One-End-Capped Oligomer Primary Coating for Optical Fiber
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Solution Overview
Problem
Optical fibers face challenges in maintaining resistance to lateral pressure while avoiding void generation in the primary coating layer, which leads to increased low-temperature transmission loss due to the irreversible breakage of polymer chains and subsequent void formation when the molecular weight of oligomers is increased to decrease Young's modulus.
Innovation Solution
A curable resin composition for the primary coating layer containing a one-end-capped oligomer in an amount of 30% or larger, which forms pseudo crosslinking through entanglement or electrical bonding, inhibiting void generation and maintaining a low Young's modulus, thereby enhancing resistance to lateral pressure and reducing low-temperature transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the molecular weight of the oligomer is increased to decrease the Young's modulus of the primary coating, then the resistance to lateral pressure is improved, but the toughness of the primary coating is decreased and voids are generated
Solution Approach 1:
The invention changes the chemical structure parameter of the oligomer from conventional both-ends-reactive types to one-end-capped types. This structural parameter change allows the resin to achieve low Young's modulus (≤0.7 MPa) while maintaining high toughness and preventing void formation, as the one-end-capped structure provides flexibility without the irreversible chain breakage associated with high molecular weight both-ends-reactive oligomers
Solution Approach 2:
The invention creates a composite resin system combining one-end-capped oligomers with specific monomers (containing carboxyl, hydroxyl, or amino groups) and crosslinking agents. This composite material approach achieves optimal balance between low Young's modulus, high toughness, and void prevention through synergistic interactions between different components
2Strength
If the Young's modulus of the primary coating is decreased to improve resistance to lateral pressure, then the resistance to lateral pressure is improved, but low-temperature transmission loss deteriorates due to void generation
Solution Approach 1:
The invention changes the oligomer structure to one-end-capped types, which fundamentally alters the curing behavior and network formation of the resin. This parameter change enables the coating to maintain low Young's modulus while preventing void formation, thereby eliminating the source of low-temperature transmission loss deterioration
Solution Approach 2:
The invention converts the potential harm of low Young's modulus (which typically leads to void formation and transmission loss) into a benefit by using one-end-capped oligomers. The unique structure of these oligomers allows the resin to achieve both low modulus and void-free curing, transforming what was previously a harmful effect into a desirable property
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of a one-end-capped oligomer in the resin composition effectively prevents void formation in the primary coating layer, ensuring high resistance to lateral pressure and maintaining low-temperature transmission loss, as demonstrated by the optical fibers' ability to withstand tension without rupturing and maintain signal integrity at varying temperatures.
Implementation Method 1
a primary resin coating layer which covers the periphery of the glass fiber, wherein the primary resin coating layer is a layer formed by curing a curable resin composition which includes one or more oligomers, one or more monomers, and a reaction initiator
Data Source
AI summary
A process for producing an optical fiber including a glass fiber, a primary resin coating layer which covers the periphery of the glass fiber, and a secondary resin coating layer which covers the periphery of the primary resin coating layer, wherein the primary resin coating layer is formed by curing a curable resin composition which includes one or more oligomers, one or more monomers, and a reaction initiator, the curable resin composition containing a one-end-capped oligomer in an amount of 30% by mass or larger based on all the oligomers. The optical fiber produced by this production process does not deteriorate in low-temperature transmission loss, because the primary resin coating layer is inhibited from generating voids even when having a low Young's modulus.