Metal working oil composition

Abstract

 A water-soluble metal working oil which comprises an oligomer component selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers is usable both in the field of cutting and in the field of grinding.

Description

BACKGROUND OF THE INVENTION

(a) Field of the Invention

[0001] The present invention relates to a water-soluble metal working oil which can be used widely in various fields, being usable both for cutting and for grinding. More particularly, the present invention relates to a water-soluble metal working oil which can be suitably used in various metal working fields, for example, in the fields of cutting, grinding, forming, drawing, and rolling.

(b) Description of the Related Art

[0002] In conventional metal working such as cutting or grinding, the kind of metal working has determined the types of working oils to be used in each metal working; for instance, emulsion or soluble working oils have been used for cutting, and solution working oils for grinding. The reasons for using different working oils are as follows.

(1) Both emulsion and soluble working oils contain mineral oils, which cause loading of grindstones when these working oils are used for grinding.

(2) On the other hand, when solution working oils are used for cutting, they cause decreases in the surface quality of machined surfaces produced by tapping or reaming and in the lives of tools.

[0003] That is, conventional metal working oils for cutting and grinding have a problem that, as mentioned above, the oils for cutting and the oils for grinding need to be different, and therefore, there has been a demand for development of metal working oils which are usable both for cutting and for grinding. The conventional metal working oils have more problems. For example, even in case the conventional metal working oils for cutting are used for cutting, or the conventional metal working oils for grinding are used for grinding, their effects in improving working efficiency are insufficient, that is, in particular, the machined surfaces of the processed articles are not sufficiently accurate or the tool life tends to be decreased. Further, the conventional metal working oils still require improvement in anti-putrefaction property. Moreover, particularly in their use for grinding, there is another problem that it is difficult to extend the intervals between dressings sufficiently.

SUMMARY OF THE INVENTION

[0004] An object of the present invention is to provide a water-soluble metal working oil which has excellent advantages in that when used for cutting, it can extend tool lives and improve the quality of the machined surfaces, and as well, when used even for grinding, it causes no loading of grindstones, thereby enabling dressing intervals to be extended, and therefore, it can also be used suitably as a working oil both for cutting and for grinding.

[0005] Another object of the present invention is to provide a water-soluble metal working oil which hardly putrefies, thereby preventing coolants from putrefying more effectively.

[0006] That is, the object of the present invention is to provide a water-soluble metal working oil which is so extremely advantageous in practical use that it can be suitably used in various metal working fields.

[0007] As the results of researches for solving the above-described problems, it was found that the above-described object can be accomplished by a water-soluble metal working oil which comprises a specific synthetic oil, i.e. an oligomer of an a -olefin having a specific number of carbon atoms or a hydrogenated derivative of the oligomer in place of or together with conventional mineral oils or synthetic oils.

[0008] That is, the present invention provides a water-soluble metal working oil, comprising: an oligomer component selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers.

[0009] The present invention further provides a water-soluble metal working oil, comprising:

(A) an oligomer component selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers; and

(B) an anionic emulsifier.

[0010] The present invention further provides a water-soluble metal working oil, comprising:

(A) an oligomer component selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers;

(B) an anionic emulsifier; and

(C) a nonionic emulsifier.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The water-soluble metal working oil of the present invention comprises at least an oligomer component (component (A)) selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers, and in addition to the component (A), it may further contain various kinds of additive components or diluents according to demand.

[0012] In preparation of the water-soluble metal working oil of the present invention, there is no particular limitation in the order and method of adding each component. Hereinafter, the water-soluble metal working oil of the present invention will be disclosed in detail as to its composition, etc. Among various embodiments of the water-soluble metal working oil of the present invention, water-soluble metal working oils containing no diluent (diluting solvent such as water) will be called base liquids, for convenience's sake.

[0013] When the water-soluble metal working oil of the present invention is used at least for cutting and grinding, water is generally used as the diluent, and a base liquid is diluted with a proper amount of water to adapt it to suit the purpose of use. When the water-soluble metal working oil of the present invention is used in a form of a dilution with water, it is generally desirable to add a proper emulsifier in addition to the above-described component (A). Any emulsifier, for example, any one selected from various known emulsifiers may be used in the present invention. However, generally, anionic emulsifiers (component (B)) are preferably used, and it is particularly preferable to use the anionic emulsifiers (component (B)) together with nonionic emulsifiers (component (C)).

