RU2476461C1 - Material for lining plates - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to composite material which can be used to protect surfaces of excavator buckets, hoppers, dump truck bodies and other mechanisms from abrasive wear under impact loads. The material is obtained by mixing mechanically activated ultra-high molecular polyethylene and aluminium oxide powder Al₂O₃. The aluminium oxide used is aluminium oxide Al₂O₃ of the corundum modification of two fractions with particle size of 0.1 mm and 0.3 mm in ratio 1:2 and in total amount of 18% of the weight of the ultra-high molecular polyethylene.

EFFECT: material for lining plates has high impact strength and wear resistance.

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Description

The invention relates to polymer materials science and can be used in mechanical engineering for the manufacture of protective linings for excavator buckets, silos, dump truck bodies and other surfaces subject to abrasive wear in shock loads.

The majority of modern structural materials based on polymer matrices have a set of requirements: impact resistance, frost resistance, wear resistance and other physical and mechanical characteristics. In this regard, when creating composites, it is necessary to select components that have a complex effect on the polymer matrix, providing a synergistic effect.

Known polymer composition containing polyformaldehyde modified with barium sulfate, talc and boron nitride, and ultra-high molecular weight polyethylene (USSR copyright certificate 1670911, C08L 59/02).

The material has high physical and mechanical properties and is effective when used as a structural material in mechanical engineering, in particular machine tool manufacturing in the manufacture of parts for copying machines of finishing and turning machines.

The disadvantage of the material is a high value of wear, low frost resistance, high fluidity under load and low resistance to impact.

Known material "Tinolen" (TU 2211-001-98386801-2007) ultra high molecular weight polyethylene, which has a high frost resistance. Tinolen is used to manufacture technical products: sheets, plates, gears, high-strength threads, sports products - sliding surfaces of skis, snowboards, hockey pitches, medical products - prosthetics and orthopedics. The disadvantage of the material is its low wear resistance.

A known composite (patent RU 2087490 C1, IPC C08L 23/04, 08/20/1997), including, wt.%, 25.5-92.0 ultra-high molecular weight linear polyethylene with a high molecular weight and melting point of crystallites above 143 ° C and a filler. In this case, polyethylene is capable of lowering the melting temperature during repeated melting by at least 3 ° C and has a crystalline morphology, which is manifested in the bimodal distribution of the folding parameter of the molecular chains in the crystal lattice.

Usage: to obtain films, prostheses, cylindrical rods, sheet materials, panels.

The disadvantage of this material is low resistance to loads, low resistance to abrasion by particles of high hardness.

The closest in technical essence and actual application to the claimed material are composite materials (patent RU 2381242 C2, IPC C08L 23/4, 04/15/2008) based on ultra-high molecular weight polyethylene containing 4 wt.% Nanodispersed modifier, which is used as carbosil, or tungsten oxide WO ₃ , or silicon carbide SiC, or alumina Al ₂ O ₃ , which have frost resistance, high abrasion resistance and aliphatic hydrocarbons. They are used for facing mining and processing and mining equipment, wear-resistant products for structural purposes, operating in the mode of abrasive wear in the environment of oil, oils, greases, fuels, acids and alkalis.

The disadvantage of materials is their lack of impact resistance and low toughness.

The material from the aforementioned patent, containing aluminum oxide powder (Al ₂ O ₃ ) with a particle size of not more than 0.1 μm, is adopted as a prototype.

An object of the invention is to increase the wear resistance, impact resistance, strength characteristics of the lining plates.

The problem is solved by the fact that ultra-high molecular weight polyethylene (UHMWPE) is activated in the mechanical activator AGO-2C, which allows the acceleration of balls up to 60 g to develop specific power up to 100 W / g, while, thanks to water cooling, the temperature in the drums is regulated. During the activation process, the molecular structure of UHMWPE changes without breaking intramolecular bonds. Due to the high ductility of UHMWPE, the specific energies during mechanical activation are insufficient for breaking C – C bonds, but sufficient for changing the packing of hydrocarbon chains. Due to the low thermal stability of UHMWPE, the process is implemented at a temperature not exceeding 140 ° C.

