HU198519B - Self-lubricating anti-friction mixture - Google Patents

Abstract

A self-lubricating antifriction composition consisting of polyamide, a lubricating oil, polyolefin, graphite and a corrosion inhibitor of donor action containing groups -NO2, <SIGN> C=O, or of acceptor action containing groups -NH2, -OH, the interrelationship between the components being as follows, in per cent by mass: polyolefin: 5-15; lubricating oil: 3-10; graphite: 5-10; corrosion inhibitor: 1-5; polyamide: the balance up to 100.

Description

The present invention relates to a self-lubricating friction reducing composition.

More particularly, the present invention relates to a polymer blend for self-lubricating friction reducing composition. The compositions of the invention can be used in the manufacture of non-lubricated sliding components such as sliding bearings, as well as in their limited (intermittent), one-off assembly or periodic use during repair.

Polymers in pure form cannot be used for the manufacture of sliding parts because they do not meet the requirements for the reliability and service life of sliding bearings, moving seals and other parts. This is due to the relatively low abrasion resistance and stability of the polymers under atmospheric conditions. The sliding parts often work in corrosive media, which damages the surface of the metal parts and, due to the increased wear, the friction points of the polymer. Similar damage occurs when storing machines and equipment consisting of interconnected polymer parts and metal parts over an extended period of time. In this case, the corrosion will cause tension in the component, which can lead to failure during operation.

U.S. Pat. No. 3,726,945 discloses a self-lubricating friction reducing composition comprising 70-99.9% by weight of polyamide and 0.1-30% by weight of polyolefin. Friction results in the formation of a polyolefin melt film on the surface of the component, which reduces the coefficient of friction and increases wear resistance. However, this effect occurs only at high loads and speeds. In addition, the mixture does not provide anti-corrosion protection when the component is to be used in an aggressive medium.

U.S. Patent No. 531,831 discloses a self-lubricating friction reducing composition comprising 100 parts by weight of polyamide. This mixture is suitable for the production of frictional components which are protected against environmental influences (humidity, sunlight, etc.) and operate at relatively low temperatures (up to 100 ° C). Overloads and unstabilized friction conditions can result in local overheating, which activates the degradation and oxidation of polymeric materials, leading to accelerated component aging and premature disintegration.

U.S. Patent No. 704,958 discloses a polyamide-based self-lubricating anti-friction lubricant composition comprising 10-15% by weight lubricating oil, 10-15% by weight polytetra fluoroethylene dry lubricant and 0.5-0.7% ethyleneamine tetraacetic acid. The mixture has high physical-mechanical properties, high abrasion resistance and low friction coefficient. High temperatures (above 100 ° C), however, cause the physical-mechanical properties to deteriorate over time. In addition, the mixture is not capable of inhibiting corrosion processes that occur on the metal counter surface during operation and storage of the metal polymer component. '

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-lubricating anti-friction compound that enables the production of components with high physical-mechanical properties and abrasion resistance, which can be used for extended periods in high temperatures and in aggressive media.

Accordingly, the present invention relates to a self-lubricating friction reducing composition comprising pollamide, lubricating oil and dry lubricant. The composition aspect of this invention to polyamide polikaproamidot flowable polyamide or glass fiber reinforced polyamide, a lubricating oil 0.85 to 10 g / cm ³ density or mineral oil is from 0.9 to 1.3 g / cm ³ density of silicone oil as a dry lubricant graphite, and, as corrosion inhibitor, nitrated, paraffinic concentrated mineral oil raffinate, or

- diethyl dihexadecyl ammonium nitrate, or

- ethylene diamine oleic acid monoamide, or - a mixture of dicyclohexylamine salts and a synthetic fatty acid of 10 to 20 carbon atoms, or

- containing a salt of cyclohexylamine and a C7-C11 synthetic fatty acid, or - a condensation product of alkenyl butanedioic anhydride and urea and polyolefin as a high pressure polyethylene or polypropylene, wherein the proportion of the components is noliolefin 5 to 15% by weight graphite 1-5 wt% polyamide 60-86 wt%

The self-lubricating friction reducing composition of the present invention exhibits stable physical-mechanical and friction-reducing properties at high temperatures (up to 150 ° C), reduces frictional corrosion of friction components in continuous or batch mode, and reduces its mechanical wear intensity through its preservative effect.

