JP2008179664A - Lubricating oil for processing copper pipe and manufacturing method of copper pipe using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil for processing copper pipes that exhibits excellent lubricating properties in draw working or in form rolling, generates little copper abrasion powder, permits excellent dispersibility of a copper abrasion powder therein, prevents cohesion of a copper abrasion powder on a plug and adhesion of a copper abrasion powder on the surface of a copper pipe, is excellent in oxidation stability, gives a small amount of residual oil after annealing and causes neither seizure nor discoloration on the external surface on annealing. <P>SOLUTION: The lubricating oil for processing copper pipes for processing a copper pipe composed of copper or a copper alloy comprises, as an oily agent, 0.5-70 wt.% of at least one or more 11-22C fatty acid esters constituted of a saturated fatty acid and esters of a polyhydric alcohol with a saturated fatty acid and the rest, as a base oil, comprising polyisobutylene having a molecular weight of at least 30,000 and polyisobutylene or isoparaffin having a molecular weight of at most 400 or a purified mineral oil containing at most 10 wt.% of aromatic components, and has viscosity of at most 1,000 cSt. The lubricating oil has kinematic viscosity of 50-2,000 cSt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricating oil for copper pipe processing used for manufacturing a copper pipe made of copper or a copper alloy used for heat exchange or the like of an air conditioner or a refrigerator / refrigerator.

  Conventionally, heat transfer tubes have been used in heat exchangers of air conditioners such as room air conditioners and refrigerators such as refrigerators and freezers. As the heat transfer tube, a copper tube made of copper and a copper alloy (hereinafter referred to as copper) excellent in heat transfer property, workability, and corrosion resistance is used. The copper pipe is provided with lubricating oil on the inner surface and the outer surface, and is subjected to a drawing process so as to have a predetermined size and an inner surface shape, thereby forming a level-wound coil in which copper pipes of several thousand meters are aligned and wound. Thereafter, an annealing process is performed to obtain a predetermined tempering. Actually, in the annealing treatment, the inside of the copper tube is replaced with a non-oxidizing gas such as nitrogen gas or hydrogen gas, and then annealed at about 500 ° C. for about 1 hour.

  In general, in the drawing process, in order to prevent seizure and make it easy to form a predetermined groove shape, a lubricating oil in which an oily agent such as fatty acid ester, alcohol, polyol ester or the like is added to a high-viscosity synthetic polymer hydrocarbon is copper. It is supplied to the inside and outside of the pipe. However, when these lubricating oils are used, there are cases where the copper tube surface cannot be completely evaporated by annealing in the subsequent process, and the copper tube surface changes to black (outer surface discoloration).

  In recent years, from the viewpoint of improving production efficiency and yield, drawing reduction tends to increase in order to reduce the number of drawing passes. Further, from the viewpoint of quality improvement and yield improvement, it is strongly required that the copper tube surface has no burn-in scratches. In order to solve these problems, an oily agent or an extreme pressure agent excellent in boundary lubricity is excessively added, or a highly viscous lubricating oil is used. The above-mentioned oiliness agent is more excellent in boundary lubricity, and the more the effect is exerted, the more chemical wear is generated and the amount of generated copper wear powder is also increased.

In addition, the lubricating oil used for drawing is often circulated for cost reduction, and in this case, the filter wears the copper abrasion powder without removing it and adheres to the surface of the copper tube to deteriorate the surface quality. There's a problem. Furthermore, copper wear powder may adhere to the drawing machine, peripheral equipment members, tank walls, piping, and the like, thereby deteriorating the environment.
Furthermore, by carrying out circulation use for a long time, the oxidative deterioration of the lubricating oil proceeds and a heavy component is generated. There is a problem that this heavy component remains on the surface of the copper tube and discoloration occurs after annealing.

  Moreover, a copper pipe may be rolled in order to make a groove in the copper pipe for the purpose of further improving thermal conductivity, when it becomes a product as it is after the drawing. When the above-described lubricating oil is used, when it becomes a product as it is after the drawing, a problem of bad odor or a problem that the lubricating oil cost increases.