[0014] Some examples of the oligomers of a -olefins of 6 to 14 carbon atoms to be used in the present invention include homopolymers (oligomers) of a -olefins of 6 to 14 carbon atoms, copolymers each consisting of two or more of the a -olefins, and mixtures thereof. The oligomer component (A) may further contain oligomers which contain monomer units of olefins other than the above-described a -olefins so long as the accomplishment of the object of the present invention is not disturbed.

[0015] The a -olefins of 6 to 14 carbon atoms include aliphatic a -olefins, alicyclic a -olefins, and aromatic a - olefins.

[0016] Among the oligomers of a -olefins of 6 to 14 carbon atoms, those which are particularly suitable for general use include oligomers of aliphatic a -olefins and oligomers obtainable by polymerizing aliphatic α - olefins as the main polymerization ingredients.

[0017] The aliphatic a -olefins include linear and branched a -olefins. The linear a -olefins include 1- hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, and 1-tetradecene. Some illustrative examples of the branched a -olefins include various ones, such as iso- and neo-a -olefins each having at least one vinyl group or at least one vinylidene group.

[0018] The above-described hydrogenation derivatives of the oligomers of a -olefins having 6 to 14 carbon atoms are compounds obtainable by hydrogenating the above-described various kinds of oligomers or mixtures of the oligomers or mixtures of the compounds.

[0019] The particularly preferred examples of the component (A) to be used in the present invention are oligomers of a -olefins of 8 to 12 carbon atoms, including 1-octene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene, and hydrogenation derivatives thereof.

[0020] The component (A) to be used in the present invention may be one oligomer or hydrogenation derivative of an oligomer selected from the above-described various kinds of oligomers and the hydrogenation derivatives thereof or may be a mixture of two or more of them.

[0021] In the present invention, the preferred oligomers, hydrogenation derivatives thereof and mixtures thereof to be used as the component (A) generally have a kinematic viscosity of from 1 to 50 cSt as measured at 100 C. If the kinematic viscosity is less than 1 cSt, lives of tools used in cutting may be decreased, and on the other hand, if it exceeds 50 cSt, emulsification may become difficult.

[0022] The suitable content of the component (A) in the water-soluble metal working oil of the present invention is generally from 5 to 95 % by weight, more preferably from 10 to 60 % by weight, when the amount of the base liquid is as defined above and comprises the component (A), etc. (i.e., the total amount of all components excluding the diluents such as water) which is defined to be 100 % by weight. If the content is less than 5 % by weight, it may become difficult to attain sufficiently the effects of the present invention. The base liquid may further contain general base oils, such as mineral oils or synthetic oils other than the component (A), in an amount not more than the amount of the component (A), with the proviso that the total amount of the component (A) and general base oils is within the range of from 5 to 95 % by weight of the base liquid.

[0023] The anionic emulsifiers to be used as the component (B) in the present invention may be of various kinds. Some examples of the anionic emulsifiers include salts of carboxylic acids or sulfonic acids with amines or metals (Some examples of the carboxylic acids include fatty acids of 8 to 30 carbon atoms such as oleic acid and polycarboxylic acids such as succinic acid and maleic acid, and some examples of the amines include alkanolamines such as mono-, di-, and tri-ethanolamines, cyclic amines such as morpholine and piperazine, cyclohexylamine, and dicyclohexylamine, and alkylene oxide adducts of these amines, and some examples of the metals include alkaline metals such as sodium and potassium and alkaline earth metals such as calcium and barium.); sulfates; phosphates; polymerized polymer emulsifiers such as partial saponification derivatives of copolymers of olefins, for example, styrene, with maleic anhydride; and polycondensed polymer emulsifiers such as naphthalenesulfonates-formalin condensates. These may be used individually or in a combination of two or more of them.

[0024] The particularly preferred anionic emulsifiers include one or mixtures of those selected from the group consisting of salts of fatty acids of 8 to 30 carbon atoms such as oleic acid with alkaline metals such as sodium and potassium, salts of fatty acids of 8 to 30 carbon atoms such as oleic acid with alkanolamines such as mono-, di-, and tri-ethanolamines, and salts of sulfonic acids with alkaline metals such as sodium and potassium.

