JPS60221450A - Metal surface treatment composition - Google Patents

Abstract

PURPOSE:The titled composition providing metal surface with high corrosion resistance and coating substrate properties, having improved adhesivity to metal surface, processing properties of deep drawing, and anti-block properties, obtained by blending water-dispersible silica with a specific cationic, ampholytic ionic acrylic resin, etc. CONSTITUTION:A metal surface treatment composition obtained by blending (A) 0.5-250g calculated as SiO2 of water-dispersible silica, colloidal silica, preferably having 5-100mmu particle diameter, with (B) 0.5-600g cationic and/or ampholytic ionic acrylic resin derived from a multi-layer structural copolymer having >=15 deg.C Tg of core part and <=10 deg.C Tg of the outermost shell, obtained by subjecting 0.1-10wt% alkoxysilane containing a polymerizable unsaturated group, 0- 20wt% polymerizable unsaturated carboxylic acid, 20-99wt% (meth)acrylic acid alkyl ester (1-8C), and 0-40wt% copolymerizable monomer to multi-stage emulsion polymerization, and <=700g total amounts of a chromium compound, acrylic resin or a hydrolyzate of a tri- and/or dialkoxysilane compound, based on 1l composition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to metal surface treatment compositions. Specifically, it relates to a metal surface treatment composition that provides high corrosion resistance and paint base properties to metal surfaces, has excellent adhesion to metal surfaces, has excellent deep drawing workability, and has excellent blocking resistance. It is something.

Conventionally, chromate treatment or phosphate treatment has been carried out for the purpose of imparting corrosion resistance to metal surfaces and providing coating base properties to improve adhesion with paints.

Among these, the chromate treatment method has fairly good corrosion resistance, but the coating base properties and deep drawing workability are insufficient, and the phosphate treatment method has disadvantages such as insufficient corrosion resistance and deep drawing workability. have. Various methods have been proposed to improve these methods, but they have problems in terms of performance and workability.

In view of the current situation, the inventors of the present invention have filed a patent application in 1983-14.
33. As No. s9, we proposed a metal surface treatment composition consisting of a specific ratio of water-dispersible silica, a hydrolyzate of tri- and/or dialkoxysilane compounds, a cationic resin and/or zwitterionic resin, and a chromium compound. Although this metal surface treatment composition is certainly excellent in corrosion resistance and coating base properties and workability, it is not always satisfactory in terms of drawing workability and blocking resistance.

The inventors of the present invention have conducted extensive research to solve these current problems, and as a result, have been able to obtain a metal surface treatment composition that is extremely excellent in terms of drawing workability and blocking resistance.

Therefore, an object of the present invention is to provide a metal surface treatment composition that imparts high corrosion resistance and coating base properties to the metal surface, has excellent adhesion to the metal surface, and also has excellent deep drawability and blocking resistance. It is something.

That is, the present invention provides metal surface treatment composition 1t4, water-dispersible silica (I)'t810. Convert to 0.5~2
Amount in the range of 50f 1 Alkoxysilane compound having a polymerizable unsaturated group (a) 0°1 to 10% by weight 9 Polymerizable unsaturated carboxylic acid (b) 0 to 20% by weight, the number of carbon atoms in the alkyl group is 1 to 1 8 (meth)acrylic acid alkyl ester (
c) 20 to 99% by weight, monomer (d) copolymerizable with these 0 to 40% by weight (however, (a), (b),
The sum of (c) and (d) is 100% by weight. ) A cationic copolymer derived from a multilayer structure copolymer whose core portion has a Tf of 15°C or more and an outermost shell portion has a Tf of 10°C or less. and/or amphoteric ionic acrylic resin (■) (hereinafter referred to as acrylic resin (n)) @ O, S ~ 600f
chromium compound (m) in an amount in the range of 70 to 50 t, a cationic and/or amphoteric acrylic resin (■) with a Tf of 10°C or more (hereinafter referred to as acrylic resin (IV ) amount in the range of 1-0 to 600t,
and a hydrolyzate (V) of a tri- and/or dialkoxysilane compound (hereinafter referred to as a hydrolyzate (V)) is
Contains an amount in the range of θ to 200f in terms of iol, provided that (I) and (n).

