NO122327B - - Google Patents

Description

Dry lubricant.

The present invention relates to a dry lubricant for metal which. can withstand high loads without cracking, which leads to the lubricating effect being lost and the film eventually breaking.

In the German patent no. 865 899 it is stated that the esters of penta-erythritol with C 1 to C 10 fatty acids are valuable lubricating oils or additives to mineral lubricating oils.

As lubricants are further known: From the German patent No. 95k 989 a mixture of molybdenum disulfide and a small amount of a binder of a hardened, heat-resistant, heat-curable phenolic resin for use as a lubricant; from British Patent No. 869,559 a mixture of molybdenum disulfide or graphite, a binder such as polyamide resin and an auxiliary lubricant such as stearic acid; from the French patent document 1 12h 303 a mixture of molybdenum disulphide or tungsten disulphide, graphite and/or high molecular and high temperature solid substances such as polyvinyl chloride, polyamides, urea and olefin polymers.

Mixtures of solid lubricants and a binder such as a phenolic or alkyd resin serving as lubricants are suitably applied in solution to the metal surface to be lubricated and air-dried or burned in. In the formed lubricant film, the solid lubricant is held in place by the binder.

It has now been found that extremely high load values determined according to the Falex method (floating load carrying capacity) are achieved by means of a dry lubricant consisting of a known solid lubricant and an alkyd resin as binder, when according to the present invention, which contains an alkyd resin which binder, which has been produced by condensation of a polymeric reaction product of an aliphatic, polyhydric alcohol and an aromatic or cycloaliphatic polycarboxylic acid, their C-^- to Cg-alkyl ester or their anhydride, at least one of the reaction components must be trifunctional, with an organo -silicon compound with the formula

where R is an aromatic hydrocarbon residue or a lower alkyl residue and n has an average value of 0.8-3 and a is a positive integer.

Examples of R in the above formula are phenyl, tolyl, biphenyl, naphthyl, n,n-diethylphenyl, anthracenyl, chrysenyl, respectively

methyl, ethyl, hexyl and isobutyl.

The dry lubricant mixture according to the invention contains 0-85% by weight of a solid lubricant and 15-60% by weight of the alkyd resin, which in turn contains 10-20% by weight of the organosilicon compound. Preferred amounts are 50-85% by weight of the solid lubricant and 15-50% by weight of the alkyd resin.

Examples of solid lubricants are molybdenum disulphide, graphite, antimony trioxide, titanium disulphide, tungsten disulphide, bismuth, lead sulphide, lead oxide, polytetrafluoroethylene, magnesium oxide, boron nitride, calcium fluoride, zirconium disulphide and colloidal solvate.

Mixtures of solid lubricants of graphite and molybdenum sulphide can also be used.

Examples of polyvalent aliphatic alcohols, of which the polymeric reaction product can consist, are ethylene glycol, propylene glycol, sugar, glycerin, diethylene glycol, triethylene glycol, 2,3-butanediol, 1^^-octanetriol, 2,2-dimethyll-1,3-propanediol , 2-methyl-2,)+-pentanediol, 1,18-octadecanediol, 1,6-dihydroxy-2,1f-hexadiene, pentaerythritol and 1,^-butadienediol.

Examples of aromatic and cycloaliphatic polycarboxylic acids that can be used for the production of the alkyd resin are phthalic acid, terephthalic acid, isophthalic acid, pyromellitic acid, mellitic acid, toluene dicarboxylic acid, homophthalic acid and

as well as diphenic acid, stilbendicarboxylic acid, a,p,6-naphthalene-tricarboxylic acid, tolandicarboxylic acid and further 1,2-cyclohexanedicarboxylic acid, l-methyllcyclopentane-2,1!—dicarboxylic acid,

Cyclic groups promote film formation; however, when a soft film is desired, some non-cyclic polycarboxylic acids can also be present. In the case of cyclic polycarboxylic acids, the carboxyl groups must not be separated from a ring by more than 2 carbon atoms and no ring must be separated from another ring by more than 2 carbon atoms.

