DE1087737B - lubricant - Google Patents

Description

GERMAN

Among the best known additives for the purpose of lowering the pour point of mineral oils belong polymeric esters of acrylic or alkyl acrylic acids, polymerized olefins, and alkylated naphthalenes. Although these additives are effective in lowering the pour point of some oils S, they are in practical use limited to a few special base oils. With other oils they are ineffective and give the finished mixture undesirable properties because they have a corrosive effect, the tendency to the formation of Have emulsions in the absence of water or steam and / or at elevated temperatures break easily.

It has now been found that certain copolymers of a vinyl pyridine and acrylic and / or alkyl acrylic acid esters, which are also derived from at least one acrylic acid ester of an aliphatic alcohol with 1 to 4 carbon atoms, not just the same excellent pour point depressants Have properties, but also extremely effective detergents and improvers for the viscosity index without the occurrence of the previously observed inconveniences To give cause.

The lubricants according to the invention contain a lubricating oil as a base and also a subordinate one Share of an oil-soluble copolymer with a molecular weight between 50,000 and 2,500,000, where this copolymer is derived from a vinyl pyridine and an acrylic acid ester component in Molar ratios between 2: 1 and 1:15.

The ester component consists of:

a) from at least two esters of acrylic acid or an α-alkyl acrylic acid with 1 to 4 carbon atoms in the alkyl radical of at least two different aliphatic alcohols with 10 to 20 and an average of 10 to 16 carbon atoms in the molecule. This part of the ester component must also contain ester pairs derived from two different alcohols each, from which one of which contains at least 4 more carbon atoms than the other alcohol, the molar ratio between the esters of such a pair is between 1:10 and 10: 1 and the representatives of such a pair Ester pairs together make up more than 50 mole percent of the fraction a);

b) from at least one ester of acrylic acid or an α-alkyl acrylic acid having 1 to 4 carbon atoms in the alkyl radical of aliphatic alcohols with 1 to 4 carbon atoms in the molecule, where this proportion makes up 10 to 80 mol percent of the proportion a) of the ester component.

The molecular weight of the copolymer is preferably between. 100,000 and 850,000. The MoI lubricants

Applicant:

N.V. De Bataafsche Petroleum

Maatschappij,

The hague

Representative: Dr. K. Schwarzhans, patent attorney,
Munich 19, Romanplatz 9

Claimed priority:
V. St. v. AmFyriicR of December 31, 1956

Lyman Edward Lorensen, Orinda, Calif.,
John Zachar and Robert Caldwell Jones,

Berkeley, Calif. (V. St. Α.),
have been named as inventors

weights are determined using the light scattering method, as described in Chem. Reviews, 40, p. 319 (1948).

From the series of a-alkyl acrylic acids, of which If the acrylic acid esters are derived, methacrylic acid is preferred.

The average number of carbon atoms of the esterifying alcohols in portion a) of the ester component is preferably 12-14.

The copolymer must be oil-soluble and is preferably in the oil under storage conditions soluble to such an extent that at least 0.1 percent by weight and particularly expediently at least 1 percent by weight remains resolved. The amount of acrylic esters of lower alcohols in the copolymer should be therefore not too high and is preferably 10 to 70 mol percent and particularly preferably 10 to 60 mol percent, calculated on the proportion a) of the ester component.

The molar ratio between vinyl pyridine and acrylic acid ester components in the mixed polymer bf * agt preferably 2: 1 to 1:11.

It has already been recommended to use copolymers of a vinyl pyridine and acrylic acid esters of aliphatic Use alcohols with more than 8 carbon atoms as additives for lubricating oils. However, such polymeric substances are not suitable for

009 588/391

any paraffin-containing lubricating oils as pour point depressants and viscosity index improvers, as confirmed by the comparative tests described below will. Rather, the advantageous and progressive results sought after according to the invention are achieved only achieved if a special selection is made with regard to those used for the formation of the copolymer Mixture of acrylic acid esters is taken and in particular at least one short-chain ester a lower alcohol having 1 to 4 carbon atoms is present in the molecule. Also must be the molar ratio between the vinyl pyridine and the ester component lie within certain limits, and furthermore, the ratio of acrylic acid esters with at least 4 carbon atoms should be differentiated Residual alcohol to the other esters of the portion a) of the ester component does not have a certain value fall below.

