ARALDITE® CW 5859 ET / ARADUR® HW 5859 ET

• Low co-efficient of thermal expansion
• Excellent mechanical properties

Insulators, Switchgear parts, Bushing and apparatus components

General instructions for preparing liquid resin systems
Long pot life is desirable in the processing of any ARALDITE® casting resin system.
Mix all of the components together very thoroughly at room temperature or slightly above and under vacuum. Intensive wetting of the filler is extremely important. Proper mixing will result in:

• Better flow properties and reduced tendency to shrinkage
• Lower internal stresses and therefore improved mechanical properties on object
• Improved partial discharge behaviour in high voltage applications.

For the mixing of medium to high viscous ARALDITE® casting resin systems and for mixing at lower temperatures, we recommend special thin film degassing mixers that may produce additional self-heating of 10-15 K as a result of friction. For low viscous ARALDITE® casting resin systems, conventional anchor mixers are usually sufficient. The prefilled ARALDITE® resin and ARADUR® hardener can be stored at elevated temperature (about 60°C) for up to about 1 week, de-pending on formulation. Intermittent agitation during storage is advisable to prevent filler sedimentation. Mixing time can vary from 0.5 to 3 hours, depending on mixing temperature, quantity, mixing equipment and the particular application. The required vacuum is 0.5 to 8 mbar. The vapour pressure of the individual components should be taken into account.

Fig.4.3: Geltime measured in function of temperature
(measurement with Gelnorm Instrument)

Note: Silica grades and quality can influence the processing data such as initial mixed viscosity...etc.

The effective pot-life is about 2 days at temperature below 25°C. Conventional batch mixers should be cleaned once a week or at the end of work. For longer interruptions of work, the pipes of the mixing and metering installations have to be clooled and cleaned to prevent sedimentation and/or undesired viscosity increase. Interruptions over a weekend (approx. 48h) without cleaning are possible if the pipes are cooled at temperature below 18°C.
Viscosity increase and gel time at various temperatures, refer to Figs: 4.1 to 4.3.

Mould temperature
APG process : 140 - 160°C
Conventional vacuum casting : 70 - 100°C
Demoulding times (depending on mould temperature and casting volume)
APG process : 10 - 40 min
Conventional vacuum casting : 5 - 8 h
Cure conditions
APG process 12h at 150°C
Conventional vacuum casting 16h at 150°C

To determine whether crosslinking has been carried to completion and the final proper- ties are optimal, it is necessary to carry out relevant measurements on the actual object or to measure the glass transition temperature. Different gel and postcuring cycles in the manufacturing process could influence the crosslinking and the glass transition temperature respectively.

Fig.4.1: Viscosity increase at 60°C, 80°C and 100 °C
(measurements with Rheomat 115, D = 10 S^-1)

Fig.4.2: Initial viscosity in function of temperature
(measurements with Rheomat 115, D=10S^-1)

System tested:
Araldite® CW 5859 ET CI / Aradur® HW 5859 ET CI
Mix ratio: 100 / 110 pbw
Cured for 10 h at 80°C + 16 h at 150°C

Fig.6.1: Loss factor (tan d) and dielectric constant (εr) as a function of temperature
(measurement frequency: 50 Hz)
(IEC 60250)

Fig.6.2: Volume resistivity (ρ) as a function of temperature
(measurement voltage: 1000 V)
(IEC 60093)

System tested:
Araldite® CW 5859 ET CI / Aradur® HW 5859 ET CI
Mix ratio: 100 / 110 pbw
Cured for 10 h at 80°C + 16 h at 150°C

The components have to be stored in tightly sealed and dry original containers according to the storage conditions on the product label. Under these conditions, the shelf life will correspond to the expiry date stated on the label. Partly emptied containers should be closed tightly immediately after use.