When selecting PBT (Polybutylene Terephthalate) material suitable for optical cable loose tubes, it is necessary to comprehensively consider the material's mechanical properties, thermal stability, processing performance, environmental adaptability, and compatibility with. When selecting PBT (Polybutylene Terephthalate) material suitable for optical cable loose tubes, it is necessary to comprehensively consider the material's mechanical properties, thermal stability, processing performance, environmental adaptability, and compatibility with. Polybutylene terephthalate (PBT) is a highly crystalline engineering plastic. It has excellent processability, stable size, good surface finish, excellent heat resistance, aging resistance and chemical corrosion resistance, so it is extremely versatile. In the communication optical cable industry. Fiber optic cables are designed to provide high-speed, no-signal-loss, and EMI-free communication in telecommunication, powergrid, datacenter, broadband, and industrial applications. These materials are strategically employed to fortify and shield the delicate optical fibers within the cable. FO-VC2 JOINT USE - VERICAL MIDSPAN CLEARANCES 48. APPENDIX A - COVER SHEET / TOC 52. RUS DRAWING. PBT resin is a widely used loose buffer-tube material because it works well across a wider range of conditions. It usually has a wall thickness of 0.