EPDM Rubber Adhesive Blend for High-Temperature Residue-Free Removal
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Solution Overview
Problem
Current pressure-sensitive adhesive tapes based on natural rubber face challenges with temperature resistance and residue-free removal, as they are susceptible to aging and show residue issues at lower temperatures due to crosslinking complications.
Innovation Solution
A pressure-sensitive adhesive tape using a blend of solid EPDM rubbers with varying Mooney viscosities, eliminating the need for crosslinking, which enhances shear force and adhesive strength, allowing for residue-free removal up to 180°C without leaving ghosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural rubber is used for pressure-sensitive adhesive tapes, then good removable properties are achieved, but temperature resistance deteriorates due to susceptibility to aging
Solution Approach 1:
The patent changes the chemical composition parameters by switching from natural rubber to EPDM rubber with specific molecular weight distribution (Mw/Mn ratio) and saturation level. This parameter change eliminates the double bonds that cause aging while maintaining the rubber's elastic properties and adhesive performance at elevated temperatures up to 180°C.
Solution Approach 2:
The patent uses a composite approach by combining EPDM rubber with specific adhesive resins and plasticizers in optimized proportions. This composite formulation enhances both the temperature resistance and removable properties, achieving a balance where the adhesive maintains strength at high temperatures while allowing clean removal without residue.
2Temperature
If crosslinking is applied to natural rubber-based PSAs, then temperature resistance improves, but residue issues occur at lower temperatures
Solution Approach 1:
The patent extracts the crosslinking step from the formulation process, achieving temperature resistance through the inherent molecular structure of EPDM rubber (saturation and molecular weight distribution) rather than through crosslinking. This eliminates the source of residue problems while maintaining high-temperature performance.
Solution Approach 2:
The patent changes the chemical structure parameters by using saturated EPDM rubber with controlled molecular weight distribution instead of crosslinked natural rubber. This parameter change provides temperature resistance through the stable saturated backbone while avoiding the residue issues associated with crosslinking at lower temperatures.
3Strength
If EPDM rubber with high molecular weight is used, then adhesive strength improves, but processing difficulty increases due to crosslinking requirements
Solution Approach 1:
The patent optimizes the molecular weight parameters of EPDM rubber, specifically using rubber with a Mw/Mn ratio between 1.1 and 1.5. This parameter optimization provides sufficient adhesive strength while maintaining processability, as the controlled molecular weight distribution prevents premature crosslinking during extrusion and coating operations.
Solution Approach 2:
The patent eliminates the need for complex crosslinking processes and extended processing times by using EPDM rubber with optimized molecular weight. This simplifies the manufacturing process, allowing for faster production cycles and easier processing without sacrificing adhesive performance.
4Strength
If adhesive resin and plasticizers are added to EPDM rubber, then adhesive strength improves, but residue and ghosting increase
Solution Approach 1:
The patent optimizes the concentration and type parameters of adhesive resins and plasticizers, using specific combinations that enhance adhesive strength while minimizing residue. The saturated EPDM matrix provides a stable foundation that prevents the formation of ghosting, even with the addition of these components.
Data Source
AI summary
An adhesive compound based on solid EPDM rubber, wherein the adhesive compound contains, in addition to plasticizers and adhesive resin, a blend of at least two solid EPDM rubbers, the blend comprising 10 to 30 wt.% of at least one first EPDM rubber with a Mooney viscosity of at least 83 (ML 1+8 150°C) and 20 to 50 wt.% of at least one second EPDM rubber with a Mooney viscosity in the range of 65 to 85 (ML 1+4 125°C), exhibits good adhesive strength and shear strength even without crosslinking and can still be removed without residue even after a temperature treatment of up to 180°C.