Ethylene Multi-Block Copolymer Release Agent for Adhesive Storage Stability
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Solution Overview
Problem
Existing release agents, such as siliconized release papers and polyethylene films, face challenges with high adhesion forces and low melting points, making them unsuitable for prolonged storage with acrylate and rubber adhesives, especially at elevated temperatures, and requiring additional processing steps.
Innovation Solution
A release agent based on ethylene multi-block copolymer with hard and soft segment blocks, produced through chain-shuttling polymerization, offering a high melting point and adjustable release force, suitable for use in adhesive tapes to maintain low adhesion even after prolonged storage at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If siliconized release papers are used, then release effect is achieved, but silicon transfer to surfaces occurs and additional coating and crosslinking steps are required
Solution Approach 1:
The invention extracts the release function from complex siliconized coatings and transfers it to a simple polyolefin functional layer that can be coextruded during film production, eliminating the need for separate coating and crosslinking steps while maintaining reliable release performance
Solution Approach 2:
The polyolefin functional layer integrates the release function directly into the film structure through coextrusion, making the film self-sufficient for release purposes without requiring additional processing steps or external coatings
2Force
If low-density polyethylene is used as release film, then release force is reduced, but melting point decreases causing blocking at elevated temperatures
Solution Approach 1:
The invention changes the density parameter of the polyethylene from low-density (0.915-0.935 g/cm³) to medium-density (0.920-0.940 g/cm³), which maintains adequate release force while significantly improving the melting point to prevent blocking at elevated temperatures up to 80°C
Solution Approach 2:
The invention introduces a functional layer with specific local properties (medium-density polyethylene with controlled thickness) that provides both release functionality and thermal stability, creating a differentiated structure within the film
3Force
If linear polyethylene with density 0.865-0.900 g/cm³ is used, then release force is maximized, but only selected acrylate adhesives can be used and strong adhesives exceed acceptable release forces
Solution Approach 1:
The invention adjusts the density parameter to 0.920-0.940 g/cm³ and controls the polydispersity index to be at least 5.0, creating a balanced release force that is compatible with both weak and strong acrylate adhesives as well as rubber adhesives, significantly expanding adhesive compatibility
4Force
If polyethylene release film is used with acrylate adhesives, then initial release is acceptable, but after prolonged storage the release forces become too high
Solution Approach 1:
The invention changes the density from low-density polyethylene to medium-density polyethylene (0.920-0.940 g/cm³) and controls polydispersity (≥5.0), which maintains stable release forces over prolonged storage periods at elevated temperatures without the adhesion forces becoming excessively high
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 ethylene multi-block copolymer release agent effectively reduces adhesion forces and maintains performance over time, even at temperatures up to 80°C, making it suitable for use with acrylate and silicone adhesives, while eliminating the need for siliconization and reducing processing steps.
Implementation Method 1
Release agents are solids or liquids which lower the forces of adhesion between two adjacent surfaces (for example moulding/mould), in other words prevent them from sticking
Data Source
AI summary
Release agent more particularly for an adhesive with an ethylene multi-block copolymer, the ethylene multi-block copolymer being composed of hard segment blocks, comprising at least 95% (w/w) ethylene and a comonomer, and of soft segment blocks, comprising ethylene and a comonomer, the fraction of comonomer in the soft segment blocks being between 10 and 20 mol %, and the fraction of the hard segment blocks in the ethylene multi-block copolymer being not more than 45% (w/w).