DE1594651C - Lubricant based on an aqueous emulsion - Google Patents

Description

The invention relates to base lubricants which can be used in metalworking an aqueous emulsion.

In metal cutting, the lubricant mainly fulfills two functions: First, it reduces the friction between two moving metallic objects in contact, for example between the "surfaces of the tool and workpiece, and secondly, it performs the during heat generated by the machining time of the metal. This prevents this when thread cutting Lubricant also, the accumulation of chips on the cutting tool, washes away the metal chips away as soon as they are formed and provides rust protection to a certain extent.

Metal-cutting lubricants can be divided into two categories, namely into

A .. The so-called high-performance lubricants, i.e. H. in liquids that are essentially made up a mineral oil and organic sulfur, chlorine or phosphorus compounds as additives exist; and in

B. the lubricants on an aqueous basis.

The first type is used with ferrous metals, where high unit pressures and strong local temperature increases occur, for example when milling or when cutting or drilling threads etc. However, these high-performance lubricants cannot be used in operations with high Speed at which an extraordinary increase in heat must be expected, as it is a have relatively poor thermal conductivity. In addition, lubricants are based on mineral oil not recommended when machining non-ferrous metals because of the possibility of a corrosive Attack or an oxide formation. Water-based lubricants, on the other hand, are very good well suited ■ for high-speed operations such as drilling, turning, milling, etc., in which during the processing load is relatively low; however, water based lubricants are that are suitable for the high-performance operations described above, not yet available.

The purpose of the invention is therefore to provide water-based lubricants that are suitable for high-performance operations, such as punching, thread cutting, tapping and the like are suitable. The inventive. modern lubricants are not only suitable for the processing of ferrous metals, such as steel and the various steel alloys, but also for processing non-ferrous metals such as copper, Aluminum, brass, bronze and the like. The lubricants mentioned are based on aqueous emulsions extremely resistant to wear and tear and prevent unwanted welding of Tool and workpiece (»seizure«).

When used in the machining of metals are those according to the invention Water-based lubricants at least equivalent to oil-based lubricants, although their ability to to dissipate the occurring heat from the processing point, is much better.

Those according to the invention which can be used in the machining of metals Aqueous emulsion lubricants contain as the main organic component about 0.1 to 25 percent by weight of a polyolefin

(ie a homo- or copolymer of an olefin) with a molecular weight between 1500 and 25,000 and also an emulsifier. Among the polyolefins, polyethylene and polypropylene are preferred. Preferably the amount of polyolefin in the emulsion is between about 0.2 and 3 percent by weight; for heavy duty use, the preferred range is about 1 to 3 weight percent.
In addition to the two preferred polyolefins,

ίο but also any other polyolefin in aqueous emulsion be present. Also the. Width of the molecular weight distribution, the polymer density or the polymer structure are arbitrary.

Polyolefins with a molecular weight between about 1500 and 25,000 are particularly suitable, which preferably have a melting point of no more than about 200 ° C. Typical examples of this are homo- and copolymers of α-olefins with 2 to 12 carbon atoms, such as ethylene, propylene,

Butylene and the like because of their particularly good emulsifiability polyolefins are on average at least one polar group for every four polyolefin molecules preferred.

The homo- or copolymers of olefins can be obtained in the molecular weight range mentioned are made by direct polymerization, emulsion polymerization or by hydrolysis of polyolefins with higher molecular weight.

The latter method is preferred since the pyrolysis of polymers with a relatively high molecular weight results in a terminal vinyl unsaturated group which is readily available for reaction with an ethylenically unsaturated polar mono-. mers, such as maleic anhydride or thioglycolic acid, as described in U.S. Patents 2,766,214 and 3,144,348; the resulting polyolefin is very easy to emulsify.

Another valuable method for the preparation of emulsifiable polymers with a sufficient The number of polar groups consists in the (optionally catalytic) oxidation, with on the polymer chain in addition to ketone, aldehyde and hydroxyl groups, carboxyl groups are also generated.

Other suitable emulsifiable polyolefins are Block copolymers that are formed in the reaction of ethylene oxide with ^ Eolyäthylen, according to U.S. Pat. No. 2,921,920, polymers with terminal hydroxyl groups are formed. Further suitable polyolefins are those described in U.S. Pat. No. 2,766,214 reacted with maleic acid Ethylene Alcohol Telomers.

