Moisture-Curable Polyethylene Composition for Rapid Ambient Crosslinking
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Solution Overview
Problem
Current moisture-curable polyethylene formulations face challenges in achieving rapid curing and high ultimate crosslinking under ambient conditions, which limits their application in wire and cable applications where high throughput and low hot creep performance are required.
Innovation Solution
A moisture-curable polyethylene formulation comprising a (hydrolyzable silyl group)-functional polyethylene copolymer and a condensation cure catalyst, optimized through specific molar ratios, molecular mass dispersity, and process conditions, enabling rapid curing and high crosslinking even at ambient temperatures and in hot water baths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional moisture-curable polyethylene formulations are used, then curing can occur under ambient conditions, but the curing rate is slow and ultimate crosslinking is insufficient
Solution Approach 1:
The patent changes the chemical parameters of the formulation by incorporating specific catalysts (tin-based catalysts at 0.01-5 wt% and/or sulfonic acid catalysts at 0.01-5 wt%) and controlling the hydrolyzable silyl group content (0.1-5 mol%). These parameter changes enable the formulation to achieve both rapid curing under ambient conditions and high ultimate crosslinking extent, resolving the contradiction between curing rate and crosslinking quality.
Solution Approach 2:
The patent creates a composite moisture-curable formulation that combines polyethylene copolymer with hydrolyzable silyl groups, condensation cure catalysts, and optional additives. This composite material system allows simultaneous achievement of rapid ambient curing and high ultimate crosslinking by leveraging the synergistic effects of different components, particularly the dual-catalyst system that accelerates both initial curing and final crosslinking.
2Adaptability or versatility
If non-crosslinkable polymers are incorporated to modify properties, then formulation versatility increases, but hot creep performance deteriorates
Solution Approach 1:
The patent maintains hot creep performance despite incorporating non-crosslinkable polymers by precisely controlling the crosslinking density through catalyst concentration and hydrolyzable silyl group content. The parameter optimization ensures that sufficient crosslinks are formed to maintain dimensional stability at high temperatures, even when non-crosslinkable polymers are present at 5-50 wt%.
Solution Approach 2:
The patent applies local quality by ensuring that the crosslinked network is distributed throughout the formulation to provide localized reinforcement. The hydrolyzable silyl groups on the polyethylene copolymer chains create crosslinks at critical locations, maintaining structural integrity and hot creep resistance even in regions where non-crosslinkable polymers are present.
3Productivity
If curing is accelerated under ambient conditions, then manufacturing throughput increases, but the extent of ultimate crosslinking is reduced
Solution Approach 1:
The patent employs preliminary action by using the condensation cure catalyst to initiate and accelerate the crosslinking reaction under ambient conditions, creating an initial crosslinked network quickly. This preliminary crosslinking achieves rapid curing for manufacturing throughput, while the formulation is designed to continue crosslinking to completion, achieving high ultimate crosslinking extent without requiring extreme conditions.
Solution Approach 2:
The patent ensures continuity of the crosslinking action by designing a formulation that maintains reactivity throughout the curing process. The hydrolyzable silyl groups and condensation catalyst system remain active from ambient curing through any subsequent hot water bath treatment, allowing the crosslinking reaction to continue progressively and achieve both rapid initial curing and complete ultimate crosslinking.
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 formulation achieves rapid moisture curing and high ultimate crosslinking, allowing for the incorporation of non-crosslinkable polymers without compromising hot creep performance, thus enhancing manufacturing throughput and suitability for cable applications.
Implementation Method 1
a (hydrolyzable silyl group)-functional polyethylene copolymer
Implementation Method 2
a condensation cure catalyst
Implementation Method 3
a condensation cure catalyst
Data Source
AI summary
A moisture-curable polyethylene formulation comprising a (hydrolyzable silyl group)-functional polyethylene copolymer and a condensation cure catalyst. The formulation is designed to be rapidly moisture curable under ambient conditions. Also methods of making and using same; cured polymer products made therefrom; and articles containing or made from same.