Suitable vinyl pyridines for the preparation of the copolymers are, for example, 2-vinyl pyridine, 3-vinylpyridine, 4-vinylpyridine and the substituted, z. B. alkyl-substituted derivatives thereof, such as 2-methyl-5-vinylpyridine, 4-methyl-2-vinylpyridine, 5-methyl-2-vinylpyridine and 2-butyl-5-vinylpyridine.

The long-chain acrylic acid esters a) are preferably derived from straight-chain and saturated ones Alcohols such as decyl, dodecyl, tetradecyl, hexadecyl, Octadecyl and eicosyl alcohol. Special mixed combinations of these esters are z. B. dodecyl methacrylate-octadecyl methacrylate, Tetradecyl acrylate - octadecyl methacrylate, Decyl methacrylate-octadecyl methacrylate, lauryl methacrylate-octadecyl methacrylate.

The short-chain acrylic acid esters b) can be derived, for example, from methyl, ethyl, propyl or butyl alcohol.

Technical lauryl methacrylate is derived from technical lauryl alcohol, which is a mixture of about 2 mole percent decyl alcohol (C ₁₀ ), 68 mole percent lauryl alcohol (C ₁₂ ), 28 mole percent myristyl alcohol (C ₁₄ ) and 2 mole percent cetyl alcohol (C ₁₆ ). As a result, there is only a single pair of esters in technical-grade lauryl methacrylate, which is derived from alcohols that differ by at least 4 carbon atoms, in the range of the molar ratio between 1:10 and 10: 1 required according to the invention, namely the pair C ₁₀ -C ₁₆ . The total amount of the representatives of this pair is only 4 mol percent, so that technical lauryl methacrylate does not fall under the definition given above under a).

In a similar way, technical stearyl methacrylate does not meet the features of the invention either. Technical stearyl methacrylate is derived from technical stearyl alcohol, which is a mixture of about 4 mol percent myristyl alcohol (C ₁₄ ), 34 mol percent cetyl alcohol (Q ₁₆ ) and 62 mol percent stearyl alcohol (C ₁₈ ). Accordingly, in technical stearyl methacrylate, the average number of carbon atoms of the esterifying alcohol is 17.2, and furthermore, technical stearyl methacrylate does not contain an ester pair in a molar ratio between 1:10 and 10: 1, which is derived from alcohols which are approximately 4 Distinguish carbon atoms.

However, by mixing technical lauryl methacrylate and technical stearyl methacrylate, a mixture according to the definition given above under a) can be obtained. For example, in Example 1, 2.52 mol of technical stearyl methacrylate and 5.04 mol of technical lauryl methacrylate are used. The mixture contains 1.3 mole percent C ₁₀ _, 45.4 mole percent C ₁₂ _, 20.0 mole percent C ₁₄ _, 12.7 mole percent C ₁₆ _ and 20.6 mole percent C ₁₈ methacrylates. The pairs C ₁₀ -C ₁₆ , C ₁₂ -C ₁₆ , C ₁₂ -C ₁₈ and C ₁₄ -C ₁₈ are present in a molar ratio between 1:10 and 10: 1, and the total amount of representatives of these pairs is 100 mol percent, so that the mixture meets all requirements.

Copolymers of a vinyl pyridine and

ίο technical lauryl methacrylate and copolymers A vinyl pyridine and technical stearyl methacrylate only act as pour point depressants in special oils. They tend to decompose, form emulsions and cause corrosion. Against are Copolymers of a vinyl pyridine, a mixture of technical lauryl methacrylate and stearyl methacrylate and methyl methacrylate in suitable proportions, excellent pour point depressants, cleaning agents and viscosity index improvers.

The polymers according to the present invention can be prepared by methods known per se take place, the size of the molecular weight can be influenced in the usual way, for. B. by the polymerization method.

