The industry that was so firmly rooted in Muscatine could not continue to perpetuity. The 1930s and 1940s brought the end of major factories such as U.S. Button Company and Pennant and the close of over a dozen long-running cutting shops. Early experiments with plastic buttons began in the 1920s. During World War II technological advancements brought better plastic buttons. Touted for their pearl-like qualities, plastic buttons attempted to provide the look of pearl at a fraction of the cost.

The switch from pearl to plastic did not occur over night. In the 1950s and 1960s many Muscatine factories made freshwater pearl, ocean pearl, and plastic buttons simultaneously. Barrys Double Automatic was adapted to finish plastic button blanks.

Weber & Sons Button Company was one of several Muscatine companies to make the switch from pearl to plastic. A number of factors caused the decline of the pearl button industry. Labor expenses, limited availability of shells, foreign competition, changes in fashion, zippers, and the development and refinement of plastics made it impossible for companies to earn a profit from pearl.

J and K Button Company was Muscatines first button factory dedicated entirely to plastic. In 1956 button veteran William Umlandt and his son-in-law Bernard Hahn launched the factory in the old Iowa Pearl Button Company building on Mississippi Drive. William Umlandt started the factory in the old Iowa Pearl building and named the company after his granddaughters Janet and Kay. Umlandt was quoted as saying, Ive always stood up for the pearl button, but Ive got to say, and with great regret, that the plastic button is a better button.

By 1957 the McKee Button Company had entirely phased out pearl buttons. Four generations of McKees have developed innovative products and machinery. Although it employed far fewer workers, McKee Button Company was producing between 60,000 and 100,000 gross of buttons each week in the 1980s. The automated machines used in making plastic buttons replaced the workers needed to handle each pearl button individually. With plastic a few employees were all that was required to oversee the various steps of the machining process.

Polyester in the form of syrup is mixed with a catalyst and shaped into a flat sheet using centrifugal force. A die cuts button blanks from the newly-formed, semi-flexible sheet of plastic. The blanks are automatically fed into machines that carve the design and drill the holes in the button.