JP2002265476A - Metal corrosion-preventing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new zinc corrosion-preventing agent. SOLUTION: A salt formed from an aminoalkoxysilane compound and a mercaptoamidecarboxylic acid compound (salt), and/or a mixture of an aminoalkylalkoxysilane compound with a mercaptoamidecarboxylic acid compound (salt) have a high effect as a metal corrosion-preventing agent, especially a zinc corrosion-preventing agent, and is further useful at a point that a self- restoration effect against injuries can be expected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal corrosion inhibitor,
In particular, the present invention relates to a compound useful as a zinc corrosion inhibitor, a protective agent for a galvanized steel sheet or a galvanized steel material.

[0002]

2. Description of the Related Art Galvanized steel sheets and galvanized steel materials are widely used as materials for building materials, mechanical devices and home electric appliances. In these materials such as galvanized steel sheet and galvanized steel material, not only the surface is protected by painting or the like, but also the steel sheet and steel material are electrochemically protected by corrosion of zinc. It is important that the protective action by zinc occurs when the underlying steel sheet or steel material is exposed due to the end face or scratches of the material.

[0003] Zinc used in the galvanized steel sheet and the galvanized steel material is a metal which is easily ionized.
It is susceptible to slow erosion itself in normal use environments. However, this is not preferable in that it causes a decrease in the amount of zinc that can be used for protecting steel sheets and steel materials. In order to suppress such erosion of zinc, a technique of surface-treating a galvanized material such as a galvanized steel sheet or a steel material with chromates or the like may be used.

[0004]

There are several problems to be solved in the above-mentioned method for protecting a galvanized material which has been widely used for the purpose of preventing zinc erosion. When chromic acid treatment is performed to prevent erosion of zinc, a hexavalent chromium compound is used, but this hexavalent chromium compound is harmful. There is also a method of forming a zinc sulfide layer on the zinc surface by treating with hydrogen sulfide,
Hydrogen sulfide is toxic and has a bad smell, and cannot be expected to have a corrosion preventing effect due to a self-healing action when it is damaged.

On the other hand, a method of preventing corrosion with aminoalkylalkoxysilanes has been developed, and aminoalkylalkoxysilanes are considered to be promising as zinc corrosion inhibitors. In this case, silanols generated by the hydrolysis are polymerized to protect the zinc surface.

The present inventors electrochemically studied zinc surface-treated with aminoalkylalkoxysilanes. As a result, it was surprisingly found that in a weakly acidic aqueous solution containing carbonic acid (salt), the polarization resistance (Faraday resistance) of zinc surface-treated with aminoalkylalkoxysilanes was small. Usually, a small polarization resistance (Faraday resistance) means that the corrosion prevention ability is small. That is, it was considered that surface treatment with aminoalkylalkoxysilanes in a weakly acidic aqueous solution containing carbonic acid (salt) was not very effective in preventing zinc corrosion.

[0007] Carbonic acid (salt) itself is contained in natural water such as air or rainwater. Therefore, it is considered that improvement of the zinc corrosion prevention property of the surface treatment with aminoalkylalkoxysilanes is an important subject.

[0008]

Means for Solving the Problems The present inventors have intensively studied to improve the properties of a zinc corrosion inhibitor. As a result, the present inventors have found that mercaptoamide carboxylic acid (salt) is effective for improving the zinc corrosion prevention property of surface treatment with aminoalkylalkoxysilanes.
That is, the present inventors have found that mercaptoamide carboxylic acid (salt) and aminoalkylalkoxysilanes exhibit a favorable synergistic effect in preventing zinc corrosion.

Accordingly, the present invention is shown in the following [1] -
[7].

[1] A compound represented by the following structural formula (1).

[0011]

Embedded image

(Where n and n ′ are each independently an integer of 1 or more, m is an integer of 2 to 2n, and m ′ is 2 or more and 2
n is an integer of 1 or less, i is an integer of 1 or more, j is 0 or more (2i + 2− (z
+ k)) The following integers, k is an integer of 1 or more, z is an integer of 1 or more, and R represents a hydrogen atom or a hydrocarbon group. [2] The compound according to [1], which is represented by the following structural formula (2) among the compounds represented by the structural formula (1).

[0013]

Embedded image

(Wherein, n and n ′ are each independently an integer of 1 to 12; m is an integer of 2 to 2n; m ′
Is an integer of 2 or more and 2n 'or less, i is an integer of 1 or more and 30 or less, j
Represents an integer of 0 to 2i, and R represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. [3] The following structural formula (3)

[0015]

Embedded image

(Where n is an integer of 1 or more, m is 2
I is an integer of 1 or more, j is 0 or more (2i + 2
-(Z + k)) or less, k is an integer of 1 or more, z is an integer of 1 or more, and M represents a hydrogen atom or a metal atom. ). A mercaptoamide carboxylic acid (salt) represented by the following structural formula (4)

[0017]

Embedded image

(Where n ′ is an integer of 1 or more, m ′ is 2
An integer not less than 2n 'and R represents a hydrogen atom or a hydrocarbon group. A method for producing a compound, which comprises mixing the aminoalkylalkoxysilane represented by the formula (1).

[4] Mercaptoamide carboxylic acid (salt)
Has the following structural formula (5)

[0020]

Embedded image

(Where n is an integer of 1 to 12; m is an integer of 2 to 2n; i is an integer of 1 to 30; j is an integer of 0 to 2i; M is a hydrogen atom or a metal atom And the aminoalkoxysilane is represented by the following structural formula (4)

[0022]

Embedded image

(Where n 'is an integer of 1 or more and 12 or less, m' is an integer of 2 or more and 2n 'or less, and R is a hydrogen atom or a hydrocarbon group having 1 or more and 12 or less carbon atoms). The production method according to the above [3].

[5] The following structural formula (3)

[0025]

Embedded image

(Where n is an integer of 1 or more, m is 2
I is an integer of 1 or more, j is 0 or more (2i + 2
-(Z + k)) or less, k is an integer of 1 or more, z is an integer of 1 or more, and M represents a hydrogen atom or a metal atom. ). A mercaptoamide carboxylic acid (salt) represented by the following structural formula (4)

[0027]

Embedded image

(Where n ′ is an integer of 1 or more, m ′ is 2
An integer not less than 2n 'and R represents a hydrogen atom or a hydrocarbon group. And a aminoalkylalkoxysilane represented by the formula:

[6] Mercaptoamide carboxylic acid (salt)
Has the following structural formula (5)

[0030]

Embedded image

(Where n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, i is an integer of 1 or more and 30 or less, j is an integer of 0 or more and 2i or less, M is a hydrogen atom or a metal atom. And the aminoalkoxysilane is represented by the following structural formula (4)

[0032]

Embedded image

(Where n 'is an integer of 1 or more and 12 or less, m' is an integer of 2 or more and 2n 'or less, and R is a hydrogen atom or a hydrocarbon group having 1 or more and 12 or less carbon atoms). And the production method according to the above [5].

