JP3347575B2 - Cleaning solvent composition for metal parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning solvent composition for metal parts, and more particularly, to a cleaning solvent composition for suppressing corrosion of metal parts when cleaning metal parts with an organic solvent. About.

[0002]

2. Description of the Related Art Freon 113 and trichloroethane have been used in large quantities as cleaning solvents in various industries such as automobiles, electric machines and machinery for cleaning various products.
However, both Freon 113 and trichloroethane were discontinued in December 1995 as substances that destroy the stratospheric ozone layer. Chlorinated organic solvents such as dichloromethane, trichloroethylene, and tetrachloroethylene are mainly used as alternative cleaning solvents, but all are highly toxic volatile organic solvents, and using them for cleaning significantly deteriorates the working environment. From the viewpoint of hygiene and air pollution control.
It is expected to be strictly regulated.

[0003] Recently, hydrocarbon solvents have attracted attention as cleaning solvents replacing chlorine organic solvents. Although hydrocarbon-based cleaning solvents have the drawback of being flammable, they have excellent characteristics such as strong cleaning power, low toxicity, and are economical, and have been widely used. The hydrocarbon-based cleaning solvent is a highly volatile solvent having low volatility and low flammability, containing a high boiling point (100 to 300 ° C.) hydrocarbon as a main component. It is a highly safe solvent that contains many aliphatic hydrocarbons (paraffins) as main components, has low odor and skin irritation, and has low toxicity and high toxicity. Further, the hydrocarbon-based cleaning solvent has a strong dissolving power for fats and oils such as metal working oils, and its cleaning power is comparable to that of Freon 113 or trichloroethane.

To clean metal parts using a hydrocarbon-based solvent, the metal parts are immersed in the solvent and contaminated by applying physical force such as rocking, rotation, jet, ultrasonic waves, shower, spray, and hand wiping. There is a method of removing. Also 10-200m
The solvent is reduced to 50 to 150 in a closed container decompressed to about mHg.
There is a method of cleaning with a steam of a hydrocarbon solvent heated and boiled to ° C.

[0005]

The hydrocarbon-based cleaning solvent itself is a stable substance which does not contain corrosive components such as chlorine, sulfur and acid, and has no corrosiveness to metals, but adheres to metal surfaces. As the dirt having corrosive components such as metal working oil and solder flux is dissolved, the solvent becomes corrosive.

[0006] Further, when the hydrocarbon solvent is boiled for steam cleaning or when the contaminated hydrocarbon solvent is distilled and reused, the cleaning solvent is heated at a high temperature for a long time.
Chlorinated paraffin in metal working oil and rosin in solder flux dissolved in the cleaning solvent are thermally decomposed to generate corrosive substances such as hydrochloric acid and organic acids. In addition, when the hydrocarbon solvent itself is heated for a long time, it is oxidatively degraded, generates an organic acid and the like, and may become a corrosive solvent. When a metal component is washed with a corrosive solvent and then dried, a corrosive component remains on the metal surface, and corrosion (discoloration, spotting, etc.) is likely to occur.

As a countermeasure against corrosion, when removing corrosive components from a solvent using an adsorbent such as activated carbon, or when performing steam washing or distillation regeneration, the pressure can be reduced and the evaporation can be performed at a temperature as low as possible and in a short time. Thus, the generation of corrosive components is suppressed, but the corrosion cannot be sufficiently suppressed. In particular, corrosion of electronic parts and precision machine parts greatly affects product performance,
The cleaning solvent needs to have excellent detergency and to completely remove corrosive components. An object of the present invention is to provide a cleaning solvent composition that can suppress corrosion of a metal component when cleaning the metal component with an organic solvent.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, have found that an organic solvent containing a basic oil-soluble metal salt is extremely excellent in preventing corrosion when cleaning metal parts. They have found and completed the present invention.

That is, in the present invention, the organic solvent has a total base number of 20.
An object of the present invention is to provide a cleaning solvent composition for metal parts, which contains a basic oil-soluble metal salt of about 500 mgKOH / g.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. Although the boiling point of the organic solvent in the present invention is arbitrary, the lower limit of the boiling range is usually 100 ° C., preferably 15 ° C.
0 ° C .; the upper limit is desirably 300 ° C., preferably 250 ° C. It is preferable to set the boiling point range to 100 ° C. or higher because the danger of ignition is reduced, and it is preferable to set the boiling point range to 300 ° C. or lower because the drying property is improved.