The preparation of the alkyd resin by condensation of the indicated polymeric reaction product and the indicated orgario-silicon compound is known from Canadian Patents 539,890, 632,033 and 677<*>+28. The organo-silicon compound reduces friction and increases the film's heat resistance. The dry lubricant mixture may further contain a small amount of a fatty acid such as octanoic acid, stearic acid, linoleic acid, heavy oleic acid and castor oleic acid. The components of the dry lubricant mixture are intimately mixed, suitably using a solvent. The solution is applied to the metal surface which is to be annealed for hardening at a temperature of 150-350°C. For testing the dry lubricant specified in the following examples, a Falex apparatus was used, in which a steel plug runs at a constant number of revolutions between two steel prisms. The experiment extends over several hours with increasing load. With the Falex apparatus used for the experiments, the pin had a Rockwell-B hardness of 87-90, and the steel prisms had a Rockwell-C hardness of 20} the prism angle was 96°. ;Example 1;A mixture consisting of 70% by weight of molybdenum disulfide, 7% of graphite and 23% of a condensate consisting of 75% by weight of glycerol isophthalate, 15% of an organosilicon compound of the average formula: ; and 10% of the linseed oil's fatty acids were mixed carefully on a wooden rolling mill twice. The mixture thus obtained was spread out to approx. 2.0% solids with monomethyl ether and ethylene glycol, sprayed on two V-shaped blocks of air-blasted steel (vapor-blasted steel V blocks) and a pin that fits in the block and hardened for h hours at 205°C; The pin and the block that were used in this sample was 0.6^-cm in diameter and had been wet sanded using $0% No. 625 and $0% No. 12^0 abrasives to produce conforming sheet finishes with maximum surface finish. For the spraying of the dry films, the pin and the block are washed in acetone and were not touched with the hands for the curing treatments and the samples had been completed. The pin was SAE 3135 steel with Rockwell-B hardness 87-90 and the V-block was Al5l-1137 steel with Rockwell-C hardness 20 and block angle 96°. The friction characteristics of the pins rotating in the block are determined with the help of a FALEX lubricant testing device using the "step test". In this way, the load on the pin is increased and blocked step by step and after periodic intervals, whereby the rotating pin's torque is constantly fed. ;The results obtained were: ; Example 2; A mixture consisting of 50% by weight of molybdenum disulphide, 7% by weight of graphite and ^3% by weight of a condensate consisting of 75% by weight of glycerol isophthalate, 15% of an organosilicon compound of the formula: ; and 10% linseed oil was passed 3 times through a colloidal sieve. Two V-shaped blocks of air-blasted steel and a pin fitting into the block were sprayed with a solution of the mixture in monomethyl ether and ethyl glycol, which solution contains approx. ?>0% solids, and was cured for h hours at 205°C. ;The friction characteristics of the pin rotating in the V-block were determined in the manner indicated in example 1. ;At the last stage of the test, the rotating pin is subjected to a load of 1679 kp for one minute. At the beginning of this period, the torque was 33 j9 x 10^ dyn. - cm. At the end of the same period, the torque was 30.5 x 10^ dyne. - cm. The test could not be continued because 1679 kp was the highest load that could be carried out with the device. ;Example;The mixture described in example 1 is prepared again, but the graphite is replaced with the same amount by weight of calcium fluoride. ;The mixture was tested in the manner indicated in example 2. ;At a load of 1679 kp for one minute, the torque at the beginning of the period was 15>82 x 10^ dyne. - cm. At the end of the same period, the torque was still 15?82 x 10^ dyne. - cm. ;Example h;A mixture consisting of 70% by weight of molybdenum disulfide, 7% by weight of graphite and 23% by weight of a condensate of 80% by weight of glycerol isophthalate and 20% by weight of of a compound with the formula: ; was tested in the manner described in Example 2. A load of 1679 kp was applied to the rotating pin for 6 minutes. The torque at the beginning of the period was 22.6 x 10 dyne. - cm. At the end of the period, the torque was still 22.6 x 10^ dyne. - cm. ;Example 5;The mixture according to example h was prepared again, but the graphite was replaced by an equal amount by weight of calcium fluoride. ;The mixture was ground for 3 hours in a vertical coal mill, and it was then placed on the pin and V-block in the manner indicated in Example 1. ;The rotating pin was tested stepwise up to 1679 kp in h minutes, whereby the following torque was achieved. ; Example 6; Eighteen technical dry film lubricants were applied to V-block and pin according to the manufacturer's recommendations and tested with Falex apparatus in the manner indicated in Example 1. The best of the eighteen mixtures tested failed at a load of 1212.9 kp, i.e. the load at which a rapid increase in torque was observed, which caused the pin and the block to rub together. The next two test mixes failed at a load of 1026 kp. The approximate average load where all lubricants did not work was 653jl kp. ;Example 7;When h0 parts by weight of boron nitride are intimately mixed with 60 parts of the condensate of 17.0 parts by weight of phthalic acid, 5?8 parts by weight of tri-methylolpropane, 6.1 parts by weight of propylene glycol and 10.8 parts by weight of diphenylethyl cyanol in 200 parts by weight of acetone, a material was formed which hardens on metal as a film and gives the metal sheet lubricating properties. Example 8 When 85 parts by weight of antimony trioxide are intimately mixed with 15 parts by weight of the condensate of 17.h parts by weight of terephthalic acid, 6.9 parts by weight of pentaerythritol, 3.1 parts by weight of ethylene glycol and 13.8 parts of ditolylmethoxysilane in 200 parts of acetone, a material was formed which hardened on metal into a film and gave the sheet metal lubricating properties. ;Example 9;When 50 parts by weight of titanium sulfide are intimately mixed with 50 parts of the condensate of 5.7 parts of mellitic anhydride, 22.2 parts of diphenic acid, 1*+.3 parts of 1,18-octadecanediol and 18.0 parts of