[7] A metal corrosion inhibitor comprising the following (a) and / or (b): (A) The compound according to the above [1] or [2] (b) The composition according to the above [3] or [4] [8] Zinc corrosion containing the following (a) and / or (b) Inhibitor. (A) The compound according to the above [1] or [2] (b) The composition according to the above [3] or [4] Note that the metal atom M mentioned here is a lithium atom, a sodium atom, a potassium atom, etc. In addition to the above, alkali metal, magnesium, calcium, strontium and other alkaline earth metal atoms and zinc, aluminum, iron, cobalt, nickel and other metal atoms also include ammonium. Ammonium means not only those obtained by adding hydrogen ions to ammonia but also those obtained by adding hydrogen ions to amines.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the present invention is a salt represented by the following structural formula (1).

[0036]

Embedded image

In the above structural formula, n and n 'are each independently an integer of 1 or more, m is an integer of 2 or more and 2n or less, m' is an integer of 2 or more and 2n 'or less, i is an integer of 1 or more, and j is 0 or more (2i + 2
-(Z + k)) or less, k is an integer of 1 or more, z is an integer of 1 or more, and R represents a hydrogen atom or a hydrocarbon group. Preferred conditions will be described.

The above salts can be obtained from aminoalkylalkoxysilanes and mercaptoamide carboxylic acids (salts).

The aminoalkylalkoxysilanes and mercaptoamic acids (salts) used in the present invention are described below.

The aminoalkylalkoxysilanes used in the present invention generally have the following structural formula (4)

[0041]

Embedded image

The minimum required conditions are that n 'is an integer of 1 or more, m' is an integer of 2 or more and 2n 'or less, and R is a hydrogen atom or a hydrocarbon group.

In the structural formula (4), Cn'Hm 'is a hydrocarbon chain. The upper limit of the number of carbon atoms n 'is moderate, but is usually an integer in the range of 1 to 12, and the corresponding number of hydrogen atoms m' is an integer of 2 to 2 n '. The number of carbon atoms n ′ of the preferably used hydrocarbon chain Cn′Hm ′ is generally about 1 to about 8 and particularly preferably the number of carbon atoms n ′
Is 1 or more and 6 or less. In the present invention As an example trimethylene chain - laden those with (-C ₃ H _6).

In the structural formula (4), R is a hydrocarbon group, and the upper limit of the number of carbon atoms is moderate, but usually 1 or more and 1 to 1
2 or less. In the surface treatment of zinc, since the -OR group bonded to the silicon atom is eliminated, the number of carbon atoms of the hydrocarbon group R is generally preferably at most 12 and is preferably 6 or less. Are preferably 3 or less, and 1 or 2 is most preferred.

In the silicon atom, three hydrocarbon groups R have --O
Although attached as R groups, they need not be identical. Thus, for example, -OCH ₃ group and -OCH ₂ CH ₃ groups can be attached to the same silicon atom. As a similar example of the —OR group bonded to the silicon atom, an —OH group may be considered, but it is generally considered to be unstable. However, since this similar example is also an important intermediate formed when the aminoalkylalkoxysilane is hydrolyzed, it is naturally included in one of the aminoalkylalkoxysilanes used in the present invention.

Particularly preferred aminoalkylalkoxysilanes meeting the conditions described herein include aminomethyltrimethoxysilane, aminoethyltrimethoxysilane, aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopentyltrimethoxysilane , Aminoalkyltrimethoxysilane such as aminohexyltrimethoxysilane, aminomethyltriethoxysilane, aminoethyltriethoxysilane, aminopropyltriethoxysilane, aminobutyltriethoxysilane, aminopentyltriethoxysilane, aminohexyltriethoxysilane, etc. Aminoalkyltriethoxysilane can be exemplified. Aminomethyltripropoxysilane, aminoethyltripropoxysilane, aminopropyltripropoxysilane, aminobutyltripropoxysilane, aminopentyltripropoxysilane, aminohexyltripropoxysilane, aminoheptyltripropoxysilane, aminooctyltripropoxysilane, aminononyl Aminoalkyltripropoxysilanes such as tripropoxysilane and aminodecyltripropoxysilane are also preferable specific examples. These are basic examples of aminoalkylalkoxysilanes, but some carbon atoms in the hydrocarbon chain Cn'Hm 'present in them may be replaced by other atoms such as nitrogen. Examples include N- (2-aminoethyl) 3-aminopropyltrimethoxysilane versus aminohexyltripropoxysilane.

The molecular structure of the mercaptoamide carboxylic acid (salt) used in the present invention generally has the following structural formula (3)

[0048]

Embedded image

## EQU5 ## The minimum required condition is that n is 1.
M is an integer of 2 or more and 2n or less, i is an integer of 1 or more, j is an integer of 0 or more (2i + 2- (z + k)), k is an integer of 1 or more, z is an integer of 1 or more M means a hydrogen atom or a metal atom.

In the above structural formula, k is an integer of 1 or more;
Although z can be described as an integer of 1 or more, practically, k is 3 or less, and z is preferably 3 or less. Specific combinations include k = 1, z = 1, and k = 2, z = 1
And k = 3, z = 1 and k = 1, z = 2 and k = 2, z = 2 and k
= 3, z = 2 and k = 1, z = 3 and k = 2, z = 3 and k =
3, z = 3, and the like. More preferably, k = 1, z
= 1.

That is, the molecular structure of the mercaptoamide carboxylic acid (salt) used in the present invention is more preferably the following (Structural Formula 5)

[0052]

Embedded image

Is represented by Here, the minimum necessary conditions are that n is an integer of 1 to 12; m is an integer of 2 to 2n; i is an integer of 1 to 30; j is an integer of 0 to 2i; Represents a hydrogen atom or a metal atom.