[0025] The suitable content of the anionic emulsifier to be used as the component (B) in the water-soluble metal working oil of the present invention is generally at least 5 % by weight, preferably from 25 to 80 % by weight, when the amount of the base liquid being defined above and comprising the component (B), the component (A), etc. (i.e., the total amount of all components excluding the diluents such as water) is defined to be 100 % by weight.

[0026] If the content of the component (B) is less than 5 % by weight, the emulsion stability may become poor.

[0027] The nonionic emulsifiers to be used as the component (C) in the present invention may be of various kinds. Some examples of the nonionic emulsifier which may be used include polyoxyalkylene emulsifiers such as polyoxyalkylene glycols, mono- or di-etherified compounds of polyoxyalkylene glycols, glycerols, alkylene oxide adducts of glycerols, and etherified compounds of glycerols or of alkylene oxide adducts of glycerols (Some examples of the alkylene include alkylene groups of 2 to 4 carbon atoms such as ethylene and propylene, and some examples of the terminal ether substituents include alkyl groups, aryl groups, alkylaryl groups, aralkyl groups, and cycloalkyl groups.); esters of carboxylic acids with alcohols (Some examples of the carboxylic acids include fatty acids of 8 to 30 carbon atoms such as oleic acid and polycarboxylic acids such as succinic acid and maleic acid, and some examples of the alcohols include aliphatic alcohols of 6 to 30 carbon atoms, phenol, alkylphenols, polyhydric alcohols such as polyoxyalkylene glycols, glycerols, sorbitans, pentaerythritol, and trimethylolpropanes, and alkylene oxide adducts thereof.); nitrogen-containing emulsifiers such as amides of alkanolamines with fatty acids or polycarboxylic acids and alkylene oxide adducts of alkylamines. These nonionic emulsifiers may be used either individually or in a combination of two or more of them.

[0028] The suitable content of the nonionic emulsifier to be used as the component (C) in the water-soluble metal working oil of the present invention is generally not more than 50 % by weight, preferably from 2 to 30 % by weight, when the amount of the base liquid being defined above and comprising the component (C), the component (B), the component (A), etc. (i.e., the total amount of all components excluding the diluents such as water) is defined to be 100 % by weight.

[0029] Using the nonionic emulsifiers together with the above-described component (B) can further improve the emulsion stability of the water-soluble metal working oil of the present invention.

[0030] In addition to the above-described component (A), component (B), and component (C), the water-soluble metal working oil of the present invention may further contain other additives used in conventional metal working oils, such as emulsifiers other than the component (B) and the component (C), rust and corrosion preventives, disinfectants, extreme pressure agents, oiliness improvers, and antifoaming agents.

[0031] In practical use of the water-soluble metal working oil of the present invention, the above-described base liquids of various compositions are diluted with diluents, generally with water. The proper degree of dilution of the base liquids with water at the time of their use is generally not more than 2,000 times, preferably about from 5 to 400 times in weight ratio.

[0032] If the degree of dilution is more than 2,000 or is too small, it may become difficult to attain sufficiently the effects of the present invention by using the water-soluble metal working oil diluted in such a degree of dilution for cutting or grinding.

[0033] In cases where the water-soluble metal working oil of the present invention comprises the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and water as a diluent, the preferred amount of the oligomer component (A) is from 10 to 60 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C); the preferred amount of the anionic emulsifier (B) is from 25 to 80 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C); the preferred amount of the nonionic emulsifier (C) is from 2 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C); and the preferred amount of water is from 5 to 400 times the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C).

[0034] In cases where the water-soluble metal working oil of the present invention comprises the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), water as a diluent, and a mineral oil, the preferred amount of the oligomer component (A) is from 10 to 60 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil; the preferred amount of the mineral oil is from 1 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil and is not more than 50 % by weight of the total amount of the oligomer component (A) and the mineral oil; the preferred amount of the anionic emulsifier (B) is from 25 to 80 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil; the preferred amount of the nonionic emulsifier (C) is from 2 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil; and the preferred amount of water is from 5 to 400 times the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil.

[0035] Herein, both the base liquids and the diluted solutions obtained by diluting the base liquids with diluents such as water in a variety of degree of dilution belong to the water-soluble metal working oil of the present invention.

[0036] In preparation of the water-soluble metal working oil of the present invention, either of a base liquid state or of a diluted solution state, the order and method in which the predetermined components (in case of a diluted solution, components including diluents such as water) are mixed or added are not particularly limited, and the preparation can be carried out by mixing or adding the components in various orders and methods.

