JP6351541B2 - Lubricating oil composition for metal working - Google Patents

Description

  The present invention relates to a lubricating oil composition for metal working, and particularly to a lubricating oil composition for machining.

Conventionally, various compositions have been used in metal working such as cutting and plastic working, and chlorine-based extreme pressure agents that are excellent in workability improvement effect and inexpensive have been used particularly frequently as metal working fluids.
However, in recent years, lubricating oils containing chlorinated extreme pressure agents have been pointed out as problems such as generation of dioxins during incineration, corrosion and damage of incinerators, and some organochlorine compounds are carcinogenic. It has been reported to have Accordingly, there is a need for the development of metalworking oils that do not contain chlorine. As metal processing oils that do not contain chlorine, those using sulfur base materials such as polysulfide, sulfurized fats and oils, calcium sulfonate, ZnDTP, and phosphorus base materials such as phosphate esters have been conventionally known (the following patent documents). 1-5). Among these, it is conventionally known that a combination of active polysulfide and sulfonate is particularly excellent.
However, these lubricating oil compositions do not have sufficient machining performance. Due to recent material hardness, high plasticity, and high machining efficiency, the cutting tool life and machining accuracy are reduced, and plastic working However, problems such as material breakage and tool breakage have occurred.

JP-A-6-313182 JP-A-6-330076 Japanese Patent Laid-Open No. 10-226795 JP 2004-059658 A JP 2003-073684 A Japanese Patent Application Laid-Open No. 2015-086347 Japanese Patent Laid-Open No. 2015-089900

  The present invention has been made in view of such circumstances, and provides a non-chlorine-based lubricating oil composition for metal processing that is excellent in processing performance and can be suitably used as a processing oil that can be applied under difficult processing conditions. The purpose is to do.

  As a result of earnest research on the above problems, the present inventors have superior cutting performance more than before by combining calcium salicylate and a specific sulfur-based additive in place of calcium sulfonate that has been frequently used as a cutting aid. In addition, the present inventors have found that a low-viscosity metal processing lubricant can be obtained and have completed the present invention.

（式中、Ｒ^１は炭素数１４〜２８の直鎖または分枝のアルキル基を示す。ｘは置換数を表し、１または２であり、ｘが２のときＲ^１は互いに同一でも異なっていても良い。） That is, the present invention provides at least one kind selected from a lubricating base oil, [A] a calcium salicylate having a metal ratio of 1 to 9 represented by the general formula (1), and [B] a sulfurized oil, sulfurized ester and polysulfide. It is a lubricating oil composition for metalworking characterized by containing a sulfur type additive.

(In the formula, R ¹ represents a linear or branched alkyl group having 14 to 28 carbon atoms. X represents the number of substitutions and is 1 or 2, and when x is 2, R ¹ may be the same or different from each other. May be.)

In addition, the present invention is the above-described lubricating oil composition for metal working, wherein R ¹ in the formula (1) is a linear or branched alkyl group having 14 to 18 carbon atoms.

（式中、Ｒ^２およびＲ^３はそれぞれ個別に水素または炭素数１〜２４のヒドロカルビル基を示す。ａ１、ｂ１、ａ２、ｂ２はそれぞれ個別に３以上の整数であり、ａ１とｂ１の和およびａ２とｂ２の和はそれぞれ個別に８〜１４である。ｙは１〜８の正の数を示す。） The present invention also provides the above-described lubricating oil composition for metal working, wherein the sulfurized ester is a compound represented by the general formula (2).

(Wherein R ² and R ³ each independently represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms. A1, b1, a2, and b2 each independently represent an integer of 3 or more, and the sum of a1 and b1 and (The sum of a2 and b2 is individually 8 to 14. y represents a positive number from 1 to 8.)

The present invention also provides the above-described lubricating oil composition for metal working, wherein the polysulfide is a compound represented by the general formula (3).
R ⁴ —Sz—R ⁵ (3)
(In the formula, R ⁴ and R ⁵ each independently represents a linear or branched alkyl group having 4 to 16 carbon atoms. Z represents a positive number of 2 to 8.)

