using an inorganic chromate solution comprising chromic anhydride and a silicate. Not enough. Chromate pollution is also a problem.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a water-based coating composition which is excellent in water resistance, chemical resistance, weather resistance, hardness, corrosion resistance, rust resistance and the like, and has excellent flexibility such as flexibility. It is a second object of the present invention to provide a product and a method for producing the same, and to provide a high-performance corrosion-resistant paint using the coating composition.

[0007]

Means for Solving the Problems] Koti according to the present invention
The composition for aging is a component A; the following general formula (I)

[0008]

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A silane compound A represented by [0009], and a water-soluble polymer composition obtained hydrolytic condensation in the presence of a surfactant in water solvent, B components; la radical polymerizable monomer (provided that The whole 10
0.1 to 30.0 parts by weight of radical polymerizable in 0 parts by weight
The monomer has a functional group consisting of at least one of a phosphoric acid group and a carboxylic acid group, and may be a radical polymerizable monomer capable of serving as a catalyst for hydrolysis and condensation of the silane compound A, and / or a hydroxyl group, A radical polymerizable monomer having at least one functional group selected from a glycidyl group and an alkoxysilyl group and reacting with the Si (OR ² ) group of the silane compound A to form a bond ) A water-dispersed polymer obtained by emulsion polymerization in water is obtained by mixing, and the weight ratio (A / B) of component A to component B is 10 to 10.
0.1 (where the A component _{^{R 1 m SiO 4-m /}} 2, converting the B component solids) Ru der.

Hereinafter, the present invention will be described in detail.

The silane compound A used in the present invention
Is not particularly limited as long as it satisfies the general formula (I), and one or more of them can be used. Specific examples of the silane compound A include a silane compound having a lower alkyl group; tetramethoxysilane, tetraethoxysilane,
Tetrapropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,
n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-
Silane compounds having a chlorine atom, such as propyltriethoxysilane; γ-chloropropyltrimethoxysilane, γ
- chloropropyltriethoxysilane, etc., a silane compound having an unsaturated aliphatic residue; vinyltrimethoxysilane, vinyltriethoxysilane, etc., a silane compound having a main mercapto group; .gamma.-mercaptopropyltrimethoxysilane, .gamma.-mercaptopropyl Silane compounds having an aryl group, such as triethoxysilane; phenyltrimethoxysilane, phenyltriethoxysilane, and the like. One or more of these can be used, but from the viewpoint of versatility. Tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane are desirable.

[0012] In the present invention, hydrolysis and condensation of the silane compound A is carried out in an aqueous solvent is carried out in the presence of a surfactant prior to mixing with the emulsion polymer is a B component.

As the surfactant used here, surfactants such as anionic, nonionic, a combination of anionic and nonionic, cationic, amphoteric and the like can be used. Examples of the anionic surfactant include higher alcohol sulfate sodium salt, alkyl benzene sulfonate sodium salt, dialkyl succinate sodium sulfonate, and alkyl diphenyl ether disulfonic acid, and the like. Oxyethylene alkyl allyl ether and the like can be mentioned. As the cationic surfactant, for example, alkylpyridinyl chloride, alkylammonium chloride and the like are used. As the amphoteric surfactant, for example, lauryl betaine can be used. Further, a reactive surfactant or the like may be used. From the viewpoint of the stability of the siloxane component, an anionic surfactant is desirable, and in particular, dodecylbenzenesulfonic acid is more preferred. In these cases, the surfactant has an effect of suppressing a rapid reaction of the silane compound A and preventing gelation. The amount of the surfactant used is based on the amount of the silane compound A.
The content is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight. If the amount is less than 0.01 part by weight, the storage stability is poor, and if it is more than 5 parts by weight, the formed polymer may be poor in water resistance. The hydrolysis condensation reaction of the silane compound A is performed under a temperature condition of 0 to 200 ° C. This hydrolysis-condensation reaction is carried out, for example, using a silane compound A.
In the case where tetraethoxysilane is used, the following formula is used.

[0014]

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In the present invention, the above reaction is carried out by using a surfactant.
It is performed in the presence of a sexual agent .

