Adhesion through solvents
Materials for medical and pharmaceutical technology have to meet stringent standards for quality and purity. KRAIBURG TPE has developed an extensive portfolio of TPE compounds for this sensitive area of application. The latest development can be processed with a hard component in conformity with medical specifications by using solvents, which completely evaporate after processing.
In about 52% of all medical and pharmaceutical applications from KRAIBURG TPE the Thermoplastic Elastomers are processed in combination with a hard component. These applications require very good adhesion or even a hermetic barrier between the materials. TPE compounds of the THERMOLAST® M portfolio from KRAIBURG TPE can be processed economically with polypropylene (PP), acrylonitrile butadiene styrene (ABS) copolymer or polycarbonate (PC) using the 2-component injection molding process. However, specially developed compounds from KRAIBURG TPE can also be processed together with hard components by using solvents, which allows their use as 2-component products in medical and pharmaceutical applications.
Polarity is not an issue
Polarity plays a key role in the adhesive binding of multiple materials. Plastics, which are processed together by means of 2-component injection molding or insertion must have a similar polarity. To work around this issue, KRAIBURG TPE has developed medical compliant TPE compounds that can adhere to hard components with other polarities through the use of solvents. Geometric conditions also play a role in this process.
Adhesion through solvents
The use of solvents is a special processing method in the plastics industry. Different types of solvents, such as cyclohexane or tetrahydrofurane (THF), dissolve the plastic and therefore change the consistency of the materials. By immersing negative profiles in dissolved TPE it is possible to manufacture hollow bodies, such as gloves, from Thermoplastic Elastomers. In addition, textile fabric can be partially or fully impregnated with TPE. It is also possible to bind hard components, such as PP, PE or PC/ABS with a partially dissolved TPE compound.
These processing methods allow stress-free processing of the Thermoplastic Elastomers, resulting in outstanding mechanical properties. As opposed to the use of adhesives, processing with solvents leaves no chemical residue. The solvents used evaporate completely to create a clean bond. After processing, the components can be sterilized with gamma and beta radiation and also through EtO.
Extensive medical certifications and service
The new compounds developed for processing with solvents are an important addition to the KRAIBURG TPE portfolio, which includes five market-oriented series for medical and pharmaceutical applications. As with all THERMOLAST® M compounds the specially developed compounds are likewise certified to ISO10993-5 (cytotoxicity) and the Drug Master File. Selected compounds of each series are also tested in accordance with USP Class VI (chapter 88), USP 661 (in vitro), ISO 10993-4 (hemolysis, indirect blood contact), ISO10993-10 (intracutaneous irritation) and ISO 10993-11 (acute system toxicity). These extensive certifications allow use of the compounds in direct contact with blood and medications. The certifications are supplemented by the KRAIBURG TPE service package, which guarantees maximum quality, safety and reliability also for the newly developed compounds.