RU2535210C1 - Plastic lubricant for feeble-current electric contacts - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to plastic lubricant for feeble-current electric contacts, on synthetic base, which contains polycarbamide thickening agent, representing product of interaction of octadecylamine, aniline and polyisocyanate. Weight part of isocyanate groups in polycarbamide thickening agent constitutes 31.5-38.0 wt %; as synthetic base, composition contains mixture of pentaerythrite ethers and fatty acids of fraction C₅-C₉ with silicone fluid at ratio from 10:90 to 90:10 wt %, or with polyalphaolefin oil at ratio from 20:80 to 80:20 wt %, and additionally contains hydrophobic silicagel with the following component ratio, wt %: polycarbamide thickening agent 5.8-12.0; hydrophobic silicagel 0.1-5.0; synthetic base to 100.

EFFECT: obtaining lubricant, which has improved tribological and dielectric characteristics, which makes it possible to apply claimed composition in low-voltage and feeble-current equipment, and selected ratio of certain dispersion media extends temperature range of application.

2 cl, 2 tbl

Description

The invention relates to greases operable in the electrical and electronic industries, in particular in low-current electrical contacts used in devices, sensors of the Russian Railways infrastructure.

Lubricants, the use of which is possible in low-current electrical contacts, must, on the one hand, have insulating properties, and on the other hand, are able to conduct weak currents. Also, the aforementioned lubricants must work in a wide temperature range, have sufficient colloidal stability and high adhesion to metals, and have anti-corrosion, anti-wear properties. These include greases with polyurea thickeners.

Known grease based on petroleum or synthetic oil and polyurea, which additionally contains petroleum extract in the following ratio of components: petroleum or synthetic oil: petroleum extract from 99: 1 to 90:10. (RF patent No. 2283859, September 20, 2006)

The disadvantage of this composition is the narrow temperature range of application and unsatisfactory tribological characteristics.

Closest to the claimed composition is a grease containing oil and / or synthetic oil and 5-25% polyurea thickener, which is a product of the interaction of octadecylamine, aniline and polyisocyanate, in which the mass fraction of isocyanate groups is 35-38%. Also, if necessary, grease may contain antioxidant, antiwear, anti-friction additives. (RF patent No. 2160766, December 20, 2000)

It has been experimentally established that this composition exhibits dielectric properties, and is also capable of conducting weak currents. The disadvantages of this lubricant is the value of the specific volume electric resistance, which does not provide the necessary level of dielectric properties, unsatisfactory tribological properties, and also the limited temperature range of application due to the dispersion medium used.

The objective of the invention is the creation of a lubricating composition with improved tribological characteristics, as well as with the optimal ratio of dielectric and conductive properties for the possibility of using it in low-voltage and low-current equipment.

To solve this problem, a synthetic-based grease composition is proposed containing a polyurea thickener, which is a product of the interaction of octadecylamine, aniline and polyisocyanate. The composition is characterized in that the mass fraction of isocyanate groups in the polyurea thickener is 31.5-38.0% by mass., As a synthetic base, the composition contains a mixture of pentaerythritol esters and fatty acids of the C ₅ -C ₉ fraction with an organosilicon liquid in a ratio of 10: 90 to 90: 10% by weight, or with polyalphaolefin oil in a ratio of 20:80 to 80: 20% by weight, and also additionally contains hydrophobic silica gel in the following ratio of components,% by weight:

Polyurea Thickener 5.8-12.0 Hydrophobic silica gel 0.1-5.0 Synthetic base up to 100

Grease may contain a multifunctional additive.

To obtain lubricant use:

Octadecylamine according to TU 6.36.1044808-89.

Polyisocyanate according to TU 113-03-604-86.

Aniline according to GOST 313-77.

Hydrophobic silica gel - Aerosil R-812, manufactured by EVONIC.

Organosilicon fluid in accordance with GOST 10957-74.

PAOM-6 polyalphaolefin oil according to TU 0253-004-54409843-2004.

Unigema brand 3939 pentaerythritol ether, either according to TU 38.101272-72, or TU 38.1011027-85.

As part of the proposed grease can be used multifunctional additive A-22 according to TU 0257-006-40065452-97 with antioxidant, antiwear properties.

The proposed lubricant is prepared as follows. The calculated amount of octadecylamine and aniline is dissolved in a reactor in an 80% mixture of pentaerythritol esters and fatty acids of the C ₅ -C ₉ fraction and heated to 120 ° C. In the rest of the mixture of pentaerythritol esters and fatty acids of the C ₅ -C ₉ fraction, a polyisocyanate solution is prepared and heated to 30-50 ° C. Then, the prepared solutions are mixed and stirring is continued for 30-60 minutes at a temperature of about 150 ° C. After that, the reaction mass is cooled and combined with a hydrophobic silica gel gel in polyalphaolefin oil or in an organosilicon liquid, then additives are added if necessary.

According to the above technology, 4 lubricant samples were prepared, and a prototype sample was also prepared (table 1).

Table 2 presents the performance characteristics of the prototypes.

Thus, the data in table 2 confirm that the proposed lubricant exceeds the prototype in dielectric and tribological characteristics. The optimal ratio of dielectric and conductive properties allows the use of this composition in low-voltage and low-current equipment, and the selected ratio of certain dispersion media expands the temperature range of application (from -50 to 220 ° C).

The compositions of the prepared samples of lubricants

Table 1 No. p / p Name of components The content of components in the lubricant,% mass. one 2 3 four one Polyurea Thickener 5.8 7.3 12.0 9.2 Mass fraction of isocyanate groups in the polyurea thickener 38,0 35.0 31.5 32.6 2 Hydrophobic silica gel 5,0 3.8 0.1 2,3 3 Additive A-22 0.3 - - 0.1 four A mixture of pentaerythritol esters and fatty acids of fraction C ₅ -C ₉ (I) and organosilicon liquid (II) up to 100 - up to 100 - I: II ratio 90:10 - 10:90 - 5 A mixture of pentaerythritol esters and fatty acids of fraction C ₅ -C ₉ (I) and polyalphaolefin oil (III) - up to 100 - up to 100 I: III ratio - 80:20 - 20:80

Characterization of the operational properties of the prototypes.

table 2 Quality indicators Sample 1 Sample 2 Sample 3 Sample 4 Prototype sample Evaporation at 150 ° C, 1 h,% 0.30 0.30 0.42 0.36 4.2 Tribological characteristics on the ChShM: Duration of work before bullying, h 18.0 19,2 14.0 21,2 9.0 Diameter of a spot of wear, mm 0.90 0.90 0.84 0.87 1,0 Volume resistivity at 20 ° C, Ohm · cm 3.110 ¹⁴ 3.7 · 10 ¹⁴ 1,110 ¹⁴ 2.610 ¹⁴ 6.410 ¹²

Claims (2)

1. Grease for low-current electrical contacts, on a synthetic basis, containing a polyurea thickener, which is a product of the interaction of octadecylamine, aniline and polyisocyanate, characterized in that the mass fraction of isocyanate groups in the polyurea thickener is 31.5-38.0% by weight, as a synthetic base, the lubricant contains a mixture of pentaerythritol esters and fatty acids of the C ₅ -C ₉ fraction with an organosilicon liquid in a ratio of 10:90 to 90: 10% by weight. or with polyalphaolefin oil at a ratio of from 20:80 to 80: 20% by mass., and also additionally contains hydrophobic silica gel in the following ratio of components,% by mass:
Polyurea Thickener 5.8-12.0 Hydrophobic silica gel 0.1-5.0 Synthetic base up to 100 2. Grease according to claim 1, characterized in that it contains a multifunctional additive.