JP2000026762A - Emulsion composition for treating metal surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare the subject emulsion composition excellent in corrosion resistance and black discoloration resistance on the surface of a galvanized iron sheet and hardly eluting chromium therefrom by including a copolymer obtained through copolymerizing an ethylenic unsaturated monomer with an acetoacetoxyethyl methacrylate and other ethylenically unsaturated monomer. SOLUTION: This emulsion composition is prepared by including copolymer particles obtained through copolymerizing (A) 1-30 wt.% ethylenic unsaturated monomer of formula I [R1a-R1c, R11, R12, R21, R22, R31 and R32 are each H, methyl, or the like; (n1)-(n3) are each 1-6; (m1)-(m3) are each 0-30 and (m1)+(m2)+(m3) is 1-30] with (B) 1-30 wt.% acetoacetoxyethyl methacrylate of formula II and (C) 98-40 wt.% other ethylenically unsaturated monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a galvanized steel sheet or a zinc alloy-plated steel sheet having corrosion resistance, blackening resistance,
The present invention relates to an emulsion composition for metal surface treatment, which is used as a binder for a coating type chromate treatment, which forms a chromate film having an excellent treatment appearance and less chromium elution during alkali degreasing.

[0002]

2. Description of the Related Art [Technical Background] Chromate treatment is widely used to improve the corrosion resistance of galvanized steel sheets, zinc alloy-plated steel sheets, aluminum-plated steel sheets, and the like, and as a base treatment during top coating. BACKGROUND ART A surface-treated steel sheet, which is a material for processing, is formed according to the purpose and is widely used, for example, for automobiles, home appliances, building materials, and the like. When the surface-treated steel sheet is formed, various rust preventives (oils) are usually used in order to prevent corrosion of the base material. Therefore, a degreasing step using an alkaline aqueous solution is required to remove the rust preventives (oils).

[Reaction-type chromate treatment] A galvanized steel sheet which is a surface-treated steel sheet is usually subjected to a rust-prevention treatment by a reaction-type chromate treatment. However, in this case, the chromate coating alone is insufficient in paint adhesion,
Further, it is necessary to apply an organic resin. A specific example of such a technique is disclosed in, for example, Japanese Patent Application Laid-Open No. 58-22417.
No. 5 can be mentioned. That is, JP-A-58-2
No. 24175 discloses a technique for improving the coating adhesion of a degreased surface-treated steel sheet by subjecting a galvanized steel sheet to a material, performing a reactive chromate treatment, washing with water, and coating with an organic resin. It has been disclosed.

[0004] However, such a technique has at least two problems as described below. The first problem is that it requires two processes, a chromate treatment process and a water-based resin coating process, and it is difficult to produce the existing production equipment using one-step chromate treatment as it is. In order to solve such difficulties, large-scale equipment remodeling is required. The second problem is that, since the chromate treatment step of the first step is a reaction type chromate treatment, a water washing step of washing the chromate treatment liquid adhering to the plated steel sheet with water is required, which occurs in the water washing step. That is, a large amount of hexavalent chromium wastewater must be treated.

[Coating-type chromate treatment] In order to solve these problems, a method of mixing an organic resin and chromium to fix chromium, that is, a coating-type chromate treatment has been proposed. Specific examples of the technique of immobilizing chromium with such an organic resin include, for example, JP-A-61-23767, JP-A-63-96275, JP-A-63-145785, and JP-A-63-175078.
JP-A-3-215683, JP-A-4-35808
No. 2, JP-A-5-148432, and JP-A-5-5-2
No. 30,666 and the like.

In Japanese Patent Application Laid-Open No. 61-23767, the mixing stability of hexavalent chromium and the resin is improved by the carboxylic acid in the resin, but the stability of the resin is ensured by mixing with chromic acid. Are difficult and have problems with the stability of the mixture over a long period of time.

[0007] In JP-A-63-145785,
An acrylic polymer emulsion obtained by emulsion polymerization using a polyoxyethylene-polyoxypropylene block polymer-based nonionic surfactant is used. When immersed in a paint film, the paint film transfers to water, which causes a paint film defect. For this reason, the water resistance and rust resistance are reduced.

In Japanese Patent Application Laid-Open No. Hei 3-215683, the resin used is simply described as an acrylic emulsion, but no clear definition and performance of the resin are specified, and a nonionic surfactant is applied. There is a problem that rust bleeding and water resistance are reduced by bleeding from the film.

In Japanese Patent Application Laid-Open No. 63-175078,
Regarding the resin used, the rules and performance of the resin are not specified.

In JP-A-4-358082, the water-soluble resin used is a polyacrylic acid-based resin containing a carboxyl group. When chromic acid is added, the pH tends to the acidic side, and aggregation and the like are likely to occur. There was a problem.

In JP-A-5-230666, resin particles obtained by copolymerizing a monomer having a hydroxyl group and a monomer having a carboxyl group are used as a resin for fixing chromium. Since no surfactant is used in the polymerization step, there is an advantage that the surfactant does not bleed from the coating film, but there is a problem in that it is difficult to control the particle diameter of the resin particles. That is, if a surfactant is not used in the polymerization step, the particle diameter of the obtained resin particles becomes large, so that the coating film obtained at the time of coating tends to cause coating film defects, and the coating film defects cause rust. Becomes

JP-A-5-148432 uses resin particles obtained by copolymerizing an acrylate ester having an acetoacetyl group or the like as a resin for immobilizing chromium. Since the resin emulsion to be used is assumed to be used in a pH range of 7 or more, the application of the present invention is that the pH is in the acidic side (p).
(H7 or less), it is impossible to use.

