Multi-Arm Vinyl Aromatic Block Copolymer Adhesive for Low-Energy Surfaces

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Solution Overview

Problem

Pressure-sensitive adhesives face challenges in achieving strong and immediate adhesion to low-energy and superhydrophobic surfaces, such as new types of painted automotive surfaces, with existing adhesives taking hours or days to build up strength and experiencing issues with dimensional stability across varying temperatures.

Innovation Solution

A pressure-sensitive adhesive composition incorporating a multi-arm vinyl aromatic block copolymer, adhesive resins, and crosslinking aids, specifically using styrene block copolymers and phenolic-modified aromatic hydrocarbon resins, which are chemically crosslinked with electron beam radicals to enhance adhesion, cohesion, and temperature resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If polyacrylate-based pressure-sensitive adhesive layers are used, then the adhesive is soft and elastic at low temperatures, but adhesion to low-energy surfaces is insufficient and bond strength builds up slowly over hours or days

Engineering Contradiction:
Improvesoftness and elasticity at low temperaturesVSAvoidadhesion to low-energy surfaces and bond strength development speed
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite adhesive system combining polyacrylate polymer with synthetic rubber (polybutadiene or styrene-butadiene rubber) and adhesive resins. This composite formulation achieves both low-temperature flexibility from the polyacrylate and immediate strong adhesion to low-energy surfaces from the synthetic rubber component, resolving the contradiction between softness and adhesion performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the adhesive by incorporating specific ratios of polyacrylate (30-70 wt%), synthetic rubber (10-50 wt%), and adhesive resins (10-40 wt%). This parameter optimization enables the adhesive to maintain elasticity at low temperatures while achieving rapid bond strength development on superhydrophobic and low-energy surfaces

Inventive Principle:
Principle #35Parameter changes

2Reliability

If synthetic rubber-based pressure-sensitive adhesive layers are used, then adhesion to non-polar surfaces is good, but dimensional stability at room temperature and above deteriorates

Engineering Contradiction:
Improveadhesion to non-polar surfacesVSAvoiddimensional stability at room temperature and above
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent creates a composite system where synthetic rubber (10-50 wt%) provides adhesion to non-polar surfaces through its chemical structure, while polyacrylate polymer (30-70 wt%) and crosslinking agents provide dimensional stability at elevated temperatures. The synergistic interaction between these components resolves the contradiction between adhesion and dimensional stability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces purely mechanical adhesion with chemical crosslinking mechanisms. By incorporating crosslinking agents (5-20 wt%) that form chemical bonds with the synthetic rubber and polyacrylate chains, the adhesive achieves both strong adhesion to non-polar surfaces and enhanced dimensional stability, substituting physical entanglement with covalent bonding

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

3Ease of operation

If viscoelastic foam backing is formulated to be very soft, then elasticity at temperatures below -18°C is maintained, but plasticity at room temperature increases and dimensional stability deteriorates

Engineering Contradiction:
Improveelasticity at low temperaturesVSAvoiddimensional stability at room temperature
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent optimizes the glass transition temperature (Tg) parameters of the foam backing material through selective polymer blending. By adjusting the ratio of polyacrylate to synthetic rubber and incorporating specific plasticizers, the foam maintains elasticity below -18°C while limiting plasticity at room temperature, achieving dimensional stability without sacrificing low-temperature flexibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent ensures continuous useful action of the foam backing across a wide temperature range by designing a polymer system that maintains its viscoelastic properties from -40°C to +80°C. The crosslinked network structure provides continuous structural support, preventing both excessive softness at low temperatures and brittleness at high temperatures

Inventive Principle:
Principle #20Continuity of useful action

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 achieves high adhesion values, rapid strength buildup within minutes, and improved long-term stability, with shear adhesion failure temperatures exceeding 100°C, suitable for bonding to low-energy and superhydrophobic surfaces in the automotive industry.

Implementation Method 1

which are chemically crosslinked with electron beam radicals to enhance adhesion, cohesion, and temperature resistance

Methodology Applied
Scientific EffectChemical crosslinking: Chemical Bonding

Implementation Method 2

chemically crosslinked with electron beam radicals

Methodology Applied
Scientific EffectElectron beam irradiation: Electron Beam

Data Source

PatentEP3310865B1Adhesive
Publication Date: 2022.01.05 LOHMANN GMBH & CO KG
  • EP3310865B1 patent drawingFigure 1A~1D

AI summary

The invention relates to an adhesive compound containing a multi-armed vinyl aromatic block copolymer, one or more adhesive resins, and one or more auxiliary crosslinking agents. The invention also relates to an adhesive means comprising said adhesive compound and a carrier material and/or a cover. The invention also relates to a method for producing such an adhesive means. Compared to adhesive systems known up until now, such an adhesive means demonstrates clearly improved adhesion to hard, non-polar surfaces such as, for example, novel coated surfaces in the automotive industry.