The total of (III), (IV) and (, V) is 700
The present invention relates to a metal surface treatment composition characterized in that it does not exceed r'i.

The water-dispersible silica (I) used in the present invention is generally a condensation product of silicic acid and is colloidal silica, and preferably has a particle size of 5 to 100 mm. As such water-dispersible silica (I), for example, as a commercial product “°
"Snowtex O", "Snowtex N", "Snowtex NC8J".

"Snowtex 20 J, rSnowtex C"
(manufactured by Ichidai Kagakusha), r Cataloid
S.N.J.

r Cataloid 81- soo J (above,
(manufactured by Catalysts & Chemicals Co., Ltd.), etc. Also, surface-treated colloidal silica, such as 7j r C
Ataloid 8A J (manufactured by Catalysts Kagaku Kogyo Co., Ltd.) can also be used. These may be used as is, or in order to improve their dispersibility in the metal surface treatment composition,
The water-dispersible silica (I) may be surface-treated in advance with an acrylic resin (I[) or an amine such as a quaternary ammonium salt, which is another essential component of the present invention, or an aziridine such as ethyleneimine. Derivatives of water-dispersible silica (1)
It may also be used by grafting onto a surface.

The water-dispersible silica (I) is contained in an amount ranging from 0.5 to 250 f per metal surface treatment composition 1 of the present invention.

If the amount is less than 0.5f, the effect obtained will be insufficient, and if it is used in an amount exceeding inverse C22502, workability will deteriorate, and both are not preferred.

The acrylic resin (II) used in the present invention is an alkoxysilane compound (a) having a polymerizable unsaturated group.
1-10% by weight Polymerizable unsaturated carboxylic acid 0-2
0 weight N%, the number of carbon atoms in the alkyl group is 1 to 8 (meta)
Acrylic acid alkyl ester (c) 20-99%
, 0 to 40% by weight of monomer (d) copolymerizable with these (
However, the total of (a) @(b) *(C) and (d) is 100% by weight. ) A cationic copolymer derived from a multilayer structure copolymer whose core portion has a Tf of 15°C or more and an outermost shell portion has a Tf of 10°C or less. and/or a zwitterionic acrylic resin. The multistage emulsion polymerization referred to here is, first,
From the monomer ash, some components are added to the Tf of the polymer.
is selected so that the temperature is 15°C or higher, and some of these components are emulsion polymerized as the first stage by a known emulsion polymerization method, and the resulting polymer is The remaining monomer components used in the first stage may be used for two-stage polymerization, or they may be appropriately divided for three or more stages of polymerization.Then, the polymer with the composition of the final stage is This is called the outer shell portion.In the present invention, the outermost shell portion T
It is necessary that f is 10°C or less. As multi-stage emulsion polymerization, generally 2 to 3 stages of polymerization are used, and the ratio of the window part to other parts is 10:90 to 90.
: It is preferable to polymerize within a weight and ratio range of 10.

A polymer obtained by such a method is referred to as a multilayer structure copolymer in the present invention.

A specific example of the polymerizable monomer component constituting the multilayer structure copolymer of the present invention is vinyldimethoxymethylsilane as the alkoxysilane compound (a).

Vinyltris(β-methoxyethoxy)silane, vinyltriethoxy7silane, vinyltrimethoxysilane, γ-
Examples include methacryloxyglobiltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and the like. One type or a mixture of two or more of these monomers is used in an amount of 0.1 to 10% by weight based on the total monomer component. If it is less than 0.1%, the adhesion to the substrate and crosslinking properties will be insufficient, and if it exceeds 10% by weight, crosslinking will proceed too much and it will not be economical.