[0013]

DISCLOSURE OF THE INVENTION The present invention has excellent mixing stability with chromium, and the coating obtained is a galvanized steel sheet.
An object of the present invention is to provide an emulsion composition for metal surface treatment which is excellent in corrosion resistance of a plated steel sheet such as a zinc alloy plated steel sheet and an aluminum plated steel sheet.

[0014]

The present invention provides the following [1].
To [8].

[1] An emulsion composition for metal surface treatment comprising a copolymer particle, wherein the copolymer particle is an ethylenic compound represented by the following general formula (1): An unsaturated monomer (a1) and acetoacetoxyethyl methacrylate (A) represented by the general formula (2)
(AEM) A copolymer obtained by copolymerizing (a2) and an ethylenically unsaturated monomer (A) containing an ethylenically unsaturated monomer (a3) other than (a1) and (a2). (A1), (a2), (a3)
(A1) is 1 to 30% by weight based on the total weight of (a1), (a2) and (a3);
(A2) is 1 to 30% by weight, and (a3) is 98% by weight.
Emulsion composition for metal surface treatment, characterized in that the content is up to 40% by weight. (In the general formula (1), R _1a ,
R _1b , R _1c , R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , R ₃₁ and R
₃₂ is each independently the same or different and is a hydrogen atom, a methyl group or an ethyl group; n ₁ , n ₂ and n ₃ are each independently the same or different and each
And m ₁ , m ₂ and m ₃ may be each independently the same or different, 0 to 30 and (m ₁
+ M ₂ + m ₃ ) = 1 to 30. Here, m ₁ , m ₂ and m ₃ indicate the total number of each repeating unit,
This includes not only the case of the block-shaped bonding structure but also the case of the random-shaped bonding structure. )

[0016]

Embedded image [2] An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles are an ethylenically unsaturated unit represented by the general formula (1) [formula 6]. (A1) and acetoacetoxyethyl methacrylate (AAEM) represented by the general formula (2) [Formula 6]
(A2) and an ethylenically unsaturated monomer (A) containing an ethylenically unsaturated monomer (a3) other than (a1) and (a2) together with a reactive surfactant (B) , Comprising a copolymer obtained by copolymerization, wherein (a)
1), (a2), (a3) and (B) are used in a
1) Based on the total weight of (a2) and (a3),
(A1) is 1 to 30% by weight, and (a2) is 1 to 30% by weight.
30% by weight, (a3) is 98 to 40% by weight, and (B) is 0.01 to 10% by weight. (In the general formula (1), R _1a , R _1b , R _1c , R ₁₁ , R ₁₂ ,
R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ may each independently be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ and n ₃ are each independently And may be the same or different, and are 1 to 6, m ₁ , m ₂ and m ₃
May be independently the same or different;
0, and (m ₁ + m ₂ + m ₃ ) = 1 to 30.
Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. )

[0017]

Embedded image [3] An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles have a repeating unit (α) represented by the general formula (3) [Formula 7].
1) a copolymer comprising a repeating unit (α2) represented by the general formula (4) [Formula 7] and a repeating unit (α3) other than (α1) and (α2), ,
When the weight ratio of (α1), (α2) and (α3) is (α
1), based on the total weight of (α2) and (α3),
(Α1) is 1 to 30% by weight, and (α2) is 1 to 30% by weight.
30% by weight, and (α3) is 98 to 40% by weight, the emulsion composition for metal surface treatment. (In the general formula (3), R _1a , R _1b , R _1c ,
R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ each represent
May be independently the same or different, and may include a hydrogen atom, a methyl group,
Or an ethyl group, and n ₁ , n ₂ and n ₃ may be each independently the same or different, and are 1 to 6;
₁ , m ₂ and m ₃ may be independently the same or different, each is 0 to 30, and (m ₁ + m ₂ + m ₃ ) = 1
~ 30. Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. )

[0018]

Embedded image [4] An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles are:
The repeating unit (α) represented by the general formula (3) [Formula 8]
1), a repeating unit (α2), a repeating unit (α3) other than (α1) and (α2) represented by the general formula (4), and a repeating unit (β) having a surface active function
Comprising a copolymer having (α)
1) The weight ratio of (α2) and (α3) is (α1),
Based on the total weight of (α2) and (α3), (α
1) is 1 to 30% by weight, and (α2) is 1 to 30% by weight.
% By weight, (α3) is 98 to 40% by weight,
(Β) is 0.01 to 10% by weight, an emulsion composition for metal surface treatment. (In the general formula (3), R _1a , R _1b , R _1c , R ₁₁ , R ₁₂ ,
R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ may each independently be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ and n ₃ are each independently And may be the same or different, and are 1 to 6, m ₁ , m ₂ and m ₃
May be independently the same or different;
0, and (m ₁ + m ₂ + m ₃ ) = 1 to 30.
Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. )

[0019]

Embedded image [5] The metal according to any one of [1] to [4], wherein the ethylenically unsaturated monomer (a3) or the repeating unit (α3) does not have a carboxyl group. Emulsion composition for surface treatment.

[6] The copolymer has a glass transition temperature of -20 to 50 ° C.,
The emulsion composition for metal surface treatment according to any one of [1] to [5].

[7] When the copolymer particles have a particle size of 0.05 to 0.5.
The emulsion composition for metal surface treatment according to any one of [1] to [6], having an average particle diameter of 5 μm.

[8] A method for treating the surface of a steel sheet, comprising using a mixture of the emulsion composition for metal surface treatment according to any one of [1] to [7] and chromic acid for coating a steel sheet. .

[9] A surface-treated steel sheet obtained by the method for treating a steel sheet according to [8].

