DE3841609A1 - LUBRICANTS FOR FRICTION CLUTCHES - Google Patents

Abstract

Lubricant compositions for traction drives are disclosed which are highly capable of exhibiting enhanced traction coefficient and viscosity stability characteristics under adverse operating conditions. Specified amounts of selected oil components are incorporated with selected polycyclohexylalkanes of the formula <IMAGE> where R1 and R2 each are hydrogen or methyl, R1 being hydrogen when R2 is methyl and vice versa and n is 0 or 1, the oil component being one or more of (a) asqualane or polyolefin oil, (b) a diester or polyol ester oil, (c) a mineral oil and (d) a polyglycol, polyphenyl ether or polysiloxane oil.

Description

The invention relates to a lubricant for friction clutches or the like

Friction clutches or train drive devices z. B. from the spherical cone, Cone ring, wheel disc, chain sieve, toroid, planetary roller Type work on the principle of power transmission, where the rolling friction is important. It is known, an oil film between the contact surfaces of the two To provide parts that become hard, which improves the rolling effect. The lubricating oil for these cases must therefore be high Traction coefficients, namely high power transmission properties, to have. Because such traction lubricants usually are subject to very high temperatures, the evaporation losses be small. In addition, a corresponding Viscosity should be ensured to form a film to allow high temperatures.

Traction fluids are e.g. B. by the Japanese patents No. 46-338, 46-339, 47-7664, 48-29 715, 48-42 067, 48-42 068, 53-36 105, 58-12 319, 58-27 838, 60-1353, 60-1354, 60-19 951, 60-43 391 and 60-43 392. Most known traction fluids are unsuitable because their manufacture is very complicated and the starting products are not readily available. There is another problem in that the fluids have too small a traction coefficient to have.

2,4-dicylohexyl-2-methylpentane mentioned in the patents 53-36 105 and 58-12 319, is the only usable substance in the way mentioned. It is in the form of a fat before, which is coupled with viscosity generators. These Although substance has a good traction coefficient, it evaporates  but light and has an unsuitable viscosity high temperatures.

The invention has for its object lubricant to create the kind mentioned that are better than the known ones.

This object is achieved by the in claim 1 mentioned lubricant solved.

Important here are the polycyclohexylalkanes and the fact that special oils are associated with these.

The lubricants according to the invention have an excellent Traction coefficients, good viscosity properties and low evaporation losses at high temperatures.

Squalane is a colorless and transparent, tasteless and odorless, oily liquid preferably with a saturated Hydrocarbon chain, e.g. B. a 2,6,10,15,19,23-hexa- Methyl tetracosane (C₃₀H₆₂). Preferred squalane oils are those their kinematic viscosity between 2 and 40 mm² / s at 40 ° C lies. This oil is generally of two industrial types Sources available. One source is a squalene material at elevated temperature and pressure in the presence to hydrogenate a suitable catalyst. Such materials arise from cleaning fish oils, e.g. B. shark liver oil u. Like., And of vegetable oils, e.g. B. Olive oil u. The other source is hydrogenolysis a reaction product of geranyl acetone and 1,3-butadiene. Geranyl acetone is available from isoprene as a synthetic Starting material for the synthesis of isophytol. 1,3-butadiene is a by-product in the manufacture of acetylene Cracking natural gas.  

Preferred polyolefin oils result from a homo- or Copolymerization of olefins with 3-12 carbon atoms and an average molecular weight of 100- 500 and a kinematic viscosity between 2 and 40 mm² / s at 40 ° C. Suitable olefins are e.g. B. propylene, butene, iso- Butylene, hexene, octene, decene, dodecene and their comonomers.

The polyolefin oil can be obtained by a known polymerization be created, especially by cationic polymerization, in the Friedel craft catalysts, e.g. B. aluminum Chloride, aluminum chloride aluminum bromide, aluminum Chloride ester, aluminum bromide, aluminum bromide hydrogen bromide, Magnesium chloride, boron fluoride, boron fluoride alcohol u. Like., And their complex connections are used. Radical polymerization is also preferred with the aid of of heat and with peroxide catalysts and on a polymerization using Ziegler catalysts. The polyolefin oil should be of such a type that the double bonds are hydrogenated in the usual way Use of a nickel or nickel molydate catalyst.