Typical examples of polymerizable unsaturated carboxylic acids (b) include:
Examples include acrylic acid, methacrylic acid, and itaconic acid. 1 m or a mixture of two or more of these monomers is used in an amount of 0 to 20% by weight based on the total monomers. Does polymerizable unsaturated carboxylic acid have zwitterionic properties in resin? It is used as a monomer to impart cationic properties or to introduce cationic properties through a post-reaction, but if it exceeds 20% by weight, the water resistance of the resin will deteriorate, which is not preferred. Typical examples of (meth)acrylic acid alkyl esters (C) in which the alkyl group has 1 to 8 carbon atoms include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
Examples include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and butyl methacrylate. One type or a mixture of two or more of these monomers is used in an amount of 20 to 99% by weight of the total monomer component.

Monomers (d) copolymerizable with these include α-olefins such as ethylene, propylene, and isobutylene, vinyl chlorides such as vinyl chloride and vinyl bromide, and vinyl cyanides such as acrylonitrile and methacrylonitrile. , vinyl esters such as vinyl acetate, propio, and vinyl chloride; aromatic vinyls such as styrene, vinyltoluene, and α-methylstyrene; Diethylaminoethyl acrylate, dimethylamine ethyl methacrylate, diethylaminoethyl methacrylate, glycidyl acrylate, acrylamide, methacrylamide.

Examples include N-methylol acrylamide. One type or 2 m or more of these monomers can be used to make the multilayer structure copolymer cationic and/or zwitterionic, and to satisfy the requirements for Tt of the window portion and the outermost shell portion. It is used in an amount of 0 to 40% by weight of the total body composition. The multilayer structure copolymer is a special acrylic resin that contains all hydrolyzable silicon compounds in its molecules, but it also has a Tt of 15°C or more in the window part and a Tf of the outermost shell part. 10
It is important that the temperature is below ℃. fc and Tf shown here indicate the total glass transition point of the copolymer, and it is preferable to actually measure the value, but as another method, Fox (F
OX) r Bull, Am, physics+ S
oc, J Vol. 1, No. 3, p. 123 (1956). If the Ti in the window portion is less than 15° C., the strength of the resulting coating film will be low, and the coating film will tend to become too soft when heated at VcL. Therefore, if the metal material coated with the composition is, for example, a steel plate, it is likely to cause blocking when wound up into a coil, which poses a problem in terms of work. The outermost shell portion must have a Tf of 10° C. or less. If the temperature exceeds 10° C., when applied to a metal material, film defects are likely to occur even if the film is formed at a low temperature, and sufficient performance cannot be expected in many cases.

The acrylic resin (n) has cationic nitrogen in the molecule derived from such a multilayer structure copolymer. Typical cationic resins include, for example, the resins listed in items (1) to (3) below.

(1) Co-containing one or more selected from vinyl compounds containing amiddiester foundations such as dialkylaminoalkyl (meth)acrylates, and cationic nitrogen-containing vinyl compounds such as vinylpyridine, vinylimidazole or their salts. A resin obtained by polymerization.

(2) A resin in which an acrylic resin copolymerized with glycidyl (meth)acrylate or chloromethyl methacrylate is cationized with dimethylamine, diethylamine, ethylenediamine, etc.

(3) A resin containing an aminomethyl group obtained by reacting an acrylic resin copolymerized with p-chloromethylstyrene and an amine and/or a polyamine.

In addition, amphoteric ionic resin is a resin having cationic nitrogen and anionic carboxyl group in the molecule, and includes, for example, the resins shown in the following items (4) to (6). I can do it.

(4) A resin in which a carboxyl group, which is an anionic group, is introduced into the cationic resin of items (1) to (3) above by a known method (for example, using chromium acetic acid or the like).

(5) Carboxyl group-containing (meth)acrylic resin and ethyleneimine, phlopyleneimine, hydroxyethylethyleneimine, cyanoethylethyleneimine, 1.
A resin containing an amphoteric ionic group obtained by reaction with an aziridine compound such as 6-hexamethylene diethylene urea or a basic nitrogen-containing alkylating agent such as glycidylamine or a salt thereof.

(6) One or more basic nitrogen-containing vinyl compounds such as dialkylaminoalkyl (meth)acrylate, vinylpyridine, vinylimidazole, or their salts, and (meth)acrylic acid, crotonic acid, or maleic acid. A copolymer obtained as all essential components of one or more carboxyl group-containing vinyl compounds such as acids.

etc. can be mentioned.

Among these acrylic resins (]l), No. (1)
The resins shown in Items and Items (5) are the resins (n
) is valid for %.

In the present invention, the acrylic resin (If) is
Various cationic resins and/or amphoteric ionic resins can be used as exemplified in items (1) to (6) above.

However, in the case of a cationic resin, the amount of cationic nitrogen measured by a commonly known method such as colloid titration or conductivity titration is in the range of 0.01 to 5 mmol per 1 part of the resin. It is desirable that there be.

In the case of amphoteric ionic resins, the amount of cationic nitrogen and the amount of ionizable carboxyl groups (these amounts can also be measured by colloid titration, conductivity titration, etc.).

) are desirably in amounts ranging from 0.01 to 5 mmol, respectively, per 1f of the resin. This range? If this occurs, the effect of the metal surface treatment composition will be insufficient, which is not preferable.

When using the acrylic resin (n)' in the present invention, it may be used as it is, or it may be added with one of the cationic nitrogen atoms.
Part or all of 7C used as a salt or quaternary ammonium salt of a mineral or organic acid such as hydrochloric acid, nitric acid, phosphoric acid, formic acid, etc.
It is also possible to use basic substances such as ammonia, amines, and polyamines in addition to gold. Acrylic resin (n
) is 0.5 to 6 per metal surface treatment composition 1 of the present invention.
00 f, preferably in the range of 1 to 400 t.

If the amount is less than 0.5 part, the adhesion between the resulting metal surface treatment composition and the metal surface will be insufficient. On the other hand, when a large amount exceeding 600f is used, the liquid stability of the composition deteriorates.

Chromium compounds (
III) is generally well-known Cr0j.

Cr(NO3)3, CrC4, Cr, (804)
, @ -18H,O*CrPO4.6H,0; chromates such as potassium chromate and ammonium chromate; potassium dichromate.

Water-soluble chromium compounds such as dichromates such as ammonium dichromate and sodium dichromate; water-insoluble chromium compounds such as strontium chromate, lead chromate, and zinc chromate can be used. Among them, water-soluble chromium compounds such as chromic anhydride and chromate 9 dichromate are preferred because they improve corrosion resistance even in small amounts. These chromium compounds (III) may be used alone or in combination of two or more, but the metal surface treatment composition 1149 of the present invention
It is contained in an amount ranging from 0 to 501 F, preferably from 0.1 to 20 t.

Next, acrylic resin CI%') added as necessary
is a cationic and/or amphoteric acrylic resin with a T1 of 10°C or higher, which can be obtained by various conventionally known emulsion polymerization methods, and representative examples include the above-mentioned (1) to Resins such as those described in each item (6) are used, and among them, resins such as those shown in item (1) or (5) above are preferred. However, the acrylic resin (
It is not necessary to have a multilayer structure like n). In the acrylic resin (IV), the amount of cationic nitrogen is preferably in the range of 0.01 to 3 mmol, more preferably 0.01 to 1 mmol, per 1 of the resin. In addition, in the case of amphoteric ionic resins, the prevalence of cationic nitrogen and the amount of carboxyl groups that can be anionized depend on the resin l? 0.01 to 3 per each
Preferably, the amount is in the range of millimole or even 0.01-1 mmol. If it is outside this range, the effect as a metal surface treatment composition will be insufficient, which is not preferable.

The acrylic resin (IV) is contained in an amount ranging from 0 to 600 tons per 1 part of the metal surface treatment composition, and has the function of completely improving the blocking resistance when wound around the entire coil of the treated steel sheet. It has little crosslinking and is thermoplastic, making it easy to draw. It also has the ability to improve. It also works to improve the water resistance of the paint film.