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to an emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles are represented by the following general formula (1): An ethylenically unsaturated monomer (a1) represented by the general formula (2):
Acetoacetoxyethyl methacrylate (AAEM) (a2) represented by the following formula (9), (a1) and (a2)
A copolymer obtained by copolymerizing an ethylenically unsaturated monomer (A) containing an ethylenically unsaturated monomer (a3) other than the above with a reactive surfactant (B). Wherein (a1), (a2), (a3) and (B) are used in an amount of (a1) based on the total weight of (a1), (a2) and (a3), (A2) is 1 to 30% by weight, and (a3)
Is 98 to 40% by weight, and (B) is 0.01 to 1% by weight.
An object of the present invention is to provide an emulsion composition for metal surface treatment, wherein the composition is 0% by weight.

(In the general formula (1), R _1a , R _1b , R
_1c , R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ each independently may be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ And n ₃ may each independently be the same or different, and are 1 to 6,
m ₁ , m ₂ and m ₃ may each independently be the same or different, are 0 to 30, and (m ₁ + m ₂ + m ₃ ) =
1 to 30. Here, m ₁ , m ₂ , and m ₃ indicate the total number of each repeating unit, and include not only the case of a block-like bonding structure but also the case of a random-like bonding structure. )

[0026]

Embedded image The present invention is achieved by using the above emulsion composition in order to achieve both prevention of chromium elution and high corrosion resistance.

N ₁ , n ₂ and n ₃ in the general formula (1) [Chemical formula 9] may be each independently the same or different;
Each is 1 to 6, preferably 1 to 2. If it is 1 or more, the length of the side chain is appropriately long, and the thickness of the hydrated layer covering the surface of the resin particles in the obtained emulsion composition can be kept sufficiently large, so that mechanical stability and electrolyte Good stability.

On the other hand, when it exceeds 6, the polymerization reaction does not proceed because the reactivity of the vinyl group of the monomer decreases. m ₁ ,
m ₂ and m ₃ may be independently the same or different, each is 0 to 30, and (m ₁ + m ₂ + m ₃ ) = 1 to 3
0.

When m ₁ + m ₂ + m ₃ is less than 1, it becomes a carboxyl group. When it becomes a carboxyl group, the chromic acid added later is on the acidic side, so that an ionic reaction is caused and the stability of the emulsion is significantly reduced.
More specifically, as described below, the stability of the emulsion is significantly reduced. When the side chain of the general formula (1) is a carboxyl group, the length of the side chain is short, so that the thickness of the hydration layer covering the surface of the resin particles in the obtained emulsion composition can be kept sufficiently large. Since it does not exist, mechanical stability and electrolyte stability are significantly reduced. When the side chain of the general formula (1) is a carboxyl group, the length of the side chain is short, and chromic acid of a multivalent ion and monovalent carboxylic acid are aggregated, and mechanical stability and electrolyte stability are remarkable. Will drop.

On the other hand, when m ₁ + m ₂ + m ₃ exceeds 30, the reactivity of the vinyl group of the monomer is reduced, and the polymerization reaction does not proceed. In addition, these monomers may be used alone or as a mixture of plural ones.

The ethylenically unsaturated monomer (a1) represented by the general formula (1) [Formula 9] is not particularly limited as long as it is a hydroxyl group-containing monomer containing an ether unit in a molecular chain. Specific examples of the ethylenically unsaturated monomer (a1) represented by the general formula (1) [Formula 9] include, for example, polyethylene glycol monomethacrylate, methoxy polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, and polyethylene glycol polypropylene. Glycol monomethacrylate, polyethylene glycol polyteramethylene glycol monomethacrylate, polypropylene glycol polyteramethylene glycol monomethacrylate, and the like are preferable, and polyethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, and the like are preferable.

As the monomer (a3) [ethylenically unsaturated monomer other than (a1) and (a2)], a monomer containing no ether unit can be used. And acrylate or methacrylate such as -hydroxypropyl-, 3-hydroxypropyl-, 2-hydroxybutyl-, 3-hydroxybutyl-, and 4-hydroxybutyl-. When these monomers are used alone, the molecular weight is relatively small as compared with the hydroxyl group-containing monomer containing an ether unit in the molecular chain, so that the number of moles increases, and as a result, the copolymer contains In such a case, the hydroxyl group content of the monomer (a1) in which at least 80% by weight of the molecular chain contains an ether unit may be decreased. It is preferable to use together with the contained monomer.

Next, the amount of the monomer (a1) represented by the general formula (1) [formula 9] needs to be 1 to 30% by weight, and preferably 3 to 15% by weight. If the amount of the necessary component is less than 1% by weight, there is no stability at the time of emulsion polymerization, and there is a possibility that gelation occurs at the time of polymerization. Also,
There is no stability on the acidic side (pH 7 or less) of the emulsion, and it gels when mixed with chromium.

On the other hand, when the content exceeds 30% by weight, the coating film formed from the obtained emulsion has high hydrophilicity,
Water resistance and rust resistance are significantly reduced.

The ethylenically unsaturated monomer containing an acetoacetyl group represented by the general formula (2) [Formula 9] is acetoacetoxyethyl methacrylate (AAEM).

When the amount of the necessary component is less than 1% by weight, the hydroxyl group or acetoacetyl group in the synthetic resin is insufficient to form a complex with a metal. If it exceeds 30% by weight, it becomes excessive, the hydrophilicity of the resin itself increases, the hydrophilicity of the obtained coating film itself increases, and the water resistance and the like are remarkably reduced.

The monomer (a1) represented by the general formula (1)
Is required to be 1 to 30% by weight, preferably 3 to 15% by weight, based on the total weight of (a1), (a2) and (a3).