[0037] Thus, the water-soluble metal working oil of the present invention can be prepared.

[0038] The water-soluble metal working oil of the present invention can be suitably used in various metal working fields, such as polishing, forming, drawing, and rolling, to say nothing of cutting and grinding, by optionally diluting it with diluents such as water according to the usage. The water-soluble metal working oil of the present invention has excellent advantages as described below. First of all, the water-soluble metal working oil of the present invention can be used particularly suitably both for. cutting and for grinding in a form of a diluted solution prepared by diluting the above-described base liquid with water within the above-described range of the degree of dilution. In addition, the water-soluble metal working oil of the present invention has excellent characteristics in that it hardly putrefies and can effectively work to prevent the putrefaction of coolants. Further, the water-soluble metal working oil of the present invention can extend the tool lives and improve the quality of machined surfaces in cutting or the like, and also causes no loading of grindstones in grinding or the like, thereby enabling dressing intervals to be extended, and therefore, it can be suitably used as a working oil both for cutting and for grinding.

[0039] The following examples are presented as specific illustrations of the claimed invention. It should be understood, however, that the invention is not limited to the specific details set forth in the examples.

EXAMPLES 1 TO 4 AND COMPARATIVE EXAMPLES 1 TO 4

[0040] Metal working oils having the compositions as shown in Table 1 were prepared, and each working oil was subjected to a grinding test (Examples 1 and 2 and Comparative Examples 1 and 4) and to a cutting test (Examples 1 to 4 and Comparative Examples 1 to 4), and the working efficiency attained in each Example was evaluated. Further, each metal working oil was subjected to an anti-putrefaction test.

[0041] Properties of the components used for the preparation of the metal working oils, properties of the objects of cutting or grinding, conditions of the working tests, the methods of evaluating working efficiency, the conditions and methods of anti-putrefaction tests, etc. are shown by the explanatory notes in Table 1.

[0042] The results are shown in Table 1.

[0043] From the results shown in Table 1, it became apparent that, for example:

(a) The metal working oil of the present invention, which contained an oligomer of an a -olefin, shows improvement in the working efficiency as compared with the conventional metal working oil, the base oil of which is a mineral oil (Compare Example 2 with Comparative Example 1.);

(b) The metal working oil of the present invention also exhibits a high working efficiency in grinding efficiency as compared even with the metal working liquid comprising the conventional oil of solution type (Compare Example 2 with Comparative Example 4.).

Explanation of the explanatory notes in Table 1

[0044] 

note ¹⁾: The content of every component is shown in % by weight reflecting the amount of the component contained in each base liquid for a working oil.

note ²⁾: an oligomer of 1-decene having a kinematic viscosity of 6 cSt (100 ° C)

note ³⁾: diethanolamine salt of oleic acid

note ⁴⁾: polyoxyethylene nonyl phenyl ether

note ⁵⁾: esters of sorbitans with oleic acid

note ⁶⁾: 150 Neutral

note ⁷⁾: chlorinated paraffin

note ⁸⁾: other additives including rust and corrosion preventives

note ⁹⁾: working efficiency tests and evaluation thereof

(1) cutting: milling test (Each working oil was diluted 10 times with water to be subjected to the test under the following conditions.) Sandwiched materials constructed with a stainless steel and a casting were subjected to milling, and the number of the materials which were processed before the milling cutter used was broken and the surface quality (R_max) attained by the processing just before the breakage were evaluated.

Conditions

[0045] Machine tool: a milling machine (produced by HITACHI SEIKI CO., LTD.) Cutter: a milling cutter (0 100) (produced by Sumitomo Electric Industries, Ltd., DHG4100R) Tip: T25A IGETAROI SPCN42TR Machined object: 80^w x 150 x 90" (mm) (A sheet of SUS310SE sandwiched between two sheets of FC-25) Testing conditions: cutting speed V = ₁4.0 m/min feed f = 0.12 mm/rev depth of cut t=0.4 mm (2) Grinding: centerless grinding test (Each working oil was diluted 20 times with water to be subjected to the test under the following conditions.) Pins made of a stainless steel were subjected to centerless grinding, and the working efficiency was evaluated from the number of the pins processed before the first dressing. The loading of the used grindstone was visually observed.

