JP2000119630A - Chelating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-performance chelating agent which does not coagulate even in the presence of a cationic compound by selecting a vinylimidazoline polymer. SOLUTION: This chelating agent is a vinylimidazoline polymer having structural units represented by the formula (e.g. polyvinylimidazoline or a copolymer of vinylimidazoline and another monomer), the content of the structural units of the formula being preferably 10-100%. In the formula, R1 to R4 are each H or 1-4C alkyl. Preferably, the polymer has a mol. wt. of 500-5,000,000. The polymer can be prepared from a polymer having CN groups [e.g. a (meth) acrylonitrile polymer] and a 1,2-diamine [e.g. one represented by H2NCHR5CHR6 NHR7 (wherein R5 to R7 are each H or an aliphatic, araliphatic, or aromatic group). Alkali or alkaline earth metal ions and transition metal ions are sequestered by this chelating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a chelating agent.

[0002]

2. Description of the Related Art Conventionally, low molecular carboxylic acids such as citric acid, aminocarboxylic acids such as ethylenediaminetetraacetic acid, and tripolyphosphates have been used as chelating agents. In addition, carboxylic acid polymers such as polyacrylic acid and polymaleic acid are widely used as polymer chelating agents having characteristics of low volatility and low corrosion.

[0003] Most of these chelating agents are salts of acids, and when used in combination with a cationic compound, there is a problem that an ion complex is formed and the solution is not uniform. In addition, carboxylic acid polymers such as polyacrylic acid have a problem in that their chelating ability is low although they are widely used.

[0004]

As described above, most of conventional chelating agents, particularly high molecular chelating agents, are anionic polymers, and no cationic polymers have been known. In addition, the conventional polymer chelating agents have low chelating ability and are not industrially satisfactory. Therefore, development of a cationic polymer chelating agent which has high chelating ability and does not coagulate even when combined with a cationic compound has been desired.

[0005]

The present inventors have conducted intensive studies on a cationic polymer chelating agent. As a result, the vinylimidazoline polymer has a high chelating ability and does not precipitate even when mixed with a cationic compound. And found the new fact, and completed the present invention.

That is, the present invention is a chelating agent comprising a vinylimidazoline polymer.

Hereinafter, the present invention will be described in more detail.

[0008] The chelating agent of the present invention comprises a vinylimidazoline polymer.

In the present invention, the vinylimidazoline polymer is represented by the following general formula (1), such as polyvinylimidazoline or a copolymer of vinylimidazoline and other monomers.

[0010]

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(R1 to R4 each independently represent hydrogen or an alkyl group having 1 to 4 carbon atoms.) A polymer containing a structural unit represented by the formula:

The vinylimidazoline polymer of the present invention contains the structural unit represented by the above general formula (1) in an amount of usually 1 to 100
%, Preferably 10 to 100%. When the content of the structural unit represented by the general formula (1) is extremely low, the chelating ability cannot be sufficiently exhibited.

[0013] Vinyl imidazoline polymers are generally prepared from a polyamine and a polymer containing nitrile groups, such as an acrylonitrile or methacrylonitrile polymer.

As the acrylonitrile or methacrylonitrile polymer, a homopolymer may be used, or a copolymer with another monomer may be used. Monomers that can be copolymerized with acrylonitrile and methacrylonitrile include vinyl halides such as vinyl chloride, vinyl bromide and vinyl fluoride, vinylidene halides such as vinylidene chloride, acrylic acid, methacrylic acid, itaconic acid, and maleic anhydride. Unsaturated carboxylic acids such as acids, and salts thereof,
(Meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; unsaturated ketones such as methyl vinyl ketone and methyl isopropenyl ketone;
Vinyl esters such as vinyl acetate and vinyl benzoate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; (meth) acrylamide and its alkyl-substituted product; vinyl sulfonic acid; (meth) allyl sulfonic acid; p-styrene sulfonic acid; -Acrylamide-2
-Unsaturated sulfonic acids such as methylpropanesulfonic acid and (meth) acryloyloxyethylsulfonic acid and salts thereof, styrenes such as styrene, α-methylstyrene and chlorostyrene and alkyl or halogen-substituted products thereof, allyl alcohol and the like Examples include esters or ethers, basic vinyl compounds such as vinylpyridine, vinylpyrimidine, vinylimidazole, dimethylaminoethyl methacrylate, and vinylbenzyldimethylamine.

