ARALDITE® CY 228-1 / ARADUR® HY 918-1 / FLEXIBILIZER DY 042 / ACCELERATOR DY 062 / Filler Silica flour

• High mechanical and electrical properties
• Good thermal shock resistance
• Possibility of high filler content

General instructions for preparing liquid resin systems

• Long pot life is desirable in the processing of any 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:

1. better flow properties and reduced tendency to shrinkage
2. lower internal stresses and therefore improved mechanical properties on object
3. improved partial diskharge behavior in high voltage applications.

• For the mixing of medium- to high viscous casting resin systems and for mixing at lower temperatures, we recommend special degassing mixers that may produce additional selfheating of 10-15°C as a result of friction.
• For low viscous casting resin sys-tems, conventional mixers are usually sufficient. In larger plants, the individual components (resin, hardener) are mixed with the respective quantities of fillers and additives under vacuum. Metering pumps then feed these premixes to the final mixer or a continuous mixer. The individual premixes 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 2 to 8 mbar. The vapor pressure of the individual components should be taken into account. In the case of dielectrically highly stressed parts, we recommend checking the quality consistency and predrying of the filler. Their moisture content should be <0.2%.

Specific Instructions

The effective pot-life of the mix is about 1 - 2 days at temperatures 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 installllations have to be cooled and cleaned with the resin component to prevent sedimentation and/or undesired viscosity increase. Interruptions over a week-end (approx. 48h) without cleaning are possible if the pipes are cooled at temperatures below 18°C. Viscosity increase and gel time at various temperatures.

Mold temperature
APG process: 120 - 150°C
Conventional vacuum casting: 80 - 100°C

Demolding times (depending on mold temperature and casting volume)
APG process: 10 - 45 min
Conventional vacuum casting: 1 - 6 h

Cure conditions
APG process (minimal postcure): 5h at 140°C
Conventional vacuum casting: 4h at 80°C + 8h at 140°C

• To determine whether crosslinking has been carried to completion and the final properties are optimal, it is necessary to carry out relevant measurements on the actual object or to measure the glass transition temperature. Different geling and cure cycles in the manufacturing process could lead to a different crosslinking and glass transition temperature respectively

End properties of this system have been tested with silica filler. No flexibilizer is added to produce switch parts, pin insulators and bushings but we recommend to add flexibilizer DY 042 BD (max 20 pbw) for the production of instrument and distribution transformers.

• Automatic pressure gelation process (APG)
• Conventional gravity casting process under vacuum

Fig.4.1: Viscosity increase at 60°C (measurements with Rheomat 115)
(Shear rate D = 10 s-1)

Fig.4.2: Initial viscosity as a function of temperature
(measurements with Rheomat 115, D =10 s⁻¹)

Fig.7.1: Decrease of Flexural Strength (ISO 178, limit: 50%)

Fig.7.2: Temperature Index 194 / 232 (Flexural Strength) (CY 228/ HY 918/ DY 062/ SiO2 : 100 : 85 : 0.8 : 345 pbw)

Determined on standard test specimen at 23°C, Cured for 10h at 140°C

System tested:

Determined on standard test specimen at 23°C
Cured for 10 h at 140°C
System tested:

Fig.6.1: Loss factor (tan δ) and dielectric constant (εr) as a function of temperature (measurement frequency: 50 Hz, IEC 60250) (without Flex)

Fig.6.2: Volume resistivity (ρ) as a function of temperature (measurement voltage: 1000 V, IEC 60093) (without Flex)

Fig.6.3: Loss factor (tan δ) and dielectric constant (εr) as a function of temperature (measurement frequency: 50 Hz, IEC 60250) (Flex. DY 042BD : 17 pbw)

Fig.6.4: Volume resistivity (ρ) as a function of temperature (measurement voltage: 1000 V, IEC 60093) (Flex. DY 042 : 17 pbw)

Contamination of the eyes by resin, hardener or casting mix should be treatedimmediately by flushing with clean, running water for 10 to 15 minutes. A doctor should then be consulted.
Material smeared or splashed on the skinshould be dabbed off, and the contaminated area then washed and treated with a cleansing cream (see above). A doctor should be consulted in the event of severe irritation or burns. Contaminated clothing should be changed immediately.
Anyone taken ill after inhalingvapors should be moved out of doors immediately. In all cases of doubt call for medical assistance.

Store the components in a dry place in tightly sealed original containers. Under these conditions, the shelf life will correspond to the expiry date stated on the label. Partly emptied containers should be tightly closed immediately after use.