Conditions

[0046] Machine tool: a centerless grinding machine Grindstone: GC (0 500) Ground object: SUS316 Revolution: 2,600m/min

[0047] note ¹⁰⁾: anti-putrefaction test and evaluation thereof

[0048] The anti-putrefaction test was conducted according to a shaking culture method under the following conditions, and the test results were evaluated. Amount of liquid: 100 ml (2 ml of a base liquid was diluted 50 times with distilled water.) Temperature: 30° C Revolution: 160 rpm Putrefying bacteria: the following stock culture bacteria ⁵ 5 ml Chips: FC-25 3 g Culture period: two weeks

[0049] ^* aerobic bacteria: 10⁷ (number)/ml fungus: 10⁴ (number)/ml sulfuric acid-reduced bacteria: 10⁶ (number)/ml

Claims

1. A water-soluble metal working oil, comprising: an oligomer component selected from the group consisting of oligomers of a -olefins of 6 to 14 carbon atoms and hydrogenation derivatives of the oligomers.

2. The water-soluble metal working oil as claimed in claim 1, wherein the oligomer component is selected from the group consisting of oligomers of a -olefins of 8 to 12 carbon atoms and hydrogenation derivatives of the oligomers.

3. The water-soluble metal working oil as claimed in claim 1, wherein the oligomer component is an oligomer of 1-decene.

4. A water-soluble metal working oil, comprising :

(A) the oligomer component as claimed in any of the claims 1 to 3, and

(B) an anionic emulsifier.

5. The water-soluble metal working oil as claimed in claim 4, wherein the anionic emulsifier (B) is selected from the group consisting of alkaline metal salts of fatty acids of 8 to 30 carbon atoms, alkanolamine salts of fatty acids of 8 to 30 carbon atoms, and alkaline metal salts of sulfonic acids.

6. The water-soluble metal working oil as claimed in claim 4, wherein the anionic emulsifier (B) is selected from the group consisting of diethanolamine salt of oleic acid, sodium sulfonates, and potassium oleate.

7. The water-soluble metal working oil as claimed in claim 4, wherein the oligomer component (A) is an oligomer of 1-decene, and the anionic emulsifier (B) is selected from the group consisting of diethanolamine salt of oleic acid, sodium sulfonates, and potassium oleate.

8. A water-soluble metal working oil, which comprises :

(A) an oligomer component as claimed in any of the claims 1 to 3;

(B) an anionic emulsifier; and

(C) a nonionic emulsifier.

9. The water-soluble metal working oil as claimed in claim 8, wherein the anionic emulsifier (B) is as defined in claim 5 or claim 6.

10. The water-soluble metal working oil as claimed in claim 8 or 9, wherein the nonionic emulsifier (C) is selected from the group consisting of polyoxyalkylene emulsifiers, esters of carboxylic acids with alcohols, and nitrogen-containing emulsifiers.

11. The water-soluble metal working oil as claimed in claim or 9, wherein the nonionic emulsifier (C) is selected from the group consisting of polyoxyethylene nonyl phenyl ether and esters of sorbitans with oleic acid.

12. The water-soluble metal working oil as claimed in claim 8, wherein the oligomer component (A) is an oligomer of 1-decene, the anionic emulsifier (B) is selected from the group consisting of diethanolamine salt of oleic acid, sodium sulfonates, and potassium oleate, and the nonionic emulsifier (C) is selected from the group consisting of polyoxyethylene nonyl phenyl ether and esters of sorbitans with oleic acid.

13. The water-soluble metal working oil as claimed in any of the claims 8 to 12, which further comprises water and wherein the amount of the oligomer component (A) is from 10 to 60 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C), the amount of the anionic emulsifier (B) is from 25 to 80 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C), the amount of the nonionic emulsifier (C) is from 2 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C), and the amount of water is from 5 to 400 times the total amount of the oligomer component (A), the anionic emulsifier (B), and the nonionic emulsifier (C).

14. The water-soluble metal working oil as claimed in any of claims 8 to 12, which further comprises water and a mineral oil and wherein the amount of the oligomer component (A) is from 10 to 60 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil, the amount of the mineral oil is from 1 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil, and is not more than 50 % by weight of the total amount of the oligomer component (A) and the mineral oil, the amount of the anionic emulsifier (B) is from 25 to 80 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil, the amount of the nonionic emulsifier (C) is from 2 to 30 % by weight of the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil, and the amount of water is from 5 to 400 times the total amount of the oligomer component (A), the anionic emulsifier (B), the nonionic emulsifier (C), and the mineral oil.