DE1121257B - Additives to lubricating oils based on mineral oils - Google Patents

Description

Today, normal mineral oil distillates or refinates no longer meet the requirements of mechanical engineering in the field of lubrication. However, it has been found that there are a number of compounds which significantly improve the lubricating properties of a mineral oil. So cause z. B. fatty acids and their esters, added to a mineral oil, a significant reduction in friction. Other compounds that contain organically bound sulfur, phosphorus or chlorine are suitable as extreme pressure additives, ie they increase the compressive strength of the oils, which is particularly important for gear oils and oils that are exposed to particular loads. Bromine compounds have also been proposed. For example, tetrabromethylene cutting oils have been added and excellent results have been achieved. However, tetrabromethylene has a considerable volatility, so that the quality of the oil deteriorates quickly.

It has also already been described that fatty acids containing a trichloromethyl group and optionally contain more chlorine atoms, lubricating oils can clog, causing seizure of machine parts avoided and the least possible wear and tear of the same should be achieved. The lubricating effect that can be achieved with these compounds is, however, relatively small.

It has now been found that brominated carboxylic acids, in which the carbon atoms each through not more than one bromine atom are substituted and their esters, amides or salts are very small The compressive strength and the lubricating effect of a lubricating oil based on mineral oil are considerable raise. The brominated compounds can optionally be used individually or as a mixture with one another in conjunction with other known additives to lubricating oils.

While the organic chlorine compounds previously used for this purpose usually show a good effect in amounts of 2 or more percent, based on the chlorine content, brominated carboxylic acids, for example, have a similarly good effect even in simple added amounts of less than 2%. Frequently, however, quantities that are several powers of ten lower than those of the organic chlorine compounds mentioned are sufficient. The addition of 0.01% of the brominated carboxylic acids increases the compressive strength of an oil considerably. The additives for an optimal effect are around 0.05 to 0.2%. Acids which are produced by bromination of unsaturated fatty acids have been found to be particularly suitable

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Erich Lück, Wiesbaden,

and Dr. Wieland Joos, Frankfurt / M.,

have been named as inventors

are easily accessible. The following brominated acids show e.g. B. a beneficial effect: χ / 3-dibromobutyric acid, / ^, y-dibromobutyric acid, Λ, / 3-dibromopropionic acid, ^. / 3-dibromoisobutyric acid, <*, / 5, y, (5-tetrabromocaproic acid, brominated higher fatty acids, e.g. B. Linseed oil fatty acids. Instead of the free acids you can also acid derivatives, for example esters of the bromine-containing acids mentioned with mono- or polyvalent ones Alcohols such as methanol, ethanol, propanol, isopropanol, butanols, undecanol, cetyl alcohol, stearyl alcohol, Oleyl alcohol, glycerine, and salts, for example ammonium or N-substituted ammonium salts, acid amides which are free or N-substituted by hydrocarbon radicals and mixtures of these compounds can be used with one another or in admixture with the free acids mentioned. Even Bromination products of naturally occurring fats and oils, in which the carbon atoms are each substituted by no more than one bromine atom, for example brominated linseed oil proved to be suitable additives for lubricating oils.

All of these substances can also be combined with other already known lubricating oil additives will.

example 1

A commercially available paraffinic oil for lubrication of precision equipment (viscosity at 5O ⁰ C 5,2 = ⁰ E 4OcSt) was Tetrabromkapronsäure in amounts of 0.01, 0.05, 0.1, 0.2 and 0.5 ° / ₀ added . These oils were tested for their lubricating behavior on an Almen-Wieland oil testing machine. Several test runs were carried out for each oil and the mean values recorded. Every trial run

109 758/501

initially consisted of 200 revolutions without load. This was followed without interruption with the Bearing load started, in such a way that after every 100 revolutions the bearing load increased by 50 kg. While when using pure paraffin oil a load of 300 kg is already possible If the bearing seizure occurred, the addition of 0.01% tetrabromocaproic acid did not result in until 600 kg Load on the camp began to eat away. Even with an addition of 0.05% tetrabromocaproic acid With the oil, no seizure of the bearing can be observed up to a load of 1550 kg, but the friction increases from about 1250 kg contact pressure to strong, with both the bearing and the shaft are heavily worn and make large grooves. With about 0.1% addition of tetrabromocaproic acid, a maximum of Lubricating effect is achieved through higher additives of 0.2 and 0.5% only in the load range up to 1000 kg is slightly exceeded, while at higher loads the friction increases again will.

Fig. 1 shows the measured values from the Almen-Wieland machine graphically represented. The damage to the bearing shells and the shaft as well as the compressive strength of the oil (load at which seizure occurs)

ίο reproduced in table 1. Table 2 gives the respective bearing load in kilograms associated coefficients of friction for different additional quantities. The coefficient of friction represents the relationship between frictional force and bearing load. High coefficients of friction result with poor lubrication, low coefficients of friction with good lubrication.

