JPS5877579A - Corrosion inhibitor for metal - Google Patents

Abstract

PURPOSE:To obtain a corrosion inhibitor for metal sustaining the effect over a long term by adding a specified amount of tungstate or molybdate to alkanolamine. CONSTITUTION:A corrosion inhibitor for metal is obtd. by adding 40-60pts.wt., especially 45-55pts.wt. tungstate and/or molybdate to 100pts.wt. alkanolamine as a base. For example, the inhibitor is added to cooling water for a heat exchanger so as to regulate the amount of alkanolamine as the base to >=150ppm, especially >=200ppm. Thus, corrosion is inhibited over a long term.

Description

[Detailed description of the invention] 3, which relates to metal corrosion inhibitors.

In equipment such as cooling towers, boilers, and heat exchangers in JP buildings used for automotive and marine engines, where gold I4 is constantly in contact with water, the metal will corrode over a long period of time [7 Equipment Lifespan] The problem has arisen of reducing the For example, 1c1'oo to 10 for heating and cooling purposes for air conditioning in buildings, etc.
00 A large amount of water at 1749 degrees Celsius is adjusted to about 15 degrees Celsius, and in winter to about 40 degrees Celsius, and stored in an above-ground heat storage tank, and this water is circulated to cool the room or to cool the room. There are systems in which the water in such systems is not replaced for about a year, which can corrode the metals such as iron, zinc, and copper used in piping materials and equipment, causing damage to the equipment. Not only does it shorten the lifespan, but it also causes deposits such as iron mackerel to adhere to the inside of the heating and cooling coil, reducing thermal efficiency and increasing energy consumption, which goes against the grain of energy conservation.

Conventionally, as a countermeasure for the problem in Section 1F, sodium nitrite has been widely used as a corrosion inhibitor for metals because it is inexpensive, but since this is a reducing agent, it heats up again over time. It turned into sodium nitrate and lost its anticorrosion effect, so it was just a gas.

Metaphosphates are also used as anticorrosive agents, but they change to antiphosphates when heated or over time.
On the contrary, it tends to increase corrosion.

Other substances, such as chromates, are toxic and are no longer used today.

As mentioned above, various anticorrosive agents have been used in the past, but in recent years, due to problems such as environmental pollution, there has been a need for something that is harmless and has a corrosion inhibiting effect.

The present invention tj1, Notes Solving the conventional problem-4/(Meno 4
, so I/r M・Left-J is free of blue and has long-term efficacy.
We also try to provide corrosion inhibitors for metals (')/)
.

Inhibitor of the present invention r;
Cutting and 1. -'/.

Add molybdenum 1'l & , li, s ) l O', / and t, to this No.
'ru. 3 Inhibitor of non-invention + till agent t, I iron, metal stand of curved lead accommodation”
'Jim all (zolXh food J'-Luka, W to'rli
It % (hereinafter -F-'Fi+', I, jr l
,,, 1ift jJ staff QI car Jd- staff 21:,
-4'-'): Approximately 1/40 of the 1-agent) 7i benzotriazole, rnj lead, and other '4th publication alloys are also added to the photozene with 1υ no 4
1. jl. 1 can be used for a long period of time as an army that generates strength.

In the present invention, 1 month 1i - tungsten 1 salt 2 ~ hismolybdic acid IλΔ as C, alkali gold 1114 1.7
tA and 0Al force, one piece of earth metal can be removed ififi>3,
More specifically, CI, 1 tungsten salt and 1,1 tungstate sulfur, for example, Na, W containing 211
, CI is used up.

Similarly, molybdenum monochloride is preferably used, such as sodium molybdate, such as Na, Mo04.2tr,.0.

In the present invention, tungsten l'Jf J7= and/or 1C of pregnant acid is added to al-)nonolamine, which is the main ingredient, and the average ratio is usually alkanolamine 100.
; Elementary If (cross 11, about 51) part, rod body iI'i40
~60 Rei (and even better 4L < 1, 45 to 55 parts will be used).

The additive amount of water in the inhibitor of the present invention is not limited to 1" and 1, but the amount of altunonolamine that is 4.2 in the main ingredient is 15
0 ppm J')-hi, good i L < Its: 2
00 ppm or more, more specifically kl: 2 (I O
VC was added to give a concentration of ~400 ppm) 1)
Yes, that's good.

