HEAT CURED SILICONE RUBBER IOTA HCR 240 U
Description：IOTA HCR 240 U is a silicone master batch, vulcanizing under heat after addition of a vulcanizing agent (chosen according to the ransformation method).
Applications：
Producing articles with good compression set.
Producing articles exposed to oils (with or without insert).
Use in blends with master batches of greater hardness (coating of cylinders, etc.).
Special properties：
No replastification
No post-curing
Low shrinkage
Low compression set
Good heat stability, up to 200℃
Low swelling in paraffin or slightly aromatic oils
Bright colors easily obtained
Characteristics：
Type(in accordance with GB/T 5576/1997) ………………………………………… VMQ
Density at 25℃, g/cm3, approx………………………………………………………… 1.09
Aspect…………………………………………………………………Colorless, transparent
Properties after working:
(1) After addition of 0.9% 2,4-dichloro-benzoyl peroxide (at 50%), and vulcanization for 8min at 115℃
(2) After addition of 1.0% 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane at 45%, and vulcanization for 10 minutes at 170℃
1. Mechanical properties
1.1 Properties without post-cure (1) (2)
Shore A hardness, approx………………………………. 44 42
Tensile strength, MPa, approx……………………………… 7 7.6
Elongation at break, %, approx…………………………… 380 475
Modulus at 100% elongatioin, MPa, approx ……………… 1.29 0.98
Tear strength, kN/m, approx………………………………… 12 12
Compression set (22h/177oC/25%), %, approx. ………… 17 8
Rebound resilience, %, approx……………………………… 68 64
Linear shrinkage, %, approx………………………… 2.15 3.80
2. Heat stability
2.1 Properties after heat-ageing 7 days at 177°C
Shore A hardness, approx…………………………………. 45 43
Tensile strength, MPa, approx……………………………… 6.8 6.8
Elongation at break, %, approx……………………… 365 410
2.2 Properties after heat-ageing 3 days at 200°C
Shore A hardness, approx……………………………. 44 44
Tensile strength, MPa, approx………………………… 7.1 6.5
Elongation at break, %, approx…………………… 370 380
2.3 Properties after heat-ageing 10 days at 200°C
Shore A hardness, approx……………………………. 42 44
Tensile strength, MPa, approx………………………… 6.9 6.1
Elongation at break, %, approx…………………… 360 315
3. Oil resistance
3.1 Variation of properties after immersion for 70 hours at 150°C in ASTM 1 oil
Shore A hardness, approx…………………………… -8 -10
Tensile strength, MPa, approx………………………… -2 -23
Elongation at break, %, approx……………………… +10 -12
Volume, %, approx………………………………… +4 +4
3.2 Variation of properties after immersion for 70 hours at 150°C in ASTM 2 oil
Shore A hardness, approx…………………………… -15 -15
Tensile strength, MPa, approx………………………… -11 -30
Elongation at break, %, approx………………………… +20 -6
Volume, %, approx……………………………………… +8 +9
Packaging: IOTA HCR 240U is delivered in 20 kg carton boxes.
Storage and shelf life: IOTA HCR 240U may be stored in its original unopened packaging at a temperature below 40℃ for up to 18 months from the date of manufacture marked clearly on the packaging.
Past this date, IOTA no longer guarantees that the product meets the sales specifications.