  Further, the drawn lubricating oil remaining in the tube or on the outer surface is easily hydrolyzed when there is heat and moisture, and as a result, lower acids such as formic acid and acetic acid may be generated. Copper pipes that have become products are often left in a hot and humid environment before shipping or assembling at the customer's site, and are often transported by container transport etc. Although rare, when the conditions of moisture, heat, oxygen, and the amount of lubricating oil become certain conditions, the copper tube surface may cause corrosion called “ant's nest corrosion”.

  On the other hand, when rolling after drawing, lubricating oil adheres to the inner surface of the copper tube, and the adhering lubricating oil is vaporized or thermally decomposed by being annealed in a non-oxidizing gas. These vaporized substances are not released to the outside of the copper tube only by volume expansion, but are aggregated when the copper tube is cooled, and remain as oil on the inner surface of the copper tube. The amount depends on the type of lubricating oil, the replacement gas, or the length of the copper tube, the size of the coil, the annealing rate, and the cooling rate.

  When there is much residual oil in a copper pipe, it will become easy to produce the joining defect in the brazing joining performed at the time of apparatus assembly. In addition, chlorine-free alternative chlorofluorocarbon refrigerants are used in accordance with regulations on the use of chlorofluorocarbons in recent years, but they are hardly compatible with copper pipe residual oil. As a result, contamination caused by the residual oil and the chlorine-free alternative chlorofluorocarbon refrigerant remains in the copper tube, which causes problems such as blocking of the capillary part and lowering the performance of the refrigerator. Countermeasures are being studied to reduce the risk.

For example, a method of cleaning the inner surface of a copper tube after processing, a method of annealing a copper tube in a vacuum (Patent Document 1), a material that has been vaporized or pyrolyzed and vaporized by annealing while passing DX gas during annealing. And a method for minimizing residual oil (Patent Document 2) has been reported.
However, these conventional techniques have the drawbacks that productivity is reduced and a huge facility cost and facility installation space are required.

JP-A-1-287258 JP-A-6-170348

  The present invention has been made in view of such conventional problems, and is excellent in lubricity by drawing or rolling, has little generation of copper wear powder, and has excellent dispersibility of copper wear powder in lubricating oil, A copper tube that prevents adhesion of copper wear powder to the plug and adheres to the surface of the copper tube, has excellent oxidation stability, has little residual oil after annealing, and does not cause seizure or discoloration on the outside during annealing. It is intended to provide lubricating oil for processing.

（但し、Ｒ¹は、炭素数９〜１７のアルキル基であり、Ｒ²は炭素数１〜４の炭化水素基である。） 1st invention is the lubricating oil for copper pipe processing for processing the copper pipe which consists of copper or a copper alloy,
As the oily agent, one or two or more of a fatty acid ester composed of a saturated fatty acid represented by the following general formula (1) and an ester of a polyhydric alcohol and a saturated fatty acid having 10 to 18 carbon atoms is reduced to 0. 5 to 70% (wt%, the same shall apply hereinafter)
As the base oil, the remainder contains polyisobutylene having a molecular weight of 30000 or more and polyisobutylene or isoparaffin having a molecular weight of 400 or less, or a refined mineral oil having a content of aromatic components of 1000 cSt or less having a content of 10% or less,
The kinematic viscosity is 50 to 2000 cSt, and is in a lubricating oil for copper tube processing (Claim 1).

(However, R ¹ is an alkyl group having 9 to 17 carbon atoms, and R ² is a hydrocarbon group having 1 to 4 carbon atoms.)

  The lubricating oil for copper tube processing of the present invention has excellent lubricity in drawing or rolling by selecting the components of the oily agent and base oil and adjusting the kinematic viscosity, and the occurrence of copper wear powder is small. Excellent dispersibility of copper wear powder in lubricating oil, prevents copper wear powder from adhering to the plug, prevents copper wear powder from adhering to the surface of the copper tube, has excellent oxidation stability, and the amount of residual oil after annealing Therefore, it is possible to obtain a lubricating oil for copper tube processing that has little seizure and no discoloration on the outer surface during annealing.