Specific examples of the organic solvent used in the present invention include hydrocarbon solvents, aliphatic halogen compounds, alcohols,
Examples include ethers, glycol ethers, aldehydes, ketones, fatty acids, glycols, terpenes, aromatic halogen compounds, and the like, with preference given to hydrocarbon solvents.

Examples of the hydrocarbon solvents include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents. The aliphatic hydrocarbon-based solvent mentioned here is a solvent containing 50% by volume or more of an aliphatic hydrocarbon.
The alicyclic hydrocarbon-based solvent referred to herein is a solvent containing 50% by volume or more of an alicyclic hydrocarbon. The aromatic hydrocarbon-based solvent referred to herein is a solvent containing 50% by volume or more of an aromatic hydrocarbon. Among these hydrocarbon solvents, aliphatic hydrocarbon solvents and alicyclic hydrocarbon solvents are particularly preferred.

The basic oil-soluble metal salt referred to in the present invention includes a basic alkali metal and / or alkaline earth metal sulfonate, a basic alkali metal and / or alkaline earth metal phenate, and a basic alkali metal and / or alkaline earth. Metallic salicylates can be mentioned. Specific examples of the alkali metal include sodium and potassium, and specific examples of the alkaline earth metal include magnesium, calcium, and barium.

The term "basic sulfonate" as used herein means a so-called basic sulfonate, carbonate overbased (ultrabasic) sulfonate and borate overbased (ultrabasic) sulfonate. For example, a so-called basic alkali metal obtained by heating a neutral alkali metal and / or alkaline earth metal sulfonate and an excess salt or base of an alkali metal and / or alkaline earth metal in the presence of water, And / or alkaline earth metal sulfonates; so-called carbonate overbases obtained by reacting a neutral alkali metal and / or alkaline earth metal sulfonate with an alkali metal or alkaline earth metal base in the presence of carbon dioxide gas (Ultrabasic) alkali metal and / or alkaline earth metal Phonates; neutral alkali metal and / or alkaline earth metal sulfonates are reacted with alkali metal and / or alkaline earth metal bases and boric acid compounds such as boric acid or boric anhydride, or carbonate overbased ( So-called borate overbased (ultrabasic) alkali metals produced by reacting an alkali metal and / or alkaline earth metal sulfonate with a boric acid compound such as boric acid or boric anhydride; And / or alkaline earth metal sulfonates; and mixtures thereof.

[0015] The neutral alkali metal and / or alkaline earth metal sulfonate referred to herein has a molecular weight of about 10
Alkali metal neutral salt (normal salt), alkaline earth metal neutral salt (normal salt) of alkyl aromatic sulfonic acid obtained by sulfonating 0 to 1500, preferably 200 to 700 alkyl aromatic compounds; Or a mixture thereof. Specific examples of the alkali metal include sodium and potassium, and specific examples of the alkaline earth metal include magnesium, calcium and barium. Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

As the petroleum sulfonic acid used herein, there are generally used those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of a mineral oil and so-called mahoganic acid which is a by-product of white oil production. Examples of the synthetic sulfonic acid include sulfonation of alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant used as a raw material of a detergent or obtained by alkylating a polyolefin to benzene. And sulfonated alkylnaphthalene such as dinonylnaphthalene. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid or sulfuric anhydride is usually used.

The neutral alkali metal and / or alkaline earth metal sulfonate is obtained by directly reacting the above alkyl aromatic sulfonic acid with a base such as an oxide or hydroxide of an alkali metal such as sodium or potassium. By reacting neutral (normal salt) alkali metal sulfonates or alkylaromatic sulfonic acids directly with bases such as oxides or hydroxides of alkaline earth metals such as magnesium, calcium and barium, or once in alkali metals As a neutral salt, a neutral (normal salt) alkaline earth metal sulfonate obtained by substituting an alkaline earth metal salt or the like, or a mixture thereof is used, and these are usually 0 to 7 mgKOH / g, preferably Is a total base number of 0 to 5 mgKOH / g (JIS K
2501) (by the perchloric acid method).

