Nowadays, various polymers other than TPE are available on the market to be overmoulded directly onto metals, ensuring effective chemical adhesion. However, these are often rigid non-elastomeric materials.
Consequently, Franplast decided to explore the development of TPEs capable of ensuring reliable chemical adhesion on the most common metals, particularly iron and steel. This approach allows the end customer to obtain multi-component products without requiring a separate assembly process.
Franplast has embarked on this path while also carefully considering the need to maintain food contact compliance of the materials. This latter aspect is particularly crucial in the production of knives for domestic and professional use, where a solid adhesion to the blade is essential to ensure operator safety.
Optimising adhesion on stainless steel
After examining materials, discarding unsuitable options and testing samples for strength and adhesion on a smaller scale, the most promising solutions were tested on a larger scale and evaluated by customers for feedback on quality and suitability for the production process.
Newly developed formulations have proven highly effective in adhering to stainless steel. In this regard, a study was conducted to optimise the cost of the compound. Chemical adhesion on stainless steel showed very satisfactory values over a wide range of hardnesses (from Shore A 70 to Shore D 50), while a material with Shore D 45 hardness is currently being tested by a customer.
