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Isonel® 31 SA

Isonel® 31 SA

Isonel® 31 SA is a solvent based isophthalic modified varnish, which has an excellent long-term tank stability. The cured product gives a tough/resilient film with an excellent chemical and moisture resistance. Isonel® 31 SA has a thermal class of 180°C and exhibits compatibility with most types of insulation products and systems. It is ideally suited for processing of transformers, especially where a clean drain characteristic and fast cure is required as well as the impregnation of small stators and coils where flexibility of connection leads has to be maintained. It is designed for use in applications where also high bond strength and good moisture and chemical resistance is required. Polymerization is initiated by the effect of heat and proceeds as a rapid chain-reaction until a three dimensionally cross linked, duro plastic cured material is produced. The product fulfils the directive 2011/65/UE e 2002/95/CE (RoHS). The raw materials of the product are pre-registered according to directive to CE 1907/2006 and s.m.i. (REACH). The product does not contain polycyclic aromatic hydrocarbons and substances listed in the SVHC Candidate List.

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Properties of varnish as supplied
Properties Value Unit
Shelf life at 23°C 24 months
Appearance/colour Liquid/brownish
Density at 23°C, DIN 51757 0,94-0,97 g/cm3
 Content of binder (1g/1h/130°C), ISO 3251 48-50 %
Flow time at 21°C with B4 cup 135-155 sec
Curing condition
Temperature 120 130 140 150 160 º C
Curing Time 6-8 5-7 3-4 h
Mechanical properties in dried condition
Test criterion Condition Value Unit
Bond strength, Elantas test following 61083 method (helical coil) 23 °C
180 °C
> 160
> 80
> 40
Mandrel test ( 3 mm ) Elantas test following 60464-3 23 °C 180 °
Temperature Index
Test criterion Condition Value
Proof voltage Elantas test following IEC 60172 (twisted pair) 1000 V
Bond strength, Elantas test Following IEC 60290 (helical coil) 20 N
Dielectric properties in dried condition
Test criterion Condition Value Unit
Volume resistivity after water immersion Elantas test following IEC 60464 part 2 Initial value
7 d storing
Ω × cm
Volume resistivity at elevated temperature Elantas test following IEC 60464 part 2 155°C
180 °C
Ω × cm
Electrical strength, after water immersion Elantas test following IEC 60464 part 2 Initial value
24 h storing
>120 KV/mm
Electrical strength, at elevated temperature Elantas test following IEC 60464 part 2 155 °C 180 °C > 80
Temperature at relative permittivity tang °= 0,1 Elantas test following IEC 60250 50 Hz
1 KHz
10 KHz
> 140
> 150
> 160
Resistance to chemicals
Test criterion Condition Value Unit
Resistance to vapour of solvents
Elantas test following IEC 60464 part 2
Carbon disulphide
resistant resistant resistant resistant resistant
Water absorption
Elantas test following IEC 62
at 23 °C
0,5 h at 100 °C
< 5
< 10
Resistance to liquids after storing
Elantas test following IEC 175
Ammonia solution 10 %
Acetic acid 5 %
Sodium hydroxide 1%
Hydrochloiric acid 10 %
Sulforic acid 30 %
Transformer oil
BeckFluid 9902
Solution of detergent

Our advice in application technology given verbally, in writing and by testing corresponds to the best of our knowledge and belief, but is intended as information given without obligation, also with respect to any protective rights held by third parties. It does not relieve your own responsibility to check the products for their suitability to the purposes and processes intended. The application usage and processing of the product are beyond our reasonable control and will completely fall into your scope of responsibility. Should there nevertheless be a case of liability from our side, this will be limited to any damage to the value of the merchandise delivered by us. Naturally, we assume responsibility for the unobjectionable quality of our products, as defined in our general terms and condition