Based on a responsible use of plastic, our "fit-for-purpose" principle aims to ensure an optimal solution. At the same time, we focus on functionality and the environmental perspective in a collaboration with you. For Proplast, plastic is a valuable resource with unique properties and endless possibilities.

When plastic is used and recycled correctly, sustainable solutions can be created with a focus on recycling and circular processes.

We guide you to a responsible use of plastic with reliable consultancy that forms the foundation for durable solutions and focuses on your need for documentation on the journey towards increased recycling and a circular economy.

That is why we are Proplast.

Proplast's values


To make a difference, our employees go the extra mile to advise you in the best and most competent manner. We welcome you with credibility and responsibility, our core values.

We believe that credibility stems from a host of premier qualities: honesty, experience, competence, and commitment, and in our dialogue with you we aim to display these qualities.

Through an open and fact-based conversation, we strive for that credibility.

Similarly, responsibility has many sides to it. We focus, however, primarily on responsibility towards you and for the climate.

Through our consultancy, we want to support your decisions in a sustainable direction, which can be both value-creating and good for the climate.

We take responsibility for ensuring optimal recycling from our production and collect and recycle our waste as a matter of course.

Finally, we take responsibility for the safety and well-being of our employees. We believe that high safety standards and a focus on well-being at the workplace are prerequisite for development and quality.

Consistency is crucial to us; what we say is what we do.

That is why we are Proplast with a green O.

Our story

In 2021, Peter Rosenkrands took over ownership of the former family-owned plastics manufacturer, Knudsen Extrusion, in Præstø, south of Copenhagen. With the new management, an ambitious mission was conceived to guide customers to a more responsible use of plastic. Thus, a new name was needed: Proplast.

Proplast draws on experience and competences that go back to 1959, when Palle Knudsen founded a production of plastic hoses for pneumatics in the old gas works in Præstø. The buildings still form the framework for the company, which remains a niche manufacturer with quality and innovation at the forefront. The company grew steadily over the years, until Christian Knudsen took over the management as the second generation in 1990. Investments were continuously made in new and more modern means of production, and new products entered the range.

In 2007, Peter Rosenkrands became director of the company, and he initiated several new projects with a focus on optimizing quality and productivity.

The company was soon after certified with ISO9001, and production was optimized with LEAN tools.

Since then, public attention has been directed at the green transition and a more efficient use of resources. In this regard, the company increased its focus on trustworthy consultancy as a core competency that ensures that products are tailormade and have a high longevity. The company's buildings have been energy renovated in several stages, and the employees are conscious of resource consumption in production as well as in the office space.

This resource awareness in the company was decisive for the new name of the company, which was coined at the same time as its ISO 14001 certification in 2023. Plastic is a strong, durable, and flexible material that can be used for numerous solutions. Plastic helps to reduce the industries’ consumption of other materials, and in the coming years, recycling and the circular economy will make plastic an even more competitive material. That is why we are Proplast.

© PROPLAST A/S - Former Knudsen Extrusion ApS