Complex sentence: During the 1950s, companies such as Johnson and Johnson, Kendall, Parke-Davis, Playtex, and Molnlycke entered the disposable diaper market, and in 1956, Procter & Gamble began researching disposable diapers.
Split into simpler sentences: During the 1950s, companies such as Johnson and Johnson, Kendall, Parke-Davis, Playtex, and Molnlycke entered the disposable diaper market. In 1956, Procter & Gamble began researching disposable diapers.