Modern transformation technologies in plastics allow the realization of products made by two or more different materials within the same production cycle. Thanks to these technologies, known as 2K technologies, it is possible to use two materials or more with different mechanical and/or functional characteristics that are transformed together to create a single product made by both materials in different areas.
The most common case is a product made of a more rigid part, which typically functions as a load-bearing structure and a soft part with different characteristics that have specific functionalities such as sealing gaskets or friction surface (grip).
Two materials can be transformed with 2K technologies, such as bi-injection or co-extrusion if they are properly chosen or prepared for the purpose. In this case the “union" of these two materials takes place without the need of glues or assemblies of any kind, avoiding assembly processes costs and making the production faster.
Our MARFRAN 2K compounds have excellent adhesion on a wide variety of substrates from polyolefins, such as polypropylene and polyethylene, to engineering plastics such as PC, ABS, PA, PET, SAN and others. The MARFRAN 2K is available in a wide range of Shore A hardnesses.
To evaluate the degree of adhesion between two different materials, Francesco Franceschetti Elastomeri follows the VDI 2019 standard. This procedure involves the molding of a specimen on a bi-injection press that is tractionated to perform the peeling strength measurements. This procedure allows us to provide the customer with scientific data on which to base serious and reliable projects.
As part of the test, the soft component of the specimen is subjected to traction at a constant speed, at an interface angle of 90 ° until the joint between the two materials separates or the softer material breaks. The required force and distance traveled are processed by a dedicated machine set according to ISO 527-1.
The peeling strength is calculated as the ratio between the detachment force in Newton and the sample width in millimeters. The modality of the breaking and/or detachment of the soft material is evaluated visually and classified in the following terms: