CORK in combination with RUBBER Provides unique properties. By itself Cork is amazing, it is natural, light, imputrescible, impervious to liquids and gases, flexible, resistant, it has great dimensional stability and is a thermal and acoustic insulator. Remarkably when combined with rubber we get properties of the polymer plus the property of true compressibility. This unique combination has a never-ending potential of applications.
Rubberized Cork has major superiorities over other gasket material, which makes it ideal for wide range of other gasket material where application of oil is involved and only choice for flanges, which are not fully flat, or having limited surface area. Other material under pressure crush, distort or extrude. Cork is endowed with a natural property allowing it to recover its initial shape after being compressed. Cork is the only material that can compress without lateral spread, and can recover up to 80% of its original thickness. This property ensures there is a Relaxation stress (outward pressure) on the flanges to maintain the seal.
Rubber Cork |
Other Material |
 |
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When Compressed |
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APPLICATION :
Synthetic Rubber bonded cork sheets have wide application where gas, oil or any other liquid is used at low bolt loads. Thus it has wide application in Transformers & switchgears, Automobiles and General electrical industry. Many applications ranging from gearboxes, inspection covers to water piping gaskets use rubber - cork. In high voltage transformers rubberized cork sheet is used as oil sealants. Even at elevated temperature, Rubberized Cork Sheets have a deformity of less than 0.1% and the physical stability of the products is excellent. They do not swell, have high tensile strengths and are resistance to the temperature as high as 110 degree Celsius. In automobile industry, rubberised cork gaskets are used as a sealant for engine heads, sumps or packing to prevent leakage of oil.
| SR. NO | Mechanical Properties. | GR - R & B (Moderate oil Resistant) |
GR - S & P (Good oil Resistant) |
GR - I & II (Very good oil Resistant) |
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RC-50 |
RC-70 |
RC-80 |
RC-50B |
RC-70B |
RC-80B |
RC-50C |
RC-70C |
RC-80C |
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1. |
Hardness IRDH |
50-10 |
70±10 |
80±10 |
50±10 |
70±10 |
80±10 |
50±10 |
70±10 |
80±10 |
2. |
Dimensional charge percent Max. |
1 5 |
1.5 |
1.5 |
1.5 |
1.5 |
1.5 |
1.5 |
1.5 |
1.5 |
3. |
Tensile Strength |
6.63 |
9.18 |
12.75 |
1 7.14 |
12.75 |
15.50 |
12.75 |
15.50 |
19.50 |
Kg/cm2 (KPa*) Min. |
(650) |
(900) |
(1250) |
(700) |
(1250) |
(1550) |
(1250) |
(1550) |
(1900) |
|
4. |
Compressibility at 28 Kg/cm2 (2800 KPa) |
45-60 |
35-50 |
25-35 |
45-60 |
35-50 |
25-35 |
35-45 |
25-35 |
15-25 |
5. |
Tpencem45-60 Recovery Percent Min. |
80 |
80 |
80 |
80 |
80 |
80 |
80 |
80 |
80 |
6. |
Compression Set Percent Max. |
80 |
85 |
90 |
80 |
85 |
90 |
80 |
85 |
90 |
7. |
Chemical Test on water extracts |
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| a) PH. where applicable | 5.0 to 8.50 |
5.0 to 8.50 |
5.0 to 8.50 |
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| b) Chloride content(as chloride ion) | 0.2 percent Max |
0.2 percent Max |
0.2 percent Max |
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| c) Sulphate content(as sulphate ion) | 0.2 percent Max |
0.2 percent Max |
0.2 percent Max |
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8. |
Volume change after immersion
in ASTM oil No 3 for 70 hours |
40 percent Max |
25 percent Max |
15 percent Max |
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