In the present invention, a hydrolyzate (V) of a tri- and/or dialkoxysilane compound is added as necessary, and the tri- and/or dialkoxysilane compound has one or two atoms per silicon atom. A silane compound in which an organic group and three or two alkoxy groups are bonded. Specific examples include vinyldimethoxymethylsilane, methyltriethoxysilane, vinyltriethoxysilane, vinyl-tris-(β-methoxyethoxysilane), and vinyltris-(β-methoxyethoxysilane). ) silane, r-methacryloxypropyltrimethoxysilane.

β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, r-crisidoxypropyltrimethoxysilane, r-chloropropyltrimethoxysilane, r
-Mercaptopropyltriethoxysilane, r-7minopropyltriethoxysilane, N-(β-aminoethyl)-r-aminopropyltrimethoxysilane, r-ureitopropyltrimethoxysilane, r-aminopropyl Methyljethoxysilane, γ-chrysidoxybrobylmethyldiethoxysilane, r-mercaptopropylmethyldimethoxysilane, γ-(3-aminoethyl)-aminopropylmethyldimethoxysilane, r-chloropropylmethyldimethoxysilane etc. can be mentioned.

In order to obtain the hydrolyzate (V)' of these tri- and/or dialkoxysilane compounds, hydrolysis can be carried out in a mineral acid such as hydrochloric acid, phosphoric acid or sulfuric acid, or an organic acid such as formic acid or acetic acid by a conventional method. good. At this time, hydrolysis may be performed in the coexistence of water-dispersible silica (I), or may be performed alone. In addition, in some cases, in the coexistence of acrylic resin (n),
Or water-dispersible silica (I) and acrylic resin (II)
) is hydrolyzed in the coexistence of both? You may go. These hydrolysates (V) are S t O
, is used in an amount in the range of 0 to 200 f. 2
When used in an amount of 0.002 or less, it works to further improve blocking resistance, corrosion resistance, solvent resistance, water resistance, etc.

Water-dispersible silica (I), acrylic resin (■).

Chromium compound (■), acrylic resin (IV), and hydrolyzate of tri- and/or dialkoxysilane compound (
When obtaining a composition consisting of the above-mentioned specific ratios of V), these and water may be mixed in any order. Further, as a mixing method, a method of energization can be used.

Is the scope of the present invention limited by these mixing orders and methods? It's not something you receive. Furthermore, tannic acid, gallic acid, thiourea, etc., which are generally known as components of rust preventive agents, may be added to the metal surface treatment composition of the present invention.

Furthermore, by using a water-insoluble or water-dispersible inorganic substance in combination, it is possible to improve the surface condition and corrosion resistance of the metal to be coated. Finely powdered silica is released as such a water-soluble or water-dispersible inorganic substance.

Merck, quince earth, calcium carbonate, clay.

Titanium dioxide, aluminum silicate, aluminum phosphate, alumina sol, magnesia sol.

Examples include titania sol and zirconia sol. Further, the amount used is preferably 50 f or less per metal surface treatment composition 1 of the present invention.

The metal surface treatment composition of the present invention obtained in this way is
Water-dispersible silica (1) and acrylic resin (n) work together to provide excellent water resistance, alkali resistance, corrosion resistance, paint base properties, and drawing workability. Compound (■).

When appropriately added to the acrylic resin (IV) or the hydrolyzate (V) of tri- and/or dialkoxysilane, it exhibits even better drawability, blocking resistance, and corrosion resistance.

The metal surface treatment composition of the present invention includes metals such as iron, Steel 1 alloy steel, zinc, zinc alloy, aluminum, aluminum alloy; and iron, Steel 9 alloy steel, and zinc.

It can be used for metal materials such as fully coated metal coatings such as zinc alloy, aluminum, and aluminum alloy.
Among these, it exhibits particularly excellent effects on metal materials fully plated with zinc or alloyed zinc. Also,
These metal materials can be used in various shapes such as a plate, a pipe, and a line.