[0016] Oite the present invention, the above component A combination
The component B used is a radical polymerizable monomer in water
A water-dispersed polymer obtained by emulsion polymerization. However, this
Radical polymerizable monomers used in emulsion polymerization of
0.1 to 30.0 parts by weight of the total 100 parts by weight is described later.
Polymerizable monomer b1 and / or polymerizable monomer b2
And the remaining 70.0 to 99.9 parts by weight of styrene,
α-styrene, divinylbenzene and their nuclear substitution induction
Body and / or (meta) exemplified below
(Hereinafter, these α-styrenes)
With ethylene, divinylbenzene and their nuclear-substituted derivatives
Ta) Acrylic esters are collectively referred to as polymerizable monomers a.
Say). Methyl (meth) acrylate, ethyl (meth)
Acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) Acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol (meth)
Acrylate and the like .

[0017] Oite the present invention, the polymerizable monomer b1 is Li
From at least one of an acid group and a carboxylic acid group
Silane compound A having a functional group
A polymerizable monomer capable of serving as a medium , for example, a polymerizable monomer having a phosphoric acid group in the molecule; 2- (meth) acryloyloxyethyl acid phosphate, acid phosphooxypolyoxypropylene glycol mono (meth) acrylate Polymerizable monomers having a carboxylic acid group in the molecule, such as acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, methacryloyloxyethyl acid phosphate monoethanolamine half-salt; (meth) acrylic acid; ) Acrylicoxyethyl succinic acid, 2- (meth) acryloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid and the like can be mentioned as examples.

[0018] Oite the present invention, the polymerizable monomer b2 are water
Selected from acid groups, glycidyl groups and alkoxysilyl groups
Silane compound having at least one functional group
A polymerizable monomer capable of reacting with the Si (OR ² ) group of the product A to form a bond , for example, a polymerizable monomer having a hydroxyl group in the molecule; 2-hydroxyethyl (meth) acrylate, Hydroxypropyl (meth) acrylate, 2
Polymerizable monomers having a glycidyl group in the molecule, such as -hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid; glycidyl (meth) acrylate Polymerizable monomers having an alkoxysilyl group in the molecule; γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, and the like.

In the present invention, the polymerizable monomers b1 and / or b2 are used in an amount of 0.1 to 0.1% based on the total amount of the polymerizable monomers.
30 parts by weight is preferable, and more preferably, 1.0 to 20 parts by weight.
Parts by weight are desirable. If the amount is less than 1.0 part by weight, the effect of b1 or b2 is not sufficient, and if it is more than 20 parts by weight, the polymer may be poor in water resistance.

In the case of the polymerizable monomer b1, the polymerizable monomer b1 or b2 acts as a condensation catalyst during film formation of the siloxane and as an agent for improving the adhesion to the substrate. Can be expected to act as a compatibilizer between the siloxane component and the emulsion polymerization component.

The emulsion polymerization of the component B in the present invention can be carried out under the usual emulsion polymerization conditions. For example, a radically polymerizable polymerizable monomer, an emulsifier, a polymerization initiator, a chain transfer agent, a pH adjuster, and the like are added as necessary to an aqueous medium, and the mixture is added at 20 to 100 ° C for about 0.5 to 30 hours. Perform polymerization.

As the emulsifier used here, emulsifiers such as anionic, nonionic, a combination of anionic and nonionic, cationic, and amphoteric can be used. Examples of the anionic emulsifier include higher alcohol sulfate sodium salt, alkyl benzene sulfonate sodium salt, dialkyl succinate sodium sulfonate, and alkyl diphenyl ether disulfonate.Examples of the nonionic emulsifier include polyoxyethylene alkyl. Allyl ether and the like can be mentioned. As the cationic emulsifier, for example, alkylpyridinyl chloride, alkylammonium chloride and the like are used. As the amphoteric emulsifier, for example, lauryl betaine or the like can be used. Further, a reactive emulsifier or the like may be used. The amount of the emulsifier used is preferably 0.001 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer. When the amount is less than 0.001 part by weight, the stability of the micelle during polymerization is poor. When the amount is more than 10 parts by weight, the water resistance when the polymer is formed may be poor.

As the polymerization initiator, water-soluble persulfate,
Hydrogen peroxide or the like can be used, and if necessary, it can be used in combination with a reducing agent. Further, an oil-soluble polymerization initiator such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4
-Dimethyl valeronitrile) and the like, and organic peroxide polymerization initiators such as benzoyl peroxide and butyl peroxide. The amount of the polymerization initiator used is 0.01 to 5 parts by weight per 100 parts by weight of the polymerizable monomer.
Parts by weight are preferred.