Likewise, the necessary amount of polar groups in the homopolymers mentioned and Copolymers of α-olefins are introduced by copolymerizing the resulting polyolefins with unsaturated monomers that contain the ethylene bond, such as ethylene acrylate, styrene, Bicycloheptene, vinyl acetate, acrylic acid, methacrylic acid and the like.

In addition, polymer chains result from direct polymerization to olefin polymers and / or from hydrolysis with the necessary amount of polar groups so that the polymers are emulsifiable and the resulting emulsion remains stable.

The emulsion polymerization can be carried out by using the olefinic starting material in the presence of a suitable emulsifier in water and then emulsified at a higher temperature

polymerized under pressure in the presence of a polymerization catalyst. Such polymerization processes are described, inter alia, in the following USA patents: 2,342,400, 2,542,783, 2 592 526 and 2703 794.

From the prior art indicated above it can be seen that numerous different ways are known and are available to prepare the polyolefins useful for purposes of the invention. The aqueous Polyolefin emulsions can be anionic, nonionic or cationic. So while basically any compatible emulsifier can be used, but are for lubricants that are used in the Metalworking should be used, the nonionic emulsifiers preferred.

The nonionic emulsifiers that come into consideration here are organic compounds of relative proportions high molecular weight and consist of a hydrophobic part with which a solubilizing or hydrophilic part is connected, which the latter certain groups, such as ethereal members . (- C-O-C-), hydroxyl groups (-OH), Carboxyl groups

and the like. .

Surfactants which have one or more hydrophilic halves are particularly useful Contain chains with one or more alkyleneoxy groups. These surfactants have the general formula

R- (Y-H),

where R is the hydrophobic portion of an aliphatic alcohol with 8 to 22 carbon atoms or an alkylated phenol with 4 to about 22 carbon atoms in the alkyl group, Y is an alkyleneoxy chain, the hydrogen atom denoted by H is bonded to an oxygen atom of the alkyleneoxy chain and y stands for a number from 1 to 6, preferably from 1 to 4.

Typical aliphatic alcohols are octyl alcohol, nonyl alcohol, decyl alcohol, "coco" alcohol (a mixture of C ₁₀ to C _ie alcohols), dodecyl alcohol, oleyl alcohol, "talc" alcohol (a mixture of C _{16 to} C ₁₈ Alcohols), octadecyl alcohol, 2,6,8-trimethyl-4-nonyl alcohol and the like.

Typical alkylated phenols are butylphenol, pentylphenol, hexylphenol, octylphenol, nonylphenol, Dodecylphenol, hexadecylphenol, octadecylphenol, nonadecylphenol and the like.

The term "alkyleneoxy chain" here means a chain which contains one or more alkyleneoxy groups, namely divalent alkylene groups such as methylene, ethylene, propylene, butylene and the like, which are bonded to an oxygen atom in such a way that one of the valences of the Alkyleneoxy group is derived from an oxygen atom, the other is derived from a carbon atom. Typical alkyleneoxy groups are: methylenoxy (—CH ₂ O—) ethyleneoxy (-C ₀ H ₄ O-), propyleneoxy (-C ₃ H ₆ O-), butyleneoxy (- C ₄ H ₈ O -) and the like.

Preferred non-tonic emulsifiers for those according to the invention Medium are the polyalkylene glycol ethers with about 4 to about 80 moles of alkylene oxide. Preferred nonionic surfactants include the nonylphenyl polyethylene glycol ethers with about 4 moles of ethylene oxide, the trimethylnonyl polyethylene glycol ethers with about 6 moles of ethylene oxide, the nonylphenyl polyethylene glycol ethers with about 7 moles of ethylene oxide, mixed polyalkylene glycol ethers with about 6OMol of a mixture

ίο Ethylene oxide and 1,2-propylene oxide in a molar ratio of about 2: 1 and the like.

