JPS5922791B2 - anti-rust - Google Patents

Description

[Detailed description of the invention] The present invention relates to rust preventive agents.

Specifically, the present invention relates to a rust preventive agent mainly comprising a copolymer of α-olefin and maleic anhydride, a hydrolyzed ring-opened product thereof, or a salt thereof.

Rust inhibitors are substances that inhibit the corrosion of metals in a gas or liquid phase environment, and are generally sulfonate-based compounds, metal soap (carboxylate)-based compounds, ester-based compounds, oxidized paraffins, or amine-derived compounds. Systematic compounds are known.

These rust inhibitors have both a relatively large lipophilic group (hydrophobic group) and a polar group (hydrophilic group) in one molecule, and the polar groups adsorb to the metal surface to form an adsorption film. Prevents rust-causing substances such as water from adhering to metal surfaces.

When these rust preventives are used as rust preventive oils, they are added to and dispersed in mineral oils such as spindle oils and process oils, and when used for the purpose of preventing rust on metal surfaces that come into contact with lubricating oils, they are added to lubricating oils. Added directly.

However, the above-mentioned rust inhibitors have low solubility in oil solvents, price,
Moreover, it is not necessarily satisfactory in terms of rust prevention effect, etc.

Accordingly, the present inventors conducted research to obtain an industrially advantageous rust preventive agent having excellent rust preventive effects and solubility in oil solvents, and as a result, they arrived at the present invention.

That is, the present invention provides an α-olefin-maleic anhydride copolymer or - The gist of the product is a rust preventive agent mainly consisting of a hydrolyzed ring-opened product of an olefin-maleic anhydride copolymer or a salt thereof. Next, the present invention will be explained in detail.

The d-olefin-maleic anhydride copolymer, which is the main component of the rust inhibitor of the present invention, is obtained by copolymerizing an α-olefin having 20 to 60 carbon atoms and maleic anhydride, and has a weight average molecular weight of is in the range of 2000-30000.

If the number of carbon atoms in the d-olefin to be reacted with maleic anhydride is too small, sufficient rust prevention cannot be obtained, and if it is too large, the solubility in oil decreases, so that rust prevention cannot be achieved. Therefore, the carbon number of α-olefin is 20 to 6.
0) Preferably 35-50. The α-olefin used is preferably linear, but may be branched. Further, as long as the number of carbon atoms as the d-olefin is within the above range, a mixture of α-olefins having various numbers of carbon atoms may be used. Regarding the molar ratio of both d-olefin and maleic anhydride when reacting, maleic anhydride/maleic anhydride/
If the molar ratio of d-olefin is less than 1, a part of α-olefin will remain unreacted, and if the molar ratio becomes large, the thermal stability of the resulting copolymer will decrease, resulting in poor hue. becomes.

Therefore, the reaction molar ratio of the α-olefin-maleic anhydride copolymer of the present invention (maleic anhydride/d-olefin)
is preferably in the range of 1 to 2, particularly 1.2 to 1.4. If the weight average molecular weight of the a-olefin=maleic anhydride copolymer is too large, the melt viscosity will increase and the solubility in oil will decrease, so the weight average molecular weight is 2000 to 30000, preferably 5000 to 20.
The range is 000.

The copolymerization reaction of a-olefin and maleic anhydride is carried out in the presence of a radical polymerization initiator by a solution polymerization method or a solventless (bulk) polymerization method according to a conventional method.

In the solution polymerization method, xylene, toluene, benzene, etc. are used as a solvent, and the polymerization conditions are 60 to 14
A suitable time is 0°C for 3 to 8 hours.

After the polymerization reaction is completed, the desired copolymer can be easily obtained by separating the solvent from the reaction mixture by distillation.
The degree of polymerization is adjusted by appropriately changing the type and amount of the solvent. On the other hand, in order to increase productivity, copolymerization without a solvent is advantageous, but it is necessary to appropriately adjust the degree of polymerization by using an appropriate radical transfer agent or increasing the polymerization temperature. .

Examples of this radical transfer agent include lauryl mercaptan,
Stearyl mercaptan, p-tert-butylphenol, etc. are used, and the ratio is 1/1 to maleic anhydride.
It is appropriate to add 00 to 1/10 mole.