In the coating composition obtained in the present invention, the ratio (A / B) of the component A and the component B is 10% by weight.
To 0.1 (however, the A component is converted to R _1m SiO _{4-m / 2} and the B component is converted to a solid content), preferably 3 to 0.3. When A / B is more than 3, flexibility such as flexibility is inferior, and when A / B is less than 0.3, chemical resistance, hardness and the like may be inferior.

In the present invention, an organic solvent can be added to improve the film forming property and the wettability. Examples of the organic solvent used herein include alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol, diethylene glycol, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, and ketones such as acetone and methyl ethyl ketone. , Methyl acetate, tetrahydrofuran and the like, and these can be used as a mixture. Of these, alcohols are preferably used. The amount of these organic solvents used is 20% of the total solvent.
Less than 10 parts by weight, preferably less than 10 parts by weight, more preferably less than 5 parts by weight.

In the present invention, various inorganic and organic additives such as a curing agent, a wettability improver, a plasticizer, an antifoaming agent, and a thickener are added as needed within a range not to impair the effects of the present invention. can do.

As the substrate to be coated with the coating composition of the present invention, resin moldings, metals, woods, ceramics and the like can be used.

After coating, the coating layer is cured and dried.
The curing and drying methods can be performed at room temperature, but when it is desired to cure and dry quickly, the heat treatment can be performed at room temperature to 300 ° C., preferably at room temperature to 250 ° C.

The coating method is not particularly limited as long as it is a coating method in which coating and drying are performed on a substrate, and examples thereof include a roll coating method, a dip coating method, a bar coating method, a nozzle coating method, and a combination of these methods. An ordinary method such as a coating method is used.

Further, a metal surface capable of imparting excellent corrosion resistance by applying the coating composition of the present invention to at least one metal or alloy selected from the group consisting of iron, steel, zinc and aluminum. It can also be used as a treatment composition.

When the coating composition of the present invention is used as a metal surface treatment composition, it can be used in combination with a chromium compound. The chromium compounds used include CrO ₃ , Cr (NO ₃ ) ₃ , CrCl ₃ , Cr
₂ (SO ₄ ) ₃ .18H ₂ O, CrPO ₄ .6H ₂ O; chromates such as potassium chromate and ammonium chromate; water-soluble such as dichromates such as potassium dichromate and ammonium dichromate Chromium compounds; or water-insoluble chromium compounds such as strontium chromate, lead chromate and zinc chromate can be used.

It is also possible to add tannic acid, gallic acid, thiouric acid, etc., which are generally known as components of a rust preventive.

The coating composition obtained in the present invention may contain a water-insoluble or water-dispersible inorganic substance. Examples include water-dispersible silica, talc, diatomaceous earth, calcium carbonate, clay, titanium dioxide, aluminum silicate, aluminum phosphate, alumina sol,
Magnesia sol, titania sol, zirconia sol and the like can be mentioned.

When the coating composition of the present invention is used as a metal surface treatment composition, it can be applied to at least one metal or alloy selected from the group consisting of iron, steel, zinc and aluminum. Alloy steel, zinc,
Metals such as zinc alloys, aluminum, aluminum alloys,
And iron, steel, alloy steel, zinc, zinc alloy, aluminum,
Metal coatings coated with an aluminum alloy or the like can be given.

Further, as the shape of these objects, various shapes such as plate, pipe, line, etc. can be used.

In order to use the coating composition of the present invention as a metal surface treatment composition, brush coating, spray coating, roll coating, and immersion are performed on a metal surface of a substrate at room temperature to 250 ° C., preferably room temperature to 100 ° C. After application by such methods as above, it is only necessary to dry at a temperature equal to or higher than room temperature for several seconds to several minutes. In this case, a sufficient effect can be obtained with a thin film having a thickness of about 0.1 to 10 μm.

[0037]

EXAMPLES The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples.