Combinations of are typical of the cationic emulsifiers which can be used according to the invention an organic acid such as acetic acid and an amine, e.g. B. a cyclic imidazoline, tertiary ethoxylated soya amine, polyethoxylated "tallow" - Amine with 2 ethoxy units in the polyethoxylated part of the molecule, the polyethoxylated oleyl amines with 2 to 5 ethoxy units in the polyethoxy part of the molecule, polyethoxylated soya-amine with 5 ethoxy units in the polyethoxy part of the molecule and the like.

The anionic emulsifiers that come into consideration according to the invention are, inter alia, amine soaps, formed by the reaction of an amine with a fatty acid such as oleic acid, palmitic acid, lauric acid, Myristic acid, the tall oil acids, the palm oil acids or the like, in approximately stoichiometric amounts Ambient or slightly elevated temperatures.

Suitable amine soaps are triethanolamine stearate, triethanolamine oleate, triethanolamine coconut oil soap, Isopropanolamine oleate, Ν, Ν-dimethylethanolamine oleate, 3-methoxypropyl amine oleate, morpholine oleate and the like

A wide variety of aqueous polyolefin emulsions have been produced examined for their suitability for purposes of the invention. These emulsions are wider are described below and are designated with the letters A to N for the sake of clarity.

For comparison purposes, the usual ones are also used Cutting oils listed.

Description of cutting fluids

Emulsion A

Aqueous nonionic emulsion of chemically inert, low molecular weight polyethylene, emulsified by a polyoxyethylene derivative one aliphatic compound.

Emulsion B

Aqueous anionic emulsion of polyethylene of medium molecular weight, emulsified by a volatile emulsifier.

Emulsion C

Aqueous nonionic emulsion of high melting point, very dense polyethylene (molecular weight 6500 to 8400) that is cracked and had been oxidized in air.

Emulsion D

Aqueous anionic emulsion of cracked high density polyethylene (molecular weight about 2000), modified with about 5 percent by weight maleic anhydride and emulsified with an amine fatty acid emulsifier.

Emulsion E.

Oil B

Aqueous cationic emulsion of fractured high density polyethylene (molecular weight about 2000), modified with about 5 percent by weight maleic anhydride and emulsified with an ethoxylated primary fatty acid amine and acetic acid. .

Soluble cutting oil with a relatively very high proportion of high-pressure-resistant and that Seizure-preventing fats and additives.

oil c

Emulsion F

Aqueous nonionic emulsion of cracked high density polyethylene (molecular weight about 2000), modified with about 5 weight-. percent maleic anhydride and emulsified with a mixture of nonylphenyl polyethylene glycol ethers containing about 4 and about 7 moles of ethylene oxide contain, and morpholine.

Emulsion G

Aqueous nonionic emulsion of cracked polyethylene of high molecular density (molecular weight about 2000), modified with about 5 percent by weight maleic anhydride and emulsified with a mixture of nonylphenyl polyethylene glycol ethers, which contain about 4 and about 7 moles of ethylene oxide, and 2-methoxypropylamine.

Emulsion H.

Aqueous anionic emulsion of low density polyethylene (molecular weight about 16,000), produced by emulsion polymerization.

Emulsion I.

Paraffin oil with a viscosity index of around 90. Does not contain any additives.

IO oil D

Aqueous nonionic emulsion made from low density polyethylene (molecular weight about 24,000), produced by emulsion polymerization.

Emulsion J

Aqueous nonionic low density polyethylene emulsion. .

Water-insoluble polyalkylene glycol.

* 5 The lubricants are assessed on a Falex tester. This experimental setup consists of an exchangeable shaft about 6 mm in diameter (Soft steel mandrel No. 8), which rotates at 290 rpm between two steel V-blocks. The wave can be made from SAE 3135 steel with a Rockwell B hardness of 87 (tempered to 8 to 10 RMS) and the two V-blocks can be made of AISI C-Il37 steel with a Rockwell C hardness of 20 (tempered to 6 to 8 RMS) (method I). With another The shaft can be made from M-2 tool steel with a Rockwell C hardness of 60 (tempered to 12 to 14 RMS) and the two V-blocks can off. stainless 440-C steel with a Rockwell-C hardness of 60 (tempered to 12 to 14 RMS) pass (method II).

The V-blocks are arranged so that they are held against the by a notched load wheel Be pressed against the shaft. The adjustment of the load wheel during the experiment to a predetermined Maintaining load gives a measure of the abrasion on the test shaft. An advance around a notch or tooth on the load wheel indicates 0.145 μ of wear on the test shaft.