  That is, as an essential component of the oily agent, 0.5 or more of one or more of fatty acid esters composed of saturated fatty acids represented by the general formula (1) and esters of polyhydric alcohols and saturated fatty acids is added. Contains ~ 70%. As a result, even in severe boundary lubrication areas, there is little generation of copper wear powder, it is excellent in dispersibility of copper wear powder in lubricating oil, and it is possible to suppress the adhesion of copper wear powder to the plug, which is necessary for drawing. The force can be reduced. Moreover, even if it is excellent in oxidation stability and is used for a long period of time, it can prevent oxidation deterioration of the lubricating oil and suppress discoloration of the surface of the copper tube after annealing.

  The base oil includes polyisobutylene having a molecular weight of 30,000 or more, polyisobutylene or isoparaffin having a molecular weight of 400 or less, or one or more kinds of refined mineral oil having a content of aromatic components of 1000 cSt or less and 10% or less. By adjusting the ratio of the combination, the kinematic viscosity of the entire lubricating oil is adjusted to 50 to 2000 cSt. Thereby, lubricity can be improved, excellent moldability can be maintained, the amount of residual oil after annealing can be reduced, and oxidation degradation can be made difficult.

2nd invention supplies the said lubricating oil for copper pipe processing of 1st invention to the copper pipe which consists of copper or a copper alloy, and performs a drawing process or a rolling process, The manufacturing method of the copper pipe characterized by the above-mentioned (Claim 5).
The copper tube manufacturing method of the present invention uses the above-mentioned copper tube processing oil of the first invention in the drawing process or the rolling process, so that there is little adhesion of copper wear powder to the surface of the copper pipe, and seizure occurs during annealing. It is possible to produce a copper tube that has no discoloration on the outer surface and a small amount of residual oil after annealing.

The lubricating oil for copper tube processing of the first invention is an oily agent, one of fatty acid esters composed of saturated fatty acids represented by the above general formula (1) and esters of polyhydric alcohols and saturated fatty acids, or 2 or more types are contained 0.5 to 70%.
When the content of the oily agent is less than 0.5%, there is a problem that the boundary lubricity is poor and the generation of copper wear powder increases. On the other hand, when the content of the oily agent exceeds 70%, the volatilization and decomposition of the oily agent does not sufficiently proceed during annealing, and a part of the oily agent remains in the pipe, and the residual oil after annealing increases. In addition, there is a problem that an insufficiently decomposed material adheres to the outer surface of the pipe and the outer surface of the copper pipe is discolored during annealing.

In addition, when the carbon number of the alkyl group R ¹ of the fatty acid ester of the general formula (1) is 8 or less, and the saturated fatty acid of the ester of the polyhydric alcohol and the saturated fatty acid having 10 to 18 carbon atoms has 9 carbon atoms. In the following cases, there is a problem that the boundary lubricity is inferior. On the other hand, when the carbon number of the alkyl group R ¹ is 18 or more and when the saturated fatty acid of the ester of the polyhydric alcohol and the saturated fatty acid having 10 to 18 carbon atoms has 19 or more, the melting point is high. In addition, there is a possibility that handling at the time of manufacturing the lubricating oil becomes difficult, and there is a possibility that the amount of residual oil after annealing increases.

  Moreover, when the fatty acid ester of the general formula (1) and the ester of the polyhydric alcohol and the saturated fatty acid having 10 to 18 carbon atoms are composed of unsaturated fatty acid, the oxidation stability is inferior and long-term circulation is used. When performing, oxidation deterioration of lubricating oil progresses, and a heavy component is generated. This heavy component remains on the surface of the copper tube, and discoloration occurs on the copper tube surface after annealing. Moreover, when the said ester consists of unsaturated fatty acid, there exists a possibility that a polymerization reaction may arise and the amount of residual oil may increase.

Further, when the hydrocarbon group R ² has 5 or more carbon atoms, industrial production is difficult, which may lead to an increase in cost and handling of the lubricating oil.
Further, examples of the hydrocarbon group R ^2, an alkyl group and the like, the hydrocarbon radical R ² is preferably an alkyl group.

  Examples of the polyhydric alcohol include neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, pentaerythritol, dipentaerythritol, 2-butyl-2-ethyl-1,3-propanediol, and 2-methyl. -2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, and the like.

  Examples of the ester of the polyhydric alcohol and the saturated fatty acid include neopentyl glycol ester, trimethylol propane ester, and pentaerythritol ester.

Examples of the neopentyl glycol ester include neopentyl glycol capric acid diester, neopentyl glycol ester myristic acid ester, neopentyl glycol lauric acid monoester, neopentyl glycol lauric acid diester, neopentyl glycol stearic acid monoester, neopentyl glycol stearin. Acid diester, neopentyl glycol isostearic acid monoester, neopentyl glycol isostearic acid diester, complex ester of neopentyl glycol 2 mol, dimer acid 1 mol, stearic acid 2 mol, and the like.
The neopentyl glycol ester is particularly preferably an ester of stearic acid or isostearic acid.

Examples of the trimethylolpropane ester include trimethylolpropane capric acid monoester, trimethylolpropane capric acid diester, trimethylolpropane capric acid triester, trimethylolpropane lauric acid monoester, trimethylolpropane lauric acid diester, trimethylolpropane Methylolpropane lauric acid triester, trimethylolpropane stearic acid monoester, trimethylolpropane stearic acid diester, trimethylolpropane stearic acid triester, trimethylolpropane isostearic acid monoester, trimethylolpropane isostearic acid diester, trimethylolpropane isostearic acid Triester and trimethylol propane 2 mol dimer acid 1 mol - 4 moles of complex ester and stearic acid.
As the trimethylolpropane ester, stearic acid and isostearic acid esters are particularly preferable.

Examples of the pentaerythritol ester include pentaerythritol capric acid monoester, pentaerythritol capric acid diester, pentaerythritol capric acid triester, pentaerythritol capric acid tetraester, pentaerythritol lauric acid monoester, pentaerythritol lauric acid diester, Pentaerythritol lauric acid triester, pentaerythritol lauric acid tetraester, pentaerythritol stearate monoester, pentaerythritol stearate diester, pentaerythritol stearate triester, pentaerythritol stearate tetraester, pentaerythritol isostearic acid monoester, pentaerythritol Isoste Phosphate diester, pentaerythritol isostearic acid triester, pentaerythritol isostearic acid tetraester, dipentaerythritol capric acid monoester, dipentaerythritol capric acid diester, dipentaerythritol capric acid triester, dipentaerythritol capric acid tetraester, di Pentaerythritol capric acid pentaester, dipentaerythritol capric acid hexaester, dipentaerythritol lauric acid monoester, dipentaerythritol lauric acid diester, dipentaerythritol lauric acid triester, dipentaerythritol lauric acid tetraester, dipentaerythritol lauryl Acid pentaester, dipentaerythritol lauric acid Kisaesuteru, and complex esters of pentaerythritol 2 mole dimer acid 1 mole of stearic acid 6 mol, and the like.
The pentaerythritol ester is particularly preferably an ester of stearic acid or isostearic acid.

In addition, the copper pipe working lubricant has a base oil of the balance, a base oil of the balance, a polyisobutylene having a molecular weight of 30000 or more, and a polyisobutylene or isoparaffin having a molecular weight of 400 or less, or an aromatic component content of 10%. It contains the following refined mineral oil of 1000 cSt or less.
When the polyisobutylene having an average molecular weight of 30000 or more is not included, there is a problem that the amount of oil introduced into the friction surface is small and lubrication is insufficient. On the other hand, when polyisobutylene or isoparaffin having an average molecular weight of 400 or less or a refined mineral oil having a content of aromatic components of 10% or less and 1000 cSt or less is included, the viscosity becomes high, handling becomes difficult and workability deteriorates. There is a problem of making it.
In addition, the content of the base oil is basically in a range in which the content of the additive can be ensured to prevent insufficient lubrication and ensure proper moldability.

The polyisobutylene having an average molecular weight of 30,000 or more is preferably a polyisobutylene having an average molecular weight of 30,000 to an average molecular weight of 60000, which is an industrially available range.
In addition, the isoparaffin or polyisobutylene having an average molecular weight of 400 or less is preferably an isoparaffin or polyisobutylene having an average molecular weight of 80 to an average molecular weight of 400 in consideration of the danger of ignition and the odor of the lubricating oil.

