DE1081586B - Lubricating oil - Google Patents

Description

GERMAN

The invention relates to lubricating oils based on mineral or synthetic oil with a Content of an isobutylene polymer or copolymer with a molecular weight of about 2000 up to 50000 '.

The production and use of isobutylene polymers and copolymers are known. Isobutylene polymers and interpolymers (high isobutylene) of molecular weights in the range of about 10,000 to 35,000 (according to Staudinger) are classified as Viscosity index improver used for lubricating oils. Similar polymers with molecular weights above about 35,000 are generally not used as viscosity index improvers because they are im Use, are strongly degraded and their viscosity index improving Properties largely lose when they are exposed to the high shear forces to which good lubricating oils are resistant have to.

So far, polymers with a high isobutylene content have been used and high molecular weight (30,000 to 250,000) already a degradation of their molecular weight subjected to viscosity index improvers having a molecular weight in the range of about 10,000 up to 35,000 to be won. These viscosity index improvers are in terms of their resistance to the Effect of shear stresses superior to the products produced by direct polymerization will. In particular, copolymers of isobutylene and isoprene with a "molecular weight." in the range of about 30,000 to 250,000 in the form of chips, a sharp degradation treatment by thermal, subject to chemical and mechanical action in order to produce low molecular weight substances, which are suitable as viscosity index improvers. However, this treatment causes discoloration, furthermore, equipment and maintenance costs are expensive. Isobutylene polymers are also used of a molecular weight in the range of about 30,000 to 250,000 dissolved in mineral oil and strong Subjected to shear forces in order to lower their molecular weight and thereby the polymer into one To convert viscosity index improvers of useful shear resistance. This procedure has become but not economically implemented because of the extraordinarily high shear rates in the usual equipment and turbulent flows cannot be maintained continuously.

The invention now relates to lubricating oils based on mineral or synthetic oils with a content of an isobutylene polymer or copolymer with a molecular weight of about 20,000 to 50,000, which are characterized in that the polymer has a known manner by irradiating a poly

Applicant:

Esso Research and Engineering Company, Elizabeth, N.J. (V.St.A.)

Representative: E. Maemecke, Berlin-Lichterfelde West,

and Dr. W. Kühl, Hamburg 36, Esplanade 36 a,

Patent attorneys

Claimed priority:
V. St. v. America February 16, 1955

2

mers or copolymers of isobutylene with ionizing rays of high energy obtained polymer is, which has a lower molecular weight than the starting polymer or copolymer having. It has been found that the polymers and copolymers degraded in this way of isobutylene have a significantly higher shear resistance than that of direct Polymerization or by other degradation of higher molecular weight polymers or copolymers of the isobutylene obtained products of corresponding molecular weights. For this reason are suitable the products degraded with the help of high-energy ionizing rays are better than viscosity index improvers for lubricating oils that are known to be exposed to high shear forces. Also own the products depolymerized with the help of ionizing radiation have a better color than copolymers of isobutylene and isoprene, which have been depolymerized by grinding with catalysts are.

Both homopolymers and copolymers of isobutylene are used as starting polymers into consideration, the isobutylene component is at least about 5 percent by weight. Preferably this proportion is at least 40 percent by weight, in particular at least about 95 percent by weight. Preferred polymers are polyisobutylene and a

009509/377

10

Copolymer of about 99 percent by weight isobutylene and about 1 percent by weight isoprene. Other Starting copolymers are e.g. copolymers of isobutylene and styrene, in which the isobutylene content usually 20 to 60 percent by weight, <and copolymers of isobutylene with Vinyl toluene, vinyl ethers, butadiene, maleic anhydride, vinyl trichlorosilane, acrylonitrile, etc.

The molecular weight of the starting polymers may range from about 1,000 to 50,000 are ¹ or more and is preferably in the range of from about 30000 to 250000. The preparation of these isobutylene polymers and -mischpolymeren is known.

The high-energy ionizing radiation can contain radioactive substances, preferably j-emitters, atomic piles, in particular by-products or waste materials from nuclear reactors, possibly also electron accelerators come from. The irradiation can be carried out with radiation intensities of about 50,000 to more than 50,000,000 x-rays / hour using radiation sources in the range of about 50 Gurie up to 1000 kCurie in a period of preferably Va up to 24 hours, but also longer or shorter, the starting polymer to be depolymerized is preferably in solution. The irradiation should be done as evenly as possible, because the products then have a better shear resistance than after uneven exposure.

In general, the amount of molecular weight decrease in the manufacture of viscosity index improvers is from isobutylene-isoprene copolymers, polyisoprene 11. The like. Preferably at least 5% and in particular at least 25%. Isobutylene polymers with viscosity index improvers Properties have molecular weights in the general range of about 2,000 to 50,000, preferably about 10,000 to 35,000, especially from about 15,000 to 20,000 (e.g. 18,000). According to the invention one uses such viscosity index improvers, the ionizing by the action of high-energy Rays received on high molecular weight polymers of molecular weights up to 500,000 or more became. The higher molecular weight polymers normally have molecular weights in the range of 30,000 to 250,000.

