Complex sentence: The Edy's name was added when Dreyer's expanded towards the East Coast in the 1980s to avoid confusion with the Breyers brand which had already established itself on the Eastern Seaboard.
Split into simpler sentences: The Edy's name was added when Dreyer's expanded towards the East Coast in the 1980s. The company decided that the name "Dreyer's" was to similar the Breyers brand which had already established itself on the Eastern Seaboard.