Specific examples of the refined mineral oil having a kinematic viscosity of 1000 cSt or less with a content of the aromatic component of 10% or less include, for example, paraffin mineral oil, naphthenic mineral oil, non-aromatic mineral oil, and the like.
In the refined mineral oil, when the content of the aromatic component exceeds 10% by weight, the oxidation stability is inferior, the oxidation deterioration of the lubricating oil proceeds in a shorter period of time, and the surface of the copper tube is discolored after annealing. There is a problem that occurs. Moreover, when content of the said aromatic component exceeds 10%, there exists a possibility that a polymerization reaction may arise and the amount of residual oil may increase.
The content of the aromatic component is more preferably 5% or less.

  As the base oil, it is useful to use polyisobutylene and isoparaffin together. In this case, there is an effect on environmental improvement and lubricity. Furthermore, since polyisobutylene or isoparaffin is more easily pyrolyzed than mineral oil having a kinematic viscosity, the amount of residual oil after annealing can be reduced.

The copper pipe working lubricant has a kinematic viscosity of 50 to 2000 cSt (at 40 ° C.).
When the kinematic viscosity is less than 50 cSt, there is a problem that the lubricity is insufficient and seizure occurs. On the other hand, when the kinematic viscosity exceeds 2000 cSt, the kinematic viscosity increases and handling is difficult. There are problems that it becomes difficult, circulation filtration of lubricating oil becomes difficult, an increase in the amount of residual oil after annealing and discoloration of the outer surface.
The kinematic viscosity of the lubricating oil for copper pipe processing is preferably 50 to 1300 cSt.

  The kinematic viscosity is measured in accordance with JIS K 2283 “Kinematic Viscosity Test Method for Crude Oil and Petroleum Products” at 40 ° C. The measuring instrument is “Glass Apparatus for Petroleum Testing” of JIS K 2839. This can be measured using a Canon-Fenske viscometer.

  In addition, as an oil agent, only 1 type (s) or 2 or more types are included among the fatty acid ester comprised from the saturated fatty acid shown by the said General formula (1), and a polyhydric alcohol and a C10-C18 saturated fatty acid. When contained, the total content of the base oil is in the range of 60 to 99.5%. However, when the additive described later is further added, the total content of the base oil changes so that the total of the oily agent, the additive, and the base oil becomes 100% according to the content of the additive. To do.

  Further, the lubricating oil for copper pipe processing of the present invention is 100% due to the base oil and the oily agent, but in actual use, in order to stably operate the above-described excellent effects, In addition to 100%, it is of course possible to further add one or more of a rust inhibitor, a corrosion inhibitor, an antifoaming agent and the like as required.

Examples of the rust inhibitor include barium dinonylnaphthalene sulfonate.
Examples of the corrosion inhibitor include benzotriazole.
Examples of the antifoaming agent include silicon-based ones.

（但し、Ｒ³は、炭素数１〜１８の炭化水素基である。）

（但し、Ｒ⁴は、炭素数１〜１８の炭化水素基である。） The lubricating oil for copper pipe processing further includes, as an additive, a phenol compound represented by the following general formulas (2) and (3) as a first additive (hereinafter referred to as a first additive), phenyl-α -It is preferable to contain 0.01-5% of 1 type, or 2 or more types of the partial ester of polyhydric alcohols, such as aromatic amine of naphthylamine, sorbitan monooleate, phosphate ester, and its derivative (Claim 2).

(However, R ³ is a hydrocarbon group having 1 to 18 carbon atoms.)

(However, R ⁴ is a hydrocarbon group having 1 to 18 carbon atoms.)

  In this case, an effect of preventing oxidation can be further obtained. When the content of the first additive is less than 0.01%, the antioxidant effect may not be sufficiently obtained. On the other hand, when the content of the first additive exceeds 5% The residual oil amount after annealing may increase.

In particular, when the phenolic compounds represented by the above general formulas (2) and (3) are contained, the generation of lower organic acids can be prevented even under harsh environments. Can be suppressed.
When the number of carbon atoms of the hydrocarbon groups R ³ and R ⁴ of the phenol compound is 19 or more, there is a problem that it is likely to precipitate at low temperatures such as in winter.
Specific examples of the hydrocarbon groups R ³ and R ⁴ include an alkyl group.

Moreover, it is preferable that the said lubricating oil for copper pipe processing contains 1-10% of aromatic hydrocarbons as a 2nd additive (henceforth 2nd additive) as an additive further (Claim 3). ).
In this case, the effect of further improving the moldability can be obtained.
When the content of the aromatic hydrocarbon is less than 1%, no effect appears. On the other hand, when the content of the aromatic hydrocarbon exceeds 10%, the residual oil amount may increase. Odor may be generated.

