HCR 345 U is a very transparent silicone heat-curing elastomer which vulcanizes after the addition of a vulcanizing agent selected in accordance with the transformation process.

Details

HEAT CURED SILICONE RUBBER  HCR 345 U

Description： HCR 345 U is a very transparent silicone heat-curing elastomer which vulcanizes after the addition of a vulcanizing agent selected in accordance with the transformation process.

Applications：Molding and extrusion of transparent parts with high mechanical properties.

Special properties：

Only slight freshening required

Short post cure

High transparency

High mechanical properties. Offers a good compromise between tear strength and ompression set

Characteristics：

Type(in accordance with GB/T 5576/1997) ………………………………………… VMQ

Density at 25℃, g/cm3, approx………………………………………………………… 1.10

Natural color…………………………………………………………Colorless, transparent

Properties after working:

(1) After addition of 1.1% 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……………………………….       41         43

Tensile strength, MPa, approx………………………………    7.3        7.8

Elongation at break, %, approx……………………………    560        600

Modulus at 100% elongatioin, MPa, approx ………    1.1         1.3

Tear strength, kN/m, approx…………………………………   36          38

Rebound resilience, %, approx…………………………………  45        44

Linear shrinkage, %, approx. ……………………………………  2.3        3.5

1.2 Properties after post-cure for 4 hours at 200℃    

Shore A hardness, approx…………………………………….    45        48

Tensile strength, MPa, approx………………………………    7.2       7.7

Elongation at break, %, approx……………………………     460       490

Modulus at 100% elongatioin, MPa, approx ………     1.2       1.5

Tear strength, kN/m, approx…………………………………    31        37

Compression set (22h/177℃/25%), %, approx………    42        26

Rebound resilience, %, approx………………………………    46       45

Linear shrinkage, %, approx. …………………………………  3.2        3.4

2. Heat stability

2.1 Properties after heat-ageing 10 days at 200°C

Shore A hardness, approx……………………………………     47        54

Tensile strength, MPa, approx………………………………    7.0       7.1

Elongation at break, %, approx………………………………   390      320

Packaging:  HCR 345 U is delivered in 20 kg carton boxes.

Storage and shelf life:  HCR 345 U 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.