Volatile Components of SARCON® series

1.Volatile Components of Silicone Materials

The volatile materials from silicone elastomers generally include low-molecular siloxane, moisture and cross-linker.
It is very difficult to measure the volume of the moisture or the cross-linker because their amounts in Silicone are too low to be measured. Therefore, we only show the content of low-molecular siloxane.
All silicone elastomers contain some low-molecular siloxane such as D4~D20 (see Fig-1), whose contents are dependent upon each specific manufacturing process or raw materials being used.

*An electrical contact failure is, in most cases, caused by a high content of the D13 or lower.
*The clouding effect of glass or mirror surface is, in most cases, caused by a high content of siloxane which is greater than D13.

We usually post-cure the product, or use volatility-controlled raw material to reduce low-molecular siloxane to a sufficiently low level.
SARCON® series is made of the volatility-controlled silicone elastomers.

2.Effect of Low Volatile Siloxane
In the 1980’s, there was an electrical defect problem when a motor and a silicone rubber were in closed space or semi closed space. After the investigation, it was found that silica was generated around the electrical contact part due to sparking, and then an electrical defect was caused.
The volatile components of siloxane are cracked by the spark on the motor then the silica is generated.

3.Contents of the Low-molecular Siloxane in SARCON® GR • XR series (D4~D20 by wt %)
[Table-1: Typical measurement value]

Dn (wt %)
D 4~20 Total
RTV *1 (General type)RTV (C.V. type) *2SARCON® XR-mSARCON® XR-Um
0.2~1.20.01~0.060.00100.0010
SARCON® GR80ASARCON® GR-aeSARCON® GR-SdSARCON® GR25A
0.00100.00100.00110.0028
SARCON® GR-PmSARCON® GR14ASARCON® GR45ASARCON® EGR-11F
0.00310.00340.00460.0071
SARCON® GR-dSARCON® PG80ASARCON® PG25ASARCON® XR-v
0.00990.01580.01600.1000
*1: RTV: Room Temperature Vulcanizing silicone rubber *2: C.V.: Controlled Volatility type

3.Contents of the Low-molecular Siloxane in SARCON® GR • XR series (D4~D20 by wt %)
[Table-2: Typical measurement value]

Dn (wt %)
D 4~20 Total
SARCON® SPG-20ASARCON® SPG-20BSARCON® SPG-30BSARCON® SPG-50A
0.00260.00100.00100.0043

Test method: Gas Chromatographic Analysis by the extraction, Solvent
• Analytical instrument: GC-14
• Column: DB-1701 (30 m x 0.53 mm I.D)
• Column Temp: 50 °C(122°F) / 2 min hold → 300°C(572°F) / rate of increase = 10°C(50°F)/min
• Detector: FID (Flame Ionization Detector)
• Injection Temp: 50 °C(122°F)/30sec → 270°C(518°F)
• Syringe Volumes: 2μL
• Detection limits: 0.0010wt%