In the composition of the invention, the polyolefin provides a self-lubricating effect at high speeds and high stress (high temperature). The lubricating oil provides a self-lubricating effect at low temperatures (up to 80-100 ° C). Graphite provides a low coefficient of friction and increases the abrasion resistance of the blend.

The use of an oil-soluble corrosion inhibitor reduces the intensity of the corrosion processes of the metal components bonded together when used in aggressive media (electrolytes, acidic and alkaline aqueous solutions). The corrosion inhibitor used also exhibits an anthloxantant effect on the polymer-based polyamide of the blend, which allows the use of a component to simultaneously reduce the thermal decomposition of the polymer blend and corrosion processes that occur at the boundary between the polymer blend and the metal part.

The weight ratio of polyolefin to liquid phase component (lubricating oil + corrosion inhibitor) is ΙΌ, 8-1: 1. This ratio is determined by the considerations below. It is known that when a polyolefin is filled with a liquid phase plasticizer (40-50% by weight) and the mixture is thawed, a colloidal solution is formed which, upon cooling, becomes a gel, i.e. an unfinished phase separation system. The resulting polymer backbone contains interconnected cells (pores) of 10-30 µιη in which a liquid (polystyrene) is present. The color distribution can ensure a uniform distribution of the liquid in the pores of the gel. In the composition of the present invention, the liquid phase consisting of lubricating oil 21 and an oil soluble corrosion inhibitor acts as a plasticizer for the polyolefin. The polymer gel is evenly distributed in the volume of the mixture according to the invention, and as a result, said liquid phase component is uniformly deposited on the surface of the product obtained from the mixture according to the invention. The friction caused by the metal counterbody causes the liquid phase component to wear out, but at this rate, the transport of the inhibitor-containing lubricating oil from the inside of the component to the friction surface is repeated. This provides self-regulation of the mixture's anti-friction and corrosion behavior.

If the polyolefin content of the blend falls below 5% by weight, the self-lubricating properties deteriorate. In contrast, more than 11% by weight polyolefin content impairs physical-mechanical properties. The same effects determine the amount of liquid component (lubricating oil + corrosion inhibitor). As mentioned above, the liquid phase binder has a certain proportion to the polyolefin. With less than 1% by weight of corrosion inhibitor, the corrosion behavior of the mixture deteriorates, while using more than 1% by weight of the inhibitor is unnecessary as it does not improve the corrosion properties.

Use of less than 10% by weight of graphite reduces the friction reducing effect of the mixture (which increases the coefficient of friction and wear), and more than 10% by weight of graphite reduces the physical-mechanical properties.

In order to prepare the self-lubricating friction reducing composition of the present invention, the amount of polyamide granulate at 100-110 ° C should not exceed 0.1-0.15% by weight), then the polyolefin granulate and the graphite powder are added and the mixture is mixed gently. The lubricating oil in which the corrosion inhibitor has previously been dissolved is then added. The resulting mixture is blended in any type of mixer such as a drum mill until a homogeneous composition is obtained. The mixture is processed by a high-performance belt extrusion process or by casting at 220-270 ° C (depending on the type of polyamide) to the desired product.

If, due to the application of the product, it is not necessary to transform the liquid phase component from the total volume of the product to the surface, the product may be manufactured by preparing the desired workpiece from the solid phase components (polyamide, polyolefin and graphite) The liquid phase consists of a 2: 1 to 3: 1 by weight mixture of a lubricating oil and an oil soluble corrosion inhibitor. The temperature of the liquid phase should be above the melting point of the polyolefin, but should not be closer to 80-90% of the melting point of the polyamide on which the mixture is based. The residence time depends on the desired depth of penetration of the lubricating oil containing the inhibitor. The impregnation rate is 500 to 10 µm / min up to 500 µm. After impregnation, the composition of the surface layer of the product is the same as that of the composition of the invention. '

