Radiation-Curable Urethane (Meth)acrylate for Optical Fiber Coatings
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Solution Overview
Problem
Existing radiation curable compositions for optical fiber primary coating layers struggle to balance flexibility and mechanical strength, leading to potential optical losses when pressure is applied.
Innovation Solution
A radiation curable composition comprising urethane (meth)acrylate formed by reacting a polyether diol with a number average molecular weight of 2,000 to 5,000, a diisocyanate compound, a hydroxyl group-containing (meth)acrylate compound, and a diol with a molecular weight of 500 or less, along with a (meth)acrylate compound and a radiation polymerization initiator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the primary coating layer is made flexible to suppress micro-bending loss, then optical performance is improved, but mechanical strength becomes insufficient
Solution Approach 1:
The patent uses a composite resin composition containing multiple components: a polyol compound (provides flexibility), a diisocyanate compound (provides strength), and a (meth)acrylate compound (provides crosslinking and mechanical properties). This composite approach allows the coating layer to simultaneously achieve low Young's modulus for flexibility and high tear strength for mechanical durability, resolving the contradiction between flexibility and strength.
2Stability of the object's composition
If a polyol compound with low molecular weight is used to improve flexibility, then Young's modulus decreases, but mechanical strength deteriorates
Solution Approach 1:
The patent specifies precise molecular weight ranges for the polyol compound (2,000-5,000) and controls the NCO group to polyol compound ratio (0.2-0.8) to optimize the balance between flexibility and strength. By carefully adjusting these parameters, the coating achieves a Young's modulus of 0.01-1 MPa while maintaining tear strength of 0.03-0.3 mN, resolving the trade-off between low Young's modulus and high tear strength.
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 composition forms a cured product with excellent flexibility and sufficient mechanical strength, reducing optical losses and enhancing the performance of optical fiber coatings.
Implementation Method 1
a radiation curable composition for forming an optical fiber primary coating layer containing: (A) a urethane (meth)acrylate... (B) a (meth)acrylate compound... (C) a radiation polymerization initiator
Data Source
AI summary
[Problem] The present invention provides a radiation curable composition for forming an optical fiber primary coating layer capable of forming a cured product having excellent flexibility and sufficient mechanical strength. [Solution] The present invention relates to a radiation curable composition for forming an optical fiber primary coating layer comprising (A) a urethane (meth)acrylate obtained by reacting at least (a) a polyether diol having a number average molecular weight of 2,000 to 5,000, (b) a diisocyanate compound, (c) a hydroxyl group-containing (meth)acrylate compound, and (d) a diol having a molecular weight of 500 or less, (B) a (meth)acrylate compound other than the component (A), and (C) a radiation polymerization initiator.