The monomer (a2) represented by the general formula (2)
Is required to be 1 to 30% by weight, preferably 3 to 15% by weight, based on the total weight of (a1), (a2) and (a3).

The ethylenically unsaturated monomer (a3) [(a
Ethylenically unsaturated monomers other than 1) and (a2)] include the ethylenically unsaturated monomer (a1) represented by the general formula (1) [formula 9] and the general formula (2) [ A monomer other than the ethylenically unsaturated monomer (a2) represented by Chemical Formula 9].

Specific examples of the monomer (a3) [ethylenically unsaturated monomer other than (a1) and (a2)] include, for example, monomers commonly used in radical polymerization. , Methyl-, ethyl-, isopropyl-, n-butyl-, isobutyl-, n-amyl-, isoamyl-,
n-hexyl-, 2-ethylhexyl-, octyl-,
Acrylic or methacrylic esters such as decyl-, dodecyl-, octadecyl-, cyclohexyl-, phenyl- and benzyl-; vinyl esters such as vinyl acetate and vinyl propionate; acrylonitrile;
Methacrylonitrile and the like; styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene and other aromatic vinyls; acrylamide, methacrylamide, N-methylolacrylamide; Amides such as N-methylol methacrylamide and diacetone acrylamide; vinylidene halides such as vinylidene chloride and vinylidene fluoride; ethylene, propylene, isoprene, butadiene, vinylpyrrolidone, vinyl chloride, vinylamide, chloroprene and the like.

Other specific examples of the monomer (a3) [ethylenically unsaturated monomer other than (a1) and (a2)] include:
For example, epoxy derivatives such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether can be used.

Other specific examples of the monomer (a3) [ethylenically unsaturated monomer other than (a1) and (a2)] include:
For example, alkylamino esters of acrylic acid or methacrylic acid such as N-methylaminoethyl acrylate, N-methylaminoethyl methacrylate, dimethylaminoethyl acrylate and dimethylaminoethyl methacrylate having an amino group in the molecule; monovinyl such as vinylpyridine Pyridines; vinyl ethers having an alkylamino group such as dimethylaminoethyl vinyl ether; unsaturated amides having an alkylamino group such as N- (2-dimethylaminoethyl) acrylamide and N- (2-dimethylaminoethyl) methacrylamide And the like.

Other specific examples of the monomer (a3) [ethylenically unsaturated monomer other than (a1) and (a2)] include:
For example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, ethylenically unsaturated carboxylic acids such as itaconic acid and fumaric acid can be mentioned, but when storage stability is particularly important, monovalent ions can be used. When chromic acid, which is a polyvalent ion, is added to the carboxylic acid, it is necessary to pay attention to the fact that an ionic reaction occurs between the two and the emulsion tends to aggregate. Therefore, when storage stability is important, it is generally not preferable to use an ethylenically unsaturated carboxylic acid as the monomer (a3).

[Reactive Surfactant] The reactive surfactant is a surfactant having a radical polymerizable double bond in a molecule, and has the same micelle-forming ability as a normal surfactant.
It has solubilizing power, emulsifying power and dispersing power. After the polymerization, it is copolymerized and incorporated into the polymer chain, and the dispersion of the produced emulsion particles can be stabilized. Reactive surfactants are well known to those skilled in the art, for example, as described on pages 1164 to 1166 of "129996 Chemical Products" (published by Nikkan Kogyo Nippo) in 1996. The present invention also includes the reactive surfactants described therein. Structurally, there are acrylic type, allyl type maleic acid type (fumaric acid type), itaconic acid type, etc. (References: AIST seminar hosted by the Industrial Technology Research Association) Technology development and application development of aqueous polymer dispersion 1
February 990). Commercially available reactive surfactants include:
For example, Aqualon RN series, HS series, BC series (polyoxyethylene alkylpropenyl phenyl ether and its sulfate) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adecaria soap series manufactured by Asahi Denka Kogyo Co., Ltd., and Sanyo Chemical Co., Ltd. Eleminor, Latemul manufactured by Kao Corporation, Antox series manufactured by Nippon Emulsifier Co., Ltd., and the like. In particular, a nonionic reactive surfactant, Aqualon RN series and Adecaria soap NE series are preferable.

[Amount of Reactive Surfactant] The reactive surfactant may not be used, but is usually preferably 0.01 to 10 parts by weight based on 100 parts by weight of the total monomers. And more preferably 0.1 to 5 parts by weight, most preferably 0.3 to 3 parts by weight.

When the amount is 0.01 part by weight or more, the polymerization stability during emulsion polymerization is further improved, and the mixing stability and storage stability when mixed with chromium are improved.
It is preferable because it hardly gels. In addition, when the amount is less than 10 parts by weight, the hydrophilicity of the coating film is appropriate, and rust prevention and water resistance are maintained. Further, as the reactive surfactant used in the present invention,
Nonionic ones are preferred, and the HLB value is preferably 10 or more, and the upper limit is 19. When the HLB value is 10 or more, the emulsion of the monomer is good, and the obtained emulsion has good mechanical stability and stability when an electrolyte such as chromic acid is added. The HLB value as used herein refers to a hydrophilic / lipophilic balance value, which is calculated by, for example, a method described on pages 60 to 64 of “Dispersion / Emulsification System Chemistry” published by Kogaku Tosho Co., Ltd.

[Emulsion Polymerization] The composition of the present invention is preferably polymerized by emulsion polymerization.