To use the metal surface treatment composition of the present invention, at room temperature to 1
The surface of the metal material at 50°C, preferably from room temperature to 70°C, is dented, spray coated, or roll coated.

After coating by dipping or other methods, it is only necessary to dry it at a temperature above room temperature for several seconds to several minutes. At that time, the thickness of the coating film obtained is 0.
．． 1. A sufficient effect can be obtained with a thin film of about 5 μm. The metal materials thus obtained and treated with the composition have excellent water resistance, alkali resistance, solvent resistance, corrosion resistance, paint base properties, and drawing workability, making them suitable for various uses. It's a useful product.

Hereinafter, the present invention will be explained in more detail using all specific examples, but the present invention is not limited to Example 1 in any way. In addition, in the reference examples and examples, ``chi'' indicates weight %.

Example 1 466 parts of deionized water and 2 parts of an anionic emulsifier were added to a flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube, and a dropping rotor, and the temperature was raised to 70°C. Next, after adding 2 parts of ammonium persulfate, 28 parts of styrene. A monomer mixture consisting of θ parts, 27.5 parts of methyl methacrylate, 39 parts of butyl acrylate, 6 parts of acrylic acid and 0.5 parts of vinyltrimethoxysilane was added over 1 hour to perform the first stage emulsion polymerization. Ta. After further polymerization for 1 hour, 30 parts of styrene and 60 parts of butyl acrylate were added.
Department.

A monomer mixture consisting of 9 parts of acrylic acid and 1 part of vinyldimethoxymethylsilane was added for t-1 hours to carry out the second stage emulsion polymerization (constituting the outermost shell part), and the T of the core part was
A multilayered polymer having a temperature of about 19°C and an outermost shell of about -12°C was obtained. Next, 7 parts of ethyleneimine and 16 parts of gold in deionized water were added to this polymer at 50°C. Water-dispersible silica (I) (
Product name: Snowtex O, 5i0220% product) 100
The water-dispersible silica (1) was prepared by adding 1 part of 5% chromic anhydride and 2 parts of chromic anhydride, and then oxidizing the whole mixture with deionized water.
A metal surface treatment composition containing a total of 180 l/l of the zwitterionic acrylic base [I[] and a total of 0.1 f/l of the chromium compound (m) was obtained. This one product is referred to as composition (A).

Example 2 Following the same method as in Example 1, starting with 55 parts of methyl methacrylate, 39 parts of butyl acrylate, 5.5 parts of acrylic acid, and 015 parts of γ-methacryloxyglobil trimethoxy 7ran in the first stage. The second stage consists of 4 parts of methyl methacrylate, 81 parts of butyl acrylate, 14 parts of acrylic acid, and 1 part of r-methacryloxypropyltrimethoxysilane, the Tf of the window part is about 24 °C, and the outermost shell part After synthesizing a multilayer polymer with a nominal temperature of -35°C,
Cationization reaction with 6 parts of ethyleneimine? After neutralization with ammonia, a zwitterionic acrylic resin (■) with a solid content of 30% and a pH of 9.0 was obtained. Water-dispersible silica (
,1') (Product name, Snowtex C, 5in120%
water-dispersible silica ('I) by mixing 200 parts of the acrylic resin (II), 20 parts of 5% anhydrous chromic acid, and bringing the total volume up to 11 with deionized water. SiO! 40/1, acrylic resin (II) total 1609/1 and chromium compound (III)
A metal surface treatment composition containing i 1 t/ was obtained. This composition will be referred to as composition (B).

Example 3 Nonionic emulsifier and cationic emulsifier as emulsifier?
The same method as in Example 1 was used except that 55 m of methyl methacrylate was used in the first stage.

The second stage consists of 33 parts of butyl acrylate, 10 parts of acetate of dimethylaminoethyl methacrylate, and 2 parts of γ-methacryloxypropyltrimethoxysilane, and the second stage contains 5 parts of methyl methacrylate and 75 parts of butyl acrylate.
5 parts, acetate of dimethylaminoethyl methacrylate
14 parts acrylonitrile and 1 part γ-methacryloxypropyltrimethoxysilane at about 27°C.

