Antifriction polymeric sealing composition assignment

 

(57) Abstract:

The invention relates to anti-friction materials, sealing purposes, which can be used for the manufacture of sealing elements pairs of rotational and reciprocating movement and friction. The composition comprises polytetrafluoroethylene and 1-2 wt. % synthetic aluminum oxide brand 124127, which is activated in a planetary mill AGO-2 within 2 minutes the Invention improves the wear resistance, deformation-strength properties and load bearing capacity of the composite material. table 1.

The invention relates to the field of polymer materials, namely, anti-friction polymeric materials sealing purposes, which can be used for the manufacture of sealing elements pairs of rotational and reciprocating movement and friction.

Known composite materials for the manufacture of bearings, mechanical seals and other elements of friction polytetrafluoroethylene (PTFE) and inorganic fillers of different chemical nature [Istomin N. P. , Semenov A. P. anti-Friction properties to the of iesa antifriction with a low coefficient of friction, but have a low deformation-strength characteristics, high stiffness, which reduces the lifetime of their work.

The closest to the technical nature of the claimed material is the low-filled composite based on PTFE (90-99,5 wt. %) and ultra-Sialon (oxynitride aluminum-silicon (0.5 to 10.0 wt. %) (prototype) [THE 301-05-120-91 "composition of the low-filled PTFE anti-friction purposes"] .

Having a high wear resistance and relatively high physical-mechanical properties, the material is characterized by insufficient bearing capacity, due to what can only be operated at low loads.

An object of the invention is to improve the wear resistance, deformation and strength characteristics and bearing capacity of composite material based on PTFE.

The positive effect is provided by the introduction of mechanically activated PTFE synthetic aluminum oxide brand 124127 in the following ratio, wt. %: oxide of aluminum (Al2ABOUT3) 124127 1,0-2,0; PTFE else.

PTFE (Teflon-4) - industrial product (GOST 10007-80), which with the g/cm3TPL327oC.

Synthetic aluminum oxide brand 124127 - the product obtained by mechanochemical synthesis at the Institute of Geology, Geophysics, Mineralogy SB RAS (, Novosibirsk), is a white powder. Physical parameters of Al2ABOUT3124127: the particle size of 1-4 μm; specific surface area of 1.0 m2/g; density is 4.03 g/cm3.

To obtain compositions of PTFE was introduced alumina subjected to mechanical activation for 2 min in a planetary mill AGO-2 [E. Avvakumov, Soft mechanochemical synthesis // Chemistry for sustainable development. - 1994. - So 2, 2-3. - S. 541-559] . Mechanical activation of the filler is carried out with the purpose of obtaining uniform dispersion of the powder and increase the reactivity of particles of aluminum oxide, so as PTFE polymer as a binder is characterized by inertness, low level of adhesion, which makes it difficult interfacial interaction in the composite and, therefore, hinders the processes of structure formation. Putting the estimated weight of the polymer and filler in the high-speed mixer, were mixed to obtain a homogeneous mass. Then from a song by cold pressing did blanks of the desired shape and silumina can improve the wear resistance of the material, but at the same time the deformation-strength characteristics are reduced.

Introduction to PTFE synthetic aluminum oxide brand 124127, mechanically activated in a planetary mill for 2 min, allows to obtain a composite material with high strain-strength and wear resistance, including when operating in conditions of high loads.

Such composite properties of the claimed composition due to the influence of active filler on the processes of structure formation of the composite are determined by the mechanical activation of the filler during processing in a planetary mill. Mechanical activation of the filler is to increase the dispersion, the defects of the crystalline structure of the particles, which is confirmed by the results of x-ray diffraction studies and electron microscopy. The average change of interplanar distances in the crystal lattice of the aluminum oxide after activation is 0.01 . The average particle size of the aluminum oxide after activation is 0.5-2 μm, a density of 6.25 g/cm3.

Example. a 99.0 g of PTFE and 1.0 g of a powder of Al2ABOUT3brand 124127, Proektirovanie for 2 min planets in the al in an oven at 100-120oC for 1 h Then the composition is placed in a cold mold and extrude the product at specific pressure of 50 MPa. Sintering of the products is carried out in an electric furnace at (3705)oC. Cooling the sintered products is carried out directly in the furnace.

Other examples of composite material of the inventive composition given in the table.

Method for determining properties of a composite

Physico-mechanical properties of the inventive anti-friction sealing material is set on standard samples (GOST 11262-80). The tests were carried out on the car "Instron" (England) when the velocity of the movable grippers 100 mm/min Technical parameters defined on the machine friction SMC-2 on a shaft-Bush". Load 67-1000 N, sliding speed of 0.39 m/s, the friction path 7 km, the sample - sleeve diameter 32-22 mm, height 21 mm, the counterbody - steel shaft. The test results presented in the table.

Technical and economic efficiency

The use of the claimed invention, which is implemented on standard equipment, allows to increase the load bearing capacity of composite materials up to 1000 N, while maintaining a high wear resistance in combination with high Phys what totype in 28-30 times the tensile strength at 15-35%, the elasticity is 30-45%. Bearing capacity of the material in comparison with the prototype has increased in 3 times. Optimal activation of the filler in the planetary mill - 2 min, the content of the mechanically activated filler 1.0 to 2.0 wt. %. Further increase of the content and time of activation of the filler leads to a decrease of deformation and strength parameters.

The use of anti-friction and sealing compositions of the inventive composition will increase the life of products at higher loads.

Anti-friction composition sealing purposes, containing polytetrafluoroethylene and an inorganic filler, characterized in that the inorganic filler it contains synthetic aluminum oxide brand 124127, activated in a planetary mill AGO-2 for 2 min, in the following ratio, wt. %:

Aluminum oxide brand 124127 - 1 - 2

Polytetrafluoroethylene - Rest

 

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FIELD: polymers.

SUBSTANCE: invention relates to polymeric composition self-lubricating materials designated for making friction unit articles working in absence of lubricant or its limiting under conditions of dust content and effect of transient loadings. Antifriction composition comprises polytetrafluoroethylene, graphite and crushed quartz with dispersity 40-60 mcm as a silicate-containing additive and, additionally, bronze powder and chalk and components are taken in the following ratio, wt.-%: crushed quartz, 0.4-0.8; graphite, 3-8; chalk, 5-12; bronze powder, 15-25, and polytetrafluoroethylene, the balance. Invention provides enhancing wear resistance and heat stability of antifriction composition and simplifying its preparing.

EFFECT: improved and valuable properties of composition.

2 tbl, 7 ex

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