  Further, the present invention is the above-described lubricating oil composition for metal working, which is for cutting work.

  According to the present invention, there is provided a lubricating oil composition for metal working that does not contain a chlorine-based extreme pressure agent, has few environmental problems, is excellent in processing performance, and can be applied under difficult processing conditions.

  Hereinafter, the present invention will be described in detail.

  As the lubricating base oil of the lubricating oil composition of the present invention, mineral oil, synthetic oil and fats and oils are used, and these may be a mixture.

  As mineral oil, for example, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing In addition, paraffinic mineral oil or naphthenic mineral oil refined by appropriately combining one or more refining treatments such as white clay treatment may be mentioned.

  Synthetic oils include, for example, propylene oligomer, polybutene, polyisobutylene, 1-octene oligomer, 1-decene oligomer, ethylene and propylene co-oligomer, ethylene and 1-octene co-oligomer, and ethylene and 1-decene. Poly α-olefin (PAO) such as co-oligomer or hydride thereof; isoparaffin; alkyl benzene such as monoalkylbenzene, dialkylbenzene, polyalkylbenzene; alkylnaphthalene such as monoalkylnaphthalene, dialkylnaphthalene, polyalkylnaphthalene; dioctyl adipate, dialkyl Dibasic acid esters such as 2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, ditridecyl glutarate; Tribasic acid esters such as limellitic acid; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane oleate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate; polyethylene glycol, polypropylene glycol Polyglycols such as polyoxyethyleneoxypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, polyoxyethyleneoxypropylene glycol monoether, polyethylene glycol diether, polypropylene glycol diether, polyoxyethyleneoxypropylene glycol diether; Monoalkyldiphenyl ether, dialkyldiphenyl Ethers, monoalkyl triphenyl ethers, dialkyl triphenyl ethers, tetraphenyl ethers, monoalkyl tetraphenyl ethers, dialkyl tetraphenyl ethers, phenyl ethers such as pentaphenyl ether; silicone oils; fluoroethers such as perfluoroethers, etc. These can be used alone or in combination of two or more.

  Examples of the fat include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, hydrogenated products thereof, or a mixture of two or more of these.

Kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 1 to 100 mm ² / s, more preferably 2~80mm ² / s, more preferably 3 to 50 mm ² / s. When the kinematic viscosity at 100 ° C. is less than 1 mm ² / s, the lubricity is lowered, and the working environment is deteriorated due to generation of mist, such being undesirable. On the other hand, when it exceeds 100 mm 2 / ^s, is not preferable because the amount of oil to be carried away adhering to the workpiece is increased.

Kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 1 to 500 mm ² / s, more preferably 3~400mm ² / s, more preferably 5 to 50 mm ² / s. If it is less than 1 mm ² / s, the workability is lowered, and if it exceeds 500 mm ² / s, the washability is lowered.

  The content of the lubricating base oil is not particularly limited, but is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and more preferably 90% by mass or more based on the total amount of the lubricating oil composition. Particularly preferred. On the other hand, 98.5 mass% or less is preferable and 97 mass% or less is more preferable.

  The lubricating oil composition of the present invention contains calcium salicylate having a metal ratio of 1 or more and 9 or less represented by the general formula (1) as the component [A].

In the general formula (1), R ¹ represents a linear or branched alkyl group having 14 to 28 carbon atoms. The number of carbon atoms in R ¹ is particularly preferably 14 to 18 because the processing efficiency is better. x represents the number of substitutions and is 1 or 2. When x is 2, R ¹ may be the same as or different from each other.

Specific examples of the alkyl group represented by R ¹ include a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group. Among these, a tetradecyl group and a pentadecyl group are exemplified. , A hexadecyl group, a heptadecyl group, and an octadecyl group are preferable. These may be linear or branched, and may be a primary alkyl group, a secondary alkyl group or a tertiary alkyl group.