During the test, the shaft and V-blocks are immersed in the lubricant to be tested.

The experiment consists of the following individual operations:

Emulsion K

45

Aqueous, cationic, low-density polyethylene emulsion.

Emulsion L

Aqueous nonionic emulsion of polyethylene with a relatively low content of emulsifiers.

Emulsion M

Aqueous nonionic emulsions of polyethylene.

55

Emulsion N

Aqueous nonionic emulsion of polypropylene.

Common mineral oil for thread cutting and drilling. Contains as an active extreme pressure agent about 3 percent by weight sulfur and about 1 percent by weight chlorine.

1. At the beginning of the experiment, the shaft between the V-blocks is left with a load for 3 minutes rotate from "45.4 kg;

2. the load is then increased by 45.4 kg per minute up to 454 kg;

3. when the load of 454 kg has been reached, the further increase per minute takes place by 113 kg until blocked or up to a maximum load of 2040 kg;

4. The rotational power (torque) and temperature are noted every minute;

5. In each individual minute interval, the abrasion on the test shaft is noted as the number of Notches (grooves) on the load wheel that had to be readjusted to get the desired one Maintain load.

Upon completion of the experiment, the average width of those generated on the V-blocks is determined

The grinding track measured microscopically and the contact pressure calculated from the following formulas:

Load when blocked _T. ,. ,
- = bearing load in kg.

Bearing load in kg _,,. ' ,,.,

5_ Q _ruc k _m kg / cm ² .

Track length X track width in cm

Track length = 1.25 cm.

The invention is illustrated by the following examples explained in more detail.

example 1

Various polymer emulsions were produced with the aid of the Falex device and according to Method I described above on loading capacity and on its effect in terms of preventing seizure (Blockage) examined. The emulsions were aqueous emulsions at about 0.5 percent by weight of solids. The results are shown in Table I.

It can be seen from the data in the table that the polyolefin emulsions of the present invention are excellent Have resilience and prevent seizing with certainty.

Table I.

emulsion Type of emulsion load
at the
To block
in kg. Emulsifier
Type* F. modified
Polyethylene > 2040 η + a A. Polyethylene > 2040 η D. modified
Polyethylene > 2040 a + a. C. Polyethylene 2040 η B. Polyethylene 1810 a I. Polyethylene 1810 η H Polyethylene 1700 a J Polyethylene 1930 η K Polyethylene > 2040 C. . M. Polyethylene 2040 η L. Polyethylene 1930 η N Polypropylene 1930 η

* η = non-ionic; a = anionic; c = cationic.

Example 2

The ability of aqueous polyolefin emulsions to prevent blocking or seizing has been demonstrated measured on the Falex experimental device according to method I described above. The results of the experiments can be seen from Table II:

Table!!

Solids content emulsion Emulsifier type (D load Number of teeth that need to be adjusted, 1590 kg 1930 kg 2040 kg . 170 . in , when seizing to compensate for the abrasion when exposed to " 185 > 1000 ■ ■ 11 ι ι "- 155 Weight percent J η in kg 1360 kg 115 220 570 270 0.5 K C. 1930 95 540 - 0.5 I. η > 2040 45 110 435 - 0.5 H a 1810 160 125 > 815 165 0.5 M. η 1700 20th 190 520 - - 0.5 L. η 2040 15th 170 400 > 660 - 0.5 C. η 1930 70 0 Seized up 0.5 B. a 2040 70 0 20th 0.5 A. η 1810 0 0 15th 0.5 D. a > 2040 0 30th 125 0.5 F. η + a > 2040 .0 180 760 0.5 N η > 2040 0 - - 0.5 B. a 1930 15th 0 10 0.2 A. η 794 > 110 - -. 0.2 D. a > 2040 0 110 - 0.2 F. η + a 680 > 20 0.2 1810 20th

O) η = nonionic; a = anionic; c = cationic.

The data in the table clearly show that the results also show that some of the emulsions even with

aqueous polyolefin emulsions according to the invention with a low solids content are particularly suitable,

are particularly well suited to prevent seizure in the event of unwanted abrasion,
to avoid lifting operations. The data

209 634/126

ίο

Example 3

In the tests compiled in Table III, the behavior of a polyethylene emulsion was at Tried different solids concentration on the Falex test device.