Tf of the outermost shell part is about -30℃, solid content is 30%, pH
A 5.0 cationic acrylic resin (II) k was obtained.

Next, 300 parts of water-dispersible silica (I) (trade name: Snowtex C, Sin, 20% product) was treated with a quaternary ammonium salt.

To the water-dispersible silica (I) treated with the quaternary ammonium salt, 460 parts of the acrylic resin I) and 10 parts of 5-thichromic anhydride were added, and the whole was heated to 1tiC with deionized water to make the water-dispersible Silica (I) total sio, converted to 60 f/L, acrylic resin (II) i1
38f/ and chromium compound (III) k o,s
A metal surface treatment composition containing t/ was obtained. This composition is referred to as composition (C).

Example 4 Methyl methacrylate 6011R (200 parts of emulsion polymer with solid content of 40% Tf obtained from 38.8 parts of 2-ethylhexyl acrylate and 1.2 parts of acrylic acid at about 13°C - ethylene) After reacting with 0.57 parts of imine,
Neutralization with ammonia gave a zwitterionic acrylic resin (IV)' having a solid content of 40% and a pH of 8.5.

To this, 267 parts of the acrylic resin (1) obtained in Example 2, water-dispersible silica (I) (trade name, Snowtex C,
20 parts of Sing 20 parts and 1 part of 5 parts of chromic anhydride
Adding 0 parts and making the whole thing up to 1 ton with deionized water, F. 40 in terms of water-dispersible silica (I)'ksiot.
t/L, acrylic resin CTI)"Ir80t7t
A metal surface treatment composition containing a chromium compound (III) with a total of 0.5 f/11 and an acrylic resin (■) 'i 80 t/ was obtained. This composition is referred to as composition CD).

Example 5 In Example 4, a hydrolyzate of r-crisitoxypropyltrimethoxysilane was further added, and water-dispersible silica (
1-) is converted into SiOl and is 40 t/l.

Acrylic resin (II) k 8o t/l, chromium compound (m) vi-0.5 pit, acrylic resin (IV) 80 t/l and hydrolyzate (V) k S
5 in terms of i Ox? A metal surface treatment composition containing / was obtained. This composition is referred to as composition (E).

Comparative Example 1 In Example 1, the storage of methyl methacrylate, acrylic acid and vinyltrimethoxysilane was the same as in Example 1.
The ratio of styrene and butyl acrylate in the monomer composition was changed so that the Tf of the window part was about 0°C and the Tf of the outermost shell part was about 0°C, and the multilayer structure was After total polymer synthesis, water-dispersible silica (I) was converted to StO, 20 f/l using the same method fc as in Example 1.
A metal surface treatment composition containing a zwitterionic acrylic resin f180t/ and a chromium compound (III)'i 0.1t/ was obtained.

Comparative Example 2 In Example 2, the composition of the monomers used was completely mixed in the first stage and the second stage and emulsion polymerized in one stage, and Tf was about -12
Water-dispersible silica (I) kSTO was prepared in the same manner as in Example 2, except that the entire emulsion polymer was used.

Converted to 40 f/L, acrylic resin 160μ
A metal surface treatment composition containing chromium compound (III) k 1 y/ was obtained.

Comparative Example 3 Except for Example 4, in which all of the methyl methacrylate/2-ethylhexyl acrylate/acrylic acid copolymer having a Tt of 0°C was used instead of the amphoteric ionic acrylic resin (■) used. was prepared by the same method as in Example 4,
Water-dispersible silica (I)? sio, converted to 40 f/
A metal surface treatment composition containing an acrylic resin (II), a chromium compound (m), a chromium compound (m), and an acrylic resin was obtained.

Example 6 In Example 2, water-dispersible silica (I)' (r8i0
Convert to 1 and convert to 40? /L, acrylic resin (II)
A metal surface treatment composition containing f160f/ was obtained.

This composition? It is referred to as composition (F).