The copper pipe processing lubricant is preferably supplied when the copper pipe is drawn or rolled.
That is, it is preferable to supply the lubricating oil for copper pipe processing as an outer surface lubricating oil and an inner surface lubricating oil when the copper pipe is drawn or rolled.

  In the outer surface lubricating oil, the lubricating oil used in the drawing process is often circulated, but it is quite difficult to completely remove the copper wear powder generated during the drawing process with a filtration device. That is, in this case, since the generation of copper wear powder and the dispersibility of copper wear powder are important, it is particularly effective.

  On the other hand, when the inner surface lubricating oil is used in a rolling process, the lubricating oil adheres to the inner surface of the copper tube after the rolling, so that the lubricating oil is vaporized or thermally decomposed. The vaporized substance is not released outside the copper tube only by volume expansion, but aggregates when the copper tube is cooled and remains as oil on the inner surface of the copper tube. That is, in this case, it is particularly effective to reduce the lubricating oil remaining on the inner surface of the copper tube after annealing.

  The said copper pipe can be used especially suitably as a heat exchanger tube used for air conditioners, such as a room air conditioner, and heat exchangers of refrigerators, such as a refrigerator and a freezer. Needless to say, it can be used for multiple purposes without specifying the type of processing.

In the method for producing a copper pipe according to the second aspect of the invention, it is preferable to perform annealing by substituting the inside atmosphere of the copper pipe subjected to the drawing process or the rolling process with a non-oxidizing gas.
In this case, it is very effective in reducing the amount of lubricating oil remaining on the inner surface of the copper tube after annealing.

(Example 1)
Next, examples of the present invention will be described.
In this example, as examples and comparative examples of the present invention, phosphorous copper removal pipes having a total weight of 540 kg and lubricating oils having compositions shown in Tables 1 and 2 (Sample E1 to Sample E19, Sample C1 to Sample C7) are used. And then drawing, copper pipe outer diameter φ11.2mm, copper pipe inner diameter φ10.9mm, wall thickness 0.15mm, length about 5800m, cut and aligned wound, level-wound coil-shaped copper weighing 250kg A tube was made.
In the drawing process, the drawing was performed under a drawing speed of 600 m / min.

The symbols in Table 1 and Table 2 will be described.
a1: Polyisobutylene having an average molecular weight of 60000 a2: Polyisobutylene having an average molecular weight of 30000 a3: Polyisobutylene having an average molecular weight of 3700 b1: Isoparaffin having an average molecular weight of 120 b2: Refined mineral oil having an aromatic component content of 5% and a kinematic viscosity of 100 cSt b3: Fragrance Refined mineral oil having a group component content of 13% and a kinematic viscosity of 100 cSt: ethyl caprate c2: trimethylolpropane lauric acid triester c3: pentaerythritol lauric acid tetraester c4: butyl stearate c5: butyl oleate d1: benzenepropanoic acid -3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-octyl ester d2: di-tertiary butyl paracresol e1: ethylbenzene

  The following evaluation tests were performed using the obtained samples.

After replacing the atmosphere inside the level-wound coiled copper tube with a hydrogen mixed gas (H ₂ : 5%, N ₂ : 95%), using a roller hearth-type annealing furnace for mass production, the copper tube Both ends were sealed, and annealing treatment was performed in a DX gas atmosphere according to the annealing conditions of the soft material.

<Residual oil amount>
After annealing, the copper pipe corresponding to the upper surface of the coil is taken 1m long for each step from the coil inlet end to the coil outlet, and the residual oil measurement copper pipe is extracted, washed with an organic solvent, and subjected to infrared spectroscopic analysis. The infrared absorbance at 3000 to 2800 cm ⁻¹ was measured by the method, and the amount of residual oil remaining in the tube was determined based on a calibration curve prepared in advance.