The basic phenates referred to herein include so-called basic phenates, carbonate overbased (ultrabasic) phenates, and borate overbased (ultrabasic).
It means phenate, specifically, for example,
An alkylphenol having 1 to 2 alkyl groups having 4 to 24 carbon atoms can be obtained by the presence or absence of elemental sulfur,
Obtained by reacting with an alkali metal base (such as an alkali metal oxide or hydroxide) or an alkaline earth metal base (such as an alkali earth metal oxide or hydroxide).
A so-called basic obtained by heating a so-called neutral (normal salt) alkali metal and / or alkaline earth metal phenate and an excess alkali metal and / or alkaline earth metal salt or base in the presence of water. Alkali metal and / or alkaline earth metal basic phenates;
A so-called carbonate overbased (ultrabasic) alkali metal obtained by reacting a neutral alkali metal and / or alkaline earth metal phenate with an alkali metal or alkaline earth metal base in the presence of carbon dioxide; Reacting a neutral alkali metal and / or alkaline earth metal phenate with an alkali metal and / or alkaline earth metal base and a boric acid compound such as boric acid or boric anhydride; or The so-called borate overbased (ultrabasic) produced by reacting a carbonate overbased (ultrabasic) alkali metal and / or alkaline earth metal phenate with a boric acid compound such as boric acid or boric anhydride. Basic) phenates; and mixtures thereof.

The basic salicylate referred to herein is:
So-called basic salicylates, carbonate overbased (ultrabasic) salicylates and borates overbased (ultrabasic)
It means a salicylate. Specifically, for example, an alkylsalicylic acid having 1 to 2 alkyl groups having 4 to 24 carbon atoms can be prepared by adding an alkylsalicylic acid in the presence or absence of elemental sulfur to an alkali metal base (of an alkali metal). So-called neutral (normal salt) alkali metal and / or alkaline earth obtained by reacting with an oxide or hydroxide) or an alkaline earth metal base (such as an oxide or hydroxide of an alkaline earth metal). A so-called basic alkali metal and / or alkaline earth metal salicylate obtained by heating an alkali metal salicylate and an excess salt or base of an alkali metal and / or alkaline earth metal in the presence of water; In the presence of neutral alkali metal and / or alkaline earth metal salicylate with alkali metal or alkaline earth metal base Obtained by response,
So-called carbonate overbased (superbasic) alkali metal and / or alkaline earth metal salicylates; neutral alkali metal and / or alkaline earth metal salicylates are converted to alkali metal and / or alkaline earth metal bases and boric acid or Reacting a boric acid compound such as boric anhydride, or reacting a carbonate overbased (ultrabasic) alkali metal and / or alkaline earth metal salicylate with a boric acid compound such as boric acid or boric anhydride And so-called borate overbased (ultrabasic) salicylates; and mixtures thereof.

The lower limit of the basic value (JIS K2501 perchloric acid method) of the basic oil-soluble metal salt in the present invention is 20 mgK.
OH / g, preferably 70 mg KOH / g;
0 mgKOH / g, preferably 400 mgKOH / g. If the base number is less than 20 mgKOH / g, sufficient corrosion inhibition cannot be obtained, and the base number is 500 mgKOH / g.
In the case where it exceeds, all of them are not preferred because storage stability is lowered.

In the cleaning solvent composition of the present invention, the content of the basic oil-soluble metal salt is arbitrary, but usually, the lower limit is 0.1 to 100 parts by weight of the organic solvent from the viewpoint of corrosion prevention performance.
It is desirable that the amount is 0001 parts by weight, preferably 0.01 parts by weight; the upper limit is 5 parts by weight, preferably 1 part by weight from the viewpoint of preventing a decrease in detergency.

The cleaning solvent composition of the present invention can be used for cleaning various metal parts. Examples of metal parts include cutting parts, stamping parts, gears for automobiles, small motors, light bulb parts and the like.

