Autoclavable PBT GL Screw Cap for Laboratory Applications
The GL screw cap is manufactured from reinforced red polybutylene terephthalate (PBT) and is designed to close bottles, containers, tubes, fittings and other laboratory components with a compatible GL thread. It is available in different sizes, making it suitable for both laboratory containers and custom-made glass assemblies and equipment.
GL14 and GL18 threads are commonly used on small containers, tubes, vials, dropper bottles and components intended for handling or storing small volumes.
GL25 and GL32 sizes are frequently found on medium-sized bottles, tubes and fittings used for reagents, samples, culture media and other laboratory preparations.
The GL45 thread is widely used on laboratory bottles and containers, as well as in transfer systems, safety closures, multi-port fittings and assemblies for liquids or gases.
The cap can also be used to close prefabricated borosilicate glass tubes with GL threads intended for glassworking, sealing and the manufacture of custom glass assemblies or laboratory equipment. It can be used to seal threaded ends, branches, chambers, reservoirs, reaction vessels and other auxiliary fittings during operation, assembly, maintenance, transport or storage.
The closure incorporates a PTFE-coated silicone gasket. The silicone provides elasticity and allows the gasket to conform to the container rim or sealing surface, while the PTFE face provides a contact surface with high chemical resistance. This combination promotes effective sealing and helps reduce leakage, evaporation, ingress of contaminants and direct contact between the contents and the PBT.
PBT offers greater thermal resistance than the polypropylene commonly used in standard closures. The complete closure can withstand temperatures of up to 180 °C under dry-heat conditions and is suitable for steam autoclave sterilisation at 121 °C or 134 °C, depending on the cycle and operating conditions.
The combination of PBT, silicone and PTFE provides good resistance to numerous compatible reagents, solutions, chemicals and solvents. The closure is therefore suitable for the storage, preparation, processing and transfer of samples, reagents, culture media, liquids and gases, as well as for chemical, biological, pharmaceutical and research applications.
The ribbed outer surface improves grip and enables safe opening and closing, even when wearing gloves. The appropriate model should be selected according to the GL thread size of the corresponding container, tube or component.
Before use, the chemical and thermal compatibility of the PBT and the PTFE-coated silicone gasket with the intended substance and process must be verified. Concentration, temperature, pressure, contact time and the specific sterilisation conditions must be taken into account.