The squalane and polyolefin oils should both be preferred have a pour point less than -30 ° C, preferably less than -40 ° C. These oils can be used alone or in combination based on suitable mixing ratios be used.

The oils according to (b) are diester and polyol ester oils.

Suitable diester oils are of the following types:

The values for R₃-R₅ result from claim 4. Preferably R₃ has 4-10 carbon atoms, and R₄ and R₅ preferably have 8-13 carbon atoms. For R₃ is preferably provided an alkylene group according to the formula

where m is 4-10.

Suitable diester oils result from claim 5.

A preferred polyolester oil is of the type

The substituents R₆ and R₇ result from claim 6. Preferably R₆ is a methyl or ethyl group. R₇ is preferred an alkyl group with 2-12 carbon atoms.

The polyol ester or esters is preferably by esterification a polyol which has a tertiary carbon atom, which is connected to a next ester link, the tertiary carbon atom the second carbon atom from the left in of the formula mentioned above, with aliphatic straight or branched chain monocarboxylic acids with 3-13 carbon atoms.

Some polyols are mentioned in claim 7. Aliphatic monocarboxylic acids in straight chain execution can by decomposition obtained from oils and fats, e.g. B. of butane Acid, Capronic acid etc., see further examples in claim 7. A branched chain fatty acid is one of neopentyl Type. There are also synthetic branched chains Fatty acids and their combinations.  

The diester and polyolester oils should be a kinematic Have viscosity in the range of 2-40 mm² / s at 40 ° C. Furthermore they should have a pour point lower than -30 ° C, preferably lower than -40 ° C. Both oils can if desired be mixed.

The oils according to (c) are mineral oils with a kinematic Viscosity of 2-40 mm² / s at 40 ° C and if desired one Pour point below -30 ° C.

The mineral oils are created by fractionating raw oil residues for the purpose of cleaning. For this purpose, a Used device that cracks and hydrocarbons refined with a solvent. You then get one Oil with improved viscosity. By refining with Solvents become the polycyclic, aromatic components removed, in such a way that by means of Solvent extraction is carried out. Come as a solvent in question furfural, phenol or the like. By cracking disassembled the aromatic components, being a nuclear Hydrogenation expires. The last-mentioned apparatus serves furthermore, impurities that are in the oil fraction, to remove. Other suitable refining devices have hydrogen formation in the final stage, the Oil fraction comes into contact with hydrogen gas. In doing so Impurities such as polar components and. Like. Removed. Further refining devices are possible in which Sulfuric acid is used to destroy the contaminants. Dewaxing can be done using benzene, toluene, Acetone or benzene-toluene-methyl ethyl ketone at low temperature. Also a catalytic dewaxer, so-called hydrogenation dewaxer, can be used by the waxes  be decomposed in a hydrogen atmosphere. Here will a zeolite type catalyst is used.

Typical examples of mineral oils are pure mineral oils Naphtha or paraffin classes, which are due to refining and dewaxing of naphthenic crude by refining and Solvent dewaxing from paraffinic crude oil and by refining and catalytic dewaxing of paraffinic crude oil surrender. Of course, the oils can also be bleached will.

The oils according to (d) include polyglycol, polyphenyl ether and polysiloxane oils.

Polyglycol oils are of the type:

For the components R, what follows from claim 9 applies. D is preferably 1-3 and preferably c : c × d <3.

The hydrocarbon groups are saturated or unsaturated, straight or branched. Preferably come into question Alkyl groups with 1-15 carbon atoms and originated from aliphatic monohydric alcohols with 1-20 carbon atoms. In particular, the groups that are eligible come into question 11 are mentioned at the beginning. Those mentioned in claim 10 Hydrocarbon parts that are made up of hydric hexahydric alcohols are preferably: glycols, Glycerol, trimethylolpropane, pentaerythritol and sorbitol.  

Substituted or unsubstituted are also possible aromatic hydrocarbon groups with 6-26 carbon atoms, preferably an alkylphenyl group a phenyl group and an alkyl group with 1-16 carbon atoms, namely toluene, ethylphenyl, propylphenyl, butylphenyl, Pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, Nonylphenyl, decylphenyl, dodecylphenyl, pentadecylphenyl, Hexadecylphenyl, and like groups.