The lubricating oils according to the invention contain as viscosity index improvers, based on the total mixture, about 0.01 to 30, preferably 0.1 to 10 percent by weight of the high-energy ionizing Radiation degraded polymers whose molecular weights are in the range from about 200O to 50,000 but preferably 10,000 to 35,000, in particular about 15,000 to 20,000 (e.g. about 18,000). The products can also be marketed as concentrates containing around 10 up to 70 percent by weight of irradiated polymer in a diluent of lubricating oil viscosity contain. The lubricating oils according to the invention are particularly suitable for internal combustion engines.

All known mineral, synthetic, animal or vegetable oils are used as the lubricating oil base Consider lubricating oils, which may also contain other lubricating oil additives known per se.

example 1

First, a solution (mixture A) of a high molecular weight isobutylene polymer in one Diluent oil (oil A) produced. Mixture A consists of 5 percent by weight polyisobutylene with a molecular weight of 100,000 and 95 percent by weight oil A (a acid-refined mineral oil with a viscosity of 5.8 oSt at 98.9 ° C and a viscosity index of 60).

Different samples of mixture A are irradiated with y-rays as follows:

When working in batches, the samples are placed in large glass tubes 3.8 to 5 cm in diameter and 60 cm length filled. The tubes are closed with plugs and placed in an aluminum canister, into a cylindrical cobalt 60-y radiation source more than 5 cm in diameter and 70 cm in length is sunk. The uniform radiation intensity in the center of the radiation source is 360,000 roentgen / hour. The samples become different irradiated for a long time at room temperature so that they absorb different amounts of ionization radiation. After exposure, the samples are evaluated as described below.

The viscosity of mixture A is determined after irradiation at different levels. Further the degradation (according to McIntyre) of that sample which was irradiated with 3.3 megarays, as well as of the original mixture A. Mclntyre degradation is a measure of shear resistance of the polymer and is determined as follows:

The polymer to be evaluated is adjusted to a suitable viscosity (2000 up to 4000 SSU at 98.9 ° C) and then this mixture with a mineral lubricating oil of a Viscosity of 57 SSU at 98.9 ° C and a viscosity index of 91 to 95 except for a viscosity of 77 SSU at 98.9 ° C.

The sample is then placed in the reservoir of the testing device, which is powered by a motor of 1 hp, a McIntyre pump (model 102-29) and a pressure regulator. The previously on The sample heated to 93 ° C. is then circulated through the test device at 93 ° C. and 70 at for 1 hour. then the percentage drop in viscosity due to the degradation of the polymer is calculated from the measured values Values of (1) the final viscosity of the sample after the 1 hour test, (2) the original Viscosity of the sample and (3) the viscosity of the base of the mixture. The higher the percentage The decrease in viscosity, the lower the shear resistance of the polymer.

The results of the y-irradiation of mixture A are given in Table I.

Table I.

^ Irradiation of mixture A
55

60 0 viscosity Dismantling Amount of radiation, 3.3 of the irradiated after Mclntyre Mega-x-rays 65 5.1 **) Mixture »/ 0 15.2 cSt at 98.9 ° C 84 30.4 2303.0 25th 342.2 *) 41.6 *) 19.0 *) 13.2

*) not determined.
**) hereinafter referred to as mixture B.

As can be seen, the viscosity of the mixture decreases as the dose of irradiation is increased. The dosage is not sufficient to significantly break down the diluent oil (Oil A), but it does a decrease in the molecular weight of the polyisobutylene, as evidenced by the decrease in viscosity can be seen (Table I). It can also be seen that when the molecular weight of the polyisobutylene is reduced the percentage of degradation according to McIntyre also decreases. This means that if the Molecular weight of the polyisobutylene improves the shear resistance of the end product.

Example 2

In this example the effectiveness of mixture B (produced by irradiation from mixture A, see Table I) to improve the viscosity

compared to a viscosity index improver of a known type that is obtained by direct polymerization is made of isobutylene. The well-known viscosity index improver is available as an additive concentrate available, hereinafter referred to as mixture C. Mixture C consists of 20 percent by weight 18,000 molecular weight polyisobutylene and 80 weight percent of a solvent extracted and dewaxed mineral lubricating oils from

to a viscosity of 150 SSU at 37.8 ° C and a viscosity index of 100 (Oil B).

Mixture B and mixture C are then mixed with oil in different amounts to form mixtures of the same Viscosity cut back to be effective

L5 improvement in viscosity index compare to can. The results are shown in Table II.

Table II
Viscosity and viscosity index of mixtures B and C.