The mercaptoamide carboxylic acids (salts) represented by the structural formulas (3) and (5) are composed of a carboxylic acid residue and a mercaptoamine residue in molecular structure. Regarding the carboxylic acid residue, when k = 1 and z = 1 (Structural formula (5)), the results of the electrochemical measurement for suppressing ionization of zinc show that the larger the number of carbon atoms i is, the better. Have been. For example, it has been observed that those having 10 carbon atoms are more effective than those having 6 carbon atoms. Therefore, when a large amount can be used as a component of the zinc corrosion inhibitor composition, it is possible that the number of carbon atoms i is 1 or more.
The lower limit of the number of carbon atoms i of the class is considered to be about 6, more preferably 8 or more, and still more preferably 10 or more. The upper limit of the number i of carbon atoms is considered to be moderate, but practically it is considered to be about 30, preferably 25, and more preferably about 20. These upper limits are given as a guide in consideration of the reasons for synthesis, and the number of carbon atoms may be greater than those shown here if the raw materials for synthesis are easily available.

It is considered that the consideration of the range shown here can also be applied to cases other than k = 1 and z = 1 in the structural formula (3). Therefore, although the number of carbon atoms i can be from 1 or more, the range of the number of carbon atoms i is practically from 2 to 30 on the synthetic technology, preferably from 6 to 30 and more preferably from 8 to 25. Hereinafter, it is more preferably considered to be about 10 or more and about 20 or less.

The number j of hydrogen atoms corresponds to the number i of carbon atoms. The minimum value is 0 and the maximum value is represented by the structural formula (3)
{2i + 2- (z + k)} in the case of, and 2i in the case of the structural formula (5)
It is.

Specific examples of the hydrocarbon chain —C _i H _j — include methylene chain, ethylene chain, propylene chain, butene chain, pentene chain, hexene chain, heptene chain, octene chain and the like.
₂ ) aliphatic hydrocarbon chain represented by i-, cyclobutene chain, cyclopentene chain, cyclohexene chain, cycloheptene chain, cyclooctene chain, cyclononene chain, cyclodecene chain, cycloundecene chain, cyclododecene chain, etc.
_{(C i H 2i-2)} - or cycloaliphatic hydrocarbon chain having a cyclic structure represented by a phenylene chain -C ₆ H ₄ -, naphthalene chain -C
₁₀ H ₆ -or -C ₆ H ₂ (CH ₃ ) _2- , -C ₆ H (CH ₃ ) _3- , -C _{6
(CH 3) 4 -, -C} 6 H 3 (C 2 H 5) -, - C 6 H 2 (C 2 H 5)
₂ −, −C ₆ H (C ₂ H ₅ ) ₃ −, −C ₆ (C ₂ H ₅ ) ₄ −, −C ₆ H _{3
(C 3 H 7) -,} - C 6 H 2 (C 3 H 7) 2 -, -C 6 H (C 3 H 7)
₃ −, −C ₆ (C ₃ H ₇ ) ₄ −, −CH ₂ CH ₂ C ₆ H ₄ −, −CH ₂ C ₆ H ₄
CH ₂ −, −CH ₂ CH ₂ C ₆ H ₄ −, −CH ₂ CH ₂ CH ₂ C ₆ H ₄ −, −
A hydrocarbon chain having an aromatic ring such as CH ₂ CH ₂ C ₆ H ₄ CH ₂ — can be exemplified. As a partial structure of these hydrocarbon chains, for example,-
_{CH 2 CH (CH 3) -} , - CH (CH 3) CH (CH 3) -, more -CH ₂ C
It is possible that a branched structure exists like HRx- (Rx is a hydrocarbon group). Further, an unsaturated bond such as a double bond may be present, for example, a dihydrophenylene chain.
-C ₆ H ₆ -, tetrahydropyran-phenylene chain -C ₆ H ₈ - and other -CH = CH-, -CH = CH- CH 2 -, - CH = C (CH 3) -, -
CH ₂ C (= CH ₂ )-, -CH ₂ CH (CH ₂ CH = CHC ₉ H ₁₉ )-, -CH ₂
It can exist at various positions such as CH (C ₁₂ H ₂₃ ) — (C ₁₂ H ₂₃ is a dodecenyl group). These correspond to k = 1 and z = 1. If k = 2, z = 1, k = 1,
The hydrocarbon chain C _i H _{j in the} case of z = 2 corresponds to a case in which one hydrogen atom has been removed from the example of k = 1 and z = 1 and has become a bond.
For _{example, -CH <, - C 2 H} 3 <, - C 3 H 5 <, - C 4 H 7 <, - C 5
A linear aliphatic saturated hydrocarbon chain such as H ₉ <, -C ₆ H ₁₁ ,
It has a linear aliphatic unsaturated hydrocarbon chain or cyclic structure such as -C ₂ H <, -C ₃ H ₃ <, -C ₄ H ₅ <, -C ₅ H ₇ <, -C ₆ H ₉ < and aliphatic saturated hydrocarbon chain, -C ₆ H ₃ <aromatic hydrocarbon chain such as a such is possible. The hydrocarbon chain C _i H _{j in} the case of k = 2, z = 2 corresponds to a chain in which two hydrogen atoms are deviated from the example of k = 1, z = 1 and become a bond. For example,> C
<,> C ₂ H ₂ <,> C ₃ H ₄ <,> C ₄ H ₆ <,> C ₅ H ₈ <,> C ₆ H
₁₀ , such as linear aliphatic saturated hydrocarbon chains,> C ₂ <,> C ₃
A linear aliphatic unsaturated hydrocarbon chain such as H ₂ <,> C ₄ H ₄ <,> C ₅ H ₆ <,> C ₆ H ₈ <or an aliphatic saturated hydrocarbon chain having a cyclic structure, or> Aromatic hydrocarbon chains such as C ₆ H ₂ <are possible. In these examples, “<” and “>” mean two bonds.

In the case of the mercaptoamine residue represented by the structural formulas (3) and (5), the minimum value of the number of carbon atoms n should be possible up to 1. The value is 2. The upper limit of the maximum value of the number n of carbon atoms is considered to be moderate, but practically it is considered to be about 12, preferably about 8. These upper limits are given as a guide in view of reasons for synthesis, and can exceed the ranges shown here. The number m of hydrogen atoms corresponds to the number n of carbon atoms, the minimum value is 2 and the maximum value is 2 n
It is. To summarize the consideration of the range shown here, the range of the number of carbon atoms n can be 1 or more, but 2 or more and 1
2 or less is practical, preferably 2 or more and 8 or less, more preferably 2 or more and 6 or less.