Acyl groups are typically: carboxylic acids, especially those made up of saturated or unsaturated monocarboxylic acids with 2-20 carbon atoms. Monocarboxylic acids are z. E.g .: acetic acid, propionic acid, lactic acid, Lauric acid, stearic acid, oleic acid and the like. the like

Alkylene groups are those that have 2-8 carbon atoms. They can have a different alkylene group, whereby the number of carbons that are bound in a molecule fluctuates are. Suitable alkylene groups are: ethylene and propylene. Suitable polyoxyalkylene groups are: polyoxyethylene, Polyoxypropylene and polyoxyethylene-polyoxypropylene.

Polyphenyl ether oils are of the type:

The components R are specified in claim 12. Preferably the number of carbon atoms in the alkyl group is 1-16. Furthermore, e is preferably 0-1. For the values R₁₁ to R₁₃ the groups mentioned in claim 13 are preferred. It is also expedient if a polyphenyl ether is used in which a phenyl group in the meta position is connected to the ether member. Such ether of the C ether type are also useful in which the ether compound (-O-) is partially or completely replaced by a thioether member (-S-).

The polysiloxane oils in question here are as follows Kind:

The groups R result from claim 15. The alkyl group preferably has 1-3 carbon atoms; preferably a phenyl group is proposed and preferably f is between 10 and 30. For R₁₄-R₁₉ are suitable: methyl, ethyl, propyl, butyl, pentyl, hexyl, phenyl, tolyl, xylyl, ethylphenyl, propylphenyl and similar groups.

Of the polysiloxanes, dimethyl silicones are particularly preferred, in which R₁₄ to R₁₉ are all methyl groups, and phenyl silicones, in which R₁₄ to R₁₉ methyl and phenyl groups are. Fluorosilicones and chlorosilicones are also suitable where fluorine and chlorine are partially or completely substituted are by the hydrogen atoms that are in the alkyl phenyl or Are alkylphenyl, which are connected to the R₁₄ to R₁₉.

The polyglycol, polyphenyl ether and polysiloxane oils should a kinematic viscosity in the range of 2-40 mm² / s  at 40 ° C and should also have a pour point lower than -30 ° C, preferably lower than -40 ° C. Two or three of these oils could be combined if desired.

Oils (a) to (d) can be used alone or in combination will.

Polycyclohexylalkane according to component (II) is represented through the formula

R₁, R₂ and n are specified in claim 1.

Component (II) can be produced, for example, by polymerization of an α- methylstyrene or by thermal decomposition of a poly- α- methylstyrene and subsequent nuclear hydrogenation of the resulting tri- or tetra-phenylalkane. The polymerization can be carried out by heat in the presence of a solid acid catalyst, e.g. B. acidic clay, active clay, silicon aluminum, montmollilonite, silica gel or the like., And using a regulator such as water or an oxygen-containing component, for. B. dihydric alcohol, ether or the like. Nuclear hydrogenation can be achieved by bringing the starting alkane into contact with hydrogen at high temperature and pressure in the presence of a catalyst. Suitable catalysts are nickel, nickel diatomaceous earth, Raney nickel, platinum, platinum aluminum, rhodium, rhodium aluminum or the like. The resulting component can, if desired, be separated from the dicyclohexylalkanes, pentacyclohexylalkanes and cyclic compounds by distillation Components that arise on the side.

The amount of component (I) that should be added in the range of 20-80% by weight, preferably 30 to 70% by weight based on component (II). Both components then give 100 wt .-%. If component (I) is less than Is 20%, the mixture is too viscous. If it is greater than 80%, there is an increased loss of evaporation and a reduction of the traction coefficient. The use of the component (II) for friction clutches alone does not make sense because this material is semi-solid at normal temperatures.

The lubricant mixture according to the invention can contain 2,4-dicyclihexyl-2-methylpentane, but in an amount that does not affect the traction properties. (This product is a by-product of component (II)). The amount of this component should not be more than 100 parts, preferably less than 50 parts, based on 100 parts (by weight) of component (II). The component can be added to a final mixture prepared or can remain in the substance as a by-product without being separated from component (II). Cyclic components, which are also by-products, can also be contained in component (II); they have nuclear hydrogens such as cyclic dimers, trimers and tetramers of α- methylstyrenes.

