Conductive Threadlike Adhesive for Narrow Bonding Regions

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Solution Overview

Problem

Existing pressure-sensitive adhesive composites, such as those described in Patent Literature 1, suffer from insufficient adhesion force due to non-adhesive areas covered by conductive linear members, compromising conductivity and adhesion.

Innovation Solution

A threadlike pressure-sensitive adhesive body comprising a conductive core material with multiple filaments coated by a pressure-sensitive adhesive, achieving a resistance value of 1.0 × 10⁶ Ω/100 mm or less in the Z-axis direction, with a compression ratio of 13% or more, and utilizing a metal-coated fiber and surfactant-containing adhesive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive linear member is provided on the surface of the pressure-sensitive adhesive body, then conductivity in the longitudinal direction and circumferential direction is improved, but the adhesion force deteriorates due to non-adhesive areas

Engineering Contradiction:
ImproveconductivityVSAvoidadhesion force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent transitions from a planar adhesive structure to a three-dimensional threadlike structure by causing the core material to protrude from the pressure-sensitive adhesive body. This dimensional change allows the conductive function to be achieved through the protruding thread structure itself rather than through surface-mounted conductive members that would block adhesive contact.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The core material serving as a threadlike structure performs multiple functions simultaneously: it provides conductivity through its inherent conductive properties, maintains structural integrity, and enables the pressure-sensitive adhesive to bond surfaces while the thread protrudes to ensure continuous conductive contact without compromising adhesion.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If the bonding region is narrowed for miniaturization or design purposes, then the device size is reduced, but the adhesion force and conductivity may deteriorate

Engineering Contradiction:
Improvedevice sizeVSAvoidadhesion force
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent applies different properties to different parts of the bonding system: the pressure-sensitive adhesive provides bonding capability in the narrowed region, while the protruding conductive core material provides localized conductivity at critical contact points. This local differentiation allows narrow bonding regions to maintain both adhesion and conductivity functions.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the bonding region has a complex bent shape, then adaptability to article shapes is improved, but manufacturing precision and conductivity uniformity deteriorate

Engineering Contradiction:
Improveshape adaptabilityVSAvoidconductivity uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The threadlike core material is designed to protrude from the pressure-sensitive adhesive body, creating a dynamic contact mechanism. When the bonded articles are pressed together, the protruding threads flex and conform to the contact interface, maintaining conductive pathways even in bent or complex shapes. This dynamic adaptation occurs during the bonding process itself.

Inventive Principle:
Principle #15Dynamics

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 threadlike adhesive body achieves excellent conductivity and high adhesion force, suitable for bonding in complex and narrow regions, with improved deformation and stress dispersion for enhanced bonding strength.

Implementation Method 1

a pressure-sensitive adhesive covering a surface of the core material in a longitudinal direction

Methodology Applied
Scientific EffectPressure-sensitive adhesive: Adhesive

Implementation Method 2

a conductive core material including a plurality of filaments... a resistance value of the threadlike pressure-sensitive adhesive body in a Z-axis direction is 1.0 × 10⁶ Ω/100 mm or less

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the pressure-sensitive adhesive may contain a surfactant

Methodology Applied
Scientific EffectSurfactant: Surfactant

Data Source

PatentEP4692269A1Threadlike adhesive body
Publication Date: 2026.02.11 NITTO DENKO CORP
  • EP4692269A1 patent drawingFigure 1~2(b)
  • EP4692269A1 patent drawingFigure 3(a)~3(b)
  • EP4692269A1 patent drawing

AI summary

Provided is a threadlike pressure-sensitive adhesive body including: a conductive core material including a plurality of filaments; and a pressure-sensitive adhesive covering a surface of the core material in a longitudinal direction, in which a resistance value of the threadlike pressure-sensitive adhesive body in a Z-axis direction is 1.0 × 106 [Ω/100 mm] or less. The resistance value of the threadlike pressure-sensitive adhesive body in the Z-axis direction is measured 30 minutes after two copper foil plates are bonded via the threadlike pressure-sensitive adhesive body and are pressure-bonded at a pressure of 0.35 MPa for 10 seconds. Here, the Z-axis direction is a direction in which a pressure is applied to the threadlike pressure-sensitive adhesive body when the two copper foil plates are pressure-bonded via the threadlike pressure-sensitive adhesive body. The measurement is performed at 23°C.