[0059] hydrocarbon chain -C _n H _m - ethylene chain Specific examples of propylene chain, butene chain, pentene-chain, such as hexene chain - (CH ₂₎ x- aliphatic hydrocarbon chain represented by, o
- phenylene chain, m- phenylene chain, p- phenylene chain and -C such phenylene chain _{6 H 3 (CH 3) -} , -C 6 H 4 CH 2 -, -
Examples thereof include a hydrocarbon chain having an aromatic ring such as CH ₂ C ₆ H ₄ CH ₂ —. Among them, an ethylene chain, a propylene chain, a phenylene chain and the like are preferable, and an ethylene chain is particularly preferable.

Particularly preferred specific examples of the mercaptoamidocarboxylic acid having a hydrocarbon chain described herein include those comprising a cysteamine residue and a dodecylsuccinic acid residue, those comprising a cysteamine residue and a dodecenylsuccinic acid residue, and those comprising a cysteamine residue. And those consisting of naphthalenedicarboxylic acid residues, those consisting of cysteamine residues and tetramethylphthalic acid residues, those consisting of cysteamine residues and trimethylphthalic acid residues, those consisting of cysteamine residues and dimethylphthalic acid residues, Those consisting of cysteamine residues and methylphthalic acid residues, those consisting of cysteamine residues and phthalic acid residues, those consisting of cysteamine residues and hexahydrophthalic acid residues, those consisting of cysteamine residues and hexahydromethylphthalic acid residues What is cysteamine residue and tetrahydrophthal Residues, cysteamine residues and dihydrophthalic acid residues, cysteamine residues and trimellitic acid residues, cysteamine residues and pyromellitic acid residues, cysteamine residues and merits Acid residues; cysteamine residues and maleic methylcyclohexene tetrabasic acid residues; cysteamine residues and endomethylenetetrahydrophthalic acid residues; cysteamine residues and methylendomethylenetetrahydrophthalic acid residues A cysteamine residue and a methyltetrahydrophthalic acid residue, a cysteamine residue and a chlorendic acid residue, a cysteamine residue and a methylnorbornene-2,3-dicarboxylic acid residue, Cysteamine residue and cyclopentanetetracar Such as those consisting of acid residues, those consisting of mercaptopropylamine residues and dodecylsuccinic acid residues, those consisting of mercaptopropylamine residues and dodecenylsuccinic acid residues, mercaptopropylamine residues and naphthalenedicarboxylic acid residues Those consisting of mercaptopropylamine residues and tetramethylphthalic acid residues, those consisting of mercaptopropylamine residues and trimethylphthalic acid residues, those consisting of mercaptopropylamine residues and dimethylphthalic acid residues, Those consisting of mercaptopropylamine residues and methylphthalic acid residues, those consisting of mercaptopropylamine residues and phthalic acid residues, those consisting of mercaptopropylamine residues and hexahydrophthalic acid residues, those of mercaptopropylamine residues Hexahydromethyl phthalate Those composed of acid residues, those composed of mercaptopropylamine residues and tetrahydrophthalic acid residues, those composed of mercaptopropylamine residues and dihydrophthalic acid residues, those composed of mercaptopropylamine residues and trimellitic acid residues Those, those consisting of mercaptopropylamine residues and pyromellitic acid residues, those consisting of mercaptopropylamine residues and melitic acid residues, those consisting of mercaptopropylamine residues and maleated methylcyclohexene tetrabasic acid residues, Those consisting of mercaptopropylamine residues and endmethylenetetrahydrophthalic acid residues, those consisting of mercaptopropylamine residues and methylendomethylenetetrahydrophthalic acid residues, those consisting of mercaptopropylamine residues and methyltetrahydrophthalic acid residues , Those composed of captopropylamine residue and chlorendic acid residue, those composed of mercaptopropylamine residue and methylnorbornene-2,3-dicarboxylic acid residue, those composed of mercaptopropylamine residue and cyclopentanetetracarboxylic acid residue And those comprising aminobenzenethiol residues and dodecylsuccinic acid residues, those comprising aminobenzenethiol residues and dodecenylsuccinic acid residues, those comprising aminobenzenethiol residues and naphthalenedicarboxylic acid residues, aminobenzenes Those consisting of thiol residues and tetramethylphthalic acid residues, those consisting of aminobenzenethiol residues and trimethylphthalic acid residues, those consisting of aminobenzenethiol residues and dimethylphthalic acid residues, those of aminobenzenethiol residues From methylphthalic acid residue Those consisting of aminobenzenethiol residues and phthalic acid residues, those consisting of aminobenzenethiol residues and hexahydrophthalic acid residues, those consisting of aminobenzenethiol residues and hexahydromethylphthalic acid residues, Those consisting of aminobenzenethiol residues and tetrahydrophthalic acid residues, those consisting of aminobenzenethiol residues and dihydrophthalic acid residues, those consisting of aminobenzenethiol residues and trimellitic acid residues, aminobenzenethiol residues And pyromellitic acid residues, aminobenzenethiol residues and melitic acid residues, aminobenzenethiol residues and maleic methylcyclohexene tetrabasic acid residues, aminobenzenethiol residues and endo Consisting of methylenetetrahydrophthalic acid residues Those consisting of aminobenzenethiol residues and methylendmethylenetetrahydrophthalic acid residues, those consisting of aminobenzenethiol residues and methyltetrahydrophthalic acid residues, those consisting of aminobenzenethiol residues and chlorendic acid residues, amino Examples thereof include those composed of a benzenethiol residue and a methylnorbornene-2,3-dicarboxylic acid residue, and those composed of an aminobenzenethiol residue and a cyclopentanetetracarboxylic acid residue.
Depending on the target of application, mercaptoamide carboxylic acids include those composed of cysteamine residues and succinic acid residues, those composed of cysteamine residues and methylsuccinic acid residues, those composed of cysteamine residues and glutaric acid residues, Those consisting of itaconic acid residues, those consisting of cysteamine residues and maleic acid residues, those consisting of cysteamine residues and citraconic acid residues, those consisting of mercaptopropylamine residues and succinic acid residues, those of mercaptopropylamine Residues and methylsuccinic acid residues, mercaptopropylamine residues and glutaric acid residues, mercaptopropylamine residues and itaconic acid residues, mercaptopropylamine residues and maleic acid residues What is a mercaptopropylamine residue and citracone Residues, aminobenzenethiol residues and succinic acid residues, aminobenzenethiol residues and methylsuccinic acid residues, aminobenzenethiol residues and glutaric acid residues, amino acids It is considered that those comprising a benzenethiol residue and an itaconic acid residue, those comprising an aminobenzenethiol residue and a maleic acid residue, and those comprising an aminobenzenethiol residue and a citraconic acid residue can also be used.

