1868, to be precise. American inventor John W. Hyatt patented a process that produced a product he called “celluloid” (not what later would eventually become movie film) which he used as a replacement for ivory in billiard balls and piano keys, among other things. Although an Englishman had produced something similar at an earlier date, Hyatt’s celluloid is considered the first commercially viable plastic. Just four years later, in 1872, he became the first to inject hot celluloid into a mold using the world’s first injection molding machine that used a plunger to inject plastic through a heated cylinder and into a mold. Some of the first products created using celluloid included collar stays, buttons and plastic personal care products, such as hair combs.
POST WORLD WAR II AND MASS PRODUCTION
The original injection molding process patented by Hyatt remained relatively unchanged until after World War II, when US consumers created a huge demand for inexpensive, mass-produced products after the scarcity of the war years. James Hendry built the first screw injection molding machine and revolutionized the plastics industry. Almost overnight, all kinds of plastic products were possible that had been inconceivable before, including colored plastics, in a seemingly endless variety of shapes. Even today, approximately 95% of all molding machines now use screws to efficiently heat, mix and inject plastics into molds.
BAKELITE: THE FIRST COMPLETELY SYNTHETIC PLASTIC
“Bakelite”, the first ever plastic made from a synthetic polymer — molecules not found in nature — was created by Leo Hendrik Baekeland, a Belgian who had immigrated to New York State. After several years of experimentation in an effort to create a smoother, more uniformly high-quality plastic, he finally succeeded in 1912 and named it after himself (albeit spelled phonetically so Americans could pronounce it correctly.) His phenol-based plastics are no longer used very often, having been replaced by cheaper and less brittle plastics, but the material is still used today in applications that benefit from their insulating and heat-resistant qualities.
From producing billiard balls and piano keys in the 19th century, to producing space-age aircraft, automotive and electronic plastic parts in the 21st century, plastic injection molding has become one of the most prevalent manufacturing processes ever conceived.