The following polyamides can be used in the composition according to the invention:

- Pollacroamide (pourable resin), product of hydrolytic polymerization in the presence of e-caprolactam catalyst, granules, 1-5 mm in diameter, density: 1130 kg / m ³ , melting point 215 ° C, tensile strength 55-77 MPa, compressive strength 100-150 MPa , polycondensed product of pourable polyamide, hexamethylenediamine salt and sebadic acid, granules having a diameter of ³ to 55 mm, density: 1140 kg / m ³ , melting point 252-260 ° C, tensile strength 80 MPa, molecular weight 2000, - glass fiber reinforced polyamide, polycaproamide resin, containing 30% by weight of glass fibers 9 to 11 µm in diameter, granules having a diameter of 3 to 9 mm, density: 1360 kg / m ³ , melting point: 217 ° C, tensile strength: 115 MPa, compressive strength: 180 MPa, molecular weight 10000-3500.

Preferred polyolefins are high pressure polyethylene (density: 900-939 kg / m ³ ) and polypropylene (density: 900-910 kg / m ³ ).

Examples of lubricants are mineral oils:

a) the alloy petroleum raffinate, and édesjiaraffinos paraffinszegény petroleum oil, density at 20 C, ^d 0.89 g / cm ^3, viscosity at 20 ° C, 1.4 x IO ^"5 m ² / s ash content is up to 0.003%, acid number 0.25 mg KOH / g, freezing point: -30 ° C, flash point: 200 ° C,

(b) Unrefined petroleum refined coal, of low sulfur petroleum species, density at 20 ° C: 0,987 g / cm, viscosity at 20 ° C: 2,05 x 10 ⁵ m ² / s, ash content: not more than 0,003%, acid value: 0,03 mg KOH / g, pour point: 018 fc, flash point: 250 ° C,

c) Pure mineral oil, density: 0.894 a / cm ³ at 20 ° C, viscosity: 20 v 4.9 xx 10 ' ^y m' / s at 50 ° C 2.0 x 10 ' ⁵ m ² / s freezing point: 045 ° C, flash point in open jar: 163 ^b C.

Other lubricating oils are silicone oils (liquid organic silicon compounds) and low molecular weight organic siloxane polymers which are capable of maintaining the properties of a liquid over a wide range of temperatures, chemically inert, corrosive, soluble in aromatic and chlorinated aliphatic hydrocarbons and. Examples of silicone oils include:

d) Polyethylsiloxane liquid, density: 0.97 g / cm ³ at 20 ° C, 4.2 x 10 ⁵ m ² at 20 ° C, boiling point: 250 ° C, flash point: 170 ° C, specific heat capacity: 1,863 x 10 ³ J / kg degree at 20 ° C,

e) Polymethylsiloxane liquid, density: 1.08 g / cm ³ at 20 ° C, viscosity: 2.0 χθΙΟ ⁵ m ² / s at 20 ° C freezing point: -60 ° C, boiling point: 250 ° C, flash point in open jar: 265

C, spedical heat capture: 1,641 x 10 ³ J / kg at 20 ° C,

f) polymethyl fenikziloxán liquid density at 20 C ^E 1.18 g / cm ^3, viscosity: 5.4 x 20 ° Chőmérsékleten IO ^'5 m ² / s, pour point: 036 ° C, boiling point: 360 ° C, spedfikus heat capture: 1.423 x 10 ³ J / kg at 20 ° C.

. Oil-soluble corrosion inhibitors useful in the compositions of the present invention include donor-type inhibitors having -NO ₂ , = O groups and containing -NH ₂ , -OH groups.

198 519

Zon acceptor type Inhibitors.