Various other additives can also be used, e.g. B. antioxidants such as conditional phenols, e.g. B. 2,6-di-T-butyl-P-cresols, aromatic amines, e.g. B. phenyl- α- naphthylamine, organic metal components, for. B. zinc dialkyldithiophosphates, sulfur compounds, e.g. As sulfides and disulfides, rust preventers such as carboxylic acids, sulfonic acids, phophoric acid salts, amines, alcohols and esters, agents that are effective at high pressures, such as. B. organic metal compounds, especially organic sulfur compounds, organic halides, zinc dialkyldithiophosphates, molybdenum dialkyldithiophosphates and molybdenum dialkyldithiocarbamates and phosphoric acid esters, substances that improve viscosity, such as polymethacrylates and polyisobutylenes, demulsifiers such as silicone oils and the like. The amount of these additives should not be greater than 20%, especially 10%, based on the total weight of the mixture.

The mixture according to the invention can also be used as fat. In this case, viscosity generators are to be used by the Soap types are e.g. B. lithium, sodium, calcium soaps, complex Soap producers, such as lithium complex, calcium complex and Aluminum complex soaps, fabrics that are not of the soap type are, such as organic siloxanes, terephthalates, polyureas, organically treated clays and silca aerogels u. Like. Regarding there is no restriction on the number of viscosity generators. However, it is expedient if this is in the range 1-30%, preferably 3-20%, based on the total weight of the compound, lie.

Examples

Various lubricants were created and related to them kinomatic viscosity, its evaporation loss and checked their traction coefficient. The investigations  were made according to the following conditions, the Results are entered in Tables 1 to 4.

2,4-dicyclohexyl-2-methylpentane was used as a control substance, a connection related to friction clutches is known.

Component (I)

Squalane:
Oil consisting mainly of 2,6,10,15,19,23-hexamethyltetracosane. This results from the hydrogenation of squalene, which is obtained from shark liver oil. The kinematic viscosity is 18.9 mm² / s at 40 ° C, the pour point is less than -65 ° C, the ignition point is 230 ° C, the average molecular weight is 423.

Polybutene 1:
Isobutylene-1-butene copolymer, formed by oligomerization of a butane-butene fraction, which is formed when naphtha is cracked. Viscosity: 2.7 mm² / s at 40 ° C, pour point: below -70 ° C, ignition point: 87 ° C, molecular weight 220.

Polybutene 2:
Isobutylene-1-butene copolymer, obtainable similar to polybutene 1. Viscosity: 7.5 mm² / s at 40 ° C, pour point: -67.5 ° C, ignition point: 115 ° C, molecular weight 280.

1-decene oligomer:
Branched chain hydrocarbon, obtainable from an oligomerization of 1-decene. Viscosity: 17.5 mm² / s at 40 ° C, pour point: less than -73 ° C, ignition point: 216 ° C, molecular weight 353.

Diester:
Diisooctyl sebacate, viscosity: 11.5 mm² / s at 40 ° C, pour point: below -60 ° C, ignition point: 222 ° C.

Polyol ester 1:
Trimethylolpropane tricaprylate, viscosity: 28.2 mm² / s at 40 ° C, pour point: -50 ° C, ignition point: 209 ° C.

Polyol ester 2:
Tetraester of pentaerythritol and a straight-chain C₆-C₁₀ fatty acid, viscosity: 33.5 mm² / s at 40 ° C, pouring point: -48 ° C, ignition point: 257 ° C.

Naphthenic mineral oil:
Oil obtained by purifying an oil fraction obtained from naphthenic crude oil-reduced residues by refining with furfural solvent and zeolite catalytic dewaxing and then hydrogenating; Viscosity: 5.2 mm² / s at 40 ° C, pour point: -60 ° C, ignition point: 120 ° C.

