JPS6133880B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to lubricant compositions, and relates to the deodorization and stabilization of phosma-sulfurized hydrocarbon polymers used in oil-based internal combustion engine lubricants to prevent deterioration. phosphosulfurized hydrocarbon polymers having a number average molecular weight (n) in the range from 150 to 50,000 and phosphosulfurized hydrocarbon polymers derived by the reaction of phosphorus sulfide, preferably phosphorus pentasulfide, and such phosphosulfurized carbons; Using hydrogen in oil-based lubricants to prevent lubricant deterioration
This has been known since the grant of US Pat. No. 2,316,079 on April 6, 1943 to Clarence M. Loans and James W. Gaynor. According to that patent, the disclosure of which is incorporated by reference and made a part of the disclosure, such phosphosulfurized hydrocarbons are low molecular weight monoolefins, such as propene, a mixture of isobutylene and butenes-1 and -2. It is made by reacting a 150-50,000 _° polymer of isobutylene with phosphorus sulfide, preferably _P2S5 , in an amount of ₅ to 25% by weight of the polymer at a temperature in the range of 93 to 232C. However, the reason why the commercial use of such phosphosulfurized hydrocarbons as additives to oil-based crankcase lubricants has not gained general acceptance is that
Such phosphosulphurized hydrocarbons characteristically have a pungent unpleasant odor, lack storage stability, and continually liberate H ₂ S, even more so when used as crankcase lubricants. Such H ₂ S emissions also cause corrosion of lead and/or copper containing bearings. The U.S.-imposed limits on gas emissions from internal combustion engines in the statute under consideration and the accompanying stringency on the performance of oil-based crankcase lubricants for such engines substantially limit the use of ashless crankcase oil-based lubricant formulations. It strongly indicates the necessity. Ashless detergent-dispersant additives such as high molecular weight succinimides and amides and high molecular weight Mannitz reaction products from alkyl phenols, amines and formaldehydes have been developed and used in oil-based crankcase lubricants. However, non-metallic inhibitors against corrosion of bearing metals and oxidative concentration of oil-based lubricating base materials are currently being studied for use under the above-mentioned severe service conditions. Quite unexpectedly, a small amount of 2,5-bis(alkyldithio)-
It has been found that the addition of 1,3,4-thiadiazole suppresses the characteristic pungent unpleasant odor and constant _H2S emission of such phosphosulfurized hydrocarbon polymers. Such suppression of odor and instability by bis(alkyldithio)thiadiazole was unexpected, as its sulfur content would have been expected to at least intensify the odor problem. such phosphosulfurized hydrocarbon polymers and a small amount, generally in the range of 0.1 to 50% by weight,
2,5-bis(alkyldithio)-1,3,4-
The formulations obtained with thiadiazole are for lubricating four- and two-stroke internal combustion gasoline and diesel engines that use crankcase lubrication or lubrication by adding lubricant to the engine fuel as is normally done in two-stroke gasoline engines. It can be used as an additive to oil-based lubricants. Such use of formulations of such phosphosulfurized hydrocarbon polymers and small amounts of bis(alkyldithio)thiadiazoles can be used to improve bearing metals, especially
Provides an ashless inhibitor against corrosion of Pb, Cu and Pb-Cu bearings and oxidative thickening of oil-based lubricants. This 2,5-bis(alkyldithio)-1.
3,4-thiadiazole and its preparation are known from the respective teachings in US Pat. Nos. 2,719,126 and 3,087,932. The bis(alkyldithio)thiadiazoles mentioned above can have alkyl substituents of 1 to 280 carbon atoms and are 2,5-dimercapto-1,3,4-thiadiazoles and C ₁ to C ₂₈₀ alkyl hydrocarbons. It can be prepared by oxidative condensation with mercaptans in a molar ratio of 1:2. For a more complete understanding of 2,5-bis(alkyldithio)-1,3,4-thiadiazole, the teachings of the two above-mentioned patents are incorporated herein by reference. Small amounts, 50% by weight, to improve the odor and stability during storage and use of the above-described phosphosulfurized hydrocarbon polymers of the Loane and Gaynor patents.
2,5-bis(alkyldithio)-1,3,4 less than but within the range of 0.1 to 50% by weight
-Thiadiazoles, provided that the alkyl group contains at least 8 carbon atoms, are preferably used. Such selection is practical and based on the solubility of said concentration of bis(alkyldithio)thiadiazole in the oil-based lubricant. Even though bis(alkyldithio)thiadiazoles with smaller alkyl groups, i.e., less than about 8 alkyl groups, have the ability to improve the odor and stability of phosphosulfurized hydrocarbon polymers, they are not practical. It does not have sufficient solubility in oil-based lubricants to allow its use in oil-based lubricants. The preferred bis(alkyldithio)thiadiazole concentration is preferably 1 to 25% by weight of the phosphosulfurized hydrocarbon polymer, and such adoption is necessary to practically inhibit bearing metal corrosion and oxidative thickening of oil-based lubricants. Based on. A phosphosulfurized hydrocarbon and 1-25% by weight of the desired 2,5-bis(alkyldithio)-
The aforementioned formulation with 1,3,4-thiadiazole is
in a concentration of 0.01 to 20% by volume (the formulation is a liquid), but preferably 0.1 to 10% by volume based on practical requirements for the suppression of bearing metal corrosion and oxidative thickening of oil-based lubricants. It can be used as an additive in oil-based lubricants in concentrated concentrations. The above compositions of phosphosulfurized hydrocarbon polymers and 1-25% by weight bis(alkyldithio)thiadiazole are useful for transmission and industrial lubricants requiring oxidative stability of the lubricant. Preferred for the present invention is the phosphosulfurized hydrocarbon polymer of the Loane and Gaynor patent, which
200 to 4000 _o polypropene or polybutene polymer and 5 to 25% by weight of P ₂ S ₅
It is derived by reacting at a temperature of 120-205°C and removing by-product H ₂ S. Such phosphosulfurized polypropene or polybutene polymers typically have a
It has a sulfur to phosphorus (S:P) weight ratio of 3.0. Examples of such phosphosulfurized polypropene and polybutene hydrocarbons are shown in Table 1 below, where, in general, for each set of polymers of the same _o , a higher S:P ratio corresponds to a longer reaction time. You can get it by twisting it.

