Cross-linkable Polyolefin Composition with Dual Silane Groups
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Solution Overview
Problem
Conventional cross-linking of polyolefins using hydrolysable silane groups with strong acid catalysts leads to corrosion issues and unwanted premature cross-linking (scorch) during extrusion, necessitating the development of a composition that can cross-link under milder conditions while maintaining high cross-linking efficiency.
Innovation Solution
A polyolefin composition containing hydrolysable silane groups that form acids or bases upon hydrolysis, allowing for faster and easier cross-linking at room temperature, potentially eliminating the need for strong acid catalysts and minimizing premature cross-linking, with a cross-linking degree of at least 40% after hydrolysis in a water bath at 90 °C for 40 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong acid catalysts are used for cross-linking polyolefins with hydrolysable silane groups, then cross-linking efficiency is improved, but corrosion issues and premature cross-linking (scorch) during extrusion occur
Solution Approach 1:
The invention changes the chemical nature of the catalyst from strong inorganic acid to weak organic acid, fundamentally altering the reaction conditions to achieve cross-linking without corrosion and scorch problems
Solution Approach 2:
The invention uses readily available organic acids (acetic acid, formic acid, citric acid) as catalysts that can be easily handled and disposed of without special corrosion-resistant equipment, replacing expensive and hazardous strong acid catalysts
2Loss of time
If cross-linking is performed quickly at room temperature, then cross-linking time is reduced, but strong acid catalysts are required which cause corrosion and scorch
Solution Approach 1:
The invention changes the catalyst type to weak organic acids that enable rapid cross-linking at room temperature without the harmful effects of strong acids, achieving both speed and safety
3Manufacturing precision
If good mixing of components is achieved in extruder, then homogeneity of end-product is improved, but undesired cross-linking (scorch) occurs due to elevated temperature and pressure
Solution Approach 1:
The invention takes preliminary action by selecting silane groups that do not cross-link under extrusion conditions, preventing scorch before it can occur during the mixing process
Solution Approach 2:
The invention changes the chemical parameters of the silane groups to be stable at extrusion temperatures and pressures, allowing thorough mixing without premature cross-linking
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 achieves efficient cross-linking under milder conditions, reducing scorch during extrusion and maintaining high cross-linking efficiency, with the acid or base formed upon hydrolysis acting as an internal catalyst, thereby minimizing the need for external catalysts and preventing premature cross-linking.
Implementation Method 1
Cross-linking may be performed by condensation of silanol groups contained in the polyolefin which can be obtained by hydrolysation of silane groups
Implementation Method 2
Cross-linking may be performed by condensation of silanol groups contained in the polyolefin
Implementation Method 3
the acid or base formed upon hydrolysis acting as an internal catalyst
Data Source
AI summary
The present invention relates to a polyolefin composition comprising a cross-linkable polyolefin with (A) hydrolysable silane groups which upon hydrolysation form an acid or a base, (B) hydrolysable silane groups different from silane groups (A).