The mechanical activation of UHMWPE provides a more effective intermolecular interaction and, as a result, an increase in the strength characteristics of products, an improvement in frost resistance, and impact resistance of the material. Powder is introduced into mechanically activated UHMWPE - an alumina modifier (Al ₂ O ₃ ) of modification of corundum of two fractions - 0.1 mm in size and 0.3 mm in size in a ratio of 1: 2, in total 18% by weight of UHMWPE. Large particles of alumina (Al ₂ O ₃ ) powder corundum modifications have extreme hardness; Due to the high dosage, they reinforce the activated UHMWPE matrix, as a result of which the impact resistance and wear resistance of the lining plates are significantly increased.

The mixture of activated UHMWPE with alumina (Al ₂ O ₃ ) powder was carried out in a disintegrator of the Osnova series DI 0.12.

An example of obtaining the claimed material for the lining plates

Weigh the ingredients of the composite material by weight according to the recipe. A portion of ultra-high molecular weight polyethylene is activated in the mechanical activator AGO-2C for 10 min at a rotational speed of the drums in a portable movement of 1820 rpm. A sample of alumina (Al ₂ O ₃ ) powder of two fractions in an amount of 18% by weight of UHMWPE, together with previously mechanically activated UHMWPE, is loaded into the receiving hopper of the Osnova DI 0.12 series disintegrator and mixed at 450 rpm of the rotor. This method of mixing provides the most uniform distribution in UHMWPE aluminum oxide (Al ₂ About ₃ ). The pressing of laboratory samples was carried out on a vulcanizing press of 250 × 250 mm at a temperature of 200 ° C for 12 minutes at a specific pressure of 70 kgf / cm ² .

The tests were carried out as follows:

- abrasion was determined according to GOST 426-77. Method for determining abrasion resistance when sliding. The tests were carried out on a MI-2 type device (grinding sand No. 16N 14A SFZh U1S GOST 13344-79, the number of revolutions of the disk - n = 600, constant load = 3.6 kg);

- tensile strength, elongation at break and yield strength under tension was determined according to GOST 11262-80. The tests were carried out on an Italian-made machine TKFD / 5;

- impact resistance was determined according to GOST 4647-80 on a pendulum head.

The properties of the composite material are shown in table 1.

Table 1 Characteristics of the material for the lining plates of the prototype Name of indicator Prototype The claimed material Patent RU 2381242 C2, IPC C08L 23/4, 04/15/2008 Abrasion, mg 45 12 Tensile Strength, MPa, less twenty 21 Tensile strength, MPa, not less 31 39 Elongation at break,%, not less than 428 430 Impact resistance, kJ / m ² , not less 32.6 43,4

As follows from the above data, the claimed material for linings exceeds the prototype in terms of abrasion, tensile strength, impact resistance, while the relative elongation and yield strength, due to the mechanical activation of UHMWPE, are at the level of the prototype. It is these indicators that determine the operational properties of the lining plates used in mechanical engineering to protect surfaces from abrasive wear, the lining of excavator buckets, silos, dump truck bodies and other surfaces subject to abrasive wear in shock loading mode.

The use of this invention will significantly increase the resistance to impact, increase the wear resistance of the lining plates, which leads to an increase in the resource of their work.

Claims (1)

Material for lining plates based on ultra-high molecular weight polyethylene, obtained by mixing ultra-high molecular weight polyethylene and aluminum oxide powder Al ₂ O ₃ , characterized in that the aluminum oxide Al ₂ O ₃ is aluminum oxide Al ₂ O ₃ modifications of corundum of two fractions - size 0.1 mm and a size of 0.3 mm in a ratio of 1: 2 and in a total amount of 18% by weight of the ultra-high molecular weight polyethylene, the ultra-high molecular weight polyethylene being mechanically activated.