Furthermore, by simply raising the polymerization temperature to 160 to 200°C, a copolymer having an appropriate degree of polymerization can be obtained without using these radical transfer agents.

In this case, an effective method for obtaining a copolymer with a good hue is to carry out polymerization while continuously feeding maleic anhydride into the α-olefin during the copolymerization reaction. The copolymer obtained in this way exhibits excellent rust prevention properties as it is, but it can be further improved by converting the acid anhydride group contained therein into a carboxylic acid type by ring-opening with hydrolysis. Furthermore, by making it into a salt type, it is possible to obtain a rust preventive agent having even better rust preventive properties.

In order to hydrolyze and ring-open the copolymer, add 0.01 to 1
Add 0 times the weight of water and reduce to 80 to 1 at normal pressure or under pressure.
It may be heated at 00°C for 1 to 6 hours.

The hydrolysis ring-opening rate is suitably 50 to 100%. The hydrolysis ring-opening rate is determined by the infrared absorption spectrum of the product after hydrolysis ring-opening (1.
R. ) is calculated from the absorption intensity ratio of acid anhydride groups and carboxyl groups in the characteristic absorption region of carbonyl. In addition, in order to convert the acid group into a salt form after ring-opening the copolymer with water, the above-mentioned ring-opening product of the copolymer is dissolved in mineral oil such as spindle oil or process oil at a concentration of 5 to 50% by weight. death,
Add 1 to 2 equivalents of a suitable base to this and heat at 20 to 60°C.
The mixture may be stirred for 10 to 60 minutes.

At this time, the bases include triethanolamine, diethanolamine, monoethano-1'amine, morpholine,
Amines such as triethylamine, diethylamine, tallow amine, calcium hydroxide, barium hydroxide, etc. are used.

The rust preventive of the present invention is usually applied to oils such as mineral oil and grease.
．． It is added and dissolved in 1 to 10% by weight, preferably 0.5 to 5% by weight, and used as a rust preventive oil.

It can also be added to various lubricating oils to impart rust prevention properties to them. The rust inhibitor of the present invention can be used alone or
It can also be used in combination with other rust preventives.

The difference between the rust preventive agent of the present invention and the conventional rust preventive agent is that the conventional rust preventive agent is a monosoap having one lipophilic group and one polar group in one molecule, whereas the present invention The rust preventive agent is an oligosoap consisting of a polymer linear lipophilic group and a large number of polar groups bonded to the lipophilic group.

From this, the rust preventive agent of the present invention has stronger adsorption to metal surfaces than conventional rust preventive agents, and as a result,
It is thought that it exhibits an excellent rust prevention effect.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example (1) Production of d-olefin=maleic anhydride copolymer α-olefin having 30 to 60 carbon atoms, Dialene 30
+ (Mitsubishi Chemical Industries, Ltd. registered trademark, average carbon number 48)
6007, maleic anhydride 90V and xylene 600
7 was placed in a flask and heated to 110°C under a nitrogen atmosphere. Next, 11.4 t of t-butyl peroctoate was added thereto in 1/4 portions at 1 hour intervals while stirring. After the addition, the mixture was heated for an additional 3 hours. The reaction was carried out.

After the reaction was completed, xylene was distilled off from the reaction mixture to obtain α-olefin monomaleic anhydride copolymer 6857.

The obtained copolymer had a hue of GN 2-3, a wax-like solid with a melting point of 72°C, and a melt viscosity of 139°C at 100°C.
．． P. It was hot.

Moreover, its weight average molecular weight is G. P. C. According to the law, it was 8,350. (2) Production of hydrolyzed ring-opened product of α-olefin-maleic anhydride copolymer (0) above
d-olefin monomaleic anhydride copolymer 508 obtained in
7 was placed in a flask, and after heating and melting it at 85 to 90°C, 12.27 g of water (equimolar to the acid anhydride group) was added, and the mixture was stirred at the same temperature for 1 hour to react.

After the reaction, the melting point was 76.5-88°C, and the hydrolysis ring-opening rate was 76% (1
．． R. A hydrolyzed ring-opened product 518f of α-olefin-maleic anhydride copolymer (measured from absorption intensity) was obtained.

(Support) Production of amine salt of α-olefin = maleic anhydride copolymer hydrolyzed ring-opened product 30.8V
was heated and dissolved in spindle oil 58.87° C. at 60 to 70° C., and then 8.4 t of diethanolamine (equimolar to the carboxyl group) was added thereto, and the mixture was stirred at the same temperature for 30 minutes to react.