The cleaning solvent composition of the present invention can be used in various cleaning methods such as immersion cleaning, rocking cleaning, rotary cleaning, jet cleaning, ultrasonic cleaning, shower cleaning, spray cleaning, hand wipe cleaning, and steam cleaning. Thus, after cleaning, the occurrence of corrosion on the surface of the metal component can be suppressed.

Further, the cleaning solvent composition of the present invention may be adjusted at any stage of the cleaning. For example, a cleaning solvent composition prepared in advance may be used for cleaning, or a high-concentration solvent in which about 10 to 150 parts by weight of a basic oil-soluble metal salt is blended with respect to 100 parts by weight of an organic solvent immediately before cleaning, Alternatively, it may be adjusted by adding to an organic solvent during washing. The method using a high-concentration solvent is suitably used particularly in a steam cleaning method. In addition, when a used solvent is subjected to distillation and regeneration, by adding a high-concentration solvent before distillation, generation of corrosive substances can be suppressed.

In the steam cleaning method and the distillation regeneration of the solvent, the cleaning solvent composition is heated by a heat exchanger to generate steam or is distilled. However, corrosive substances are generated in the heat exchanger. This corrosive substance may adhere to the surface of the heat exchanger or block the heat exchanger. The cleaning solvent composition of the present invention can particularly prevent adverse effects due to corrosive substances generated in such a heat exchanger.

[0026]

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

(Example 1) Using a reduced-pressure steam cleaner, a machined part (iron) to which cutting oil stains adhered was continuously washed with an organic solvent by a steam washing method. A new liquid of an alicyclic hydrocarbon solvent having a boiling point of 195 to 222 ° C., an aromatic content of 1% by volume or less, an olefin content of 1% by volume or less, an alicyclic hydrocarbon content of 63%, and a flash point of 71 ° C. It was used. The organic solvent was repeatedly used by regenerating by distillation, but when cleaning was continued for about three months, red rust began to be generated on the parts to be cleaned. At this point, the concentration of the corrosive substance in the organic solvent was measured, and the total acid value was 0.89 mg KOH.
/ G, 110 ppm of chlorine ions and 2 ppm of sulfate ions. Therefore, at this point, the base number is 320 mgKOH /
g (JIS K2501 perchloric acid method), a high-concentration solvent containing 50% by weight of an overbased calcium sulfonate was added to a steam generator of a reduced-pressure steam cleaner. The overbased calcium sulfonate concentration in the organic solvent in the steam generator is 100
It was 00 ppm. Thereafter, the cleaning was continued for three months, but no rust was generated on the object to be cleaned.

(Comparative Example 1) When overbased calcium sulfonate was not added in Example 1, red rust continued to be generated on the entire surface of the object to be cleaned.

Comparative Example 2 In Example 1, the base number was 0 to 5 mg KO instead of the overbased calcium sulfonate.
H / g (JIS K2501 perchloric acid method) neutral calcium sulfonate was added, but red rust continued to be generated on the entire surface of the object to be cleaned even after the addition.

(Example 2) Using a three-tank type washing machine, a bulb part (copper) to which press oil stains adhered was continuously washed with an organic solvent by an immersion / ultrasonic washing method. A new liquid of an alicyclic hydrocarbon solvent having a boiling point of 155 to 198 ° C., an aromatic content of 1% by volume or less, an olefin content of 1% by volume or less, an alicyclic hydrocarbon content of 66%, and a flash point of 44 ° C. It was used. The organic solvent was repeatedly used by regenerating by distillation, but when washing was continued for about one month, discoloration corrosion began to occur on the copper portion of the part to be cleaned. At this time, when the concentration of the corrosive substance of the organic solvent was measured, the total acid value was 0.0
It was 3 mgKOH / g, 1.3 ppm of chloride ions, and 0.6 ppm of sulfate ions. Therefore, at this point, the base number 3
20mgKOH / g (JIS K2501 perchloric acid method)
A high concentration solvent containing 50% by weight of an overbased calcium sulfonate was added to the distillation regenerator. The overbased calcium sulfonate concentration in the organic solvent in the distillation regenerator is 100
ppm. After this, cleaning was continued for one month,
No discoloration corrosion occurred on the object to be cleaned.