Paraffinic mineral oil:
Oil obtained by purifying an oil fraction obtained from paraffinic crude oil-reduced residue in a manner similar to the production of the naphthenic mineral oil; Viscosity: 28.6 mm² / s at 40 ° C, pour point: -30 ° C, ignition point: 210 ° C.

Polyglycol:
Mixture of two materials of the following formula, viscosity: 32.8 mm² / s at 40 ° C, pour point: -56 ° C, ignition point: 202 ° C, molecular weight 700.

Polyphenyl ether:
Mixture of two materials of the following formula, viscosity: 16.1 mm² / s at 40 ° C, pour point: -55 ° C, ignition point: 220 ° C, molecular weight 350.

Polysiloxane:
Dimethyl silicone of the following formula, viscosity: 16.3 mm² / s at 40 ° C, pour point: below -60 ° C, ignition point: 240 ° C, molecular weight 1300.

Component (II)

Polycyclohexylalkane:
Component derived by active clay catalytic polymerization of α- methylstyrene followed by nickel catalytic nuclear hydrogenation of the resulting polymer, followed by vacuum distillation to obtain a material of the following formula in a yield of 95% by weight or more, boiling point: 415 -430 ° C (based on atmospheric pressure), appearance: semi-solid at normal temperature (20 ° C)

R₁ = CH₃, R₂ = H or R₁ = H, R₂ = CH₃

Viscosity at high temperature

The kinematic viscosity was 100 ° C according to JIS K-2283 measured.

Evaporation loss

JIS K-2540 followed. The weight reduction was in percent by weight determined after heating for 100 hours.  

Traction coefficient

A quarter-cylinder rolling friction tester was developed used at a rotation of 1500 rpm (U / m), a load of 92.5 kg / mm² and a sliding ratio of 2%.

As can be seen from Tables 1 to 4, the compounds are according to the invention with respect to all characteristics tested extremely satisfactory. The control attempts where component (I) was used alone, gave unsatisfactory results in that the viscosity was not stable. 2,4-dicyclohexyl-2-methylpentane had a large loss of evaporation at high temperatures.  

Table 1

Table 2

Table 3

Table 4

Claims (20)

1. Lubricant for friction clutches or the like, consisting of:

• (I) 20-80% by weight of at least one of the following components:
  • (a) Squalane and / or polyolefin oil, the polyolefin oil being formed by homopolymerization or copolymerization of olefins having 3-12 carbon atoms, which have an average molecular weight of 100-500;
  • (b) diester and / or polyol ester oil;
  • (c) mineral oil; and
  • (d) polyglycol, polyphenyl ether and / or polysiloxane oil, each of components (a) to (d) having a kinematic viscosity in the range of 2-40 mm² / s at 40 ° C; and
• (II) 80-20% by weight polycyclohexylalkane of the formula wherein R₁ and R₂ are a hydrogen atom or a methyl group, R₁ is hydrogen when R₂ is methyl and vice versa and n is 0 or 1.