Particularly suitable polymerization initiators are the various catalysts that generate free radicals, such as benzoyl peroxide, lauryl peroxide, sodium or potassium persulfate, sodium or potassium percarbonate, Peracetic acid and the like

The polymerization temperature varies depending on the type of initiator chosen, the desired one Reaction rate and the desired molecular weight. In general, it is between about 50 and 150 ° C, particularly useful between 60 and 150 ° C.

In most cases it has been found to be useful to carry out the polymerization in the absence of Air, e.g. B. in the presence of an inert gas such as nitrogen. It can be more atmospheric or reduced or superatmospheric pressure can be applied.

At the end of the polymerization, any unreacted monomer or monomer and / or Solvent can be removed, preferably by distillation or by precipitation with a suitable Solvent.

The lubricating oil used as a base in the mixtures according to the invention can be selected from paraffinic, naphthenic, asphaltic or mixed basic crude oils or mixtures of such crude oils has been obtained be. The viscosity can vary over a wide range, e.g. From 100 SUS at 37.8 ° C to 100 SUS at 98.9 ° C. The mineral oils can be mixed with fatty oils such as castor oil or Bacon oil, and / or with synthetic lubricants such as polymerized olefins, copolymers Alkylene glycols and alkylene oxides, organic esters (e.g. 2-ethylhexyl sebacate) and silicone polymers (e.g. dimethyl silicone polymers).

The copolymers according to the invention are generally used in an amount of 0.1 to 10% and preferably from 1 to 5 weight percent based on the total lubricant applied.

The following example serves to explain the invention in more detail.

example

A mixture of 2.52 moles of technical stearyl methacrylate, 5.0 moles of technical lauryl methacrylate,

0.83 moles of methyl methacrylate and 1 mole of 2-methyl-5-vinylpyridine and 0.2 percent by weight of α, α'-azodiisobutylonitrile, dissolved in acetone, was stirred for 36 hours at 65 ° C in a nitrogen atmosphere implemented. The polymer was then dispersed in the same volume of benzene and • then precipitated with 5 to 10 parts by volume of a mixture of acetone and methanol. After repetition this measure fell to a copolymer with a molecular weight between 750,000 and 800,000, its Nitrogen content was 0.60 percent by weight, which corresponds to the theoretical value. This copolymer is hereinafter referred to as copolymer A.

The following copolymers were prepared in a similar manner.

Mixed
poly
merisat SMA Moles of monomers LMA MMA BMA MVP EPP B. 2.24 4.48 1.86 1 C. 2.24 4.48 - 1.86 1 - D. 2.05 3.92 2.43 - 1 - E. 2.05 3.92 - 2.43 " 1 - F. 1.68 3.36 3.36 - 1 - G 1.68 3.36 - 3.36 1 - H 1.40 2.80 - 4.2 1 - I. 1.40 2.80 4.2 - 1 - J 1.12 2.24 5.04 - 1 - K 1.12 2.24 - 5.04 1 - L. 2.52 5.04 0.83 - - 1 M. 2.24 4.48 - 1.86 - 1 N 2.05 3.92 2.43 - - 1 O 2.05 3.92 - 2.43 - 1 P. 2.20 4.70 3.80 - 1 - Q 2.10 4.40 4.80 - 1 -

35

40

45

SMA = stearyl methacrylate, LMA = lauryl methacrylate, MMA = methyl methacrylate, BMA = butyl methacrylate,
MVP = 2-methyl-5-vinylpyridine, EVP = S-ethyl-2-vinylpyridine.

The molecular weight of these copolymers was between 650,000 and 850,000.

These copolymers according to the invention and some copolymers that are not of the invention were added to samples of a mineral lubricating oil for comparison purposes, and the pour points and the viscosity-temperature behavior of the samples were determined.

The mineral lubricating oil used was solvent refined from a Texas crude derived oil with the following properties:

Pour point

(ASTM D-97-47) -12 ⁰ C.