Examples of donor-type corrosion inhibitors include:

A) Nitrated paraffin (10 wt.%) Concentrated mineral oil raffinate, oily liquid, dark brown color density: 0 96 g / cm ³ (20 ° C), viscosity: 1.00 x 10 ⁴ m ² / s (20 ° C) ) and 3.0 x 10 ⁵ m ² / s (100 ° C), ash content: 3.5%, soluble in mineral oils and organic solvents, contains -NO ₂ ,

B) [(C ₂ H ₅ ) ₂ N (C ₁₄ H ₃₃ )] NO ₂ diethyl dihexadecyl ammonium nitrate,

C) NH ₂ CH ₂ CH _{2 NHCO-C) 7} H-oleic acid-ethylenediamine monoamld formula _33rd

Preferred acceptor type corrosion inhibitors include:

D) Mixture of dlcyclohexylamine salt (43% w / w) and C 10-20 synthetic fatty acid (57% w / w) (C * Hu) ₂ 'NHC Hn 1 / COOH, paste, density: 0.92 g / cnr (20 ° C) ), melting point: 15-20 ° C, soluble in oil and in organic solvents,

E) Salt of Cyclohexyllamine and C 7-11 Synthetic Fatty Acid (Formula C _n H2 _{p +} jCOOHC _# H, NH ₂ ), paste product, dark brown color, melting point -12 ° C, soluble in alcohol, oil, gasoline and acetone 0.92 g / cm ³ ,

F) a condensation product of an alkenyl-butanediyl anhydride and urea, light brown liquid, density: 0.89 g / cm ³ (20 ° C), viscosity: 2.5 x 10- ⁵ m ² / s (50 ° C) oil and organic soluble, containing -NH ₂ .

The mechanism of action of Inhibitors is as follows: Upon reaching the friction surface, donor-type inhibitors release excess electrons into the metal counterpart and form a chemosorption compound on the surface.

^'Υ The acceptor-type inhibitors absorb electrons and form metal kemoszorpciós layer which protects the metal against the body surface from corrosion. The selected Inhibitor types also contain an antioxidant as well as substances that inhibit the thermal oxidation degradation of the polymers. The donor-type corrosion inhibitors contain an antioxidant agent and a reducing agent, such as organic sulfides, selenides, or fatty aromatic fatty acids, which react with the hyperoxide group of the polyamide without forming free groups. Acceptor inhibitors contain aromatic amides and alkylated phenols which block the oxidation of the polyamide, i.e., react with free active groups.

Some of the compositions of the invention as well as the composition of the composition disclosed in US Patent No. 704,958 are shown in Table 1.

Table 1

components I II III ARC Composition (% by weight) V VI VII VIII IX X No. 704,958. Soviet copyright doctrine. according to. Polikapro- amide 86 73 60 - - 86 73 60 - - 73.4 Liquid polyamide glass fiber 73 73 reinforced polyamide petroleum 73 73 al 3 7 10 - - - - - - - 12 bf - - - 7 - - - - - - cl silicone oil - - - 7 · " - - dl - - - - - 3 7 10 - - - «1 - - - - - - - - 7 fiction 7 Graphite 5 7 10 7 7 5 7 10 7 7 - polyethylene 5 10 15 - 10 - 10 10 Polypropylene Donor type inhibitor 10 5 10 15 THE/ 1 3 5 bl - - 3 - - - - - - - cl Acceptor type inhibitor 3 dL - - - - 1 3 5 - - - NIGHT - - - - - - - 3 ff Politetra- 3 - fluoroethylcamptothecin Ethylene diamine 14 -tetrae acetic acid 0.6

198 519

Table 2 shows the physical-mechanical properties (tensile strength and compressive strength), frictional properties (friction coefficient and abrasion resistance), and corrosion behavior of the compositions in Table 1.

The physical-mechanical properties of the self-lubricating anti-friction mixture of the present invention were determined using a tensile machine at 50 mm / min.

Friction tests were performed on a shaft-insert scheme on a friction machine. Carbon steel containing 0.42-0.50% carbon by weight, HRC hardness 40-45, and coarseness (R) = 0.8-1 µm was used as the counterpart. The workpiece made of the self-lubricating anti-friction composition has a surface of 2 cm ¹ . The linear velocity is 0.1-1.0 m / sec and the load is 2.5 and 0.5 PMa, respectively. The wear intensity (I) can be calculated using the formula below;

BRANCH

J · ------ Jo,

p.A.S in the formula

ÁG = mass weight wear, mg, δ = density of the sample at 20 ° C, g / cm ³ ,

A = workpiece surface, cm ¹ ,

S = friction distance, km. '

Corrosion tests were carried out by an accelerated method, which measured the polarization resistance (Rp) of two electrodes immersed in an electrolyte and connected to a sample of the material to be tested. Electrodes made of carbon steel containing 0.09 to 15% by weight of carbon were used. The effective electrode tip overlay was polished to a roughness R _a = 0.4-0.5 μπι and the inactive surface was sealed with paraffin. The electrolyte used was 0.1 l HCl and In NajSO ₄ .

