Materials and procedures
To own know-how is more than only formality!
What is the right material for my application?
To answer this question correctly, the exact requirements for the material have to be defined. In which temperature range is the material used? Which mechanical properties and chemical resistance must the material fulfill? Is your application static or dynamic? Are there any standards to be observed? … Only after clarifying these and other questions a suitable material or material mix can be selected. Through our know-how, we can help you with action and advice.
We deliberately buy our elastomer compounds as well as TPE and Thermoplast granules from SPT’s long-standing partners, since only specialized partners work together to develop the best possible solution for the customer.
Elastomers are characterized by their excellent elastic material properties under severe conditions. In a chemico-physical process, we vulcanize moldings according to customer requirements. During vulcanization, the long-chain rubber molecules are crosslinked by sulfur bridges (or peroxides). The rubber moldings resulting from this process have permanent elastic properties compared to the starting product (the compound), which return to their original position when subjected to mechanical stress, have a higher resistance to tearing, elongation and resistance to aging and weathering influences.
Thermoplastics, also called plastomers, are plastics which can be thermoformed within a certain temperature range. This process is reversible, that is to say it can be repeated as often as required by cooling and reheating to the molten state, as long as the so-called thermal decomposition of the material does not occur by overheating. SPT produces plastic clips for secure fastening, inlays for rubber overmolding and covers as well as other small parts to customer specification for the exterior and interior.
Thermoplastic elastomers (TPE) combine the positive properties of plastics for processors and, on the other hand, the elastomers for product developers and designers. In contrast to chemical crosslinking in the elastomers, however, TPE is a physical cross-linking, which is reversible by renewed heat input. During cooling, crosslinking sites form, which connect the elastic blocks to fixed spatial networks. This results in elastic properties which are comparable to elastomers and which, as with thermoplastics, enable repeatable deformation processes. Therefore, they are also flowable and deformable. Since the processing process is basically the same as that of the thermoplastics, there are advantages such as short cycle times, low energy consumption and complete recyclability. However, the TPE material is more expensive than an elastomer and does not permanently offer the material properties of a chemically cross-linked elastomer.
2K parts are produced on injection molding machines with two injection units. In the first step, the hard component (e.g., PP) is injected. By rotating the tool, the second component (e.g., TPS) can be injected directly thereafter. The materials are securely adhered to one another and the finished component can be produced efficiently in a working cycle by short cycle times.
For multi-component parts, we combine elastomer materials with thermoplastics. For this purpose, thermoplastics or plastic parts are inserted into the vulcanisation mold and overmolded with rubber. For example, we combine for the automotive industry the best possible elastic material properties for damping and sealing with high-quality thermoplastic clips for secure and fast fastening to the body on the running line.