Comparative Example 4 In Comparative Example 2vc, water-dispersible silica CI) t-8i01 was prepared in the same manner as in Comparative Example 2 except that chromic anhydride was not used.
Converting to 40t/l, acrylic resin gold 160t
A metal surface treatment composition containing 7 was obtained.

Examples 7 to 12 and Comparative Examples 5 to 9 Chromate-treated commercially available electrogalvanized steel sheets with a thickness of 0.6 mm (trade name: ZINKOTE, manufactured by Nippon Steel Corporation)
Comparative Examples 1 to 5 were prepared using the compositions obtained in Examples 1 to 5.
Using each of the compositions obtained in step 3, after spray coating to a film thickness of 2.0μ, dry at 100°C for 60 seconds.
A surface treated plate was obtained. Table 1 shows the test results of these treated plates. The evaluation was conducted as follows.

01st corrosion resistance: All salt spray tests were conducted according to JISZ-2371K, and the white rust-generated surface & was evaluated by "Q".

o3T bending processability: The entire folded surface was crimped with adhesive tape and then peeled off, and evaluated using a 10-point (full score) method.

0 drawing workability: after oiling, 50 mm x 50 mm
After drawing to a depth of 30 mm using a square head of 500 kg of wrinkle suppressor, it was degreased, and the adhesive tape was crimped and peeled off to evaluate its inner and outer surfaces.

◎... No peeling, ○... Almost no peeling, △
...partially peeled off, ×...completely peeled off.

Blocking resistance: 50 m of treated plate coated on both sides
Cut it into a size of m x 5G mm, stack 4 pieces and make 50
After crimping for 20 minutes at a pressure of 1,000 degrees Celsius, the blocking property was measured.

◎: No blocking, ○: Slight blocking, △: Part of the coating film is blocked and peeled off.

×Full surface blocking O Paint adhesion II Commercially available melami/-alkyd resinffc
After baking 50% of the film at 90°C for 20 minutes to a film thickness of 25 μm, extruding it to a 77 mm film, crimping it with cellophane tape, and then peeling it off and evaluating it on a 10-point scale (full score).

The above test results show that the treatment composition of the present invention is excellent and that the treated galvanized steel is extremely useful.

Example 13 The composition (D) obtained in Example 4 was prepared using a commercially available zinc-aluminum alloy coated steel sheet (trade name: Super Zinc, manufactured by Nippon Steel Corporation) with a thickness of 0.6 mm. After treating the film to a film thickness of 2 μm, the T-corrosion resistance and blocking resistance were tested in the same manner as in Example 7. Commercially available zinc-aluminum alloy coated steel sheet No. 7 showed rust on the entire surface of TLC after 24 hours;
) No rust was observed even after 96 hours, and no abnormality was observed in the blocking test.

Patent applicant Nippon Steel Corporation Nippon Shokubai Chemical Co., Ltd.

Claims (1)

[Claims] 1. 0.5 to 2 in terms of water-dispersible silica (I) ksio per 11 of the metal surface treatment composition.
an amount in the range of 50f, an alkoxysilane compound (a) having a polymerizable unsaturated group;
0.1-10% by weight Polymerizable unsaturated carboxylic acid 0
-20% by weight, (Meme) acrylic acid alkyl ester (c) whose alkyl group has 1 to 8 carbon atoms, 20 to 99% by weight, monomer copolymerizable with these (a) o to 40% by weight ( However, the total of (a), (b), (c) and (d) is 100% by weight). Yes, Tf of the outermost shell part
Cationic and/or amphoteric acrylic resin (II
) io, an amount ranging from 5 to 6002, chromium compound (III) k an amount ranging from O to 501,
Cationic and/or zwitterionic acrylic resin (IV) with a Tf of 10°C or more i An amount in the range of 0 to 600f, and a hydrolyzate of tri- and/or dialkoxysilane compound (V) 'k 0 to 200 converted to stow
t, with the proviso that CI). A metal surface treatment composition characterized in that the sum of (n), (m), (IV) and (V) does not exceed 700f.