The corrosion rate (, g / m ¹ h) was calculated as follows:

2K

I »------,

S.Rp in the formula

K = weighting factor of corrosion, depending on the type and concentration of the electrolyte, ohm g / h (0, ln in HG solution K = 20,1, in In NajSO * solution K = '0,032),

Rp - polarization resistance, ohm, λ- S = electrode surface, m ¹ .

(Zaschita Metallov, No. 6, Verlag Nauka, Moscow, 1982, pp. 946-949)

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The results of Table 2 show that the corrosive Ihhibitor significantly increases the thermal stability or the resistance to heat oxidation of the workpieces of the present invention, so that after tensile oxidation at 150 ° C for 100 hours, the tensile strength of the composition according to the invention is only 5-20%. , while the tensile strength is less than half that of the composition according to Soviet Authorization No. 704958. By using corrosion inhibitors, the rate of corrosion of the carbon moiety can be reduced by 50 to 100. At the same time, the frictional properties of the composition according to the invention are the same as those of the composition according to the US Patent No. 704958.

The products of the present invention have been used as friction components in motor vehicles, agricultural machinery, and oil and gas installations. According to the results of the tests, the components of the composition according to the invention are significantly better used than anti-friction cast iron, babbit and alloys containing copper, aluminum and zinc.

The self-lubricating anti-friction composition of the present invention has high physico-mechanical and anti-friction properties and allows the inhibition of frictional corrosion of frictional components and thereby the reduction of mechanical corrosion wear of the components. They stabilize the physical-mechanical properties of components at high temperatures and are easy to process technologically.

Claims (1)

Patent Claim self-lubricating friction reducing composition comprising a polyamide, a lubricating oil and a dry lubricant, characterized in that poharaidként 1130 kg / m ³ density to 1000 35000 molecular weight polikaproamidot, 1140 kg / m ³ density and 20 0000 MW cast polyamide or 1360 kg / m ³ mineral oil of a density of 10,0000 and 35,000 molar glass fiber reinforced with mineral oil of a density of 0,85 to 1,0 g / cm ³ and of a viscosity of 1 to 5 x 10 ^{5 5} m ² / s at 20 ° C or 0,1 to With a density of 3 g / cm ³ and a viscosity of 2 to 6 x 10 &lt; 10 &gt; ^S viscosity at 20 ° C, graphite as dry lubricant and as corrosion inhibitor - paraffin-refined petroleum-refined petroleum raffinate of a density of 0,96 g / cm ³ and of a viscosity of 1 x 10 ³ m ² / s at 20 ° C, or - diethyl dihexadecyl ammonium nitrate salt, or - an ethylenediamine-oleic acid mono-amld salt, or - a mixture of dicyclohexylamine salt and a synthetic fatty acid of 20 to 20 carbon at a melting point of 15 to 20 ° C and a density of 0,92 g / cm ^3, or - 0,92 g / cm ³ salt of cyclohexylamine and C 10 -C 20 fatty acids, or - a condensation product of alkenyl butanedioic anhydride and urea having a density of 0.89 g / cm ³ and a viscosity of 2.5 x 10 'm ² / s at 20 ° C and 900939 kg / m ^{3 of} high pressure polyethylene or 900-910 as pollolefin Contains polypropylene with a density of kg / m ³ where the proportion of components is polyolefln lubricating oil graphite corrosion inhibitor polyamide 5-15% by weight 3-10% by weight 5-10% by weight 1-5% by weight 60-86% by weight Published by: National Talent Office Responsible publisher: Fflmer Zoltán o.v. UNITAS-CODE