(Comparative Example 3) When overbased calcium sulfonate was not added in Example 2, discoloration corrosion continued to occur on the copper portion of the object to be cleaned.

(Comparative Example 4) In Example 2, a base number of 0 to 5 mg KO was used instead of the overbased calcium sulfonate.
H / g (JIS K2501 perchloric acid method) neutral calcium sulfonate was added, but after the addition, discoloration corrosion continued to occur on the copper portion of the object to be cleaned.

(Example 3) A gear (iron) for automobiles to which heat treatment oil stains adhered was continuously washed with an organic solvent by a steam washing method using a reduced-pressure steam washing machine. A new liquid of an alicyclic hydrocarbon solvent having a boiling point of 195 to 222 ° C., an aromatic content of 1% by volume or less, an olefin content of 1% by volume or less, an alicyclic hydrocarbon content of 63%, and a flash point of 71 ° C. It was used. The organic solvent was repeatedly used by regenerating by distillation, but when cleaning was continued for about 2 months, the trap on the discharge side of the vacuum pump of the reduced-pressure steam cleaner started to corrode. At this point, when measuring the concentration of corrosive substances in the organic solvent, etc.,
Total acid value 0.42 mgKOH / g, chlorine ion 1 ppm or less, sulfate ion 1 ppm or less, formic acid 11 ppm, acetic acid 3
It was 4 ppm. Therefore, at this point, a base number of 70 mg
A high concentration solvent containing 50% by weight of an overbased calcium salicylate of KOH / g (JIS K2501 perchloric acid method) was added to the steam generator. The overbased calcium salicylate concentration in the organic solvent in the steam generator is 2500 ppm
Met. Thereafter, cleaning was continued for two months, but no new apparatus corrosion occurred.

Comparative Example 5 When overbased calcium salicylate was not added in Example 3, the apparatus continued to corrode.

Example 4 A motor component (copper) to which solder flux dirt was adhered was continuously washed with an organic solvent by a dipping / ultrasonic cleaning method using a three-tank type washing machine.
A new liquid of an alicyclic hydrocarbon solvent having a boiling point of 155 to 198 ° C., an aromatic content of 1% by volume or less, an olefin content of 1% by volume or less, an alicyclic hydrocarbon content of 66%, and a flash point of 44 ° C. 95% by volume and 5% by volume of aliphatic alcohol
Those containing are used. The organic solvent was used repeatedly by regenerating by distillation, but when washing was continued for about one month,
The copper part of the parts to be cleaned began to discolor. At this time, when the concentration of the corrosive substance of the organic solvent and the like were measured, chlorine ion 0.2 ppm, sulfate ion 0.1 ppm, formic acid 0.1 p
pm, acetic acid 1.2 ppm. So, at this point,
A high concentration solvent containing 50% by weight of an overbased calcium phenate having a base number of 30 mgKOH / g (JIS K2501 perchloric acid method) was added to the distillation regenerator. The concentration of overbased calcium phenate in the organic solvent in the distillation regenerator is 10
ppm. Thereafter, washing was continued for one month, but the object to be washed did not change color.

(Comparative Example 6) When the overbased calcium phenate was not added in Example 4, the copper portion of the object to be washed continued to be discolored.

As shown in the examples, as a result of cleaning the metal parts using the actual cleaning device, the object to be cleaned or the cleaning device was corroded, but the basic oil-soluble metal salt was added to the cleaning solvent. By doing so, the occurrence of corrosion could be prevented. On the other hand, in the case of the comparative example, the occurrence of corrosion could not be prevented.

[0038]

As described above in detail, the cleaning solvent composition for metal parts of the present invention comprising an organic solvent containing a basic oil-soluble metal salt having a specific total base number and a metal part using the same Excellent corrosion prevention, heat resistance, oxidation stability, and cleanliness can be obtained by the corrosion prevention method in washing. In particular, it is possible to suppress the occurrence of corrosion on the surface of the metal component after cleaning.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C23G 5/02 C11D 7/50

Claims (1)

(57) [Claims] 1. An organic solvent having a total base number of 20 to 500 mgK
A cleaning solvent composition for metal parts comprising an OH / g basic oil-soluble metal salt.