An important point of the present invention is to use a mixture of the aminoalkylalkoxysilanes described above and a mercaptoamide carboxylic acid (salt) or / and a salt obtained by reacting both.

The salt comprising a cation moiety based on aminoalkylalkoxysilanes and an anion moiety based on mercaptoamide carboxylic acids (salts) used in the present invention is represented by Structural Formula 1.

[0063]

Embedded image

First, aminoalkylalkoxysilanes (Structural Formula 4)

[0065]

Embedded image

Although the chain C _{n ′} H _{m ′} and the group Si (OR) ₃ have been described, this description applies to the aminoalkylalkoxysilane residue of the salt represented by Structural Formula 1 and relates to mercaptoamide carboxylic acid (salt ) Class (structural formula 3)

[0067]

Embedded image

The description of the mercaptoamine residue and the carboxylic acid residue applies to the mercaptoamide carboxylic acid residue of the salt represented by the structural formula 1. Therefore, a preferable and somewhat specific range of the salt represented by the structural formula 1 is a salt synthesized from a combination of the aminoalkylalkoxysilane exemplified above and the mercaptoamide carboxylic acid exemplified above. This range is also applicable to mercaptoamide carboxylic acid salts of aminoalkylalkoxysilanes and / or mixtures of aminoalkylalkoxysilanes and mercaptoamide carboxylic acids.

Preferred examples of the salt represented by the structural formula 1 include a salt represented by the structural formula 2

[0070]

Embedded image

Is possible. Specific examples of preferred salts include HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COO H ₃ NC ₃ H ₆ Si (OC
H ₃ ) ₃ , HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COO H ₃ NC ₃ H ₆ Si (OC
₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆
Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COO H ₃ NC ₃ H ₆ Si
(OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COO H ₃ NC ₃ H ₆ Si (OC
₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COOH · H ₂ NC ₂ H ₄ NHC ₃ H ₆
Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₁₀ H ₆ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HS
C ₂ H ₄ NHCOC ₁₀ H ₆ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOC ₁₀ H
₆ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₆ H (CH ₃ )
₃ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COO H ₃
NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COOH ・ H ₂ NC ₂ H ₄
NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₆ (CH ₃ ) ₄ COO H ₃ NC ₃ H ₆ Si
(OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₆ (CH ₃ ) ₄ COO H ₃ NC ₃ H ₆ Si (OC
₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOC ₆ (CH ₃ ) ₄ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OC
H _{3) 3,} those with a cysteamine residue, such as, HSC ₃ H ₆ NHCO
CH ₂ CH (C ₁₂ H ₂₅ ) COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOCH ₂
CH (C ₁₂ H ₂₅ ) COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOCH ₂ CH
(C ₁₂ H ₂₅ ) COOH · H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOC
H ₂ CH (C ₁₂ H ₂₃ ) COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOCH ₂ C
H (C ₁₂ H ₂₃ ) COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOCH ₂ CH
(C ₁₂ H ₂₃ ) COOH · H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOC
₁₀ H ₆ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOC ₁₀ H ₆ COO H ₃ NC ₃
H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOC ₁₀ H ₆ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si
(OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOC ₆ H (CH ₃ ) ₃ COO H ₃ NC ₃ H ₆ Si (OC
H ₃ ) ₃ , HSC ₃ H ₆ NHCOC ₆ H (CH ₃ ) ₃ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ ,
HSC ₃ H ₆ NHCOC ₆ H (CH ₃ ) ₃ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ ,
HSC ₃ H ₆ NHCOC ₆ (CH ₃ ) ₄ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NH
COC ₆ (CH ₃ ) ₄ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOC ₆ (C
_{H 3) 4 COOH · H 2} NC 2 H 4 NHC 3 H 6 Si (OCH 3) 3, those with the mercaptopropyl amine residues, such _{as, HSC 6 H 4 NHCOCH 2 CH} (C 12
_{H 25) COO H 3 NC 3} H 6 Si (OCH 3) 3, HSC 6 H 4 NHCOCH 2 CH (C
_{12 H 25) COO H 3 NC} 3 H 6 Si (OC 2 H 5) 3, HSC 6 H 4 NHCOCH 2 CH (C 12
H ₂₅ ) COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ NHCOCH ₂ CH
(C ₁₂ H ₂₃ ) COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ NHCOCH ₂ CH (C
_{12 H 23) COO H 3 NC} 3 H 6 Si (OC 2 H 5) 3, HSC 6 H 4 NHCOCH 2 CH (C 12
_{H 23) COOH · H 2 NC} 2 H 4 NHC 3 H 6 Si (OCH 3) 3, HSC 6 H 4 NHCOC 10 H 6 C
OO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ NHCOC ₁₀ H ₆ COO H ₃ NC ₃ H ₆ Si
(OC ₂ H ₅ ) ₃ , HSC ₆ H ₄ NHCOC ₁₀ H ₆ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OC
H ₃ ) ₃ , HSC ₆ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , H
SC ₆ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₆ H ₄ N
HCOC ₆ H (CH ₃ ) ₃ COOH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ N
HCOC ₆ (CH ₃ ) ₄ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ NHCOC ₆ (C
_{H 3) 4 COO H 3 NC} 3 H 6 Si (OC 2 H 5) 3, HSC 6 H 4 NHCOC 6 (CH 3) 4 CO
OH ・ H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ , etc., which have an aminobenzenethiol residue, or HSC ₂ H ₄ NHCO
C ₆ H ₄ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₂ H ₄ NHCOC ₆ H ₄ COO H ₃ NC ₃ H
₆ Si (OC ₂ H ₅ ) ₃ , HSC ₂ H ₄ NHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ ,
HSC ₂ H ₄ NHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOC ₆
H ₄ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₃ H ₆ NHCOC ₆ H ₄ COO H ₃ NC ₃ H ₆ S
i (OC ₂ H ₅ ) ₃ , HSC ₃ H ₆ NHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HS
C ₃ H ₆ NHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ , HSC ₆ H ₄ NHCOC ₆ H ₄
COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC ₆ H ₄ NHCOC ₆ H ₄ COO H ₃ NC ₃ H ₆ Si
(OC ₂ H ₅ ) ₃ , HSC ₆ H ₄ NHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OCH ₃ ) ₃ , HSC
₆ H ₄ NHNHCOC ₆ H ₁₀ COO H ₃ NC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ . Here, a mercaptoamide carboxylate of an aminoalkylalkoxysilane having two amino groups is particularly used.
COOH ・ H ₂ NC ₂ H ₄ NH− is indicated as −COO H ₃ NC ₂ H ₄ N
H- a _{-COO H 2 NC 2 H 4 NH} 2 - because the form of salts are contemplated. For the mercaptoamide carboxylate salt of aminoalkylalkoxysilanes having two amino groups, (HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₂ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₂ H ₄ NHCOC ₁₀ H ₆ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH ₃ ) ₃ (HSC ₂ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH
₃ ) ₃ (HSC ₂ H ₄ NHCOC ₆ (CH ₃ ) ₄ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OC
H ₃ ) ₃ (HSC ₃ H ₆ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₃ H ₆ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₃ H ₆ NHCOC ₁₀ H ₆ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH ₃ ) ₃ (HSC ₃ H ₆ NHCOC ₆ H (CH ₃ ) ₃ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH
₃ ) ₃ (HSC ₃ H ₆ NHCOC ₆ (CH ₃ ) ₄ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OC
H ₃ ) ₃ (HSC ₆ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₅ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₆ H ₄ NHCOCH ₂ CH (C ₁₂ H ₂₃ ) COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si
(OCH ₃ ) ₃ (HSC ₆ H ₄ NHCOC ₁₀ H ₆ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH ₃ ) ₃ (HSC ₆ H ₄ NHCOC ₆ H (CH ₃ ) ₃ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OCH
₃ ) ₃ (HSC ₆ H ₄ NHCOC ₆ (CH ₃ ) ₄ COO) ₂ H ₃ NC ₂ H ₄ NH ₂ C ₃ H ₆ Si (OC
Salts of the form H ₃ ) ₃ can also be formed.

