Cartonstrong is strong in quality, service and responsibility towards the environment


New plant in Grezzago (MI), new Fosber corrugator, state-of-the-art warehouse with underfloor heating, new cogeneration system with gas turbine: this is Cartonstrong, which produces exclusively corrugated cardboard sheets for customers in Italy and is part of Pro-Gest Group since 2009

Mirco Bottero, responsabile tecnico e Fabio Colleoni, responsabile di stabilimento
Mirco Bottero, responsabile tecnico e Fabio Colleoni, responsabile di stabilimento

Cartonstrong, which started the business in 1948 in Monza, is a historical reality in the corrugated cardboard packaging sector and after various changes of ownership, it became part of Pro-Gest Group in 2009. Cartonstrong machinery, which has always been a point of reference in the corrugated cardboard market in Lombardy and in the North in general, needed technological renewal and the owners could modernize the old plant or conceive a new one in another place.

“We could only choose the second option, so we bought 100,000 square metres of land, facing the motorway, where a 51,000 square metres warehouse was built, 23,000 of which are occupied by the production area and the storage of paper reels, while the remaining spaces are dedicated to the warehouse of sheets ready for shipment; after a phase in which we produced both in Monza and here in Grezzago (MI), also to give continuity to the supply of sheets to customers, in March 2021 we transferred all the production activity, and since then we have never stopped”, explains Mirco Bottero, technical manager.

quadro di comando ondulatore

In Grezzago production takes place continuously on three shifts seven days a week, just like in a paper mill, after all the plant has been designed to guarantee this type of operation, thus avoiding switching on and off which would cause waste, in favor instead of a continuity of work to guarantee service and quality for customers. It is a real example of technology and avant-garde, unique in the corrugated cardboard sector. Today in Grezzago they have the capacity to produce 250 million square meters a year, which represents a good part of the total product of Pro-Gest, which produces 850 million.

State-of-the-art production technology

The focus on quality has always been fundamental for Cartonstrong and therefore when it came to purchasing the new corrugator the choice was almost obvious: the latest generation S Line 420 model by Fosber, an over 130 m long machine, whose declared maximum speed is 400 m/min. World record almost reached by the Cartonstrong staff last winter for which the company also received an award directly from Fosber. “A result of which the company is proud, and I want to thank all the operators who have obtained it, with their constant commitment to give their best in their work, because we are convinced that all the 80 people who work here are a precious resource and therefore a pillar of our success”, underlines Mirco.


This plant is equipped with the best technologies that allow total control of the processes. But the real distinctive feature of Cartonstrong is the warehouse for the finished product characterized by underfloor heating which guarantees that the quality of the corrugated cardboard produced does not undergo any alterations. When the cardboard sheets leave the corrugator, their temperature is in fact around 60-70° C. An environment that is too cold is often the cause of non-compliant cardboard that is difficult to work with. The decision to invest in a finished product warehouse with heated floor was made precisely in consideration of being able to avoid thermal shock and to manage a controlled lowering of the temperature to keep the performance of the cardboard sheets stable. This greater attention will allow the converting plants to use a better quality product to build their boxes which will be more robust and long-lasting in the logic of serving the final customers in the best possible way.


The Cartonstrong headquarters are located in a strategic point, a few meters from the entrance to the Trezzo sull’Adda motorway exit, a project designed to create a functional plant with a production flow divided linearly between the raw material warehouse, corrugator, finished product and logistics. The future of Cartonstrong is very clear for Fabio Colleoni, recently named plant manager, with previous experience in the plastics sector, “I immediately felt involved in the activity of this company, for me this sector was a discovery and realizing how much technology hides behind a cardboard box immediately fascinated me, besides my function is particularly demanding because I represent the property. It is my intention to fully implement all the aspects in which so much has been invested, that is machinery, performances, service and product quality and naturally support the people who work here, leading them to always give their best, precisely for this reason in this period we are investing heavily in internal and external training by making the operators grow professionally to  concretize completely the project implemented here in Grezzago”.

cartonstrongThe advantages of being part of an integrated group

When the corrugator was started, the paper market was already under pressure as regards the supply of raw materials, anyway Cartonstrong was able to cope with the difficulties also thanks to the paper coming from the group’s paper mills.

“It is useless to deny that the past year has been complex for the whole sector, with the staggering increases in the costs of raw materials and energy. We have faced the moment trying to protect our customers as much as possible, not only in terms of price but also in terms of service and quality”, concludes Mirco.