JPS5845383A - Rust and corrosion preventive agent - Google Patents

Abstract

PURPOSE:To improve the corrosion preventiveness of a titled chemical and to decrease the discoloration of a treated metal by using the alkali metallic salt or amine salt of the half ester of alkylene oxide additive of polyhydric alcohol and bivalent carboxylic acid as an effective component. CONSTITUTION:This rust and corrosion preventive agent contains the alkali metallic salt or amine salt of the half ester expressed by the formula (R is a residual group of polyhydric alcohol, R' is a residual group of bivalent carboxylic acid, X is H or CH3, m is 2-6, n>=1) as an effective component. This rust and corrosion preventive agent has good adhesiveness to metals and highly prevents corrosion of iron, Al, etc. and rust of cast iron. The agent foams less and is easy to handle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rust and corrosion inhibitor. Sodium nitrite has traditionally been used as a water-soluble rust and corrosion inhibitor.

A large number of types are commercially available, including those based on inorganic compounds such as sodium borate, and those based on organic compounds such as amines.

It has also been used for temporary rust prevention of steel ropes. but,
Such conventional rust and corrosion inhibitors, for example, inorganic compound-based rust and corrosion inhibitors, have excellent rust prevention effects while immersed in the rust preventive solution, but rust occurs in a short period of time after being removed. .

However, the use of inorganic compound-based rust and corrosion inhibitors poses problems of water pollution and carcinogenic substances when discharged outside the system, and their use is being regulated. Furthermore, organic compound-based rust and corrosion inhibitors do not have sufficient rust prevention effects, and for example, their rust prevention effects are extremely reduced in hot and humid atmospheres during the summer and rainy seasons. The problem is that it has almost no rust-preventing effect on cast iron. However, they had various drawbacks such as a large degree of discoloration in the treated metal and a relatively large foaming property.

The present inventor conducted extensive research to overcome these drawbacks and obtain an excellent rust and corrosion inhibitor, and as a result, finally arrived at the present invention.

That is, the present invention is based on the general formula % (11 (R is a polyhydric acid residue, R' is a divalent acid residue, This invention relates to a rust and corrosion preventive agent containing as an active ingredient an alkali metal salt or amine salt of a compound represented by:

The rust and corrosion preventive agent of the present invention has good adhesion to metals (II resistance), and is excellent in preventing corrosion of not only iron but also aluminum, etc., and is also extremely effective for cast iron, which has traditionally been considered difficult to rust prevent. It has a special effect. Furthermore, the rust and corrosion preventive agent of the present invention has the remarkable effects of low foaming, easy handling, and little discoloration of treated metals.

The salt of the compound represented by the general formula (1), which is the active ingredient of the rust and corrosion inhibitor of the present invention, is a half-ester compound ("half-ester") of an alkylene oxide adduct of a polyhydric alcohol and a dihydric carboxylic acid. It can be obtained by forming a salt with an alkali metal or an amine.

To prepare half-ester μ, mix the required amount of two-run carboxylic acid that matches the hydroxy equivalent of the alkylene oxide adduct of polyhydric alcohol, and if the reaction is heated without a catalyst, the half-ester product can be used quantitatively. The preparation of half-esters is then much more straightforward. There is no problem in using one type of divalent carboxylic acid or a mixture of two or more types.

Any polyhydric alcohol can be used as long as it is a divalent to hexavalent hydroxy compound, and the alkylene oxide to be added with the 6mK compound is either ethylene oxide or propylene oxide, used alone or in combination.

The amount of alkylene oxide added is in the range of 1 to 407μ.

Preferably, the amount is from 2 to 107 μm, and whether the amount added is small or large, the semi-esthete solidifies and becomes inconvenient to handle, and if it is too large, the corrosion resistance becomes weak.

Specifically, the polyhydric alcohol is ethylene glycol/
L/, 7'robilene glycol~, butanedio-μ, bentanediol, hexanedio~.

Glycerin, diglycerin, trimethylo-ethane, trimethylolpropane, erythritol-, pentaerythritol μ, xylypto, so-bib F, cyclohexanedio-μ, cyclohexane dimethanol μ, cyclohexane trio-μ.

Hydrogenated bispheno-1vy fathom is mentioned.

The divalent carboxylic acid, which is one of the constituent components of the half ester, is a divalent carboxylic acid having an aliphatic, alicyclic, or aromatic skeleton, as a typical example.