  Calcium salicylate can be obtained by reacting alkyl salicylic acid directly with a calcium base such as calcium oxide or hydroxide, or by replacing it with an alkali metal salt such as sodium salt or potassium salt and then replacing with calcium salt. Neutral (normal salt) calcium salicylate; or basic calcium salicylate obtained by heating neutral calcium salicylate and excess alkaline earth metal salt or alkaline earth metal base in the presence of water; Also included are overbased (superbasic) calcium salicylates obtained by reacting alkaline earth metal hydroxides with carbon dioxide or boric acid in the presence of calcium salicylates.

The metal ratio of the component [A] must be 1 or more, preferably 1.5 or more, and more preferably 2 or more. On the other hand, it must be 9 or less, preferably 7 or less, more preferably 5 or less, and particularly preferably 3 or less.
When the metal ratio is less than 1, cutting and grinding workability may be insufficient when used in combination, whereas when the metal ratio exceeds 9, the metal salicylate detergent is unstable and the product is This is not preferable because it may cause precipitation.
The metal ratio here is represented by the valence of metal element × metal element content (mol) / soap group (that is, group such as alkyl salicylic acid group) content (mol). The calcium content relative to the alkyl salicylic acid group content in the calcium salicylate is shown.

Although the total base number of [A] component does not have a restriction | limiting in particular, It is preferable that it is 50-500 mgKOH / g, More preferably, it is 100-450 mgKOH / g. When the total base number is less than 50 mgKOH / g, the lubricity improvement effect tends to be insufficient. On the other hand, those whose total base number exceeds 500 mgKOH / g are very difficult to manufacture and difficult to obtain. It is not preferable.
The total base number referred to here is JIS K 2501 “Petroleum products and lubricants—Test method for neutralization number”. The total base number [mgKOH / g] by the perchloric acid method measured according to the above.

Although there is no restriction | limiting in particular in content of [A] component, 0.5 mass% or more is preferable on the basis of the composition whole quantity, 1 mass% or more is more preferable, and 1.5 mass% or more is further more preferable. On the other hand, 20 mass% or less is preferable, 15 mass% or less is more preferable, 10 mass% or less is more preferable, 7 mass% or less is especially preferable, and 5 mass% or less is the most preferable.
If the content of the component [A] is less than 0.5% by mass, the effect of improving the machining efficiency and the tool life tends to be insufficient, and if it exceeds 20% by mass, the stability of the metalworking oil composition decreases. Therefore, precipitates tend to be generated, which is not preferable.

The lubricating oil composition of the present invention contains a specific sulfur-based additive as the [B] component.
Specifically, the specific sulfur-based additive is sulfurized fat, sulfurized ester or polysulfide. Each of these may use one type of compound or two or more types of compounds. Two or more kinds of sulfurized fats and oils, sulfurized esters and polysulfides can be contained at the same time.

  Sulfurized fats and oils refer to compounds obtained by sulfurizing fats and oils having unsaturated bonds. Such fats and oils are not particularly limited, and examples thereof include the beef tallow, pork tallow, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, or a mixture of two or more thereof. Moreover, there is no restriction | limiting in particular in the sulfuration processing method, Arbitrary methods can be selected.

  The sulfurized ester refers to a compound obtained by sulfurizing an ester compound having an unsaturated bond. There is no restriction | limiting in particular as such sulfurized ester, Arbitrary compounds can be used. Of these, in the present invention, a sulfurized ester represented by the following formula (2) is preferable.

In the general formula (2), R ² and R ³ each independently represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms, preferably 1 to 8 carbon atoms.
Specific examples of the hydrocarbyl group having 1 to 24 carbon atoms include an alkyl group, an alkenyl group, a cycloalkyl group, an alkylcycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group. Among these, an alkyl group is preferable, and a methyl group and an ethyl group are particularly preferable.

In the general formula (2), a1, b1, a2, and b2 are each independently an integer of 3 or more, and the sum of a1 and b1 and the sum of a2 and b2 are individually 8 to 14, preferably 10 to 12, respectively. is there.
If the sum of a1 and b1 and the sum of a2 and b2 are less than 8, the solubility is lowered. On the other hand, if it exceeds 14, the workability is lowered, which is not preferable.

