LE/LH 8214F High quality outdoor epoxy resin for medium& high voltage transformers casting process
LE-8214F/LH-8214F System
on of 2019.10 No:2019108214F
Epoxy resin LE- 8214F 100pbw Formulation
Hardener LH-8214F 100pbw
Filler Silica Flour 250pbw
Color paste LC series * Appropriate pbw
Properties
Two-component epoxy resin system, liquid at room temperature, suitable for vacuum casting process
Lower curing shrinkage, dimensional stability of end product, excellent processing performance and high dielectric and mechanical properties.
Application
Medium and high voltage electrical insulation products
such as dry type transformers, 10-66kV current and voltage transformers etc.
Product Data
| Properties | Unit | Value |
| Appearance | Visual | Light yellow- yellowish liquid |
| Viscosity at 25℃ | mPa.s | 300-600 |
| Density at 25℃ | g/cm3 | 1.17-1.24 |
| Vapor Pressure at 25℃ | Pa | about 0.5 |
| Flash point | ℃ | about 140 |
LE-8214F is a modified BPA type epoxy resin. LH-8214F is a modified carboxylic anhydride liquid Hardener
| Properties | Unit | Value |
| Appearance | Visual | Transparent viscous liquid |
| Viscosity at 25℃ | mPa.s | 7500-12000 |
| Density at 25℃ | g/cm3 | 1.16-1.20 |
| Vapour Pressure at 25℃ | Pa | ﹤0.01 |
| Flash point | ℃ | about 135 |
Epoxy resin LE-8214F and hardener LH-8214F with a certain quantity of filler can be processed by following conditions after fully mixed under vacuum conditions. Process condition
| Processing parameters | Vacuum casting |
| Epoxy resin / hardener mixture temperature | Premix 70°C/2h + final mix 15-30mins |
| Feeding process | 100℃/8h |
| Mold temperature | 105℃/4-6h |
| Gelation time | 80℃/6h+90℃/4h +100℃/2h+120℃/2h |
| Post cure | 130℃×10h |
Page1 of 3 8214F Specification Page1 of 3
Gelation time
Epoxy resin LE- 8214F /Hardener LH-8214F =100/100
| Temperature | Gelation time |
| at 120℃ | 24-40mins |
| at 140℃ | 12-20mins |
| at 160℃ | 6-10mins |
Mechanical and physical properties
Tested system: Epoxy resin LE- 8214F / Hardener LH-8214F/ Filler =100/100/300
conditions:120℃×4hours+140℃×8hours
Note: the following data are tested based on GB standard, and only for customers’ reference, Detailed properties should be tested by in accordance with customers’ actual conditions.
| Properties | Value |
| Thermal conductivity | 0.8-0.9W / mk |
| Thermal decomposition | ＞320℃ |
|
Water absorption (23℃×10days) |
0.10-0.20 % by wt. |
| Water absorption (100℃×60 mins) | 0.08-0.15 % by wt. |
| Surface resistivity | 1014Ω |
| Volume resistivity | 1015Ω.cm |
| Dielectric strength | 30 kV / mm |
| Loss factor | 0.02 |
| Properties | Value |
| Tg(DSC) | 75-95℃ |
| Tensile strength | 65-85N/mm2 |
| Flexural strength | 100-140N/ mm2 |
| Compressive strength | 140-180N/ mm2 |
| Impact strength | 9-16kJ/ m2 |
| Curing shrinkage | 0.8-1.0% |
| Flammability(4mm) | HB Class |
| Flammability(12mm) | HB Class |
Storage
The components have to be stored in tightly sealed and dry original containers in an environment at 6~35℃;. Under these conditions, the shelf life will correspond to the expiration date stated on the label ( normally 12 months). After this date, the product may be reanalyzed to confirm if it validates yet. Partial emptied containers should be closed tightly immediately after use.
Packing
Resin 20kg / barrel or 240kg / barrel or 1200kg / barrel, curing agent 20kg / barrel or 240kg / barrel or 1200kg / barrel
First aid
Contamination of eyes by resin, hardener of casting mix should be treated immediately by flushing with clean,running water for 10 to 15minutes, a doctor should then be consulted.
Material smeared or splashed on the skin should be dabbed off, and the contaminated area then washed and treated with a cleaning cream. A doctor should be on the event of severe imitation of burns. Contaminated clothing should be changed immediately. Anyone taken ill after inhaling vapors should be moved out of doors immediately,in all case of doubt call for medical assistance.
Page 2 of 3 8214F Specification Page 2 of 3
8214F Application process recommendation
1. Preparation of ingredients
1.1 The casting mold should be preheated in the oven at 100-110 ° C for more than 10 hours, and above 4000kva transformer coil shall be given a longer preheating time,
To ensure that the coil is completely dry and its temperature is not less than 80 ° C when installed.
1.2 The silica powder shall be sealed to normal temperature for more than 6 hours in an oven at 110-120 ° C.
2. Ingredients
2.1 Static mixture degassing
2.1.1 Premixing
Material A (epoxy) is based on weight ratio, resin: filler: color paste 100:(125-color paste amount):proper amount, and mixed separately after adding resin, filler and color paste,
The temperature is 65-70 ℃, stirring and degassing for no less than 2 hours, and 100 < p < 200pa.
Material B (curing agent) is based on the weight ratio, curing agent: filler 100:125, mixed separately, temperature is 65-70 ℃, stirring and degassing are not less than 2 hours, 100 < p < 200pa.
2.1.2 Final mixing
Then the components A and B are finally mixed, the accelerator agent is not needed, and put material A and B are mixed in the proportion of 100:100 into (or vacuum suction) final mixing tank, and in order to stir well, we advise put the resin and hardener at same or alternate time
2.1.3 Start stirring after feeding,make sure the the spiral lifter can lift the mixture onto the umbrella degassing hood at its rotate speed
2.1.4 After stirring for 15 minutes, start the vacuum pump for degassing. The vacuum degree shall not be less than 300pa
2.1.5 The mixing degassing time is about 15-30 minutes, and the degassing is completed when there is no bubble on the umbrella surface
3. Casting
3.1 Set the casting tank temperature at 80-85 ℃, preheating shall start 4-5 hours before batching, and to ensure that the temperature of the mold during installation is not less than 80 ° C
3.2 After batching, the dried and preheated mold is pushed into the casting tank for vacuum treatment
3.3 The space temperature of the casting tank is 80-85 ° C, the vacuum degree is not less than 300pa, and the vacuum treatment time is not less than 2 hours
3.4 , The feeding should not be too fast during casting. It can be stopped for 10-15 minutes, and the vacuum can be continued for 20-30 minutes after the material is full. If possible, it can be pressurized by 0.2-0.3mpa after vacuum treatment
3.5 The final mixing casting shall be completed within 90 minutes. Please strictly control the temperature and time to prevent tank solidification. The excess single component resin and curing agent can be stored for several days, but it must be sealed and the temperature should be well controlled
