The Development Of The UV-curing Fiber Grating Coating

Fiber grating is one of the most important sensors for optical fiber communication. The fiber coating has none effectively transparent at 248nm when etching the fiber grating by phase mask method, and need to remove the coating and re-coated which is complicate and time-consuming. The fiber grating would be damaged, and affected the strength and the sensitivity. In this paper, the traditional UV- curable optical fiber coatings, based on the redesign of the resin by optimizing the molecular structure and synthesis, synthetic aliphatic urethane acrylate and silicone acrylate two prepolymers, and through the reactive diluent, photoinitiator research agents, and ultimately developed for 248nm UV can effectively through, and excellent overall performance of UV-curable coatings fiber grating.The aliphatic polyurethane acrylate (PUA) is compounded by different diols, IPDI and HEA. And discused the impacts to performance by the routes, compositions, temperature, catalysts, structure type, and molecular weight. The optimal synthes is PTMG-1000,0.05%DBTDL, and the first step temperature is 50 ℃ and 2h, PTMG trickled to IPDI; the second step temperature is 65 ℃,3h. The prepolymer made by synthesis trimer-based when IPDI:PTMG:HEA= 2:1:2.05, and had fast cure rate, mechanical properties,and the transmittance is 59% at 248nm.The polysiloxane acrylates (PSA) is compounded by terminal hydrogen silicone oil and acrylate,with Pt catalyst and hydrosilylation reaction.Get the optimal synthesis through discussion the temperature,catalyst, and the functionality of acrylate,by 65 ℃,6.5h,0.05% polymerization inhibitor,1.8% H% and BDDA. The product has good cure activity, low unsaturation residual, and the transmittance is 87% at 248nm. Photoinitiator has greater impact for the coating by the high absorption at 248nm. By studied the absorption of the photoinitiators and its decompositions,Irgacure 2959 and its decompositions had the lowest absorption at 248nm.Eventually, compounded the UV- curable coatings by the polyurethane acrylate, and the polysiloxane acrylate, and the efficient active diluents, and the photoinitiator which have the lowest absorption at 248nm. The viscosity is 4000-5000cps(25℃), curing speed^80m/min, tensile strength≥10MPa, tensile modulus≥ 100MPa, the transmittance is more than 75% at 248nm by 60μm.