Tabel

additive

OVo

0.01 Vo 0.05 Vo

0.2Vo

0.5 V »

Area damage
Limit load
(Compressive strength)

eat away
300 kg

eat up coarse grooves 600 kg j 1500 kg fine grooves fine grooves

fine grooves

> 1600 kg ι> 1450 kg j> 130 kg

OVo 0.01 Vo Table 2 to 0.2Vo 0.5Vo Bearing load
in kilograms 0.300 0.217
0.200 0.05Vo unj 0.143
0.128
0.120
0.144 0.140
0.130
0.124
0.146 300 Friction
0.194
0.175
0.149
0.148
0.224 600 sentence
0.1 Vo 900 ; numbers
0.173
0.140 1200 i Oll28 1500 0.121
0.167

Example 2

45

A commercially available paraffinic oil for lubrication of precision devices (viscosity at 5O ⁰ C 5.2 ° E = 40 cSt) was Dibrombuttersäure in amounts of 0.01, 0.05, 0.1 and 0.5% were added. The tests on the Almen-Wieland oil testing machine were carried out as in Example 1. In Fig. 2 the measured values of the Almen-Wieland machine are shown graphically.

Dibromobutyric acid, added in an amount of 0.01%, also gives a substantial increase in the Compressive strength and a reduction in friction. Even an addition of 0.05% gives an increase in the Load capacity at which the bearing seizes up to 1250 kg. With an addition of 0.1% dibromobutyric acid a maximum of lubricating effect is reached again compared to paraffin oil. Here occurs up to one Bearing load of 1500 kg no seizure. At a concentration of 0.5% dibromobutyric acid leaves the lubricating effect decreases somewhat above 1150 kg of contact pressure. The damage to the wave surface and the storage areas are given in Table 3. As can be seen from the table, take the storage damage decreases with increasing concentration of dibromobutyric acid. The grooving will always finer. Table 4 also shows the coefficients of friction.

Tabel

o ° / o 0.01Vo additive
0.05Vo 0.1 Vo 0.5Vo Area damage eat away
300 eat away
650 eat away
1250 fine grooves
> 1500 fine grooves
> 1400 Compressive strength in kilograms.

Tabel

Bearing load in kilograms 0% 0.01% additive
0.05% 0.1% 0.5% 300 0.300 0.244
0.208 Friction coefficients
0.216
0.187 0.193
0.163 0.180
0.153 600 0.170 0.163 0.144 900 - - 0.171 0.146
0.233 0.162 1200 1500

Example 3

A commercially available unalloyed lubricating oil (viscosity at 5O ⁰ C 2.8 ⁰ E = 19.5 cSt) was Tetrabromkapronsäure in concentrations of 0.01 and 0.1% added. The testing of the lubricating properties was carried out as in Example 1 on the Almen-Wieland machine. The measured values are shown graphically in Fig. 3.

Although the base oil already endured a limit load of 950 kg, was already at an addition of 0.01 ° ^/ o Tetrabromkapronsäure an increase in the load at which seizure of the camp occurred kg to determine the 1250th The friction was significantly lower under all loads than with pure oil. With 0.1% addition of tetrabromocaproic acid, the lubricating effect was so good that the load limit on the bearing was exceeded. Table 5 shows the damage to the shaft and the bearing shells as well as the compressive strength of the individual oils, and Table 6 shows the coefficients of friction for some loads.

Table 5

o ° / " additive 0.1% 0.01% Surfaces eat away fine grooves; damage .... eat away wave rolled out Compressive in kilos 950 > 1800 gram 1250

35

40

45

Table 6

Bearing load
in kilograms 0% additive
0.01 ». " 0.1% 300 0.290
0.230
0.217 Friction coefficients
0.240
0.197
0.190
0.190 0.167
0.142
0.150
0.128
0.115 600 900 1200 1500

55 chlorinated carboxylic acids were added according to the bromocarboxylic acids used.

Example 4

A commercially pure mineral oil (viscosity at 50 ⁰ C 2.8 ° E = 19.5 cSt), 2.5 percent by weight / 3-dichlorobutyric acid added. The testing of the lubricating properties was carried out as described in Example 1 on the Almen-Wieland machine.

Example 5

The same oil as described in Example 4 was given 2.5 percent by weight of a chlorinated sorbic acid with a chlorine content of about 50% and also using the same method as in Example 1 checked for lubricating effect.

The measured values of the Almen-Wieland machine obtained in Examples 4 and 5 are shown in Fig. 4 reproduced. The resulting curves were shown in the same diagram with some measurement results contrasted brominated carboxylic acids used according to the invention. The curves are closed it can be seen that with the addition of 2.5 parts by weight of a chlorinated carboxylic acid to the mineral oil the same bearing load can generally not yet achieve the favorable low frictional force that obtained with the addition of only about 0.1 to 0.05 parts of an analogous brominated carboxylic acid. In particular is based on the comparison of the curves of Λ, / 3-dichloro and «, ß-dibromobutyric acid demonstrated that effectiveness dibromobutyric acid exceeds that of dichlorobutyric acid by more than 50 times.

Claims (1)

PATENT CLAIM: Use of brominated carboxylic acids in which the carbon atoms are each by not more than one bromine atom are substituted, as well as their esters, amides or salts individually or in Mixing with one another, optionally in conjunction with other known additives, as Additives to lubricating oils based on mineral oil. The examples 4
with which one and 5 represent comparative examples, mineral oil instead of the documents considered for the invention:
French patent specification No. 1 050 806,
1 098 408, 1 145 476. For this purpose 2 sheets of drawings O 109 758/501 12.