Adhesive Layer Radiation Gelation Gap Filling

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Solution Overview

Problem

Film or sheet type adhesives require processing steps to tailor their shape and application, leading to material loss and restrictions in shape flexibility, while existing adhesives struggle to maintain adhesive force and fill gaps between members effectively.

Innovation Solution

A method using a liquid composition with a thermosetting resin, hardener, radiation-polymerizable and heat-curable compounds, and thermally expanding capsules, which is semi-solidified by radiation and then heated to expand and solidify, forming an adhesive layer with excellent adhesive properties that can fill gaps between members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If film or sheet type adhesive is used, then handling and storage stability are improved, but processing steps are required to tailor shape and transfer to adherent surface, causing material loss and shape restrictions

Engineering Contradiction:
Improvestorage stabilityVSAvoidmaterial loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The adhesive composition undergoes parameter changes through radiation-induced polymerization, transitioning from a liquid state that can be applied freely to a gel state with improved handling stability. This allows the adhesive to be applied without pre-formed films or sheets, eliminating material loss during shape tailoring while achieving storage stability through the gelation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical system of pre-formed film handling and shape tailoring with a chemical/physical system where radiation induces polymerization to create the desired shape in place. This substitution eliminates the need for mechanical processing steps that cause material loss.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If film or sheet type adhesive is used, then handling and storage stability are improved, but processing steps are required, leading to loss of time

Engineering Contradiction:
Improvestorage stabilityVSAvoidprocessing time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent replaces time-consuming mechanical processing steps (cutting, shaping, transferring films) with a rapid radiation-induced polymerization process. The adhesive is applied in liquid form and quickly gels upon radiation exposure, dramatically reducing processing time while maintaining storage stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The radiation-induced polymerization creates a continuous process where application and gelation occur in sequence without interruption. The adhesive remains in a workable liquid state during application, then continuously transforms to a stable gel state, eliminating the discontinuous steps required for film handling and shaping.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If adhesive is applied to fill gaps between members, then bonding reliability is improved, but adhesive force may be insufficient with conventional adhesives

Engineering Contradiction:
Improvebonding reliabilityVSAvoidadhesive force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs a composite adhesive system combining a thermosetting resin base with radiation-polymerizable components. This composite structure provides both the gap-filling capability of a liquid adhesive and the high strength of a crosslinked polymer network, achieving superior bonding reliability and adhesive force simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The adhesive undergoes parameter changes through radiation-induced polymerization and subsequent thermal curing, transforming from a low-viscosity liquid that fills gaps to a high-strength crosslinked network. This dual-stage parameter change ensures both gap-filling capability and high adhesive force.

Inventive Principle:
Principle #35Parameter changes

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 method allows for mass production of adhesive-backed members with excellent adhesive properties, ensuring high reliability in bonding gaps between members by expanding during heating, and provides a simplified process with no material loss or shape restrictions.

Implementation Method 1

a first radiation-polymerizable compound having a radiation-polymerizable functional group and a heat-curable functional group, a second polymerizable compound having a radiation-polymerizable functional group

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

thermally expanding capsule; the step of joining the first member and the second member by heating to expand and solidify the semi-solidified adhesive layer

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

a thermosetting resin not having a radiation-polymerizable functional group; the step of joining the first member and the second member by heating to expand and solidify the semi-solidified adhesive layer

Methodology Applied
Scientific EffectThermal curing: Heat Treatment

Data Source

PatentEP3071611B1Adhesive, adhesive-backed member, and method for connecting between members
Publication Date: 2021.03.31 3M INNOVATIVE PROPERTIES CO
  • EP3071611B1 patent drawingFigure 1A~1C
  • EP3071611B1 patent drawingFigure 2~3
  • EP3071611B1 patent drawingFigure 4~5

AI summary

A method for joining between members, the method comprisint: forming an adhesive layer by applying onto a first member surface a liquid composition containing a thermosetting resin not having a radiation-polymerizable functional group, a hardener, a first polymerizable compound having a radiation-polymerizable functional group and a heat-curable functional group, a second polymerizable compound having a radiation-polymerizable functional group and not having a heat-curable functional group, and a thermally expanding capsule; semi-solidifying the adhesive layer by irradiating radiation onto the adhesive layer; disposing a second member above the semi-solidified adhesive layer so as to oppose the first member surface; and joining the first member and the second member by heating to expand and solidify the semi-solidified adhesive layer.