Table III ■.

load Number of teeth that are set have to, 1930 kg 2040 kg Emulsion A diluted with water when seizing to the Compensate for abrasion when exposed to . 95 380 in kg 1360 kg 1590 kg 95 405 3.0 weight percent solids > 2040 0 30th 20th 170 1.0 weight percent solids > 2040 0 35 10 165 0.5 weight percent solids > 2040 0 0 0.2 weight percent solids > 2040 0 0 0.1 weight percent solids 1130 0

The data presented show that at concentrations of about 0.2 to 3.0 weight percent solids the ability to prevent seizure, the limit of the ver ^ possible on the device search exceeds. Particularly good abrasion prevention was obtained at 0.2 to 0.5 percent by weight The lubricants according to the invention showed solids, but also at higher concentrations still very good properties.

20th

Example 4

The tests listed in Table IV were used to determine the contact pressure at various Lubricants of the known type compared to the lubricants according to the invention. The trials were performed on the Falex device using Method II described above would.

Table IV

Lubricant contained in water load
when seizing
in kg Average
Track width
in mm Contact pressure
in kg / cm ² ÖIA 1700
1810
1360
1130
1810
1130
2040
1360
1250
1250
1130
1590
1470 0.94
0.74
0.61
0.41
0.53
0.38
0.48
0.41
0.41
0.66
0.46
0.46
0.46 9 840
14100
12 700
15 500
19,000
16 900
23 200
18 300
16 900
10 500
14 100
20 400
19,000 oil B diluted (15/1) with water
Oil C:; ........ Oil D 1.0 weight percent solids, emulsion F
0.2 weight percent solids, emulsion F.
1.0 weight percent solids, emulsion A
0.2 weight percent solids, emulsion A
0.2 weight percent solids, emulsion D.
1.0 percent by weight triethanolamine (soap)
0.2 percent by weight triethanolamine (soap)
1.0 weight percent solids, emulsion N
0.2 weight percent solids, emulsion N

The values given in the table show that contact pressures of more than about 15,500 kg / cm ² could only be obtained with aqueous polyethylene and polypropylene emulsions. These emulsions are therefore superior to the oil emulsions.

Example 5

The ability of the polyolefin lubricating fluids of the invention To prevent abrasion and seizing or welding of tool and workpiece, was carried out in a thread cutting test measured. The behavior of the lubricants according to the invention was compared with that des c ') ls A, to the oils normally used in thread cutting in stainless steel heard.

Details of the experiments

Device 4 'radial drilling machine No. 4;

American-Hole Wizard.

304 stainless steel workpiece

(2V * x I ¹ A. x 12 inches).

Blind Holes Drilled with # 7 Drill Bit (0,201 "diameter), IV ₈ " deep at 610 RPM; Feed 0.01 cm / rev .; Coolant: what

water soluble oil, diluted.

Taps ... »Λ · 20 N. C .; H. S. Grd. H 3 4 FIt. (Special version for stainless steel).

Device coupling with adjustable rotating

moment (slip clutch),
Swedish model,
SPV-SA-IE.

Evaluation of the lubricant

1. A blind hole 2.5 cm deep is threaded along its full length to the end of the groove provided (80% thread, 2.5 cm deep).

2. Cutting speed 70 rev / min.

3. The lubricant is introduced; it completely fills the blind hole.

4. Once the transmitted torque hit the tapping device can slip through, the direction of rotation is reversed and the chips and lubricant are removed with the help of an air hose blown out of the borehole; this completes one operation.

