Curable Adhesive with Block Copolymer for Diecuttability
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Solution Overview
Problem
Existing curable adhesives face challenges in achieving a balance between high cohesion and good processability, particularly in terms of diecuttability and peel adhesion, especially on rough surfaces.
Innovation Solution
The use of (meth)acrylate block copolymers with a specific structure A-B-A, where the A blocks have a glass transition temperature of 50° C. or more and the B blocks have a lower glass transition temperature, combined with polymerizable compounds, to achieve optimal cohesion and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high mass fraction of reactive resin is used to ensure sufficient curing, then the curability is achieved, but the viscosity becomes too low and processing properties deteriorate
Solution Approach 1:
The patent uses a composite adhesive system combining a polymerizable compound (reactive resin) with a specific polymer additive. This composite approach allows the adhesive to maintain both high curability through the reactive resin and improved processing properties through the polymer additive, which provides structural integrity and prevents excessive flow during application.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the adhesive by introducing a polymer additive that changes the viscosity and rheological properties of the formulation. This parameter change enables the adhesive to maintain appropriate consistency for processing while still allowing sufficient curing when exposed to initiators.
2Ease of operation
If the viscosity is reduced to improve flow-on behavior, then the adhesion to rough surfaces improves, but the cohesion of the adhesive deteriorates
Solution Approach 1:
The adhesive composite combines a polymerizable compound with a specific polymer additive that provides cohesive strength. The polymer additive forms a network structure within the adhesive, maintaining cohesion even when the base formulation has low viscosity for improved flow-on behavior on rough substrates.
Solution Approach 2:
The polymer additive acts as an intermediary substance that mediates between the conflicting requirements of low viscosity for flow-on behavior and high cohesion for structural integrity. It provides the necessary mechanical strength while allowing the reactive resin to flow adequately during application.
3Strength
If the adhesive is made more cohesive to prevent residue, then the peel adhesion improves, but the diecuttability deteriorates
Solution Approach 1:
The patent uses a polymer additive that changes the rheological parameters of the adhesive, providing sufficient cohesion for peel adhesion while maintaining appropriate flow characteristics for diecutting. The additive modifies the adhesive's response to mechanical stress during both curing and processing operations.
Solution Approach 2:
The polymer additive creates localized structural reinforcement within the adhesive formulation, providing cohesion where needed for peel strength while allowing the overall adhesive to remain sufficiently fluid for diecutting operations. The additive distributes uniformly but provides targeted mechanical support.
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
This approach results in curable adhesive compounds with excellent cohesion, diecuttability, and peel adhesion, even on rough surfaces, while maintaining good shock resistance and handling properties.
Implementation Method 1
the A blocks independently of each other are a poly(meth)acrylate having a glass transition temperature Tg of 50° C. or more
Implementation Method 2
the A blocks independently of each other are a poly(meth)acrylate having a glass transition temperature Tg of 50° C. or more
Implementation Method 3
can be cured by external influences, by initiating the polymerization in the curable adhesive and thereby increasing the degree of crosslinking
Implementation Method 4
initiating the polymerization in the curable adhesive and thereby increasing the degree of crosslinking
Implementation Method 5
joining using an adhesive, i.e. joining using an adhesive
Implementation Method 6
insufficient cohesion in the curable adhesive
Data Source
AI summary
The invention relates to a curable adhesive substance comprising the following, in relation to the mass of the curable adhesive substance: a) one or more (meth)acrylate block copolymers X with an A-B-A structure in a combined mass fraction of 20% or more, wherein the A blocks independently represent a poly(meth)acrylate with a glass transition temperature Tg of 50° C. or more, which can be produced by polymerising an A monomer composition formed of A monomers, wherein the B block represents a poly(meth)acrylate with a glass transition temperature Tg of less than 50° C., which can be produced by polymerising a B monomer composition formed of B monomers; and b) one or more polymerisable compounds Y in a combined mass fraction of 20% or more, and wherein, for the polar fractions (weighted by substance amount) of the Hansen solubility parameters <δp>: i) of the monomer units in the A blocks <δp>(A) derived from A monomers, ii) of the monomer units in the B block <δp>(B) derived from B monomers, and iii) of the polymerisable compounds Y <δp>(Y), the following is true: −|<δp>(A)−<δp>(Y)|>3.5 MPa0.5, and −|<δp>(B)−<δp>(Y)|<3.5 MPa0.5.