HCR 240 U is a silicone master batch, vulcanizing under heat after addition of a vulcanizing agent (chosen according to the ransformation method).

Details

HEAT CURED SILICONE RUBBER HCR 240 U

Description：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:  HCR 240U is delivered in 20 kg carton boxes.

Storage and shelf life: 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, no longer guarantees that the product meets the sales specifications.