(Evaluation criteria)
5: 0.03 mg / m or less 4: 0.03 mg / m or more and 0.05 mg / m or less 3: 0.05 mg / m or more and 0.07 mg / m or less 2: 0.07 mg / m or more and 0.10 mg / m or less 1: Over 0.10 mg / m

<Lubricity and copper wear powder generation test>
Using a pin-on-disk test apparatus, lubricity and copper wear powder generation were evaluated. The pin-on-disk test apparatus has a support part for fixing a pin-shaped copper material, and a disk part rotatably disposed so as to face the support part. As the pin, a rod-shaped (pin-shaped) member made of pure copper and having a cross-sectional area of 5 mm ² was used. Further, SKD was used for the disk portion. The load F applied to the support part was measured under the conditions of 10 kgf, rotation speed 30 rpm (rotation radius: distance 15 mm from the center of the disk part to the center of the pin), measurement time 20 min, and room temperature.
Moreover, the pin and the disk are immersed in 100 mL of various test oils.

The frictional force applied to the support portion during the measurement was measured with a load cell, and the average value was divided by the load of 10 kgf to obtain the friction coefficient, and the lubricity was evaluated.
(Evaluation criteria for lubricity)
○: When the friction coefficient is 0.15 or less ×: When the friction coefficient exceeds 0.15

Further, after the measurement, the copper wear powder in the test oil was dissolved in aqua regia (mixed acid of nitric acid and hydrochloric acid), and copper was quantified by atomic absorption spectrometry to evaluate the amount of copper wear powder generated.
(Evaluation criteria for copper wear powder generation)
5: 50 ppm or less 4: 50 ppm to 100 ppm or less 3: 100 ppm to 200 ppm or less 2: 200 ppm to 500 ppm or less 1: 500 ppm or more

<Discoloration after annealing>
Discoloration after annealing was performed by placing 2 g of the test oil in a 5 mL glass container, heating and holding it in an electric furnace at 150 ° C. for 12 hours, and then placing 0.5 g of the test oil on a copper plate in a nitrogen atmosphere. The discoloration of the copper plate after annealing at 580 ° C. was judged visually.
(Evaluation criteria)
5: No discoloration observed 4: Light brown discoloration observed 3: Brown discoloration observed 2: Partial black discoloration observed 1: Black discoloration observed throughout

<Lower acid generation evaluation>
6 mL of test oil, 50 mL of distilled water and 1 g of copper powder were added to a 100 mL beaker and heated in a constant temperature dryer at 90 ° C. for 48 hours. After cooling, about 2 mL of the aqueous layer was extracted, and the concentration of organic acid ions eluted in the water tank was analyzed by ion chromatography to evaluate lower acid generation. Analytical elements were formate ion, acetate ion, propionate ion and butyrate ion.
(Evaluation criteria)
5: 1 ppm or less 4: 1 ppm exceeding 3 ppm or less 3: 3 ppm exceeding 5 ppm or less 2: 5 ppm exceeding 10 ppm or less 1: 10 ppm exceeding

  These evaluation results are shown in Tables 3 and 4. As for the lubricity, those with an evaluation of ○ were accepted, and those with an evaluation of × were rejected. Moreover, the amount of residual oil, copper abrasion powder generation | occurrence | production, and discoloration after annealing set evaluation 3 or more as the pass, and made evaluation 1 and 2 the rejection.

As is known from Table 3, Sample E1 to Sample E19, which are examples of the present invention, show good results in all evaluation items of lubricity, residual oil amount, copper wear powder generation, and discoloration after annealing. It was.
Therefore, according to the present invention, the drawing process or rolling process has excellent lubricity, the occurrence of copper wear powder is small, the copper wear powder is highly dispersible in the lubricating oil, and the copper wear powder adheres to the plug. , Prevents copper wear powder from adhering to the surface of the copper tube, has excellent oxidation stability, has a small amount of residual oil after annealing, and can obtain a lubricating oil for copper tube processing that does not cause seizure or discoloration on the outer surface during annealing. .

  Samples E8 to E15, which are examples of the present invention, are benzenepropanoic acid, 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-octyl ester or ditertiary as the first additive. Since it contains butyl paracresol, the lower organic acid generation is particularly excellent.