Succinic acid, maleic acid, fumaric acid, gluten acid, adipic acid, sebacic acid, azefinic acid.

dodecanedioic acid, tetophhydrophthalic acid, methyltetophhydrophthalic acid, endomethylenetetrahydrophthalic acid,
Methyl endomethylene tetophhydrophthalic acid, hexahydrophthalic acid, methyl hexahydrophthalic acid, endomethylene hexahydrophthalic acid, methylene to endomethylene hexahydrophthalic acid, chlorindivucic acid, phthalic acid,
These include isophthalic acid, terephthalic acid, and anhydrides of the above-mentioned hydrophilic acids.

Mention may be made of the alkali metals or amines which can be used to form the salts of the compounds of general formula (1).

The above-mentioned amines that can be used in the present invention include aliphatic, aromatic and heterocyclic amines. A specific example is seven no.

Mono-, di- and tri-ethylamine; mono-, di- and tri-isoglobilamine; mono-, di- and tributylamine; mono-, di- and triamylamine; mono- and di-octylamine; mono- and di-coconutamine; mono- and di-oleylamine; Dimethyoleiamine; tallow amine; morpholine N-ethyl A/pipefudine; bipefuzine pyrrolidone; N-ethylpyrrolidone; Mono-, di- and dory isopropano
μamine; O#σ-dimethylethanolamine; aniline N-methyaniline iN@N'-dimethylaniline;N-ethylaniline;N・N'-diethylaniline;
Toluidine;Xylylamine; Kylylene diamine; Diphenylamine ink ethylene diamine; Diethylene triamine; ; N-Bit-y'robylene diamine and derivatives thereof (e.g. alkylene oxide adducts).

When using the rust and corrosion inhibitor of the present invention, the concentration of the active ingredient is usually about 0.01 to 5% by weight, preferably about 0.05 to 5% by weight.
It is preferable to use it at 2% by weight since good results can be obtained.

The rust and corrosion preventive agent of the present invention can be widely applied to various fields, for example, it can be added to poifu, water storage tanks, fugiators, or mixed into water-soluble metal processing fluids, water-soluble paints, adhesives, etc. Of course, it is also possible to use the general water-soluble rust and corrosion preventive agent of the present invention in combination with known rust and corrosion preventive agents, such as temporary rust prevention after surface treatment of metals.

The present invention will be described below with reference to Examples and Comparative Examples.

The half esters used in the examples are shown in Table 1.

Example 1 Salts are formed using the compounds in Table 1 and equivalent amounts of various amines listed in Table 2 below. Using the obtained salt, its anticorrosion performance was investigated by the immersion corrosion test method described below. The results are shown in Table 2.

Table 1 Table 2 [Immersion corrosion test method] Test piece Cast iron J-Ko S G 5501 (FC
-20) Surface area 3td 7/L'mi casting, TIS H5202 (AC-2A)
Surface area: 31 d Test liquid: Tap water temperature containing 1.0% by weight of sample for 9 periods
Treatment of test piece after 6o soil 2℃ 7 days (168 hours) test 111 iron; 10% citric acid = ammonium in boiling water
Aluminum castings immersed for seconds, washed with water, washed with acetone, and dried; immersed in nitric acid solution (4 nitric acid: 1 water) for 10 minutes, washed with water, then washed with acetone, drying corrosion protection rate (corrosion amount % when comb sample is not added) ”/io.

Comparative Example The corrosion protection rate of conventional products in the immersion corrosion test was as shown in Table 3.

Next, the test pieces were visually judged after the immersion corrosion test, and the results were as shown in Table 4 below.

Table 3 Table 4 Example 2 A cast iron plate of J Engineering SG 5501 (FC-20) was immersed in tap water containing sample tOwt96 for 30 seconds, and after death.
It is immersed half-submerged in the same sample solution and left standing in a constant temperature bath at 30±2°C for 24 hours. Observe changes in rust formation at the liquid layer, gas layer, and gas/liquid interface.

The results of the semi-immersion test were as shown in Table 5 below.

Table 5 Example 3 Washed and dried: fXS G 5501 (FC-2
After immersing the cast iron tA powder in sample 0) in tap water containing 1.0 Wt of sample for 30 seconds, drain the liquid and place it in a Petri dish lined with paper, cover it lightly and leave it at room temperature for 24 hours. . Observe the presence or absence of rust. The results of the powder test are shown in Table 96 below.

Table 6 (that's all)

Claims (1)

[Claims] General formula % formula %) (R is a polyhydric alcohol-μ residue, R' is a divalent carboxylic acid residue, A rust-preventing and corrosion-inhibiting agent containing an alkali metal or amine salt of a compound represented by the following as an active ingredient.