In the case of mixing aminoalkylalkoxysilanes and mercaptoamidocarboxylic acids (salts) or reacting both, it is possible to mix and react both without solvent. Further, hexane, benzene, toluene, hydrocarbons such as xylene, dimethyl ether, diethyl ether, diisopropyl ether, tetrahydrofuran, ethers such as dimethoxyethane, dichloromethane, chloroform, halogenated hydrocarbons such as carbon tetrachloride, methyl acetate, methyl acetate, Both can be mixed and reacted in various organic solvents such as acetonitrile and esters such as ethyl acetate, propyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexane. Depending on the purpose, both can be mixed or reacted in an alcohol such as methanol, ethanol, propanol, butanol, an aqueous solvent or water.

The reaction between aminoalkylalkoxysilanes and mercaptoamide carboxylic acid is a reaction between a base and an acid such as an amine and a carboxylic acid. Therefore, according to common general knowledge, it can be considered that a salt is formed only by mixing. This can be confirmed by an NMR spectrum or the like. Conveniently 3-
N- (2-mercaptoethyl) dodecenylsuccinamic acid is added to aminopropyltriethoxysilane in a molar ratio of 1:
When mixed with 1, the amine odor derived from 3-aminopropyltriethoxysilane becomes very weak, and strong heat generation is observed, so that salt formation is easily presumed.

In mixing and especially reacting the aminoalkylalkoxysilanes and the mercaptoamide carboxylic acids (salts), the equivalent ratio is in principle 1: 1. However,
Depending on the purpose of use, it may be better to make it acidic or to make it basic. In this case, the mixing ratio (reaction ratio) of the two can be changed, and a combination of an acid-salt or a base-salt is obtained, so that a buffering action of the hydrogen ion concentration can be expected. When this buffering action is also expected, it is practical to set the equivalence ratio to a mixing ratio range of 1: 200 to 200: 1, and preferably 1:20 to 20: 1. The metal (zinc) corrosion inhibitor composition of the present invention is also useful in that the effect of buffering the hydrogen ion concentration can be expected.

These aminoalkylalkoxysilanes and mercaptoamidocarboxylic acids (salts) can be applied sequentially. In this case, from the viewpoint of molecular level, it is considered that mixing or reaction occurs at the application site, and therefore, it can be considered that the present invention falls within the scope of the present invention. Even when aminoalkylalkoxysilanes and mercaptoamide carboxylic acids (salts) are used successively, the above-mentioned quantitative ratios for mixing and reaction can be applied.

The use of the metal corrosion inhibitor of the present invention as a zinc corrosion inhibitor, which is a particularly suitable form, will be described below.

The utility of the mixtures or salts of the present invention as zinc corrosion inhibitors can be clearly confirmed by electrochemical tests and salt spray tests.

First, the test by the electrochemical method is as follows.
This is an example of an operation method that operates sequentially. In this method, mercaptoamide carboxylic acid (salt) is allowed to act on the surface-treated zinc electrode in order to separately investigate the effect of surface treatment with aminoalkylalkoxysilanes and that of mercaptoamidocarboxylic acid (salt). Was.
This corresponds directly to the application of aminoalkylalkoxysilanes followed by the application of mercaptoamidocarboxylic acids (salts). Here, as examples of aminoalkylalkoxysilanes, 3-aminopropyltriethoxysilane, and as examples of mercaptoamide carboxylic acid, N- (2-
(Mercaptoethyl) dodecenylsuccinamic acid was used.

First, the results of a study on the protective action of the aminoalkylalkoxysilanes serving as controls will be described. When a zinc electrode surface-treated with 3-aminopropyltriethoxysilane was immersed in a 3% aqueous sodium chloride solution,
A polarization resistance of about 30 kΩ was observed. In this state, carbonic acid (salt) was added.
It became about 100Ω. As a control, a clean zinc electrode was also measured, but a polarization resistance value of about 500 to 800 Ω was observed in a 3% aqueous sodium chloride solution, and the polarization resistance became about 80 to 100 Ω by the addition of carbonate (salt). From a simple comparison of resistance values, surface treatment with aminoalkylalkoxysilanes is effective in preventing corrosion of zinc present in an aqueous solution of sodium chloride. However, from this result, it is judged that when carbonic acid (salt) coexists, the surface treatment with aminoalkylalkoxysilanes is less effective in preventing zinc corrosion.

Next, the action of another control mercaptoamide carboxylic acid (salt) will be described. N- (2-
When mercaptoethyl) dodecenylsuccinamic acid or the like is used for preventing corrosion of zinc, it is effective in the presence of carbonic acid (salt) according to electrochemical measurements. However, the rate of manifestation of the zinc corrosion preventing effect is not always high.

