A special material for modified polypropylene loose tube

Abstract

The invention discloses a material special for modified polypropylene loose tubes. The material comprises, by weight, 80-90% of polypropylene, 3-9% of polyethylene, 5-15% of filling materials, 0.3-1% of antioxidant, 1-3% of nucleating agent, 0.1-0.6% of heat stabilizer, 0.1-1% of lubricating agent, 0.1-1% of oil resistant penetrant, and 0.1-1% of anti coagulation agent. As the material special for the optical cable loose tubes, the material is high in hardness and toughness, good in extrusion performance and appropriate in extrusion press; optical fiber extra length is stably controllable; good processing stability can be provided at wide cable outlet speed, and good long-term heat resistance, pressure resistance and oil resistance are provided; molecular structure is modified via material rheological property and crystallization property, so that shrinkage is reduced, the optical fiber extra length is stably controlled; relative to PBT (polybutylece terephthalate), the material is good in hydrolytic stability, needless for drying before being extruded, and is convenient to use and cost-saving.

Description

technical field [0001] The invention relates to the technical field of optical fiber and cable, in particular to a special material for modified polypropylene loose tube. Background technique [0002] In the material selection design of the loose tube, the chemical compatibility and processing performance of the loose tube and other materials (such as optical fiber ointment, UV curing resin on the surface of the optical fiber) are the most important. It can withstand high pressure and high-speed shear during processing, and has low residual stress after forming. The selected polymer has a small dimensional change with temperature changes in processing engineering. Usually we hope that the loose tube material has a low linear expansion coefficient (coefficient of thermal expansion, CTE) to ensure that the internal optical fiber will not change under different ambient temperatures. Stresses due to changes in size of the loose tube. The selected polymer has as little orientat...

AI Technical Summary

Problems solved by technology

The selected polymer has as little orientation effect as possible after being sheared during processing, and has less mold expansion and shrinkage after extrusion at high temperature, because the extrusion shrinkage will make it difficult to control the excess length of the optical fiber, resulting in Increased attenuation

Due to the above reasons, the conventional polyolefin materials polyethylene PE, polypropylene PP, and polystyrene PS cannot meet the requirements. Therefore, in engineering resins, polybutylene glycol methacrylate PBT, polycarbonate PC, nylon 12 (polyamide Nylon-12) has been widely used. These three engineering plastics have high Young's modulus and low linear expansion coefficient CTE (Table 1 shows the main parameters of several materials), but they also have some problems, high cost, high melting point , high melt viscosity, difficult processing and other disadvantages

Specifically: Polybutylene glycol methacrylate (PBT): It is currently the most commonly used material for loose tubes, but it has some inherent shortcomings, such as easy hydrolysis, resulting in a decrease in strength; polycarbonate, poor processing fluidity, easy to Stress cracking and poor wear resistance; polyamide, referred to as nylon, has very good mechanical properties and chemical corrosion resistance, but it is also hydrolyzed under certain conditions, and nylon has strong water absorption. There are large changes in mechanical properties, electrical properties and dimensional stability, and the cost is high