[Mechanical Stability] The composition obtained by the present invention is excellent in mechanical stability, and has a Marlon mechanical stability in which the amount of coarse particles remaining on # 100 mesh is 1000 p.
pm or less. When it is 1000 ppm or less, even when using an air spray, an airless spray, or the like when applying to the metal surface, nozzle clogging does not occur and uniform coating can be performed. Here, as a guideline of the test conditions of the Marlon mechanical stability, 100 g of the emulsion was subjected to # 100 mesh filtration, and the emulsion was subjected to 1 filtration under a load of 10 kg.
The test is carried out for 0 minutes, and thereafter, the emulsion is filtered through a # 100 mesh wire mesh, and the amount when the amount of the emulsion aggregate remaining on the wire mesh is measured is shown. The test method of the Marlon mechanical stability test described here is based on JIS K6828-19.
The test is performed according to the method of the mechanical stability test described in No. 96.

[Other Surfactants] Other surfactants besides the reactive surfactants that can be used in the present invention include those usually used in emulsion polymerization.

Specific examples of the anionic surfactant include, for example, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium alkyldiphenyletherdisulfonate, sodium alkylnaphthalenesulfonate,
Sodium dialkyl sulfosuccinate, sodium stearate, potassium oleate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether
Examples thereof include sodium tersulfate, sodium polyoxyethylene alkylphenyl ether tersulfate, sodium dialkyl sulfosuccinate, sodium stearate, and sodium oleate.

Nonionic surfactant Specific examples of the nonionic surfactant include, for example, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, Oxyethylene / oxypropylene block copolymer can be exemplified.

Cationic Surfactant Specific examples of the cationic surfactant include, for example, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride and the like.

Of these, nonionics and cationic surfactants are preferred. However, these surfactants
After forming the coating film, it bleeds from the coating film, which may reduce the corrosion resistance and water resistance. Even if used, it is preferably 1% by weight or less based on the total weight of all ethylenically unsaturated monomers.

[Polymerization temperature] The polymerization temperature varies depending on the type of the monomer used, the type of the polymerization initiator and the like, but usually, a temperature range of 30 to 90 ° C is appropriate.

[Polymerization Initiator] Specific examples of the polymerization initiator include, for example, persulfates such as hydrogen peroxide, ammonium persulfate and potassium persulfate; azo-based initiators such as azobisisobutyronitrile; Peroxide, te
organic peroxides such as rt-butyl hydroperoxide; metal ions such as persulfates or peroxides and iron ions; and sodium sulfoxylate, sodium pyrosulfite, and L-alcorbic acid. Redox initiators in combination with a reducing agent can be exemplified. These initiators are used at 0.1 to 4% by weight, based on the total weight of the total solids. Further, these polymerization initiators may be added all at once or continuously. Further, if necessary, a chain transfer agent such as mercaptans can be added.

[Average Particle Diameter of Resin Particles] The average particle diameter of the resin particles in the obtained emulsion is from 0.05 to 0.05.
It is preferably in the range of 0.5 μm. 0.05μm
If it is above, the viscosity of the emulsion is appropriate and the workability during use is good. In addition, since the emulsion has an appropriate specific surface area, the stability of the emulsion itself is maintained, and even if an electrolyte such as chromic acid is mixed, aggregation is unlikely to occur.
On the other hand, when the thickness is less than 0.5 μm, the film forming property when the emulsion is formed into a film is good, the fusion of the emulsion itself is easy to proceed, no coating film defects occur, and the rust resistance and water resistance are maintained.

[Nonvolatile Content of Emulsion] The emulsion used in the present invention has a nonvolatile content of 20 to 60.
% By weight. When the amount is less than 20% by weight, the emulsion usually has a low nonvolatile content at the time of use, and thus lacks practicality. On the other hand, when it exceeds 60% by weight, usually,
Emulsion has high viscosity and poor workability. Also,
It has poor stability during polymerization and has drawbacks such as gelation.
From the above, the nonvolatile content is preferably in the range of 20 to 60% by weight.

[Glass Transition Temperature of Copolymer Constituting Resin Particles] In the present invention, the glass transition temperature of the copolymer constituting the resin particles is preferably -20 to 50 ° C., and more preferably -10 to 50 ° C. -30 ° C. The glass transition temperature is measured by a method usually used for measuring a polymer. The glass transition temperature is measured by, for example, a rigid pendulum type viscoelasticity meter (model name: DD-OPA3) manufactured by A & D. Apply the emulsion on a steel plate, dry,
Provide for the test. The temperature condition at this time is -50 to 100 ° C.
, And the portion showing the maximum value of tan δ at this time is identified as the glass transition temperature. As another specific example of the measurement method, a differential scanning calorimeter (DSC)
Method. Differential scanning calorimeter (DSC)
The method is described in, for example, "Physical Properties and Evaluation Methods of Coating Films" (by Takeyuki Tanaka, published by Science and Engineering Publishing Co., Ltd.).

The glass transition temperature can also be calculated by the Fox equation. Since there is data that can be calculated by the Fox equation for typical monomers, if the glass transition temperature can be calculated, for special monomers such as the reactive surfactant (B) used in the present invention, There may be no data. However, even if (B) is used, (B)
Is used in a small amount, and a numerical value obtained by calculation assuming that the component (B) is not contained may be used as the glass transition temperature.

When the glass transition temperature of the copolymer is -20 ° C. or higher, the hardness of the obtained coating film is appropriate, no blocking occurs, and no fingerprint remains. On the other hand, when the glass transition temperature is 50 ° C. or lower, a sufficient coating film can be formed, and no coating film defects occur, and desired corrosion resistance and water resistance can be obtained. The data for calculating the glass transition temperature of each ethylenically unsaturated monomer is described in 168 to 168 of "Introduction to Synthetic Resins for Paints" of the Society of Polymer Publishing.
The values shown on page 169 are used as representative examples, and are not limited thereto.