After the reaction, spindle oil solution 987 (concentration 40% by weight) containing diethanolamine salt of a hydrolyzed ring-opened product of α-olefin-maleic anhydride copolymer was obtained. Next, various rust preventives obtained by the above method (in addition, α1 above), (2) and (
The rust preventives obtained by each method of 3) are hereinafter referred to as rust preventive agent (1), rust preventive agent (2), and rust preventive agent (3), respectively.
A rust prevention effect test was conducted using

(1) Hydrostatic drop test The rust preventive chemicals X1), (support) and (3) of the present invention were added to gear oil (SAE9O) in an amount of 0.01% or 0.05% by weight, and was manufactured.

On the other hand, JISO236 “Rust preventive oil general test method 6.
A test piece having a concave surface in the center was prepared according to the provisions of 6.1 "Test Piece". Next, 25 d of the various rust preventive oils produced by the above method were placed in a Petri dish with a diameter of EO, and the test piece was immersed in this and kept at 60° C. for 1 hour in a constant temperature bath. After that, take out the test piece and fill the indentation of the test piece with 0.
2d of purified water was added dropwise.

After dropping, this was maintained at 60° C. for 20 hours, the state of rust generation was observed, and the degree of rust formation was measured. In addition, the degree of rust is expressed in 11 stages from 0 to 10, with rust occurring over the entire area as 10, and no rust occurring at all as 0. be done.

For comparison, the degree of rust on the test piece was measured in the same manner as above using oxidized paraffin and oxidized microcrystalline wax, which are commercially available rust inhibitors.

These results are shown in Table 1 below.

(11) Wet test The rust preventives (4), (2) and (g) of the present invention were added to white spindle oil in an amount of 3% by weight to produce a rust preventive oil.

Next, JISZO2363. l [test piece]! A 1.2111 x 6011 x 80 cold rolled steel plate test piece prepared according to the regulations was immersed in the above rust preventive oil at 30°C for 1 hour.

After immersion, the test piece was taken out from the rust preventive oil and dried in a desiccator for 24 hours.
In accordance with the method of 366 "Test Method 3", the test piece was placed in a constant temperature and humidity chamber (temperature 49±1℃).

It was suspended for 40 days in a room with a relative humidity of 98%, and then taken out of the constant temperature and humidity chamber and tested under JIS ZO2363.2
The degree of rust occurrence of the test pieces was measured on the 14th and 42nd day after removal, according to the provisions of ``Rust Incidence 1 Measuring Method''.
The results are shown in Table 2 below. In addition, the degree of rust occurrence is 5111 on one side! When a measuring plate with 100 square base marks carved on it is superimposed on a test piece, it is expressed by the number of base marks where one or more spots of rust are observed with the naked eye.

For comparison, 3% by weight of oxidized varaffin or oxidized microcrystalline was added to white spindle oil, respectively.
The degree of rust occurrence was measured in the same manner as in the above method using the rust preventive oil produced by adding the following amount.

The results are also shown in Table 2. 0 Salt water spray test In the same manner as the above wet test, the test piece was treated with rust preventive oil containing various rust preventive agents, and then it was suspended in a constant temperature and humidity machine for 40 days, and then JIS ZO2366.2
A salt spray test was conducted according to the "Salt Spray" method.

1 hour, 2 hours, 4 hours, and 10 hours after starting salt water spray
JISZO2 determines the degree of rust on each test piece over time.
Measurements were made in accordance with the provisions of 363.2.

The results are shown in Table 3 below.

Claims (1)

[Scope of Claims] 1. Obtained by copolymerizing an α-olefin having 20 to 60 carbon atoms and maleic anhydride, and having a weight average molecular weight of 200
A rust inhibitor mainly composed of an α-olefin-maleic anhydride copolymer having a molecular weight of 0 to 30,000. 2 Obtained by copolymerizing α-olefin having 20 to 60 carbon atoms and maleic anhydride, with a weight average molecular weight of 200
A rust preventive agent mainly containing a hydrolyzed ring-opened product of an α-olefin-maleic anhydride copolymer or a salt thereof having a molecular weight of 0 to 30,000.