Example 1 A four-necked flask was equipped with a stirrer and a thermometer, and 200
g, sodium dodecylbenzenesulfonate 0.6
g, ammonium persulfate (0.68 g), the atmosphere was replaced with nitrogen gas, and the temperature was raised to 80 ° C.
5 g, methyl methacrylate 41.8 g, methacrylic acid 1
A mixture of 1.7 g, 30 g of water and 0.7 g of sodium dodecylbenzenesulfonate was continuously added dropwise over 3 hours. After completion of the dropwise addition, the mixture was heated at 80 ° C. for 1 hour, cooled, and then filtered through a 200-mesh wire gauze to obtain an emulsion polymer 1. The average particle size of the obtained emulsion polymer was 94.5 nm. Next, 20.3 g of methyltrimethoxysilane,
8.7 g of tetraethoxysilane, 0.3 g of sodium dodecylbenzenesulfonate and 80 g of water were mixed, and 2
The mixture was stirred at 3 ° C. for 3 hours to obtain a transparent water-soluble polymer. To this solution, 57.3 g of the emulsion polymer 1 was added dropwise over 30 minutes, and the mixture was further stirred for 3 hours to obtain a coating composition 1.

The coating composition 1 was applied to a glass plate and a steel plate using a bar coater to a thickness of 2.0 μm. Each of the obtained coating films was transparent.
Table 1 shows the physical property test results of this coating film.

Examples 2 to 7 The same operation as in Example 1 was performed, and the results are shown in Table 1.

Comparative Example 1 20.3 g of methyltrimethoxysilane, 8.7 g of tetraethoxysilane, 80 g of water and 0.4 g of sodium dodecylbenzenesulfonate were mixed and stirred at 23 ° C. for 3 hours. I got

The composition for comparative coating 1 was applied to a glass plate and a steel plate using a bar coater to a thickness of 2.0 μm. Each of the obtained coating films was transparent. The coating film had a Gobang test evaluation of 8, chemical resistance of ○, pencil hardness of 3H, Erichsen of ×, and corrosion resistance of ×. The storage stability was x.

Comparative Example 2 The emulsion polymer 1 obtained in Example 1 was applied to a glass plate and a steel plate using a bar coater so as to have a thickness of 2.0 μm. Each of the obtained coating films was transparent. The coating film had a Gobang test evaluation of 10, a chemical resistance of ×, a pencil hardness of 6B, an Erichsen of ○, and a corrosion resistance of ×.
The storage stability was ○.

Comparative Example 3 A stirrer and a thermometer were attached to a four-necked flask.
g, sodium dodecylbenzenesulfonate 0.6
g, ammonium persulfate (0.68 g), the atmosphere was replaced with nitrogen gas, and the temperature was raised to 80 ° C.
A mixture of 5 g, 53.5 g of methyl methacrylate, 30 g of water and 0.7 g of sodium dodecylbenzenesulfonate was continuously added dropwise over 3 hours. After dropping,
The mixture was heated at 80 ° C. for 1 hour, cooled, and filtered through a 200-mesh wire gauze to obtain Comparative Emulsion Polymer 3. The average particle size of the obtained emulsion polymer was 101.5 nm. Next, 20.3 g of methyltrimethoxysilane, 8.7 g of tetraethoxysilane, 0.3 g of sodium dodecylbenzenesulfonate and 80 g of water were mixed and stirred at 23 ° C. for 3 hours to obtain a transparent water-soluble polymer. Was. To this solution, 57.3
g of the emulsion polymer 1 was added dropwise over 30 minutes, and the mixture was further stirred for 3 hours to obtain a comparative coating composition 3.

The composition for comparative coating 3 was applied to a glass plate and a steel plate using a bar coater so as to have a thickness of 2.0 μm. All of the obtained coating films were transparent. The coating film had a Goban test evaluation of 9, chemical resistance of ○, pencil hardness of H, Erichsen of ×, and corrosion resistance of ×. The storage stability was ○.

Comparative Example 4 A stirrer and a thermometer were attached to a four-necked flask,
g, sodium dodecylbenzenesulfonate 0.6
g, ammonium persulfate (0.68 g), the atmosphere was replaced with nitrogen gas, and the temperature was raised to 80 ° C.
5 g, methyl methacrylate 41.8 g, methacrylic acid 1
A mixture of 1.7 g, 30 g of water and 0.7 g of sodium dodecylbenzenesulfonate was continuously added dropwise over 3 hours. After completion of the dropwise addition, the mixture was heated at 80 ° C. for 1 hour, cooled, and filtered through a 200-mesh wire gauze.
I got The average particle size of the obtained emulsion polymer is 94.5 nm.
Met. Next, methyltrimethoxysilane 20.3
g and 8.7 g of tetraethoxysilane were added dropwise to 57.3 g of Comparative Emulsion Polymer 4 over 30 minutes. However, after 2 hours, the solution gelled.

