Stretchable Adhesive Strip for Residue-Free Removal

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Solution Overview

Problem

Existing strippable pressure-sensitive adhesive tapes often tear when peeled off at angles greater than 45° relative to the bonding plane, making it impossible to remove them without leaving residue or damage, and they lack sufficient shock resistance, which is a concern for mobile devices where space is limited and mechanical stress is high.

Innovation Solution

A pressure-sensitive adhesive strip with a carrier that has an elongation at break of at least 250% and a PSA layer based on solid acrylonitrile-butadiene rubber with 30-130 phr adhesive resin, allowing for easy removal at various angles without tearing and providing improved shock resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If adhesive strips are made thin to reduce space in mobile devices, then space utilization is improved, but susceptibility to tearing increases

Engineering Contradiction:
Improvethickness of adhesive stripVSAvoidsusceptibility to tearing
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The adhesive strip uses a composite structure combining a stretchable carrier (polyurethane or TPE) with a pressure-sensitive adhesive layer based on solid acrylonitrile-butadiene rubber. This composite design allows the thin adhesive layer to gain enhanced mechanical properties from the carrier, particularly elongation at break of at least 250%, which prevents tearing during removal while maintaining minimal thickness for space-constrained mobile devices.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If adhesive strips are removed at angles greater than 45° to achieve clean removal, then residue-free detachment is improved, but susceptibility to tearing increases

Engineering Contradiction:
Improveclean removal capabilityVSAvoidsusceptibility to tearing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention changes the mechanical parameters of the adhesive strip by specifying a carrier with elongation at break of at least 250% and an adhesive layer with specific composition (solid acrylonitrile-butadiene rubber with 30-130 phr adhesive resin). These parameter changes enable the adhesive to withstand the higher stresses encountered during removal at angles greater than 45°, allowing clean residue-free detachment without increasing tearing susceptibility.

Inventive Principle:
Principle #35Parameter changes

3Strength

If adhesive strips are made with high adhesive strength to ensure secure bonding, then bonding strength is improved, but shock resistance decreases

Engineering Contradiction:
Improveadhesive strengthVSAvoidshock resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The adhesive strip incorporates a flexible stretchable carrier with elongation at break of at least 250% that acts as a shock-absorbing element. This flexible carrier maintains strong adhesive bonding through the pressure-sensitive adhesive layer while providing cushioning against mechanical shocks and impacts, thereby improving shock resistance without sacrificing adhesive strength. This is particularly important for mobile devices that experience frequent handling and potential drops.

Inventive Principle:
Principle #30Flexible shells and thin films

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 strip can be removed without residue or damage at angles up to 90° relative to the bonding plane with low susceptibility to tearing, and exhibits enhanced shock resistance and adhesive strength, suitable for mobile devices.

Implementation Method 1

a pressure-sensitive adhesive layer HS1 which is arranged on one of the surfaces of the carrier

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the PSA layer HS1 consists of a PSA which has at least one solid acrylonitrile-butadiene as the base polymer - Rubber contains

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3585852B1Removable pressure-sensitive adhesive strip
Publication Date: 2021.06.30 TESA SE
  • EP3585852B1 patent drawingFigure 1
  • EP3585852B1 patent drawingFigure 2
  • EP3585852B1 patent drawing

AI summary

The invention relates to a pressure-sensitive adhesive strip comprising a carrier and a pressure-sensitive adhesive compound layer HS1 on one of the surfaces of said carrier, wherein (i) the carrier has a breaking elongation of at least 250% in the longitudinal direction and/or transverse direction, particularly in the longitudinal direction and the transverse direction, and (ii) the pressure-sensitive adhesive compound layer HS1 consists of a pressure-sensitive adhesive compound which contains, as the base polymer, at least one solid acrylonitrile-butadiene rubber as well as at least one adhesive resin, wherein the proportion of adhesive resin is in total 30 to 130 phr.