First, in the physical realm, the following relationships are typical:
– The weight of an alicyclic epoxy resin is less than 70% of the weight of porcelain, which means that epoxy insulators are much lighter than porcelain insulators.
– The coefficient of thermal expansion of epoxy is 1/20th that of porcelain.
– The tensile strength of epoxy resin is about 11 times that of glazed porcelain.
– The compressive strength of epoxy resin is 4-6 times that of glazed porcelain.
– The flexural strength of epoxy resin is 16 to 18 times that of glazed porcelain.
– Epoxy resin Impact strength, without chipping, is approximately the same as glazed porcelain.
– Epoxies are easier to control in size and shape than porcelain.
– While epoxy has limited repairability, porcelain is not repairable.
In the electrical field, you will find:
– The dielectric constant of epoxy is only about two-thirds that of porcelain.
– Porcelain has a much higher temperature rating than ring, but ring compounds with a temperature rating of 105 C or 130 C are readily available.
– Epoxy resins are slightly less resistant to electrical traces than porcelain.
– The water absorption of epoxy is slightly greater than porcelain, but still in the range of 2/10 of 1%.
Finally, epoxy resins exhibit excellent resistance to common industrial chemicals, are easy to clean, and have excellent erosion and weathering resistance.
In conclusion, we believe that the excellent physical properties of epoxy resins make them the insulating material of choice, albeit with some small sacrifices in electrical performance. This is particularly true for applications requiring high strength under severe dynamic loads, such as support insulators in circuit breakers and switchgear.
Epoxy resins have excellent insulating properties, and APG pressure gel technology has greatly improved the quality and performance of the products, and the problems with epoxy insulators are more obvious.
There are many protective measures needed for the handling of epoxy resins, protective clothing, gloves, windscreen/safety glasses, masks/dust masks are recommended . Spills are disposed of by sucking them off with sawdust or waste cotton wool and placing them in plastic woven baskets.
Ventilation:Ventilate the workshop 3 to 5 times per hour.
When eyes are stained with resin, hardener or castables, flush immediately with clean, running water for 10 to 15 minutes. See a doctor. Wipe off any material that has been stained or splashed on the skin, then wash the contaminated area with running water. See a doctor if there is severe pain or burns. Change dirty clothes immediately. If you feel unwell due to inhaling vapours, move outside immediately. If in doubt, seek medical help immediately.
The epoxy resin manufacturing process is energy intensive and the production process is heated at high temperatures and for long periods of time.
Production process, mould temperature APG process: 130 – 160°C, conventional vacuum casting 70 – 100°C
Demoulding time (depending on mould temperature and pouring volume), APG process: 10 – 40 min, conventional vacuum casting 5 – 8h
Curing conditions, APG process (min. curing time) 4h 130°C or 3h
140°C, conventional vacuum casting: 12h 130°C or 8h 140°C.
Waste is difficult to dismantle and dispose of
Cured thermoset plastics are not considered hazardous waste and can be disposed of in landfills. In fact, more than 90 per cent of this type of waste is disposed of in this way. However, the massive increase in waste materials, coupled with the limited space available to dispose of these wastes, has led to the need for more advanced and sustainable technologies to reuse these materials.
Thermoset reuse of these wastes is not economically attractive as a building material. Epoxy resin materials are widely used which means that various metal parts (cores, windings) must be removed from the interior before reuse. Some companies use cryogenic treatment of epoxy parts containing metal inserts, but the quality of the recovered material is poor.
The use of engineering plastics thermoplastic materials offers high productivity, low energy consumption and the same properties as epoxy resins.