As can be seen from Table 4, the sample C1 as a comparative example of the present invention has an oiliness agent content lower than the lower limit of the present invention, so the boundary lubricity is inferior and the occurrence of copper wear powder increases. Abrasion powder generation was unacceptable.
Sample C2 as a comparative example of the present invention has an oily agent content that exceeds the upper limit of the present invention, so that during the annealing, the volatilization and decomposition of the oily agent do not proceed sufficiently, and a part of the oil is contained in the pipe. Residual oil amount and post-anneal discoloration are inferior due to the problem that residual oil increases after annealing, and that the insufficiently decomposed material adheres to the outer surface of the pipe and the outer surface of the copper pipe changes color during annealing. It was a pass.

In addition, the sample C3 as a comparative example of the present invention failed in lubricity and wear powder generation because the kinematic viscosity of the entire lubricating oil was lower than the lower limit of the present invention and the lubricity was insufficient. .
In addition, the sample C4 as a comparative example of the present invention has a low residual oil amount because the kinematic viscosity of the entire lubricating oil exceeds the upper limit of the present invention, so that the kinematic viscosity increases and the residual oil after annealing increases. It was a pass.

  Further, the sample C5 as a comparative example of the present invention does not contain polyisobutylene having an average molecular weight of 30000 or more, so that the amount of oil introduced into the friction surface is small and lubrication is insufficient. The occurrence was rejected.

  In addition, sample C6 as a comparative example of the present invention contains refined mineral oil having an aromatic component content of more than 10%, so that it is inferior in oxidative stability and oxidative deterioration proceeds in a shorter period of time. When heated and maintained in an electric furnace at 150 ° C. for 12 hours, oxidation of the lubricating oil progresses and heavy components are generated, and these heavy components remain on the copper tube surface, so discoloration after annealing is rejected. Met. Moreover, since content of an aromatic component exceeded 10%, the polymerization reaction occurred and the amount of residual oil was disqualified.

  Moreover, since sample C7 as a comparative example of the present invention contains butyl oleate, which is an ester composed of an unsaturated fatty acid, as an oily agent, when heated and held in an electric furnace at 150 ° C. for 12 hours. Since the oxidative deterioration of the lubricating oil progressed and a heavy component was generated, and this heavy component remained on the surface of the copper tube, discoloration after annealing was unacceptable. Moreover, since it is ester which consists of unsaturated fatty acid, the polymerization reaction occurred and the amount of residual oil was disqualified.

Claims (6)

A lubricating oil for copper pipe processing for processing a copper pipe made of copper or a copper alloy,
As the oily agent, one or two or more of a fatty acid ester composed of a saturated fatty acid represented by the following general formula (1) and an ester of a polyhydric alcohol and a saturated fatty acid having 10 to 18 carbon atoms is reduced to 0. 5 to 70% (wt%, the same shall apply hereinafter)
As the base oil, the remainder contains polyisobutylene having a molecular weight of 30000 or more and polyisobutylene or isoparaffin having a molecular weight of 400 or less, or a refined mineral oil having a content of aromatic components of 1000 cSt or less having a content of 10% or less,
A lubricating oil for copper tube processing, wherein the kinematic viscosity is 50 to 2000 cSt.

(However, R ¹ is an alkyl group having 9 to 17 carbon atoms, and R ² is a hydrocarbon group having 1 to 4 carbon atoms.) In claim 1, further, as additives, phenol compounds represented by the following general formulas (2) and (3), aromatic amines of phenyl-α-naphthylamine, partial esters of polyhydric alcohols such as sorbitan monooleate, A lubricating oil for copper pipe processing characterized by containing 0.01 to 5% of one or more of phosphoric acid esters and derivatives thereof.

(However, R ³ is a hydrocarbon group having 1 to 18 carbon atoms.)

(However, R ⁴ is a hydrocarbon group having 1 to 18 carbon atoms.)   The lubricating oil for copper pipe processing according to claim 1 or 2, further comprising 1 to 10% of an aromatic hydrocarbon as an additive.   The lubricating oil for copper pipe processing according to any one of claims 1 to 3, which is supplied when the copper pipe is drawn or rolled.   A copper pipe made of copper or a copper alloy is supplied with the lubricating oil for copper pipe processing according to any one of claims 1 to 4, and subjected to drawing or rolling. Production method.   6. The method of manufacturing a copper pipe according to claim 5, wherein the pipe tube atmosphere subjected to the drawing process or the rolling process is replaced with a non-oxidizing gas and annealing is performed.