Built on Ingenuity. Driven by Progress.
Plastics Engineering Company (PLENCO) began in 1934 as a family partnership
founded by Frank G. Brotz and his five sons. What started as American Molded
Products in Chicago quickly became a focused pursuit of engineered materials
innovation. Early work concentrated on thermosetting liquid resins used in everyday
molded components, laying the foundation for a company built on precision problem-solving and technical expertise.
Within months, PLENCO relocated to Sheboygan, Wisconsin, where it continues to
operate today. By 1935, the company made a pivotal shift from liquid resins to dry,
granular molding compounds, embracing more scalable and efficient manufacturing
methods. Even in its earliest years, PLENCO demonstrated a defining trait that still
drives it forward: a commitment to continuous improvement that includes adapting,
refining, and advancing materials to meet evolving applications.
Engineering Through Challenge
As global demands intensified in the late 1930s and 1940s, Plastics Engineering
Company focused its efforts on custom molding and precision manufacturing. During
World War II, the company scaled rapidly, supporting U.S. military operations with
critical phenolic components used across Army, Navy, and Air Force applications. From
electrical connectors to specialized training materials, PLENCO’s work contributed to
systems where reliability was non-negotiable.
In the post-war years, material shortages pushed the PLENCO to evolve again. Rather
than wait on limited supply chains, PLENCO re-established resin and compound
manufacturing in 1946, strengthening control over performance and supply. This
decision marked the beginning of PLENCO as not just a manufacturer, but a long-term
partner, developing formulations designed to meet both internal needs and emerging
market demands.
Expanding Capability. Advancing Materials
Through the 1950s and beyond, PLENCO expanded its technical footprint, introducing
new resin systems, including melamine and melamine-phenolic compounds, and
scaling production to meet growing industrial demand. Facility expansions, advanced
warehousing, and dedicated Research and Development (R&D) capabilities positioned
the Company to respond quickly and reliably to customers across increasingly complex
and high-performance applications.
Strategic growth continued into the late 20th century through targeted acquisitions and
technology investments. By integrating established product lines and advancing internal
processes such as phenol recovery, PLENCO strengthened both its technical depth and
commitment to sustainable manufacturing practices. The introduction of bulk molding
compounds (BMC) further expanded its portfolio, enabling high-performance,
lightweight alternatives to traditional materials like steel and aluminum in industries
where strength, efficiency, and reliability are critical
A Legacy That Powers What’s Next
Today, Plastics Engineering Company, known as PLENCO, remains a family-owned
business spanning three generations. From its headquarters in Sheboygan, Wisconsin,
PLENCO engineers and manufactures high-performance thermoset resins, molding
compounds, and molded components that enable critical applications across advanced
industries.
PLENCO operates with a clear purpose: to create materials that shape the future of
innovation. Through continuous investment in technology, close collaboration with
customers to co-develop tailored solutions, and an unwavering commitment to quality,
PLENCO delivers precision-engineered materials designed to help customers meet
today’s demands and lead what comes next.
