FR2510602A1 - General-purpose machining lubricant based on polybutene - of low viscosity, contg. 3-7 vol. per cent of surfactant, is powerful coolant - Google Patents

Abstract

General purpose machining lubricant is based on a low-viscosity polybutene, pref. with addn. of 3-7 vol.% of an anionic or non-ionic surfactant. A pref. polybutene, Napvis (RTM), comprises 90-92% polyisobutene and 8-10% polybutene-1. The compsn. is varied according to use. Used for turning, milling, threading, tapping, drilling, etc. on steels (including hard and stainless steels), Al and light alloys. The lubricants give powerful cooling, and are stable, odourless harmless to skin and eyes and paint, non-corrosive and non-gumming. They are stable to 350 deg.C, where they polymerise without gas evolution.

Description

 The present invention relates to lubricating agents relating to metal machining operations, as well as the protection of machined mechanical parts and machine tools for manufacture.

 The various machining operations require the use of multiple lubricants, depending on the nature of the metals, the type of machine used, the speed of rotation or advance. Among the known lubricants available on the market, the most common are soluble mineral oils.

 These soluble lubricants have serious drawbacks. They oxidize quickly and present a very favorable environment for bacterial proliferation. This results in the need for users to empty and regularly clean the tanks containing these lubricants to alleviate repelling odors and clogging of the pumps.

 With regard to special steels and hard alloys, in particular, recourse is had to cutting or tapping lubricants constituted by mineral oils comprising often toxic additives such as lead or chlorinated derivatives. When heated, these lubricants give off gases which can be dangerous. In addition, these lubricants are expensive.

 The main disadvantages of these lubricants are, however, the damage caused to the machines themselves: corrosion and attack by paints.

 The object of the present invention is the use of a basic lubricant consisting of a low viscosity polybutene to which a surfactant is added.

 For conventional turning or milling work, the particularly suitable viscosity of polybutene is 120 to 150 centipoise to oo centigrade, the proportion of surfactant 3% by volume.

 The work of special and stainless steels requires a polybutene viscosity of between 180 and 200 centipoise at OO centigrade, the proportion of surfactant being 5% by volume.

 For threading operations and tapping of steels or hard alloys, the particularly suitable viscosity of the polybutene is between 200 and 240 centipoise at OO centigrade, the proportion of the surfactant being 7% by volume.

 Polybutene combined with a surfactant, object of said invention, provides stable lubricants, with very high cooling power. Polybutene is odorless, harmless to the skin and eyes. It does not cause any corrosion or gumming effect, it has no effect on paints.

 Polybutene supports heating up to 3500 centigrade. At this temperature, it polymerizes without causing toxic degassing.

 Those skilled in the art will be able to determine, by routine tests, according to each type of machine or metal to be machined, the percentage of surfactant and the viscosity of polybutene which are particularly suitable.

 In a preferred embodiment of the invention, the polybutene used is sold under the name "NAPVIS"; it contains 90 to 92% of isobutenes by volume and 8 to 10% of butene 1; the surfactant is a partial phosphoric ester of ethoxylated aliphatic alcohol. However, other surfactants such as polyglycolic ether of fatty alcohol or any other anionic or nonionic surfactant compatible with polybutene can be used.

The following examples are intended to illustrate the invention without in any way limiting its scope:
EXAMPLE 1
Mixture used: polybutene 95%, phosphoric ester 5%, viscosity approximately 100 centipoise.

Operation: tapping in blind holes on AG5 aluminum. Hole diameter 10 millimeters.

Tool: push-in tap (special tap without flute and chips).

Machine: Constant
Speed: 450 rpm.

Number of threaded parts: 150
The tap is sprayed using a hand gun. Its heating is controlled after each piece. The lubricant layer adheres well to the tap.

After the fourth piece the end of the tap begins to heat up. The spraying is resumed and the operation is carried out with a weak spraying of all the four parts. The lubricant consumption was 2 centilitres to tap the 150 pieces. The appearance of the tool did not change after this series of tapping.

EXAMPLE 2
Mixture used: polybutene 97%, phosphoric ester 3%, viscosity around 150 centipoise.

Operation: drilling on steel stretched to 40 KG, thickness 10 millimeters.

Forest diameter: 8 millimeters.

Tool: Steel forest with 5% cobalt (re-sharpened tool).

Machine: Constant
Speed: 680 rpm.

Number of pieces: 800
The forest is sprayed approximately every ten holes. The consumption is around 3 deciliters of lubricant. The forest does not heat up. The series of 800 parts was made without the need to re-sharpen the tool.

The pressure to exert in the 800th piece was identical to the first.

EXAMPLE 3
Mixture used: polybutene 97%, phosphoric ester 3%; viscosity around 150 centipoises.

Operation: drilling and tapping on 90 kg steel, thickness 30 millimeters, diameter 8 millimeters.