TABLE The references and examples below illustrate the benefits to be obtained by the invention and how to carry it out. Reference Example 1 A phosphosulfurized polybutene hydrocarbon polymer having an S:P ratio of 1.65:1.0 ( _O of the polymer is 900) and 25% by weight of 2,5-bis(octyldithio)-1,3,4-thiadiazole thereof Make a mixture of. The characteristic pungent unpleasant odor of the phosphosulfurized polybutene virtually disappeared. After storing this mixture for 7 days, there was still no pungent unpleasant odor, a small amount of sediment formed and
H ₂ S (easily detectable even at very low concentrations) was not detected. The precipitate is probably the reaction product of some H ₂ S precursor and bis(alkyldithio)thiadiazole, since untreated phosphosulfurized polybutene hydrocarbons stored for 7 days did not produce any precipitate but were irritating. This is because not only an unpleasant odor but also some H ₂ S was liberated. The following tests were conducted to demonstrate inhibition of H ₂ S release from phosphosulfurized polypropene or polybutene hydrocarbon polymers. Reference Example 2-5 The phosphosulfurized hydrocarbon polymer used is a phosphosulfurized polypropene having an S:P ratio of 1.53:1.0 in Table 1. This phosphosulfurized polypropene and 0 (control) to 5% by weight of 2.5-
Bis-(octyldithio)-1,3,4-thiadiazole was used and copper strips were suspended over this composition in a sealed jar for 16 hours. The copper strips were graded for copper corrosion according to ASTM-D 130 after 16 hours of exposure. The amount of bis(octyldithio)thiadiazole and the corrosion rating of the copper strips are shown in Table 2.

TABLE The above ratings illustrate that the vapors on the compositions of Reference Examples 2-5 are less corrosive than the vapors on the untreated phosphosulfurized polypropene of the control experiment. The irritating unpleasant odor was not present in the composition of Reference Examples 2-5, but was present in the control experiment. The following examples illustrate the corrosion inhibition of compositions of the present invention used as additives in oil-based lubricants. Example 1-5 Mannitz reaction type ashless detergent in oily base oil (SAE-30 oil) - dispersant 4.0% and first
1.7% by weight of phosphosulfurized polypropene having a table S:P ratio of 1.53 was dissolved. 0 (control) to 0.1% by weight of 2,5-bis(octyldithio)-1,3,4-thiadiazole was dissolved in this solution. Copper strips were soaked in this solution for 3 hours at 135°C and then graded according to ASTM-D130. The results of these tests are shown in Table 3 below.

