The 1960s and 1970s
By the 1960s, the perception of cartoons as children's entertainment was entrenched in the public consciousness. Animation began to disappear from movie theaters; while Disney continued to produce animated features after losing its founder, MGM and Warner Bros closed their studios, outsourced their animation, and got out of it entirely by the end of the decade. The majority of American animation came to be dominated by limited animation made for TV and aimed primarily at children. However, there were a number of attempts to challenge this perception during the 1960s and 1970s with ambitious (and often controversial) animated projects that were definitely not for children.
Read more about this topic: Animation In The United States In The Television Era