Hollow Corundum Microspheres in Industrial Rubber and Polyurethane Goods

The main objective of using hollow corundum microspheres (here in after, HCM) in industrial rubber goods and elastomers is to
increase durability of industrial rubber goods.
Areas of application of hollow corundum microspheres in industrial rubber goods:
The durability of industrial rubber goods increases two to five times due to the hollow corundum microsphere self-sharpening
effect accompanied by formation of open sharp edges of corundum which prevent rubber from disintegrating because of severe
exposure to abrasives.
The spherical shape of hollow corundum microspheres enables their easy intrusion in rubber mixture and even distribution
throughout it, and the extended surface of microspheres secures them in rubber.
The low conductivity and small thermal expansion coefficient of corundum microspheres enables us to enhance manufacturing
parameters of end products by increasing the time of pre-vulcanisation and improving moulding characteristics of rubber mixture,
and to improve its fire- and frost-resistance properties.
Conveyer bands with HCM
Rubber cushions for railroads with HCM
Inner lining for barrel and raw mills with HCM
For sliding bearings, OAO NIIRPI [Rubber Coatings and Goods Research Institute, Joint Stock Company] has developed elastomer compositions modified by hollow corundum
microspheres based on NBR and HNBR with enhanced physical and mechanical characteristics: enhanced heat resistance and high durability.
Elastomer compositions modified by HCM based on NBR and HNBR
Characteristics
No. 1
(initial)
No. 2
(modified)
Nominal tensile strength, GOST 270-75, MPa
28.9
28.2
Tensile strain at break, GOST 270-75, %
270
280
Relative breaking strain, GOST 270-75, %
6
7
Hardness, GOST 263-75, Shore A unit
72
71
Tear resistance, GOST 262-93, N/mm
35
36
Rate of set, GOST 9.029-74, A/B Method [in Cyrillic characters, ‘А/Б’], 130°C × 24hrs
16/54
19/57
Abrasive wear resistance, GOST 426-77, J/mm3
25.9
146.2
Change in weight after effects of aggressive environments, GOST 9.030-74, %
Standard rubber testing liquid SZhR-3 [in Cyrillic characters, ‘СЖР-3’] (standard liquid IRM 903), 125°C × 24hrs
5.7
5.9
Aviation kerosine ТС-1, 23°C × 24hrs
3.5
4.5
The durability of the modified elastomer composition is five times higher than that of the initial composition and exceeds characteristics of durable thermoplastic
polyurethane by 36%.
The developed modified elastomer composition has the optimum level of physical and mechanical properties, high grease and heat resistance, and may be used in production of
industrial rubber items which must meet strict requirements to durability and heat resistance (gaskets, friction pairs, rubber-lined rollers, sliding bearings, etc.).

In Yaroslavl Rubber Plant was developed a rubber composition 60-446 (sole for shoes) with mix of NBR-40AM (60% wt.) and BR (40% wt.) modified by hollow corundum microspheres (HCM-L, 5% wt.), the results present in the table below:
Rubber composition 60-446 with mix of NBR-40AM (60% wt.) and BR (40% wt.) modified by HCM-L, 5% wt.
Characteristics
Norm
Initial
Modified
Nominal tensile strength, GOST 270-75, MPa
12
17.3
15.7
Tensile strain at break, GOST 270-75, %
300
430
400
Hardness, GOST 263-75, Shore A unit
62
60
62
Abrasion wear resistance, GOST 426-77, J/mm3
13
28
Change in weight after effects of aggressive environments, GOST 9.030-74, %,
Oil I-40A
3
0.7
0.9

Results of test HCM in different type of rubber

Type of goods

Type of rubber

(type of caoutchouc)

Abrasive wear resistance, GOST 426-77, J/mm3

Abrasion,

GOST 426-77

m3/TJ

without

HCM

with

HCM

without

HCM

with

HCM

sliding bearing, rubber for petrol and oil industry

NBR, HNBR

25,9

146,2

-

-

mud pump piston cup

NBR

-

-

44,3

9,4

rubber stator of downhole motor

NBR

-

-

27

4

sole shoes

mix of IR, SBR, BR NBR

-

-

80

59

sole shoes, inner lining for raw mills

NBR and BR

13

28

-

-

rubber coated roller

12,8

20,2

-

-

HNBRG-80

50,2

147,7

-

-

rubber cushions for railroads

mix of NR and SBR

-

-

88,2

38,5

Articles and reports about using of Hollow Corundum Microspheres in rubber goods.

HOLLOW CORUNDUM MICROSPHERES IN THE MANUFACTURE OF RUBBER COMPOUNDS. M.A. Salyaeva, E.M. Kashina, L.A. Noskova PJSC "Ural Zavod RTI", Yekaterinburg, Russia

TRIBOTECHNICAL PROPERTIES OF ELASTOMER COMPOSITIONS MODIFIED BY HOLLOW CORUNDUM MICROSPHERES OF ALUMINUM OXIDE. Tselykh E.P., Khodakov S.Y., Tretyakova N.A. FSUE "FRPC Progress", Omsk, Russia

EFFECT OF HOLLOW CORUNDUM MICROSPHERES ON PROPERTIES OF SOLE SHOE RUBBER. N.F. Ushmarin¹, D.V. Pelipenko¹, S.I. Sandalov¹, E.N. Egorov¹, N.I. Koltsov². ¹JSC "V.I. Chapaev Cheboksary Production Association”, Cheboksary, Russia. ²FSBEI HE "N.I. Ulyanov Chuvash State University”, Cheboksary, Russia.

Report "Mixing and testing of compounds with HCM" made in  the German Institute of Rubber Technology (DIK) in the Materials Development and Testing Laboratory (WE).

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