Evaluation method : Gobang test The coating film coated on the glass plate was cut by a cutter knife at 200 mm × 200 mm intervals.
After the cellophane tape was pressed and peeled off, the degree of peeling of the coating film was evaluated by a 10-point method.

10 points (good) → 1 point (poor) ・ Chemical resistance The coating film coated on the glass plate is immersed in xylene for 6 hours. ○: No change in the coating film ×: The coating film is whitened and the coating film is dissolved ・ Pencil Hardness The coating was performed on a glass plate according to JIS-K5400.

Ericksen The coating film coated on the steel plate was extruded by 5 mm Ericksen and the state of the coating film was observed.

：: no change in coating film ×: crack in coating film Corrosion resistance A coating film coated on a steel plate was subjected to a salt spray test of 250 in accordance with JIS Z-2371.
Performed over time ○: No change ×: Red rust, white rust, etc. occurred ・ Storage stability Observed the condition of the surface treatment composition after 3 months ○: No change ×: Aggregation, gelation (Note) Examples, comparison The example steel sheet is an electrogalvanized steel sheet.

Abbreviation PM: 2-methacryloyloxyethyl acid phosphate BA: butyl acrylate MMA: methyl methacrylate MAA: methacrylic acid HEMA: 2-hydroxyethyl methacrylate GMA: glycidyl methacrylate γMTMOS: γ-methacryloxypropyltrimethoxysilane

[0052]

[Table 1]

Continuation of the front page (72) Inventor Tadahiro Yoneda 5-8 Nishiburi-cho, Suita-shi, Osaka Inside of Nippon Shokubai Central Research Laboratory Co., Ltd. (56) References JP-A-62-158767 (JP, A) JP-A-28752 (JP, A) JP-A-3-281679 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 1/00-201/10

Claims (3)

(57) [Claims] 1. A component: the following general formula (I): In the silane compound A represented, and the obtained water-soluble polymer composition hydrolytic condensation in the presence of a surfactant in water solvent, B components; la radical polymerizable monomer (provided that the total 10
0.1 to 30.0 parts by weight of radical polymerizable in 0 parts by weight
The monomer has a functional group consisting of at least one of a phosphoric acid group and a carboxylic acid group, and may be a radical polymerizable monomer capable of serving as a catalyst for hydrolysis and condensation of the silane compound A, and / or a hydroxyl group, A radical polymerizable monomer having at least one functional group selected from a glycidyl group and an alkoxysilyl group and reacting with the Si (OR ² ) group of the silane compound A to form a bond ) A water-dispersed polymer obtained by emulsion polymerization in water is obtained by mixing, and the weight ratio of component A and component B (A /
B) is 10 to 0.1 (provided that A component is R ¹ _m SiO
To _{4-m / 2,} B-component is the converted to solids), co over Te <br/> Ingu composition. 2. A component: the following general formula (I): In the silane compound A represented, and the obtained water-soluble polymer composition hydrolytic condensation in the presence of a surfactant in water solvent, B components; la radical polymerizable monomer (provided that the total 10
0.1 to 30.0 parts by weight of radical polymerizable in 0 parts by weight
The monomer has a functional group consisting of at least one of a phosphoric acid group and a carboxylic acid group, and may be a radical polymerizable monomer capable of serving as a catalyst for hydrolysis and condensation of the silane compound A, and / or a hydroxyl group, A radical polymerizable monomer having at least one functional group selected from a glycidyl group and an alkoxysilyl group and reacting with the Si (OR ² ) group of the silane compound A to form a bond ) A water-dispersed polymer obtained by emulsion polymerization in water has a weight ratio (A / B) of component A and component B of 10 to 0.1 (provided that component A is R ¹ _m SiO _{4-m / 2} , mixing the B component such that converted to solid content), the manufacturing method of the coating composition according to 請 Motomeko 1. 3. A corrosion-resistant paint on a metal surface, comprising the coating composition according to claim 1 .