Non-stick solutions – an ongoing evolution

By Saint-Gobain

When Saint-Gobain’s CHEMFAB® coated fabrics group was first approached in the early 1990s to assist Formcook from Sweden, a new start-up equipment manufacturer founded by Winje Green, Lars Holmlund and Mijo Kopljar, we didn’t know how this would change our business. Winje Green, the “technical guru”, was well aware of the advantages of Teflon® non-stick frying pans and wanted to incorporate the benefit of needing less oil for the cooking or frying process into continuous cooking machines. His vision was to develop a new generation of contact grilling machines that were based on relatively thin non-stick fabric belts rather than the traditional stainless steel belts and deliver much higher yields than other traditional high temperature cooking equipment such as fryers. Given their concept to cook food between two process conveyor belts at temperatures up to 260°C, they presented us with a clear challenge. To make their machine an attractive “value sell” to major food processors, they needed a durable and robust non-stick conveyor belt material that is easily cleaned. As the conveyor belts in their machines are a replacement part, it is vital that the lifetime of the belt in terms of product output is sufficiently high so that the return on investment is sufficiently high to convince their target customers to switch to this new technology.

With the clear demand from Formcook for non-stick belts, Saint-Gobain first supplied standard PTFE-dip coated belting products as used in many industrial applications as an alternative to the traditional steel mesh conveyor belts. In the contact cooking process there is a sandwich system of two conveyor belts top and bottom. Meat, poultry, fish or other foods are placed on the bottom belt and transported through heated platens operating at temperatures up to 260°C where it is partially or fully cooked. Formcook wanted to minimise energy consumption and get maximum heat transfer through to the surface of the food. Therefore they needed a mechanically robust but flexible belting material that would resist the oils and greases in the cooking environment as well as any additives or sauces that would be used for flavouring. The traditional PTFE-dip coated belting products, while working initially, were losing their non-stick performance in a short period of time and food was sticking to the surface. Also the grease and oils from the food were penetrating through the belting material after a short period in use and necessitating additional machine cleaning. Worst of all, the belts were losing their mechanical strength and needed to be replaced after short periods. As the belts were not achieving the required lifetimes or output levels to make this type of equipment a real winner, the need for an improved belting material was critical. Throughput figures are always process and customer specific but on standard applications such as meatballs, belt lifetimes were often less than 100 tonnes. Our unique solution to this challenge was to combine a non-porous cast PTFE film laminated to a mechanically robust fabric to make a non-stick composite that is highly resistant to the greases and oils involved in typical contact cooking processes and provides a durable and easily cleaned cooking surface with the necessary high temperature capability. Additionally, in order to meet the required processing speeds to be economical, the belting material had to be thin enough to enable high heat transfer to the food being processed. With this new laminated belting fabric, Formcook was able to offer machines with higher productivity and better yields and clearly demonstrate more attractive returns on investment. Throughput figures on a standard application such as the meatballs mentioned above went from 100 tonnes to over 250 tonnes and cleaning time was reduced substantially. Key to maximising the belt lifetime is regular cleaning and these PTFE laminated belts cleaned easier and maintained their non-stick surface for longer thus contributing to a more hygienic working environment.

The development work on designing and manufacturing the optimal belting fabric for the contact cooker machine was to be a major impetus in expanding our range of products to meet the demands of the food processing industry for flexible non-stick solutions. The test work done in cooperation with Formcook and their customers during a 12 month period to verify the real improvements achieved with the laminated product allowed us to gain a much greater understanding of the modes of failure and critical-to-quality requirements for food cooking applications.

Formcook managing director, Mats Olson, can clearly attest to the benefits of these laminated belts versus standard coated materials and that the higher throughput achieved with high quality belts makes it easier to sell their machines. “We have looked at a range of PTFE-fabric coaters but in terms of overall product performance and versatility in covering a wide range of recipes and food products, CHEMFAB® laminated belts still remain today our product of choice when supplying new machines.”

Since that early development period hundreds of contact cookers have been sold to the food processing industry worldwide and the range of food products processed on such machines has expanded significantly from meat, poultry and fish to potato cakes, pancakes, tofu as well as a wide variety of vegetables.

For Saint-Gobain, the focus on food processing applications has continued to gather strength and momentum over the last two decades and it is now our biggest single market sector. During this period, we have expanded the CHEMFAB® Non-stick Solutions range to include cooking sheets, pan and oven liners, grill platen covers, silicone toaster belts, flexible oven trays and baskets as well as a plethora of customised high temperature non-stick belting materials for cooking, steaming and drying of various foods. These flexible non-stick solutions are finding increasing use throughout the food industry where they facilitate higher productivity and healthier prepared foods. We are constantly looking for new opportunities for these materials and supported by our own extensive R&D group, the drive to solve the challenges of other customers remains the cornerstone of our ongoing success.