5. A new cutting process is carried out while adding lubricant again (second step).

6. The up to the cutting of a completely

The necessary number of work steps formed by a thread of 2.5 cm deep forms the criterion for the performance of the lubricant.
· '"

The usual water-based liquids used for metalworking and others, such as aqueous suspensions of graphite or haloalkane resins, could be used for thread cutting ίο fail to use the above conditions with success. Suspensions of non-emulsifiable poly- ' ethylene or polyethylene modified with maleic anhydride in mineral oil (kerosene, medium oil, light oil) were not suitable. >

When tapping with "Oil A" compared to various aqueous polyolefin emulsions The results obtained are summarized in Table V. -

Table V

Thread cutting lubricant evaluated in an aqueous emulsion Number of work
courses to education
of a thread
2.5 cm deep Borehole numbers öi a; * 3, 3, 3
4, 4, 4
3
2, 2, 2
4th
4th
5
2
2
3
2
3, 3
3
2
5 57, -66, 112
75, 106, 107
56
.51, 53, 61
52
49
50
72
75
74
62
63, 71
64
70
108 oil A .... . .... ... 15 weight percent solids, emulsion G
3 weight percent solids, emulsion G
1 percent solids by weight, emulsion G
3 weight percent solids, emulsion D,
1 percent solids by weight, emulsion D.
25 weight percent solids, emulsion E.
3 weight percent solids, emulsion E.
1 percent solids by weight, emulsion E.
20 weight percent solids, emulsion F
3 weight percent solids, emulsion F '.
1 percent solids by weight, emulsion F
1 percent solids by weight, emulsion F
+ 3 percent by weight of triethylene glycol
0.5 weight percent solids, emulsion F
+ 3 percent by weight of triethylene glycol

The above data demonstrate the benefits of using aqueous polyolefin emulsions as lubricants when thread cutting.

Example 6

The behavior of aqueous polyolefin emulsions was further evaluated when working on a Thread cutting lathe (lead screw lathe), with a rod 2.5 cm in diameter made of stainless Steel No. 304 with an 8-point thread at 67 rev / min. on a 40 x 137 cm Axelson lathe has been edited. The results are shown in Table IV:

Table VI

Lubricant and dilution ratio Pre-cuts Finish cuts Overall rating oil A useful
bad
Well excellent
useful
Well excellent
useful
excellent oil B (dilution 30: 1)
1 percent by weight, emulsion F

The test results show that aqueous polyolefin emulsiqnen in their behavior and their performance on the high-performance lubricants Mineral oil base are at least equivalent.

In addition to the active ingredients already mentioned, the lubricants according to the invention can also contain the usual additives that give the agents certain desirable properties, such as anti-corrosion agents, Antifoam agents, antibacterial agents, and the like.

Corrosion-preventing agents include morpholine, alkali nitrites (e.g. potassium or Sodium nitrite), alkali mercaptobenzodiazoles (e.g. the sodium salt of mercaptobenzodiazole), polyphosphates (e.g. hexametaphosphate) and the like can be used.

Illustrative of antibacterial agents are chlorophenols, neomycin sulfates, and 6-acetoxy-2,4-dimethyl-m-dioxane and the like. An aqueous solution with di- (phenylmercuri) ammonium propionate in an amount corresponding to 6 percent by weight of mercury, also has an antibacterial effect. ■

As the anti-foaming agent mentioned: Alcohols having 6 to 10 carbon atoms, e.g. B. 2-ethylhexanol, or surfactants with a low hydrophilic / liophilic balance u. like

The manufacturing process is not decisive for the agents according to the invention, i.e. the Components of the agents can be mixed with one another in any sequence and in any suitable device and for their preparation can be used in the manufacture of the usual aqueous lubricants best practices are applied.

The use of the agents according to the invention has been described above with a view to processing described by iron or steel. The lubricants are particularly stressful here subject. Of course, the means are also used in the processing of metals of all kinds, So for example of copper, aluminum, bronze, brass and the like. In short, everywhere where moving metal surfaces come into contact with each other, usable with success.

Claims (3)

Patent claims: 1. Lubricant based on an aqueous emulsion, consisting of . 1. water, 2. an emulsifier, 3. the lubricant and, if necessary, from preserving, anti-corrosive or foam-preventing additives, characterized in that as component 3 in the lubricant Homo- or copolymer of an olefin with a molecular weight of 1500 to 25,000 in a proportion of 0.1 to 25% of the total weight is included and that as component 2 optionally contain a nonionic emulsifier is. 2. Lubricant according to claim 1, characterized in that it contains 3 polyethylene as component or polypropylene is included. 3. Lubricant according to claim 2, characterized in that the component 3 therein in one Amount of 0.2 to 3, in particular 1 to 3 percent by weight is included.