In the case of the present invention, there was no problem that the effect of the aminoalkylalkoxysilanes in the presence of carbonic acid was low compared to these controls. The rate of onset of the zinc corrosion inhibiting effect was about 8.6 times that of N- (2-mercaptoethyl) dodecenylsuccinamic acid alone. These characteristics cannot be expected by using aminoalkylalkoxysilanes and mercaptoamidocarboxylic acids (salts) alone. It is considered that the zinc corrosion inhibiting composition of the present invention is characterized in that mercaptoamide carboxylic acid interacts with a silicone polymer formed by decomposition and polymerization of aminoalkylalkoxysilanes. It is understood that this interaction does not adversely affect the effect of the mercaptoamide carboxylic acid, but has an effect of increasing the speed at which the zinc corrosion inhibiting effect of the mercaptoamide carboxylic acid is exhibited. Such desirable properties were difficult to predict from the properties of each single agent itself. The features of the zinc corrosion inhibiting composition of the present invention are understood as a simple sum of the properties of 3-aminopropyltriethoxysilane and the properties of N- (2-mercaptoethyl) dodecenylsuccinamic acid (salt). is not.

Further, tests according to actual use were also conducted.
Zinc corrosion inhibiting composition (3-aminopropyl triethoxysilane N-(2-mercaptoethyl) dodecenylsuccinimide amide acid salt), 3-aminopropyltriethoxysilane, N-(2-mercaptoethyl) dodecane A mixture of the same amount of senylsuccinamic acid in the coating resin was applied to a zinc steel plate and subjected to a salt spray test. From the comparison of the results, the strength of the zinc corrosion inhibiting composition was confirmed.

It is believed that the zinc corrosion inhibiting composition of the present invention inherits the merits of the corrosion inhibiting properties of mercaptoamide carboxylic acids. For example, a zinc corrosion inhibitor of the type that forms an immobilized protective layer cannot be expected to prevent corrosion of the scratched portion if the protective layer on the zinc surface is damaged.
On the other hand, in the case of the zinc protective layer formed by the zinc corrosion inhibitor of the present invention, it is considered that at least a part of the mercaptoamide carboxylic acid (salt) exists in a free state or a dissociable state. Since mercaptoamide carboxylic acid (salt) itself also has a corrosion inhibiting effect on zinc, if the protective layer is damaged, the free or dissociable mercaptoamide carboxylic acid (salt) will seep into the damaged area. It can be expected to exert a protective effect. In addition, mercaptoamide carboxylic acid (salt) has the effect of inhibiting corrosion of iron and the like. For example, when a zinc steel plate is deeply scratched and the iron material is exposed, it is not only on the zinc surface but also on the iron material surface. It can be expected that a favorable effect of gradually oozing out to suppress corrosion is obtained.

The case where the compound of the present invention is used as a zinc corrosion inhibiting composition has been described above. Thus, the product of the present invention is particularly useful as a zinc corrosion inhibitor.
It can be applied to other metals as a metal corrosion inhibitor. As other metals, for example, iron-based metals such as iron and iron alloys, copper and brass, copper alloys such as copper, zinc and zinc alloys,
Magnesium and magnesium alloys, aluminum and aluminum alloys, nickel and nickel alloys, chromium and chromium alloys, and other lead, tin, manganese, cobalt, molybdenum, tungsten, vanadium, cadmium, and alloys thereof, and the like, and the compounds of the present invention Can be applied to these metals as a metal corrosion inhibitor. When the corrosion inhibitor of the present invention is used for these metals, it may be carried out in the same manner as in the case of zinc corrosion prevention described in the following section.

The zinc corrosion inhibitor of the present invention can be used as it is or after being diluted with an organic solvent and applied to the surface of the object requiring protection. The application method may be freely selected, such as brushing or dipping. Organic solvents used for dilution include alcohols such as methanol, ethanol, propanol and butanol, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran and dimethoxyethane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, benzene, toluene, xylene and hexane. Various esters such as hydrocarbons, esters such as methyl acetate, ethyl acetate and butyl acetate, and, depending on the circumstances, halogenated carbons such as dichloromethane, chloroform and carbon tetrachloride, and acetonitrile can be used. The zinc corrosion inhibitor of the present invention can be applied by spraying as a spray. In this case, the organic solvent diluent described in the above-mentioned method of use can be used as a mist with air or the like. Further, as a spray in a container such as a can, it can be filled in a container together with a substance generally used as a propellant, such as propane, butane, or dimethoxyethane, and sprayed in a mist as needed. In addition, depending on circumstances, the zinc corrosion inhibitor of the present invention can be diluted with water and used.

The zinc corrosion inhibitor of the present invention applied to the surface of an object by a method such as coating or spraying can exhibit a corrosion preventing effect by drying in air at room temperature or the like. Alternatively, heating may be performed after application and spraying on the surface of the target object.
Also, depending on the situation, the zinc corrosion inhibitor of the present invention can be introduced into water or a liquid such as an oil agent to be used for protecting zinc and the metal described above.

[0087]

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

Example 1 Synthesis of N- (2-mercaptoethyl) dodecenylsuccinamic acid salt of 3-aminopropyltriethoxysilane. N- (2-mercaptoethyl) dodecenyl succinamic acid was added to 221.4 mg (1 mmole) of 3-aminopropyltriethoxysilane.
3.5 mg (1 mmole) were mixed and reacted to obtain 564.9 mg of N- (2-mercaptoethyl) dodecenylsuccinamic acid salt of 3-aminopropyltriethoxysilane.

Example 2 In order to confirm that a salt could be synthesized using a reaction solvent, 221.4 mg (1 mmole) of 3-aminopropyltriethoxysilane and N- (2-mercaptoethyl) dodecenylsuccinine were used. Amidic acid 34
0.5 ml of deuterated chloroform was added to 3.5 mg (1 mmole), and mixed and reacted at room temperature (25 ° C.). The NMR spectrum of the obtained substance was measured, and the results are shown in FIG. In the measurement results of the NMR spectrum, N-CH2- of 3-aminopropyltriethoxysilane (residue) is δ
At 2.813 ppm, C-CH2-C has δ 1.712 p
At pm, -CH2Si showed a signal at 0.651 ppm.

On the other hand, the outline of the NMR spectrum of 3-aminopropyltriethoxysilane alone (200 MHz,
δ (ppm)) is 0.573 (2H, t, -CH2Si),
1.170 (9H, t, -CH3), 1.495 (2H, d
t, C-CH2-C), 2.625 (2H, t, N-CH2-),
3.767 (6H, q, -OCH2-). The situation of the shift of the signal in the NMR spectrum is as follows: from 3-aminopropyltriethoxysilane and N- (2-mercaptoethyl) dodecenylsuccinamic acid to 3-aminopropyltriethoxysilane N- (2-mercaptoethyl) It was considered to mean that decenyl succinamidate was formed.

