Epoxy-PU Adhesive Tape with Continuous Polymer Phase
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current pressure-sensitive adhesive systems for structural bonding face limitations in achieving high epoxy content without compromising tackiness, leading to lower shear strengths and adhesive properties.
Innovation Solution
A pressure-sensitive adhesive tape with a high epoxy content, where the epoxy resin forms a continuous phase with a thermoplastic polyurethane, allowing for high shear strengths and improved adhesive properties post-curing, while maintaining tackiness due to a partially crystalline polyurethane and specific epoxy resin characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy content is increased to achieve higher shear strengths, then bond strength is improved, but tackiness is lost
Solution Approach 1:
The invention uses a composite adhesive system combining epoxy resin with a polymer matrix (polyester, polyurethane, or vinyl aromatic block copolymer). This composite structure allows the epoxy to provide high strength while the polymer matrix maintains tackiness, resolving the contradiction between bond strength and initial adhesion.
Solution Approach 2:
The invention changes the chemical composition parameters by incorporating polymers with specific functional groups (hydroxyl, carboxyl, or vinyl aromatic groups) that can react with epoxy. This parameter modification enables the system to achieve both high epoxy content for strength and polymer-based tackiness for initial bonding.
2Strength
If epoxy resin is used as crosslinking agent at high concentrations, then structural bond strength is achieved, but pressure-sensitive adhesive properties are compromised
Solution Approach 1:
The patent creates a composite where epoxy resin (providing structural strength) is combined with pressure-sensitive polymer matrices. The polymer continuous phase maintains pressure-sensitive adhesive properties while the epoxy provides post-curing structural bond strength, enabling both functions to coexist.
Solution Approach 2:
The polymer matrix acts as an intermediary between the epoxy resin and the substrate. It provides the pressure-sensitive adhesive interface for easy application while the epoxy resin embedded within provides the ultimate structural bond strength after curing.
3Manufacturing precision
If high epoxy content is used to achieve wrinkle- and bubble-free bonding, then bonding quality is improved, but application ease is reduced due to loss of self-adhesive properties
Solution Approach 1:
The composite adhesive combines epoxy resin with polymer matrices that provide self-adhesive properties. This allows the adhesive to be applied easily like pressure-sensitive tapes while the high epoxy content ensures wrinkle- and bubble-free bonding through proper wetting and adhesion.
Solution Approach 2:
The invention modifies the adhesive composition by incorporating polymers with specific glass transition temperatures and molecular weights that maintain tackiness despite high epoxy content, enabling both easy application and high bonding quality.
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 adhesive tape achieves significantly higher shear strengths after curing and maintains pressure-sensitive tackiness, suitable for applications requiring strong and stable bonding, such as in the automotive industry.
Implementation Method 1
the at least one polymer is present as a continuous polymer phase in the uncured state of the pressure-sensitive adhesive... the at least one polymer is a thermoplastic selected from the group of polyurethanes, characterized in that the polyurethane is semi-crystalline and exhibits a melting or crystallization peak in the DSC measurement which corresponds to a fusion enthalpy of at least 25 J/g
Implementation Method 2
The chemical crosslinking of the resins with the elastomers results in very high strengths within the adhesive film... the reactive resin is an epoxy resin... at least one initiator and/or hardener
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an adhesive tape comprising an adhesive mass comprising - at least one polymer - optionally an adhesive resin - at least one reactive resin, wherein the adhesive mass contains at least 104 parts of the at least one reactive resin per 100 parts polymer and adhesive resin - at least one initiator and/or hardener and/or accelerator, wherein the adhesive mass is a pressure-sensitive adhesive mass, wherein the at least one polymer is present as a continuous polymer phase in the uncured state of the pressure-sensitive adhesive mass.