Machine: SYDERIC
Speed: 465 rpm
Number of rooms: 5
This test was the subject of a comparative test with a known product, marketed as tapping oil and threading under the name
TARFIL. Results: first drilling, the polybutene coated forest is lukewarm after having crossed 30 millimeters of hard steel. It is wiped and blown with compressed air. It is coated with TARFIL product for the second drilling. At the end of the operation the forest is very hot, it is impossible to touch the end.

 Tapping: it is done manually, direct pass without backtracking. In both cases the tap is clean and the manual effort is comparable. However, the adhesion of the chips is much greater with the TARFIL product. It emerges from this test that a viscosity more suitable for this work will be approximately 200 centipoise.

EXAMPLE 4
It is a very delicate job with tolerance to 1 / 100th of a millimeter. The tool is a high-speed steel blade at a half-moon cutting angle according to the sketch below. The metal is stainless steel NS 22 S.

Operation: bore a conical blind hole according to sketch on next page.

Machine: SYDERIC drilling machine
Speed: 110 rpm.

Comparative test with TARFIL.

Results: with TARFIL, the tool must be sharpened after 1 piece. With the polybutene / phosphoric ester lubricant, we reaffute after 2 pieces. There is less chip adhesion. The surface finish is good with the polybutene / phosphoric ester lubricant. Numerous scratches appear on parts lubricated with TARFIL.

EXAMPLE 5
Mixture used: polybutene 95%, phosphoric ester 5%, viscosity 200 centipoises at approximately 0 centigrade.

Operation: turning a 140 kg steel cylinder (2 millimeters in diameter).

Machine: Hernault Batignolles lathe
Tool: high speed steel
Speed: with soluble oil: 150 rpm, with polybutene / phosphoric ester: 300 rpm. Good cooling.

 The turner wants to push the test to the extreme and increases the speed to 600 rpm, the chip turns blue. Despite regular spraying with the polybutene / phosphoric ester mixture after a few seconds, the tool turns red. It should be noted that the quantity of sprayed lubricant is much lower than that of the soluble oil pumped continuously by the machine.

EXAMPLE 6
Mixture used: polybutene 95%, phosphoric ester 5%, viscosity 200 centipoise to 00 centigrade.

Operation: bar turning on Z 2 CN 18-10 stainless steel bar. Diameter 18 millimeters.

Tool: carbide tip without cutting.

Machine: CAZENEUVE HB 725 lathe.

Adjustments: feed 260 millimeters / minute, or 0.26 millimeters per revolution.

Rotation 1000 revolutions / minute. Depth passes 3 millimeters. Regular spraying of tool and workpiece.

 Results i satisfactory draft pass. Good tool performance. (Experiment carried out over 250 millimeters in length). Slightly yellowed chip. The color of the stainless rod did not change. The chip is flexible and not brittle.

Those skilled in the art will deduce from the examples presented in the description of the invention that the range of lubricants resulting from the combination of low viscosity surfactant polybutene covers all machining operations and can be used by all mechanical industries with a significant improvement in working conditions and attractive profitability. The exceptional resistance to heating of the lubricants which are the subject of the present invention allow faster advances, deeper roughing passes and less wear of the cutting tools.

Claims (9)

1. Synthetic machining lubricant characterized in that it comprises a  low viscosity polybutene base. 2. Synthetic machining lubricant characterized in that it comprises a  surfactant. 3. According to claims 1 and 2, synthetic lubricant machining character  laughed in that the proportion of surfactant is 3 to 7% by volume. 4. According to claim 1, 2 or 3 synthetic lubricant of machining charac  terized in that the viscosity index of polybutene suitable for  current work on lathes and milling machines is 150 centipoise  around Oo centigrade, the proportion of surfactant being 3%  in volume-. 5. According to claim 1, 2 or 3, synthetic lubricant for machining charac  terized in that the viscosity index of polybutene suitable for  mechanical work on hard steels and stainless steels is 200  centipoise approximately at 0 centigrade, the proportion of surfactant  being 5% by volume. 6. According to claim 1, 2 or 3, synthetic lubricant for machining charac  terized in that the viscosity index of polybutene suitable for  mechanical work on aluminum and light alloys is 150 cen  tipoises around 0 centigrade, the proportion of surfactant being  from 5 to 7% by volume.  7. According to claim 1, 2 or 3, synthetic lubricant for machining charac  terized in that the viscosity index of polybutene suitable for ope  thread and thread rations on hard and stainless steels is  200 centipoises approximately at 0 centigrade, the proportion of surfactant  being 7% by volume. 8. According to claims 1, 2, 3, 4, 5, 6 and 7, taken as a whole or  any of them, synthetic machining lubricant charac  terized in that the surfactant most suitable for various opera  tions is the phosphoric ester as indicated in the description of  the invention. 9. Synthetic machining lubricant according to any one of the claims  tions 1 to 8 characterized in that any anionic surfactant or not  ionic other than the phosphoric ester, compatible with polybutene,  can be used.