ELASTOSIL RT 772 - Wacker Chemie - White Goods

General purpose sealing and potting grade
Typical fields of application: household appliances, automotive, mechanical engineering, electrical industry.

Processing

Mixing and curing:

ELASTOSIL® RT 772 is processed in combination with a curing agent, such as WACKER® Catalyst T 77 or WACKER® Catalyst T 77 PLUS. Prior to application the two compounds should be thoroughly mixed, either manually or by automatic metering lines equipped with static or dynamic mixing devices.
The recommended mixing ratio is 10:1 by weight. Potlife and curing speed can be modified within limits by adjusting the ratio of base compound (ELASTOSIL® RT 772) to curing agent (WACKER® Catalyst T 77 or WACKER® Catalyst T 77 PLUS).
Varying the mixing ratio between 8:1 and 12:1 usually has a small effect on the properties of the cured rubber. However, if the mixing ratio differs substantially from the recommended scope, preliminary tests should be carried out to check the cured material’s suitability.
General information about pot life and resulting curing times are given in the respective tables "Catalyzed". Moreover curing speed can be slightly accelerated by raising the temperature. Heating, however, must not exceed 60 °C before curing is completed.
After completion of the vulcanization process the product may continuously be exposed to constantly changing climatic conditions, UV radiation and very high temperature without damage. Cured ELASTOSIL® RT 772 usually shows good primerless adhesion to many substrates, e.g. glass, ceramics, metals, plastics and powder coatings.

Removal:
If removal of the silicone from machines or dispensing equipment is necessary, white spirit or similar nonpolar solvents are recommended. However, cleaning ideally should take place before the silicone is fully vulcanized. Cured silicone needs to be removed mechanically, if necessary in combination with a swelling agent (solvent).

Properties

Flame Rating

UL 94 HB

Typical Properties


	Value	Units	Test Method / Conditions
Recommended Service Temperature	-50 to +230	°C	-

Catalyst Properties


	Value	Units	Test Method / Conditions
Pot Life (Mixed with WACKER Catalyst T 77, 10:1, at 23°C)	10 - 15	minutes	DIN EN ISO 3219
Pot Life (Mixed with WACKER Catalyst T 77 PLUS, 10:1, at 23°C)	5 - 8	minutes	DIN EN ISO 3219
Pot Life (Mixed with WACKER Catalyst T 77, 12:1, at 23°C)	15 - 20	minutes	DIN EN ISO 3219
Pot Life (Mixed with WACKER Catalyst T 77 PLUS, 12:1, at 23°C)	8 - 10	minutes	DIN EN ISO 3219
Pot Life (Mixed with WACKER Catalyst T 77 PLUS, 8:1, at 23°C)	3 - 5	minutes	DIN EN ISO 3219
Pot Life (Mixed with WACKER Catalyst T 77, 8:1, at 23°C)	5 - 10	minutes	DIN EN ISO 3219
Tack-Free Time (Mixed with WACKER Catalyst T 77 PLUS, 10:1, at 23°C)	approx. 45	minutes	-
Tack-Free Time (Mixed with WACKER Catalyst T 77, 10:1, at 23°C)	approx. 90	minutes	-
Tack-Free Time (Mixed with WACKER Catalyst T 77 PLUS, 12:1, at 23°C)	75	minutes	-
Tack-Free Time (Mixed with WACKER Catalyst T 77, 12:1, at 23°C)	approx. 120	minutes	-
Tack-Free Time (Mixed with WACKER Catalyst T 77 PLUS, 8:1, at 23°C)	approx. 35	minutes	-
Tack-Free Time (Mixed with WACKER Catalyst T 77, 8:1, at 23°C)	approx. 60	minutes	-
Viscosity (of the mixture (10: 1), Mixed with WACKER Catalyst T 77, at 25°C, Shear rate 0.5 s⁻¹)	approx. 25000	mPa·s	DIN EN ISO 3219
Viscosity (of the mixture (10: 1), Mixed with WACKER Catalyst T 77 PLUS, at 25°C, Shear rate 0.5 s⁻¹)	approx. 25000	mPa·s	DIN EN ISO 3219
Viscosity (of the mixture (10: 1), Mixed with WACKER Catalyst T 77, at 25°C, Shear rate 25 s⁻¹)	approx. 15000	mPa·s	DIN EN ISO 3219
Viscosity (of the mixture (10: 1), Mixed with WACKER Catalyst T 77 PLUS, at 25°C, Shear rate 25 s⁻¹)	approx. 15000	mPa·s	DIN EN ISO 3219

Cured Properties


	Value	Units	Test Method / Conditions
Density (in water, at 23°C)	1.23	g/cm³	DIN EN ISO 1183-1 A
Elongation (at break)	130	%	ISO 37 Type 1
Shore Hardness A	32	-	DIN ISO 48-4
Tear Strength	3.8	N/mm	ASTM D 624 B
Tensile Strength	2	N/mm²	ISO 37 Type 1

Uncured Properties


	Value	Units	Test Method / Conditions
Density (at 23°C)	1.28	g/cm³	DIN EN ISO 2811-2
Dynamic Viscosity	20000	mPa·s	Brookfield

Properties

Uncured:

High extrusion rate
Flowable
Medium to fast curing at room temperature
To be cured with WACKER® Catalyst T 77 or WACKER® Catalyst T 77 PLUS (recommended mixing ratio: 10:1).

Cured:

Medium hardness
Primerless adhesion to many substrates (glass, ceramics, metals, plastics and powder coatings).
Outstanding heat resistance
recommended service temperature range: -50 °C to +230 °C
UL 94 HB listed (when cured with WACKER® Catalyst T 77).

Note

Cured with WACKER Catalyst T 77 or WACKER Catalyst T 77 PLUS, mixing ratio 10:1 (by weight). Curing Conditions: 14 days at 23 °C and 50 % rel. humidity, 2 mm sheet, no post-curing for cured properties.

Safety & Health

Safety Note: While curing ELASTOSIL® RT 772 releases a total of approx. 1.5 - 2 wt.% alcohol. These vapors should not be inhaled for long periods or in high concentrations. Hence ventilation of the work place is recommended.