[Mixing Ratio of Emulsion Composition and Chromic Acid Component] In the present invention, the resin is used by mixing with chromic acid. The mixing ratio of chromic acid and resin is not particularly limited, but preferably, for example, when CrO ₃ is used, the emulsion composition (solid content) according to the present invention is based on 1 part by weight of CrO _3. It is used in an amount of 0.05 to 50 parts by weight, preferably 1 to 40 parts by weight.

[Chromic Acid Component] The chromic acid component used in preparing the coating type chromate treatment liquid by mixing the chromic acid component with the emulsion composition of the present invention as a binder is not particularly limited. Usually, water-soluble chromates are used. Specific examples of the water-soluble chromate include, for example, sodium chromate, potassium chromate, ammonium chromate, magnesium chromate, potassium dichromate, calcium chromate, zinc chromate, manganese chromate, nickel chromate, Cobalt chromate, strontium chromate and the like can be mentioned. The ratio of hexavalent chromium to trivalent chromium in the chromic acid component used by mixing the emulsion composition according to the present invention with a binder is not particularly limited, but usually, hexavalent chromium.6% by weight is used. Parts / trivalent chromium / 4 parts by weight is preferred. These items are described in "Polymer Coat of Metal" edited by Surface Technology Association (Maki Shoten) 26-29
Page.

[Coating-type chromate treatment solution] The coating-type chromate treatment solution obtained by mixing the chromic acid component with the emulsion composition of the present invention as a binder is preferably used at a pH of 7 or less. If the pH is not less than 7, the rust preventing effect of chromium is not exhibited, and the effect cannot be expected.

[Coating with Coating-Type Chromate Treatment Solution] The emulsion composition for metal surface treatment according to the present invention is finally mixed with a chromate or other additives and the like, and is coated with a galvanized steel sheet or a zinc alloy-plated steel sheet. Is applied so that the film thickness is in the range of 0.3 to 5 μm. If it is less than 0.3 μm, no performance is exhibited. On the other hand, when the thickness exceeds 5 μm, the drying property is deteriorated. However,
There is no particular limitation as long as the heat is sufficient to evaporate the water.

[Additives] In the emulsion composition according to the present invention, additives which are added to ordinary emulsion compositions, for example, colloidal silica, defoaming agents, dispersants, thickeners, as long as the desired effects are not impaired , A pigment, a film-forming aid, an organic solvent, a plasticizer, a preservative, a bactericide, a rust preventive, etc. may be added.

[0066]

The present invention will be described in detail with reference to the following examples.
The present invention is not limited in any way by this. Parts and% indicate parts by weight and% by weight, respectively.

[Test Method] The emulsions obtained in Polymerization Examples 1 to 6 and Comparative Polymerization Examples 7 to 16 were mixed with hexavalent chromium and / or 3
A mixture of an inorganic compound such as valent chromium and water was applied to an electrogalvanized steel sheet, and dried with a hot-air drier so that the reached sheet temperature was 120 ° C. to obtain a test piece.

Mechanical Stability A Marlon-type mechanical stability test was performed on the emulsion obtained by polymerization in an unneutralized state. 100g emulsion
Was filtered through a # 100 mesh and tested under a load of 10 kg for 10 minutes. Thereafter, the emulsion was filtered through a # 100 mesh wire mesh to measure the amount of emulsion aggregates remaining on the wire mesh. ○ means 1000 ppm or less. × is 1000 ppm
More.

Fingerprint Resistance An emulsion diluted to a nonvolatile content of 20% by weight is applied to an electrogalvanized steel sheet and dried. The finger was pressed on the coating film to confirm the presence or absence of a fingerprint.

Chromic Acid Mixed Stability The emulsion was diluted to 20% by weight of non-volatiles,
Normal chromic anhydride is added to the emulsion nonvolatile matter at 10
% By weight. This formulation was placed in a constant temperature box at 40 ° C., and the stability of the formulation after 30 days was confirmed. ○ indicates that the gel is not formed. X: Gelled.

Corrosion resistance The above composition was applied to galvanized steel sheet. A test piece obtained by drying at a metal reaching temperature of 120 ° C. was subjected to a salt spray test for 1
The moisture resistance test was performed for 20 hours and for 200 hours.

[Polymerization Example 1] Stirrer, reflux condenser,
The following raw materials were charged into a reaction vessel equipped with a dropping device and a thermometer. 83.9 parts of pure water 0.2 parts of Adecaria Soap SE10N (reactive surfactant; hereinafter, abbreviated as SE10N) 0.2 parts of potassium persulfate was added at 70 ° C. in a nitrogen atmosphere with stirring.
To this is added 1% of the emulsifying monomer described below,
After leaving for 0 minutes, the remaining emulsified monomer was added over 4 hours. The composition of the emulsion monomer is as follows. Styrene (hereinafter abbreviated as ST) 47.0 parts 2Ethylhexyl acrylate (hereinafter abbreviated as 2EHA) 41.0 parts Polyethylene glycol monomethacrylate (PE9)
0. 10.0 parts of acetoacetoxyethyl methacrylate (hereinafter referred to as AAE)
2.0 parts pure water 40.0 parts Aqualon RN50 (reactive surfactant; active ingredient 65%, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.31 parts (1.5 parts based on 100 parts of monomer) ) An emulsion composition having a nonvolatile content of 45% and an average particle diameter of 0.17 µm was obtained. Table 1 shows the composition and glass transition temperature of the raw materials used, and Table 4 shows the evaluation results of the obtained emulsion composition.

[Polymerization Examples 2 to 5 and Comparative Polymerization Examples 6 to 16]
Polymerization was carried out in the same formulation as in Polymerization Example 1 at the monomer ratio shown in Table 1.