  In the above formula (2), y represents the number of sulfur bridges, but in the mixture represents the average number of sulfur bridges. Usually, the compound obtained by sulfiding is a mixture of compounds having different numbers of sulfur bridges. y (average number of sulfur bridges) is 1 to 8, preferably 2 to 6.

The sulfurized ester represented by the above formula (2) is obtained by sulfur-crosslinking an ester of an unsaturated fatty acid having 14 to 20 carbon atoms (for example, oleic acid) having one unsaturated bond in the molecule. The raw material unsaturated fatty acid ester is preferably purified, but can be used even if it contains impurities. The content of impurities in the raw material is preferably 50% by mass or less, more preferably 30% by mass or less, and most preferably 10% by mass or less.
As the unsaturated fatty acid ester, oleic acid esters such as methyl oleate, ethyl oleate, and propyl oleate are preferable, and among these, methyl oleate is preferable because it exhibits an effective friction reducing effect.

Polysulfide refers to all compounds cross-linked with two or more sulfur, and dialkyl polysulfide compounds are particularly preferable. Dialkyl polysulfide is a compound represented by the following general formula (3).
R ⁴ —Sz—R ⁵ (3)

In the general formula (3), R ⁴ and R ⁵ each independently represent a linear or branched alkyl group having 4 to 16 carbon atoms, preferably 6 to 14 carbon atoms.

  In the above formula (3), z represents the number of sulfur bridges, but in the mixture represents the average number of sulfur bridges. Usually, the compound obtained by sulfiding is a mixture of compounds having different numbers of sulfur bridges. 2-8 are preferable and, as for z (average number of sulfur bridges), 3-6 are more preferable.

Specific examples of R ⁴ and R ⁵ in the general formula (3) include n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, and various octyl groups. Groups, various nonyl groups, various decyl groups, various dodecyl groups, and the like.

  Specific examples of the dialkyl polysulfide include di-tert-butyl polysulfide, di-tert-octyl polysulfide, di-tert-nonyl polysulfide, di-sec-octyl polysulfide, di-sec-decyl polysulfide, di-sec-dodecyl polysulfide, Examples include di-sec-hexadecyl polysulfide.

Although there is no restriction | limiting in particular in content of a [B] component, 1 mass% or more is preferable on the basis of the composition whole quantity, 1.5 mass% or more is preferable, 2 mass% or more is more preferable, 2.5 mass% or more is Further preferred. On the other hand, 20 mass% or less is preferable, 15 mass% or less is more preferable, 10 mass% or less is more preferable, 7 mass% or less is especially preferable, and 5 mass% or less is the most preferable.
When the content of the component [B] is less than 1% by mass, a sufficient effect as an extreme pressure agent cannot be obtained, and when it exceeds 20% by mass, the oxidation stability of the lubricating oil composition tends to decrease. Therefore, it is not preferable respectively.

  In addition, the lubricating oil composition of the present invention may contain conventionally known additives other than the above-described [A] component and [B] component, if necessary. Examples of such additives include metal detergents other than [A] component; non-chlorine extreme pressure agents other than [B] component; wetting agents such as diethylene glycol monoalkyl ether; acrylic polymer, paraffin wax, microwax, Film forming agents such as slack wax and polyolefin wax; water displacement agents such as fatty acid amine salts; solid lubricants such as graphite, graphite fluoride, molybdenum disulfide, boron nitride, polyethylene powder; amines, alkanolamines, amides, carboxylic acids , Carboxylate, sulfonate, phosphoric acid, phosphate, partial esters of polyhydric alcohol, etc .; metal deactivators such as benzotriazole, thiadiazole; methyl silicone, fluorosilicone, polyacrylate, etc. Antifoaming agent; alkenyl succinimide, benzylamine Ashless dispersants such as polyalkenyl amines polyaminoamide; and the like. The content when these known additives are used in combination is not particularly limited, but the amount is such that the total content of these known additives is 0.1 to 10% by mass based on the total amount of the lubricating oil composition. It is preferable to add. It is preferable that chlorine is not substantially contained, and the chlorine element content is 10 mass ppm or less, particularly 1 mass ppm or less.