The polyamine reacted with the nitrile group-containing polymer is 1,2-diamine. 1,2-Diamine is a compound represented by the following formula (2).

H ₂ NCHR5CHR6NHR7 (2) (wherein, R5 to R7 are each independently hydrogen, an aliphatic,
An araliphatic or aromatic group is meant. Examples of the 1,2-diamine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, ethyleneamine such as aminoethylpiperazine, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminooctane, and diaminononane. , Diaminodecane, cyclohexylethylenediamine, benzylethylenediamine, phenylethylenediamine, methoxyphenylethylenediamine, dimethylphenylethylenediamine, tolylethylenediamine, N-cyclohexylethylenediamine, N-benzylethylenediamine, N
-Phenylethylenediamine, N-methoxyphenylethylenediamine, N-dimethylphenylethylenediamine, N-tolylethylenediamine, N-methylethylenediamine, N-ethylethylenedimine, N-isobutylethylenediamine, N-phenylethylenediamine, N
-(2-aminoethyl) ethylenediamine and the like are exemplified.

The chelating agent of the present invention can be used in the form of an amine or an amine salt.

The molecular weight of the polymer used in the chelating agent of the present invention is preferably in the range of 5 to 5,000,000.
When it is less than 500, the chelating ability is low, and polyvinylimidazoline having a molecular weight of more than 5,000,000 has a high viscosity when it is made into a solution, and is difficult to use.

The metal ions sequestered by the chelating agent of the present invention include alkaline earth metals such as calcium and magnesium,
Transition metals such as iron, nickel and silver, and alkali metals such as sodium and potassium.

Examples of the use of the chelating agent of the present invention include:
Builders for detergents, metal surface treatment in the metal and plating industries, metal removal in the textile and dyeing industries, prevention of decomposition of bleaching agents, prevention of bleaching solutions, bleach-fixing solutions, reducers, boilers and cooling water for photographic photosensitive materials Although it is used for preparations, pharmaceuticals, cosmetic preparations, etc., it may be used for other purposes.

A specific method of using the chelating agent of the present invention,
Since the amount of use varies depending on each application, it cannot be said unconditionally, but in principle, it does not greatly differ from the general use method for each of the above-mentioned applications. However, it is needless to say that the chelating agent of the present invention can be expected to have an unprecedented use example because of its excellent function and effect, and it is possible to reduce the amount used to achieve the same effect.

[0022]

Industrial Applicability The present invention provides a cationic chelating agent having high chelating ability, and it can be expected to have an unprecedented use example, which is extremely industrially significant.

[0023]

EXAMPLES Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited thereto.

Example 1 1 mmol / L of an aqueous solution of polyvinyl imidazoline (weight average molecular weight: 10,000) in terms of vinyl imidazoline of 1 mmol / L
An equal amount of 1 / L calcium chloride aqueous solution was added. pH1
The calcium ion concentration at 0 was measured with a calcium ion electrode, and the stability constant pKCa ^{2+ of} calcium ions was measured.
I asked. The pKCa ^{2+ at} 20 ° C. was 3.11. The aqueous solution of polyvinyl imidazoline is treated with N-
Addition of polyoxyethylene-N, N, N-trimethylammonium chloride did not cause cloudiness.

Example 2 1 mmol / in terms of vinylimidazoline and acrylic acid
L of polyvinyl imidazoline-polyacrylic acid (weight average molecular weight 10,000, imidazoline ring: carboxyl group = 9:
An equal amount of a 1 mmol / L calcium chloride aqueous solution was added to the aqueous solution of 1). The calcium ion concentration at pH 10 was measured with a calcium ion electrode, and the stability constant pKCa ²⁺ of calcium ions was determined. PK at 20 ° C
Ca ²⁺ was 2.99.

Comparative Example An equal amount of a 1 mmol / L calcium chloride aqueous solution was added to an aqueous solution of 1 mmol / L polyacrylic acid (average molecular weight: 2,000) in terms of acrylic acid. The calcium ion concentration at pH 10 was measured with a calcium ion electrode, and the stability constant pKCa ²⁺ of calcium ions was determined. The aqueous solution of polyacrylic acid whose pKCa ^{2+ at} 20 ° C. was 2.71 was added to the fungicide N-polyoxyethylene-N, N,
Addition of N-trimethylammonium chloride resulted in a white precipitate.

Claims (1)

[Claims] 1. A chelating agent comprising a vinylimidazoline polymer.