Viscosity 27 cSt at 37.8 ° C

Viscosity index 95

The quantities of copolymers used and the test results are shown below Table compiled:

Mixed
poly
merisat Amount in
Weight percent Pour point, ° C VT *) A. 1.5 -43 115 B. 1.5 -43 126 C. 2 -43 116 D. 2 -43 149 E. 2 -43 122 F. 2 -43 178 G 2 -43 131 H 2 -37 205 I. 2 -40 142 K 2 -23 172 X 2 -43 104 Y 2 - 9 104 Z 2 - 7th 104

*) The viscosity-temperature properties (VT) were calculated according to the following formulas, in which r) denotes the viscosity.

25 VT =

100,

98.9-98.9
η mixture η base oil

η base oil

37 ^ 8 - 37.8

η mixture η base oil

37J8
η base oil

where η means the viscosity.

The copolymers X, Y and Z do not meet the conditions according to the invention.

X is a copolymer of stearyl methacrylate-lauryl methacrylate-2-methyl-5-vinylpyridine in a molar ratio 2.8: 5.6: 1.0.

Y is a copolymer of lauryl methacrylate-2-methyl-5-vinylpyridine in a molar ratio of 1.7: 1.0.

Z is a copolymer of stearyl methacrylate-2-methyl-5-vinylpyridine in a molar ratio of 4.3: 1.0.

Mixtures according to the invention can be modified by adding smaller amounts (e.g. 0.1 to 2 percent by weight) of known additives. These include B. Corrosion inhibitor, Extreme pressure additives, anti-wear agents and antioxidants.

Claims (9)

Patent claims: 1. Lubricant based on a lubricating oil, in particular a mineral lubricating oil, with a content of a smaller amount of a copolymer with a molecular weight of more than 50,000 from a vinyl pyridine and acrylic and / or alkyl acrylic acid esters of an aliphatic alcohol with at least 10 carbon atoms in the molecule, characterized in that firstly the molecular weight of the copolymer is not more than 2,500,000 and the molar ratio of vinylpyridine to ester component is between 2: 1 and 1:15, and secondly the acrylic acid ester component is composed as follows:
a) from at least two esters of acrylic acid or an α-alkyl acrylic acid with 1 to 4 carbon atoms in the alkyl radical of at least two different aliphatic alcohols with 10 to 20, on average 10 to 16 carbon atoms, with more than 50 mol percent of these Ester component a) consist of ester pairs which are derived from two different ones Alcohols, one of which has at least 4 carbon atoms more than the other, and wherein the molar ratio between the esters of each ester pair is 1:10 to 10: 1 amounts to; b) from 10 to 80 mol percent, based on a), of at least one ester of acrylic acid or one a-alkyl acrylic acid with 1 to. 4 carbon atoms in the alkyl radical of aliphatic alcohols with 1 to 4 carbon atoms. 2. Lubricant according to claim 1, characterized in that the copolymer in one Amount of 0.1 to 10 percent by weight, preferably in an amount of 1 to 5 percent by weight, based on the total weight. 3. Lubricant according to claim 1 or 2, characterized in that the copolymer has a molecular weight between 100,000 and 850,000. 4. Lubricant according to claim 1, 2 or 3, characterized in that the vinyl pyridine is 2-methyl-5-vinyl pyridine or 5-ethyl-2-vinylpyridine. 5. Lubricant according to claim 1 to 4, characterized in that the a-alkyl acrylic acid is methacrylic acid is. 6. Lubricant according to claim 1 to 5, characterized in that the two ester components under a) are lauryl methacrylate and stearyl methacrylate. 7. Lubricant according to claim 1 to 6, characterized in that the ester component b) of the Copolymer is methyl methacrylate or butyl methacrylate. 8. Lubricant according to claim 1 to 7, characterized in that the molar ratio of vinyl pyridine to ester component is between 2: 1 and 1: 11. 9. Lubricant according to claim 1 to 8, characterized in that the ester component b) 15 to 45 mole percent of a) is. Considered publications:
German Patent No. 947 186;
French patents nos. 1061771, 1111338. © 009 588/391 8.60