The kinematic viscosity of the lubricating oil composition of the present invention is not particularly limited, but it is preferable that the viscosity is not too high from the viewpoint of easy supply to a processed site. That is, the kinematic viscosity at 40 ° C. is preferably 500 mm ² / s or less, more preferably 400 mm ² / s or less, and most preferably 50 mm ² / s or less. On the other hand, it is preferable that the viscosity is not too low in terms of sufficient oil film formation at the processing site. That is, the kinematic viscosity at 40 ° C. is preferably 1 mm ² / s or more, more preferably 3 mm ² / s or more, and further preferably 5 mm ² / s or more.

  Since the lubricating oil composition of the present invention is excellent in processing performance such as processing efficiency and tool life, and further in handleability, it can be suitably used in a wide range of applications in the metal processing field. The metal processing here is not limited to cutting / grinding, but broadly means general metal processing. Moreover, the lubricating oil composition of the present invention can be applied not only to metal processing by a normal oil supply method, but also to cutting / grinding processing (MQL processing) and the like with an extremely small amount of oil supply.

  Specific examples of metal processing include cutting, grinding, rolling, forging, pressing, drawing, rolling, and the like. Among these, the lubricating oil composition of the present invention is very useful for applications such as cutting, grinding, and rolling.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Examples 1-10 and Comparative Examples 1-4)
Each lubricating oil composition was prepared as shown in Table 1. The content of the base oil is based on the total amount of the base oil, and the content of the additive is based on the total amount of the composition. The following tests were conducted on each lubricating oil composition, and the results are also shown in Table 1.
The calcium salicylate was added so that the amount of calcium was 1000 ppm by mass based on the total amount of the composition, and the sulfur-based additive was added so that the amount of sulfur was 1% by mass based on the total amount of the composition.

(Tapping test)
About each lubricating oil composition, the tapping energy efficiency E with respect to standard oil was measured on the following processing conditions, and cutting performance evaluation by this test was performed.
・ Work material: S25C
・ Tool diameter: 8mm
・ Tap pitch: 1.25mm
-Tap rake angle: 10 degrees-Tap biting angle: 1.5 degrees-Tap pilot hole diameter: 6.8 mm
・ Rotation speed: 360rpm
・ Number of processing: 1 hole ・ Standard oil: DIDA (diisodecyl adipate)
-Supply oil amount: 9.0 ml / min

  The tapping energy efficiency E is defined by tapping energy efficiency E (%) = (tapping energy when using a comparative standard oil) / (tapping energy when using an oil composition).

  The lubricating oil composition for metal working of the present invention is useful because it does not contain a chlorinated extreme pressure agent, is easy to handle with few environmental problems, and can improve machining efficiency and tool life. .

Claims (4)

Lubricating base oil is 90 to 98.5% by mass based on the total amount of the composition , and [A] calcium salicylate having a metal ratio of 1 to 9 represented by the general formula (1) is 0.5 to 5 % by mass based on the total amount of the composition. % , And [B] 1 to 7% by mass of a sulfurized ester based on the total amount of the composition, a lubricating oil composition for metalworking.

(In the formula, R ¹ represents a linear or branched alkyl group having 14 to 28 carbon atoms. X represents the number of substitutions and is 1 or 2, and when x is 2, R ¹ may be the same or different from each other. May be.) 2. The lubricating oil composition for metal working according to claim 1, wherein R ¹ in the formula (1) is a linear or branched alkyl group having 14 to 18 carbon atoms. The lubricating oil composition for metal working according to claim 1 or 2, wherein the sulfurized ester is a compound represented by the general formula (2).

(Wherein R ² and R ³ each independently represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms. A1, b1, a2, and b2 each independently represent an integer of 3 or more, and the sum of a1 and b1 and (The sum of a2 and b2 is individually 8 to 14. y represents a positive number from 1 to 8.) The lubricating oil composition for metal working according to any one of claims 1 to 3 , which is for cutting work.