[Table legend] ST: Styrene MMA: Methyl methacrylate 2EHA: 2 Ethylhexyl acrylate PE200: Polyethylene glycol monomethacrylate (n = 4 to 5) Tg64 ° C PE90: Nippon Yushi Co., Ltd. PE90: Polyethylene glycol monomethacrylate (n = 2) ) Tg58 ° C manufactured by NOF Corporation HEMA: 2-hydroxyethyl methacrylate AAEM: acetoacetoxyethyl methacrylate T
g9 ° C Mac: Methacrylic acid DBS: Sodium dodecylbenzenesulfonate RN50: Reactive surfactant (HLB 17.9) Daiichi Kogyo Seiyaku Co., Ltd. RN20: Reactive surfactant (HLB 15.4) Daiichi Kogyo Pharmaceutical SE10N: Reactive surfactant manufactured by Asahi Denka Co., Ltd. Emulgen 840S: Polyoxyethylene octyl phenyl ether manufactured by Kao Corporation

[0075]

Table 1 Table 1 (1) Raw material composition, Tg, average particle diameter {Example 12} 3456 * monomer (a1) PE90 10 15 04 10 10 PE200 00 150 0 0 {Monomer (a2) AAEM 2 5 10 5 15} ────────────────────── Monomer (a3) HEMA 000 1000 ST 4745 035 435 MMA 0 500 000 2EHA 41 38 30 23 50 33 ───────────────────────────── Emulsified RN50 1.5 3.0 1.5 5.0 1.5 3.0 Emulsified RN20----- − ─── ＤＢ Prepared DBS--0.1---Prepared RN50---0.5--Prepared SE10N 0.2 0.1--0.5 0.1 ─粒度 Particle size (μm) 0.17 0.46 0.15 0.26 0.13 0.20 Non-volatile content (%) 45.0 25.0 50.0 45.0 45.0 42.9 ─ {Tg [° C] 25 19 32 -15 7} ━━━━━━━━━━━━━━━━━━

[0076]

[Table 2] Table-1 (2) Raw material composition, Tg, average particle diameter {Comparative Example 7 8 9 10 11 12 13 14 14 15 16} {Monomer (a1) PE90 40 0.5 10 0 10 10 10 10 10 10 PE200 00 100 100 0 100 0} {Monomer (a2) AAEM 10 100 35 0.5 10 10 2 210}単 量 体 Monomer (a3) HEMA 0000 000 000 ST 22 49.1 53 31.4 52.5 25 70 47 47 47 MMA 00 0 0 0 0 00 00 2EHA 28 40.4 37 23.6 37 55 10 4 13 10 ─────────────────────────────────── ─ Emulsified RN50 3.0 1.5 3.0 1.5 3.0 3.0 3.0-15.0 1.5 Emulsified emulsion-------3.0--Gen 840S ─────────────────────── DB Prepared DBS − − − 0.1 − 0.1 − − − − Prepared SE10N 0.05 0.2 0.2 − 0.2 − 0.1 0.1 0.1 0.005 ─────────────粒度 Particle size (μm) 0.36 0.17 0.17 0.20 0.18 0.20 0.23 0.20 0.20 0.63 Non-volatile content (%) 23.0 45.1 45.0 43.0 45.0 45.3 40.0 50.0 32.1 35.0 Tg [° C] 100 10 9 10 -25 60 4 13 10 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━

[0077]

[Table 3] Table-2 (1) Performance test results {Example 1 2 3 4 5 6} ━━━━━━━━━━━━━━━━━━━━━━━━━ Mechanical stability ○ ○ ○ ○ ○ ○ ───────────────指紋 Fingerprint resistance ○ ○ ○ ○ ○ ○ 安定 Storage stable ○ ○ ○ ○ ○ ○ 食 Corrosion resistance ○ ○ ○ ○ ○ ○ ────────湿 Moisture resistance ○ ○ ○ ○ ○ ○ ━━━━━━━━━━━━━━━━━━━━━━━ ━━━━

[0078]

Table 4 Table 1 (2) Raw material composition, Tg, average particle diameter {Example 7 8 9 10 11 12 13 14 14 15 16} ━━ Mechanical stability ○ × ○ ○ ○ ○ ○ ○ ○ ○ ──────────────────────────────────指紋 Fingerprint resistance ○ × ○ ○ ○ × ○ ○ × ○ ─────────────────────────────────── ─ Storage stability ◎ × ○ ○ ○ ◎ ◎ ◎ ○ ○ ──────────────────────────────────── Corrosion protection × × × × × ○ × × × × ───────────────────────────────────湿 Moisture resistance × × × × × ○ × × × × ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

[0079]

The composition emulsion for metal surface treatment according to the present invention is excellent in the mixing property with chromium, and the composition produced from the obtained emulsion is excellent in rust prevention. It was confirmed that. That is, the composition emulsion composition for metal surface treatment according to the present invention is excellent in suppression of elution of chromium, excellent in mixing with chromium, useful as a binder for metal surface treatment, and a composition for metal surface treatment. By doing so, excellent rust prevention properties are exhibited. Hereinafter, the effects of the invention of the composition emulsion composition for metal surface treatment according to the present invention will be listed. The composition emulsion composition for metal surface treatment according to the present invention is excellent in miscibility with a chromic acid component. The composition emulsion composition for metal surface treatment according to the present invention has excellent storage stability even after being mixed with a chromic acid component. Using the emulsion composition according to the present invention as a binder, a coating type chromate treatment solution obtained by mixing and preparing a chromic acid component is applied to a plated steel sheet such as a galvanized steel sheet, a zinc alloy plated steel sheet, and an aluminum plated steel sheet. Thereby, excellent rust prevention can be exhibited. Using the emulsion composition according to the present invention as a binder, a coating type chromate treatment solution obtained by mixing and preparing a chromic acid component is applied to a plated steel sheet such as a galvanized steel sheet, a zinc alloy plated steel sheet, and an aluminum plated steel sheet. Thereby, the amount of the oil agent used at the time of molding can be significantly reduced. Therefore, the degreasing step using an aqueous alkali solution for removing the oil agent can be omitted.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 22/00 C23C 22/00 Z