The range of use of Inhibitor Q of the present invention can be expanded by adding other corrosion inhibitors. For example, +'Jil 1
～/This benzotriazole etc.
~ 10 ppm I'a IIjl
lJ: Monthly 1st! 6.

nihe] 慴、/("-uni、本))h ty+ suppress! till
l Hari Q1 ゛""Jl is also in the human body...] [7k1.l<
Hzγ Niyama k Iteil/Kome, J. '；J＞、
1'l'1'1+ or C) mobejtme dispute-r''a/
).

Unexploded 1s 1 gold 1., 4) 1 stone erosion suppression cutt'', l? Fl Note 1, / (For ships, free) 1 For vehicles, 1-'6 cooling water and cooling power 1] 1- for the purpose of 1υJF14j. J Jul L 7'? - Canned water from Hoif (r) is added as a corrosion inhibitor and used as a corrosion inhibitor.
Heat soup soup indirectly with water and cool 17: I-non-reel coil l'+b food sharpening (, ill, month 1
Sari. /1.

Next ir(, 41 All the effects of the invention/V-meshi,
Test example ・A&I-c i. I will clarify.

Trial 1. (Follow the method described in Law Example 1, and add 6 to %l-1.?・1
j7, I went to see the good effect.

1) The surface performance of the sample fiK 11 is approximately 3 2 rrd /I-1,
Next (1) Illustrate the specimen)〃.

1. Boiler specimen (boiler) pressure 6 paulownia pipe S l” if-
42 4 (Used.) I Zinc test piece (A bent lead 1 mm thick metal steel plate was used.) 111 Copper test piece (Copper alloy (3 N i't', plate was used) 2) Mulberry agent used 3) Trial 1 Eyelid method 3 Suspend the specimen with a thread in a 0 0 fnl beaker.
Pour 500 ml of test melt into the aluminum i
The product was soaked for 72 hours, and then the liquid was soaked for 72 hours.
” Do not stir or introduce oxygen.

4) No pre-treatment or post-treatment of specimen H1 Both pre-processing and post-processing were performed in IIM of F' At2.

I) Wash the specimen with water 0) Apply methyl alcohol to cotton and gently wipe the surface of the specimen 111) Perform in the same manner as acetone-T”li) lv)
-C' in desiccator 111. ! 1 ken trunk,・j Eisen/) ■) 01 ~ 捷 with a balance to fit Hl" 5) Test results and effect comparison V) Plankl Hi 1111 Ni 1'i'&
Test L 1rr-o for soda and other drugs with different blending ratios of the drugs used above! 444 “I’ll post on the next table.

1.9/, , , [1,,6T,
, , jn f33 bi] t
lLl ”l 11 II 11 ”“'-
1. N procedure 1 for test M1 as seen from the table results 1 +
The mixed concentration of O = 20 fl + 100 + 5 (ppH 1) is the best (showing 100% efficacy, but the test Nn 9
N 10M1-0 = 1o otos o+5 (ppm
) is less effective at mixed concentrations. -Tsuchita, N
10M +r3 = 400+IDO+5 (ppn
Since the mixed wIW of l) also has an effect of 100%, if the agent of the present invention is used at a mixed concentration where the N content in the cutting is 200 ppm or more, the rust prevention effect can be maintained by 1 [10%]. , W in place of M (1 history) 11t, Tatoke,
Although the effect is slightly inferior, it shows the same characteristics as above and is much more effective than conventional anticorrosive agents.

Conventional commercially available anticorrosive agents such as sodium nitrite and sodium metaphosphate were not effective even at concentrations above 11,000 pp, but the agent of the present invention was found to be effective at concentrations of 200 to 4 ['l] as shown in [4].
An effect of 100 units can be obtained with low #I Ill of Oppm.

In addition, go to Jube "C in 1 exam" 4. Both W used separately 1
2, but it has been confirmed that both may be used in combination, and even if benzotriazole (0) is added in a very deep amount, similarly good results can be obtained.

As can be seen from the results in the above table, none of the inhibitors of the present invention caused precipitation H'll//A, and the corrosion rate was much lower than that of the other inhibitors.

Tungsten and molybdenum are harmful substances as can be seen from the fact that they are essential components of (I) products, so the inhibitor of the present invention is safe to use under any conditions, and the above-mentioned light As shown in Figure 11, it has an excellent effect on inhibiting corrosion of metals, so its utility value is extremely high.

1 other person

Claims (1)

[Scope of Claims] A metal corrosion inhibitor characterized by 10 parts by weight of an alkanolamine and 40 = -, 60 parts by weight of a tungstate and/or it molybdate.