2. Lubricant according to claim 1, characterized in that that the squalane oil is mostly from 2,6,10,15,19,23-hexamethyltetracosane. 3. Lubricant according to claim 1, characterized in that that the polyolefin oil to the group: Polypropylene, polybutene, polyisobutylene, polyhexene, polyoctene, Polydecene, polydodecene and copolymers thereof belongs. 4. Lubricant according to claim 1, characterized in that the diester oil of the type is, where R₃ is a divalent hydrocarbon group with 4-12 carbon atoms, R₄ and R₅ are an alkyl group with 6-16 carbon atoms and R₄ and R₅ are the same or different. 5. Lubricant according to claim 4, characterized in that the diester oil to the group: Di- 2-ethylhexyl adipate, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate, Di-2-ethylhexyl dodecanoate, diisooctyl adipate, Diisooctyl dodecanoate, diisodecyl adipate, diisodecyl azelate, Diisodecyl sebacate, diisodecyl dodecanoate, ditridecyl adipate, Ditridecyl azelate, ditridecyl sebacate, ditridecyl dodecanoate and combinations of them. 6. Lubricant according to claim 1, characterized in that the polyol ester oil of the type where R₆ is an alkyl group with 1-4 carbon atoms, R₇ is an alkyl group with 2-17 carbon atoms, applies to a 0 ≦ a ≦ 2, and b is 2 ≦ b ≦ 4 and a + b is 4. 7. Lubricant according to claim 6, characterized in that that the polyol ester oil was created by Esterification of polyol with an aliphatic monocarboxylic acid with 3-13 carbon atoms, the polyol for Group: neopentyl glycol, trimethylolethane, trimethylolpropane, Pentaerythritol and combination thereof is heard and the monocarboxylic acid to the group: butanoic acid, caproic acid, Caprylic acid, capric acid, uralylic acid, a synthetic straight fatty acid with 7 or 9 carbon atoms, one  branched chain neopentyl-type fatty acid, a synthetic branched chain fatty acid and combinations thereof belongs. 8. Lubricant according to claim 1, characterized in that that the mineral oil to the group: oil, obtained by refining and dewaxing naphthenic Crude oil, oil created by refining and solvent dewaxing of paraffinic crude oil, oil derived by Refining and catalytic dewaxing of paraffinic Heard of crude oil and combinations thereof. 9. Lubricant according to claim 1, characterized in that the polyglycol oil of the type is, where R₈ and R₁₀ are each a hydrogen atom or a hydrocarbon group or an acyl group, R₈ and R₁₀ are the same or different, R₉ is an alkyl group, d is 1-6 and the following applies to c : c × d <2. 10. Lubricant according to claim 9, characterized in that the hydrocarbon group for Group: alkyl group with 1-15 carbon atoms, hydrocarbon Part, obtained from a dihydric to with hexahydric alcohol and an alkylphenyl group a phenyl group and an alkyl group with 1-16 One of the carbon atoms belongs to the saturated acyl group or unsaturated monocarboxylic acid with 2-20 Carbon atoms is derived from the alkylene group the group: Ethylene and propylene groups originates and the  Polyoxyalkylene group from the group: polyoxyethylene, Polyoxypropylene and combinations thereof. 11. Lubricant according to claim 10, characterized in that that the alkyl group from the group: Methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, Decyl and pentadecyl groups, the dihydric to hexahydric alcohol from the group: glycol, Glycerin, trimethylolpropane, pentaerythritol and sorbitol the alkylphenyl group comes from the group: tolyl, Ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, Hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, Decylphenyl, dodecylphenyl, pentadecylphenyl and hexadecylphenyl comes, and the carboxylic acid from the group: Acetic acid, propionic acid, lactic acid, lauric acid, lauric acid, Stearic acid and oleic acid comes from. 12. Lubricant according to claim 1, characterized in that the polyphenyl ether oil of the type is, where R₁₁, R₁₂ and R₁₃ are each a hydrogen atom or an alkyl group having 1-20 carbon atoms, three of these R are the same or different and e : 0-3. 13. Lubricant according to claim 12, characterized in that that the alkyl group from the group: Methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, Octyl, nonyl, decyl, dodecyl, tetradecyl and hexadecyl groups comes from.   14. Lubricant according to claim 12, characterized in that that the polyphenyl ether oil is a Phenyl group, which in metaposition with the ether Link is connected. 15. Lubricant according to claim 1, characterized in that the polysiloxane oil of the type is where R₁₄, R₁₅, R₁₆, R₁₇, R₁₈ and R₁₉ are each an alkyl group having 1-6 carbon atoms or a phenyl or an alkylphenyl group having 6-9 carbon atoms and six of the R are the same or different and f is 4-40. 16. Lubricant according to claim 15, characterized in that that the alkyl group from the group: Methyl, ethyl, propyl, butyl, pentyl and hexyl groups, the phenyl group from the group: phenyl, tolyl and xylyl groups and the alkylphenyl group from the group: ethylphenyl and propylphenyl groups. 17. Lubricant according to claim 15, characterized in that the polysiloxane oil is a methyl group has, which is connected to each substituent R₁₄-R₁₉.   18. Lubricant according to claim 15, characterized in that that the polysiloxane oil is methyl and Has phenyl groups with the substituents R₁₄-R₁₉ are connected. 19. Lubricant according to claim 1, characterized in that that each component (a) - (d) has one Pour point that is less than -30 ° C. 20. Grease consisting of a lubricant according to claim 1 and a viscosity generator.