TABLE The above ratings demonstrate that the compositions of Examples 1-5 are much more non-corrosive to copper chips than the control test compositions. The compositions of Examples 1-5 did not produce any pungent unpleasant odors, but the control test compositions did. EXAMPLE 6-7 Bench testing of the effectiveness of compositions of the present invention in inhibiting corrosion of lead and copper-lead bearings and SAE-30 as a crankcase lubricant with leaded gasoline.
The results are illustrated by the results of a test run in an L-38 engine with Cu-Pb, a standard test using class oil. In bench tests, control test compositions were prepared using Examples 1-5 in an oil-based lubricant (SAE-30 grade oil).
Detergency as described for - 4% dispersant dissolved and no corrosion inhibitor dissolved. Example 6 The composition contains 1% by weight of phosphosulfurized polypropene (with S:P of 1.53:1.0 in Table 1) and 0.3% of 2,5-bis(octyldithio)- in the same lubricant.
1,3,4-thiadiazole (33% of phosphosulfurized polypropene) was dissolved. The composition of Example 7 also contained 1% phosphosulfurized polybutene (S:P of 1.5:1.0 in Table 1) in the same lubricant.
0.3%2.5-bis(octyldithio)-1.3.
4-Thiadiazole (33% of phosphosulfurized polybutene) was dissolved. 162− of three compositions
Lead strips weighed separately in each were heated to 163°C and immersed for 20 hours, during which time 30
Blow air at ml/min. After such exposure, the lead strips are washed with a solvent to remove oil, dried and reweighed to determine weight loss. The results of this bench test are shown in Table 4.

[Table] Example 8 Oil-based crankcase lubricant formulation used for L-38 engine testing with new weighed Pb-Cu bearings was detergent-dispersant as described for Examples 1-5.
7.0%, Phosma sulfurized polypropene 1.7% and 0.3% 2.5- with an S:P ratio of 1.53:1.0 in Table 1
For bis(octyldithio)-1,3,4-thiadiazole and phosphosulfurized polypropene, its
It is an oily (PAE-30 grade oil) base oil solution consisting of 17.65%. Upon completion of the standard operating hours of this test, the engine pistons are inspected and rated for varnish deposits on a scale of 0-10, where 0 means thick and completely varnished and 10 means clean. Represents a piston. The Pb-Cu bearings are cleaned with solvent to remove oil, dried and reweighed. From this L-38 engine test, with the use of the oil-based crankcase lubricant composition described above, the piston varnish rating was 9.6 (96% clean) and Pb-
The weight loss of the Cu bearing was found to be only 33.6 mg. A weight loss of 50 mg is allowed. Reference example 6 10% by weight of 2,5-bis(dodecyldithio)-
Reference Example 1 is repeated except that 1,3,4-thiadiazole is used. Even after 7 days of storage, no precipitate is registered (the reaction product with H ₂ S is soluble), but the treated phosphosulfurized hydrocarbon polymer still does not have any pungent unpleasant odor, on the contrary. Untreated phosphosulfurized hydrocarbon polymers have a characteristic pungent unpleasant odor. The foregoing examples and tests demonstrate that other desirable phosphosulfurized polypropene or polybutene hydrocarbon polymers and other 2,5-bis(alkyldithio)
-1,3,4-thiadiazole can be practiced and similar improved results will be obtained.

Claims (1)

[Claims] 1 Phosphosulfide hydrocarbons derived from the reaction of oil-based lubricants with P ₂ S ₅ and alkene hydrocarbons having a molecular weight in the range from 200 to 4000 and 2.5% by weight of 1.1-50% of this phosphosulfide hydrocarbons. -Bis(alkyldithio)-1,3,4-thiadiazole (alkyl substituents contain 1-280 carbon atoms)
A lubricant composition comprising % by volume.