Claims (9)

[Claims] 1. An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles comprise an ethylenically unsaturated compound represented by the general formula (1): Saturated monomer (a1), acetoacetoxyethyl methacrylate (AAEM) represented by general formula (2) [Formula 1]
A copolymer obtained by copolymerizing (a2) and an ethylenically unsaturated monomer (A) containing an ethylenically unsaturated monomer (a3) other than (a1) and (a2), (A1), (a2) and (a3) are used in an amount of (a1), (a2) and (a3), and (a1) is 1 to 30 (A2) is 1 to 30% by weight, and (a3) is 98 to 40% by weight. (In the general formula (1), R _1a , R _1b , R _1c , R ₁₁ , R ₁₂ ,
R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ may each independently be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ and n ₃ are each independently And may be the same or different, and are 1 to 6, m ₁ , m ₂ and m ₃
May be independently the same or different;
0, and (m ₁ + m ₂ + m ₃ ) = 1 to 30.
Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. ) 2. An emulsion composition for metal surface treatment comprising a copolymer particle, wherein the copolymer particle is an ethylenically unsaturated compound represented by the general formula (1). A saturated monomer (a1) and acetoacetoxyethyl methacrylate (AAE) represented by the general formula (2) [Formula 2]
M) (a2) and an ethylenically unsaturated monomer (A) containing an ethylenically unsaturated monomer (a3) other than (a1) and (a2), with a reactive surfactant (B ) Together with a copolymer obtained by copolymerization,
(A1), (a2), (a3) and (B) use amount is
Based on the total weight of (a1), (a2) and (a3), (a1) is 1 to 30% by weight, and (a2) is
(A3) is 98 to 40% by weight.
And (B) is 0.01 to 10% by weight, an emulsion composition for metal surface treatment. (In the general formula (1), R _1a , R _1b , R _1c , R ₁₁ , R ₁₂ ,
R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ may each independently be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ and n ₃ are each independently And may be the same or different, and are 1 to 6, m ₁ , m ₂ and m ₃
May be independently the same or different;
0, and (m ₁ + m ₂ + m ₃ ) = 1 to 30.
Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. ) 3. An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles are composed of a repeating unit represented by the general formula (3): α1), a copolymer having a repeating unit (α2) represented by the general formula (4) [Formula 3] and a repeating unit (α3) other than (α1) and (α2). , (Α1), (α2) and (α3) have a weight ratio of (α
1), based on the total weight of (α2) and (α3),
(Α1) is 1 to 30% by weight, and (α2) is 1 to 30% by weight.
30% by weight, and (α3) is 98 to 40% by weight, the emulsion composition for metal surface treatment. (In the general formula (3), R _1a , R _1b , R _1c ,
R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ each represent
May be independently the same or different, and may include a hydrogen atom, a methyl group,
Or an ethyl group, and n ₁ , n ₂ and n ₃ may be each independently the same or different, and are 1 to 6;
₁ , m ₂ and m ₃ may be independently the same or different, each is 0 to 30, and (m ₁ + m ₂ + m ₃ ) = 1
~ 30. Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. ) 4. An emulsion composition for metal surface treatment comprising copolymer particles, wherein the copolymer particles are composed of a repeating unit represented by the general formula (3): α1), a repeating unit (α2) represented by the general formula (4) [Formula 4], a repeating unit (α3) other than (α1) and (α2), and a repeating unit (β) having a surface active function
Comprising a copolymer having (α)
1) The weight ratio of (α2) and (α3) is (α1),
Based on the total weight of (α2) and (α3), (α
1) is 1 to 30% by weight, and (α2) is 1 to 30% by weight.
% By weight, (α3) is 98 to 40% by weight,
(Β) is 0.01 to 10% by weight, an emulsion composition for metal surface treatment. (In the general formula (3), R _1a , R _1b , R _1c , R ₁₁ , R ₁₂ ,
R ₂₁ , R ₂₂ , R ₃₁ and R ₃₂ may each independently be the same or different and are each a hydrogen atom, a methyl group or an ethyl group, and n ₁ , n ₂ and n ₃ are each independently And may be the same or different, and are 1 to 6, m ₁ , m ₂ and m ₃
May be independently the same or different;
0, and (m ₁ + m ₂ + m ₃ ) = 1 to 30.
Here, m ₁ , m ₂ and m ₃ indicate the total number of the respective repeating units, and include not only the case of the block-like bonding structure but also the case of the random-like bonding structure. ) 5. The metal according to claim 1, wherein the ethylenically unsaturated monomer (a3) or the repeating unit (α3) has no carboxyl group. Emulsion composition for surface treatment. 6. The copolymer according to claim 1, wherein the copolymer has a glass transition temperature of −20 to 50 ° C.
6. The emulsion composition for metal surface treatment according to any one of claims 1 to 5. 7. The copolymer particles having a particle size of 0.05 to 0.5 μm
Characterized by having an average particle diameter of
The emulsion composition for metal surface treatment according to any one of claims 1 to 6. 8. A method for treating the surface of a steel sheet, comprising using a mixture of the emulsion composition for metal surface treatment according to claim 1 and chromic acid for coating a steel sheet. 9. A surface-treated steel sheet obtained by the method for treating a steel sheet according to claim 8.