in 200 parts of acetone, a material formed as a film and gave the sheet metal lubricating properties.

Example 10

When 60 parts by weight of polytetrafluoroethylene are intimately mixed together with ho parts of the condensate of 10.1 parts of

8.6 parts of cyclohexanedicarboxylic acid, 15.8 parts of 1,>+,8-octanetriol and 13.7 parts of dianthracenyldipropyldihydroxydisiloxane in 200 parts of the monomethyl ether of ethylene glycol, a metal was obtained which hardens on metal to a film and gave the metal plate lubricating properties.

Example 11

When 70 parts by weight of lead sulphide are intimately mixed with 30 parts of the condensate of 19, h parts of trioctyl-1,2,5-naphthylenate, 0.6 parts of maleic acid, 7 parts of 1,>+-butadienediol and 8 parts of a copolymer of 70 mol -percent monophenylsiloxane and 30 mole percent monopropylsiloxane, which copolymer contains 3 wt% silicon-bonded H0 groups, in 200 parts diethyl ether, a material was formed which cured on metal to a film and which gave the sheet metal lubricating properties.

Claims (1)

Dry lubricant consisting of a known solid lubricant and an alkyd resin as binder, characterized ■v. ,e, d that it contains an alkyd resin which has been produced by condensation of a polymeric reaction product of an aliphatic polyhydric alcohol and an aromatic or cycloaliphatic polycarboxylic acid, their C₁ to C₆ alkyl ester or their anhydride, at least one of the reaction components must be trifunctional, with an organo-silicon compound of the formula where R is an aromatic hydrocarbon residue or a lower alkyl- remainder and n have the average value 0.8-3 and a is a positive integer.