Example 3 N- (2-mercaptoethyl)
The zinc corrosion inhibiting effect of dodecenyl succinamic acid was evaluated by the method described in Reference Example. The zinc electrode used was one immersed in an isopropyl alcohol solution of 3-aminopropyltriethoxysilane (concentration: 20% by weight), air-dried, and heated to 120 ° C. for 1 hour. If not added, Rp is 100Ω,
In the case of addition (final concentration: 3.9 ppm, 11.4 μmole / liter), after 20 minutes, 1990Ω (corrosion prevention ability 95.0%),
After 15 hours, it showed 14600Ω (corrosion prevention ability 99.3%). As a rough estimate of the relative effect onset rate, the increase in Rp after 20 minutes was 1890Ω, and was estimated to be 8.6 times based on the result of Comparative Example 1 (Rp increase was 230Ω).

Example 4 N- (2-mercaptoethyl)
The product obtained by mixing and reacting dodecenyl succinamic acid and 3-aminopropyltriethoxysilane (mixing molar ratio 1: 1) is applied to a zinc steel sheet as a 1% by weight 2-propanol solution ( Using a bar coater, 10 g / m ² )
Thereafter, the mixture was heated at 120 ° C. for 1 minute, and an aqueous urethane resin solution was further applied (final coating thickness: 1 μm). This was subjected to a salt spray test (based on JIS Z-2371 test method). No change was observed up to 24 hours at room temperature, and slight white rust occurred after 39 hours. The area occupied by white rust was large and was about 5% of the total area. Comparative Example 1 The zinc corrosion inhibiting effect of N- (2-mercaptoethyl) dodecenylsuccinamic acid was evaluated by the method described in Reference Example. The zinc electrode used was not subjected to surface treatment with 3-aminopropyltriethoxysilane. Rp is 80 Ω when not added, and when added (final concentration 3.9 ppm, 11.4 μmole / liter)
310 Ω after 20 minutes (corrosion prevention ability 74.2%), 2 after 15 hours
120 Ω (corrosion prevention ability 96.2%)
It showed about 00 Ω (corrosion prevention ability 99.6%).

Comparative Example 2 N- (2-mercaptoethyl)
For dodecenyl succinamic acid alone,
The test was performed in the same manner as in Example 4. After 39 hours, a large amount of white rust was generated. The area occupied by white rust was large and reached about 50% of the total area.

Comparative Example 3 A test was conducted in the same manner as in Example 4 except that 3-aminopropyltriethoxysilane was used alone. White rust after 39 hours has been a large amount generated. The area occupied by white rust was large and reached about 50% of the total area.

(Comparative Example 4) The same test as in Example 4 was conducted on a sample to which only the aqueous urethane resin solution was applied. In this case, it was very rusty, and a large amount of white rust was generated within several hours, and the area occupied by white rust reached 100% of the total area within 15 hours.

(Reference Example) <Electrochemical evaluation method of corrosion prevention ability. The electrochemical evaluation of the corrosion prevention ability was performed by measuring the influence on the polarization resistance (Faraday resistance, Rp) of a cylindrical zinc electrode having a diameter of 12.5 mm and a length of 12.5 mm. The measurement was performed at room temperature (about 25 ° C.). The measurement system is a 3.0% by weight aqueous sodium chloride solution (pH: 2) in which two zinc electrodes are deoxygenated with nitrogen containing a carbonate-sodium bicarbonate buffer (20 mmol / L).
5.9). Sample is aqueous solution or 2
-Propanol solution, stirring when adding, but usually stopped stirring. Polarization resistance is measured between electrodes
It was calculated according to Ohm's law based on the voltage change observed when a current of 50 nA was passed. Corrosion prevention ability (%)
Was calculated according to equation (1). Corrosion prevention capability = 100 x (Rp sample-Rp cont) / Rp sample Equation (1) where Rp cont is Rp before adding the corrosion inhibitor.
(Ω), Rp sample is Rp after adding corrosion inhibitor
(Ω).

[0097]

EFFECTS OF THE INVENTION A salt formed from aminoalkylalkoxysilanes and mercaptoamidocarboxylic acids (salts) or / and a mixture of aminoalkylalkoxysilanes and mercaptoamidocarboxylic acids (salts) are used to effectively remove zinc and the like. Prevention of corrosion.

[Brief description of the drawings]

FIG. 1 shows the results obtained in Examples of the present invention, 3-aminopropyltriethoxysilane and N- (2-mercaptoethyl).
It is a measurement result of the NMR spectrum of the reaction product with dodecenyl succinamic acid.

Claims (4)

[Claims] 1. A compound represented by the following structural formula (1). Embedded image (Here, n and n 'are each independently an integer of 1 or more, m is an integer of 2 or more and 2n or less, m' is an integer of 2 or more and 2n 'or less, i is an integer of 1 or more, j is 0 or more (2i + 2 -(Z + k)) or less, k is an integer of 1 or more, z is an integer of 1 or more, and R represents a hydrogen atom or a hydrocarbon group.) 2. The following structural formula (3): (Where n is an integer of 1 or more, m is an integer of 2 or more and 2n or less, i is an integer of 1 or more, j is an integer of 0 or more and (2i + 2- (z + k)) or less, k is an integer of 1 or more, z represents an integer of 1 or more, and M represents a hydrogen atom or a metal atom.) And a mercaptoamide carboxylic acid (salt) represented by the following structural formula (4): (Here, n 'is an integer of 1 or more, m' is an integer of 2 or more and 2n 'or less, and R represents a hydrogen atom or a hydrocarbon group.)
A method for producing a compound, which comprises mixing an aminoalkylalkoxysilane represented by the formula: 3. The following structural formula (3): (Where n is an integer of 1 or more, m is an integer of 2 or more and 2n or less, i is an integer of 1 or more, j is an integer of 0 or more and (2i + 2- (z + k)) or less, k is an integer of 1 or more, z represents an integer of 1 or more, and M represents a hydrogen atom or a metal atom.) And a mercaptoamide carboxylic acid (salt) represented by the following structural formula (4): (Here, n 'is an integer of 1 or more, m' is an integer of 2 or more and 2n 'or less, and R represents a hydrogen atom or a hydrocarbon group.)
And a aminoalkylalkoxysilane represented by the formula: 4. A metal corrosion inhibitor comprising the compound according to claim 1 and / or the composition according to claim 3.