Mixtures containing semic B. Viscosity, SUS
at 98.9 ° C Viscosity
index Mixtures containing mixture C Polymer
concentration
in the oil
Weight percent Viscosity, SUS
at 98.9 ° C Viscosity
index concentration
Weight percent Polymer
concentration
in the oil
Weight percent 44.7. . 63 concentration
Weight percent 0 44.7 63 0 0 55.4 103 0 1.0 54.1 103 18th o; 9 67.2 114 5 1.8 , 63.9 113 32 1.6 9

As can be seen, the viscosity index is from Mixture B at corresponding viscosity values similar to those of Mixture C, indicating that the irradiated Products according to the invention have excellent viscosity-improving properties.

Example 3

In this example, two different ones are produced by exposure to high-energy ionizing rays Degraded polymers (D and G) compared with two known viscosity index improvers (J and L).

With high-energy, ionizing rays
irradiated polymers

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D. It irradiates a polyisobutylene having a molecular weight of about 200,000 ¹ with y-rays at a radiation dose of 5 Mega X-ray. The irradiated finished product (D) has a molecular weight of about 20,000. The irradiation is carried out as described in Example 1 for mixture A, but the radiation intensity in the center of the cobalt-60 radiation source here 311,000 X-rays / hour. amounts to.

G. A copolymer is irradiated in the same way of 99% isobutylene and 1% isoprene with a molecular weight of about 35,000 with γ-rays a radiation dose of 6 megarays, with a product (G) having a molecular weight of about 20,000 is obtained.

Known non-irradiated lubricating oil additives

J. A polyisobutylene of molecular weight about 20,000 obtained by direct polymerization of Isobutylene is produced.

L. This mixture is made from a copolymer of 99% isobutylene and 1% isoprene of molecular weight of about 35,000 produced by placing the copolymer on a hot roller (160 to 180 ° C) using 0.5 weight percent mercaptobenzothiazole as a catalyst depolymerized. The product has a molecular weight of about 20,000. An 15 weight percent concentrate of this Additive in a lubricating oil (of a color value of 14 days Robinson) has a color value of 4 days Robinson.

These various additives are combined into one (hereinafter referred to as "oil C") lubricating oil added in such an amount that the oil mixtures each contain 3.6 percent by weight of additive. Oil C is a solvent-extracted dewaxed mineral lubricating oil with a viscosity of 46 SUS 98.9 ° C. and a viscosity index of 113. The viscosity (SUS at 98.9 ° C.), the viscosity index, is determined these oil mixtures and the breakdown (according to McIntyre) of these polymers. The results are compiled in Table III.

Table III Comparison of various viscosity index improvers

Viscosity index improver

Exposure amount mega-x-rays

Molecular weight after Stauclinger degradation
Mclntyre

Ro

colour

(T ^a s

ibinson)

Mix with oil

(Concentration

3.6 percent by weight)

Viscosity,

SUS
at 98.9 ° C

Viscosity index

I. According to the invention

D (irradiated polyisobutylene)

G (Irradiated copolymer of isobutylene and isoprene)

II. Known Improvers

J (polyisobutylene)

L (chemically degraded copolymer of isobutylene and isoprene)

*) Not determined.

20000 20000

20000 20000 9.0
12.5

18.0
14.0

water white
water white

water white

101.3
101.0

*)
100.0

135

135

*)
135

Claims (5)

Patent claims: 1. Mineral or synthetic oil-based lubricating oil with an isobutylene polymer content or -mischpolymerisat a molecular weight of about 2000 to 50,000, thereby characterized in that the polymer is obtained in a known manner by irradiating a polymer of isobutylene copolymers with high energy ionizing rays Polymer is which has a lower molecular weight than the starting polymer or -mischpolymerisat has. 2. Lubricating oil according to claim 1, characterized by a content of the polymer in quantities from about 0.01 to 30 percent by weight, based on the total mixture. 3. Lubricating oil according to claim 1 and 2, characterized by a content of a polymer molecular weight from about 10,000 to 35,000 in amounts from about 0.1 to 10 percent by weight of the total mixture. 4. Lubricating oil according to claim 3, characterized by a content of a by irradiation Copolymer of isobutylene and isoprene with an isoprene component content of about 1 percent by weight and a molecular weight of about 30,000 to 250,000 obtained with y-rays Mixed polymer. 5. Lubricating oil according to claim 1 to 4, characterized by a content of a concentrate of mineral oil and about 10 to 70 percent by weight of one obtained by irradiating a polymer of isobutylene or a copolymer of isobutylene containing at least 95 percent by weight isobutylene of a molecular weight of about 30,000 to 250,000 with γ-rays to the point of degradation of the original molecular weight by at least 5% of the polymer obtained. Pamphlets considered;
Chem. Zentralblatt, 1954, p. 5767. © 009 509/377 5.